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Feasibility Study of Dual-targeting Paclitaxel-loaded Magnetic Liposomes using Electromagnetic Actuation and Macrophages

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... Recent studies have shown that TAMs are recruited to the tumors and can form up to 70% of tumor mass [15]. The characteristic enables macrophages to be valuable biocarriers that can ferry therapeutic agents deep into the tumors [16]. Currently, many research groups have adopted macrophages as transporters to deliver therapeutic agents and proved the effectiveness of these systems in animal models. ...
... Relied on the intrinsic ability of macrophages to effectively cross the blood barrier and penetrate deeply to tumor tissues, which are main limitations that traditional nanoparticles-based drug delivery systems are facing with, many cell-mediated delivery systems have recently been prepared and have confirmed the efficiency of the immune cells as active biocarriers to ferry therapeutics deep into tumors [15,17,18,[28][29][30]. It has been shown that, as a payload of the vehicle, free drug was not applicable for the drug to be directly encapsulated into the cells because it will cause severe toxicity to the cells, thereby killing them, before they approach to the targeted area even at low concentrations [16,31]. Therefore, we used liposomes, because with their ability to control the drug liberation rate, they could prevent premature drug release to defend the macrophages. ...
... We aim to our final goal of adopting immune cells derived from a cancer patient, encapsulating with drug containing NPs, and sending back the engineered cells to the same patient to reduce the immune response, thus augmenting the efficacy and bringing our cell-based platform closer to clinical trials. In addition, as extended from our previously published works [16,33], in this report, we have focused on analyzing the NIR-light sensitivity of the magnetic liposomes (therapeutic agents) and the microrobots in terms of enhancing drug release behaviors upon exposure to the laser irradiation, thus providing a better perspective for practical applications of our cell-based system. ...
Article
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In the present work, we prepare and evaluate a cell-based microrobot for active drug delivery to tumors. The microrobots are fabricated using the engulfment activity of immune macrophages with drug-loaded magnetic liposomes (MNP-DLs) via phagocytosis. The synthesized MNP-DLs and the microrobots have high energy absorbance to NIR light with increased drug release rate after laser irradiation. The tumor killing ability of the prepared microrobots is validated on a colorectal cancer cell line. In addition, the active tumor targeting function by an external electromagnetic actuating (EMA) system and chemotaxis is verified. Experiment results show that a single microrobot can be manipulated by the EMA system to obtain the average velocity of approximately 11 μm/s, and the robots can cross the membranes mimicking the blood barrier to tumor chemo-attractants with the infiltration rate up to 74%. Consequently, this study proposes and analyzes an innovative aspect of the developed therapeutic cellular micro-platform for active tumor targeting and externally triggered drug delivery.
... Next, the MLVs were homogenized using ultra-sonication (VC750, Sonics & Materials, Newtown, CT, USA) at 50 • C for 10 min to obtain nano-sized liposomes. The liposomal solution was centrifuged at 1000 rpm for 15 min to separate un-encapsulated MNPs, and the supernatant was retained [33]. To collect the liposomes and remove free DTX, the solution was then centrifuged at 10,000 rpm for 10 min. ...
... Next, the cells were washed twice with cold PBS and the nuclei were stained with DAPI (1 g/mL) for 10 min. Finally, the cells were rinsed three times with PBS and imaged using CLSM [33]. For quantitative study, confluent MCF-7 cells were inoculated into 96-well plates (1 × 10 4 viable cells/well). ...
... The cytotoxicity of blank and drug-loaded non-targeting and targeting liposomes was evaluated by MTT assay [33]. Briefly, 1 × 10 4 MCF-7 cells were seeded in DMEM in a 96-well plate (SPL Life Sciences). ...
Article
The aim of this work is to prepare and evaluate a novel lipid-polymer hybrid liposomal nanoplatform (hyaluronic acid-magnetic nanoparticle-liposomes, HA-MNP-LPs) as a vehicle for targeted delivery and triggered release of an anticancer drug (docetaxel, DTX) in human breast cancer cells. We first synthesize an amphiphilic hyaluronic acid hexadecylamine polymer (HA-C16) to enhance the targeting ability of the hybrid liposome. Next, HA-MNP-LPs are constructed to achieve an average size of 189.93 ± 2.74 nm in diameter. In addition, citric acid-coated magnetic nanoparticles (MNPs) are prepared and embedded in the aqueous cores while DTX is encapsulated in the hydrophobic bilayers of the liposomes. Experiments with coumarin 6 loaded hybrid liposomes (C6/HA-MNP-LPs) show that the hybrid liposomes have superior cellular uptake in comparison with the conventional non-targeting liposomes (C6/MNP-LPs), and the result is further confirmed by Prussian blue staining. Under near-infrared laser irradiation (NIR, 808 nm), the HA-MNP-LPs aqueous solution can reach 46.7 °C in 10 min, and the hybrid liposomes released over 20% more drug than non-irradiated liposomes. Using a combination of photothermal irradiation and chemotherapy, the DTX-loaded hybrid liposomes (DTX/HA-MNP-LPs) significantly enhance therapeutic efficacy, with the IC50 value of 0.69 ± 0.10 μg/mL, which is much lower than the values for radiation monotherapy or DTX monotherapy. Consequently, the prepared hybrid nanoplatform may offer a promising drug delivery vehicle with selective targeting and enhanced drug release in treating CD44-overexpressing cancers.
... Efficient cargo loading can be achieved by using porous materials, such as biological hydrogels, or empty vesicles, such as liposomes or cell ghosts. Loading of drug molecules, genes, photosensitizers, and antibiotics, including paclitaxel (79,80), docetaxel (81), doxorubicin (82)(83)(84), mRNAs (85), indocyanine green (84), and ciprofloxacin (86), into a variety of artificial substrates, including nano-and microliposomes (79,80), poly(lactic-co-glycolic) acid (PLGA) particles (81), mesoporous silica nanoparticles (83) and microtubes (86), red blood cell (RBC) ghosts (84), and polyelectrolyte multilayers (82), has been shown in microrobotic applications. While the propulsion of drug-loaded biohybrid microrobots was demonstrated for short periods, further investigations are needed to confirm the noninvasiveness of any potential drug toward the biological unit. ...
... Efficient cargo loading can be achieved by using porous materials, such as biological hydrogels, or empty vesicles, such as liposomes or cell ghosts. Loading of drug molecules, genes, photosensitizers, and antibiotics, including paclitaxel (79,80), docetaxel (81), doxorubicin (82)(83)(84), mRNAs (85), indocyanine green (84), and ciprofloxacin (86), into a variety of artificial substrates, including nano-and microliposomes (79,80), poly(lactic-co-glycolic) acid (PLGA) particles (81), mesoporous silica nanoparticles (83) and microtubes (86), red blood cell (RBC) ghosts (84), and polyelectrolyte multilayers (82), has been shown in microrobotic applications. While the propulsion of drug-loaded biohybrid microrobots was demonstrated for short periods, further investigations are needed to confirm the noninvasiveness of any potential drug toward the biological unit. ...
... An attractive aspect of chemical control is the availability of a wide variety of chemical signals released locally by targeted cells or tissues, which can induce taxis behavior in different microorganisms. For example, biohybrid microrobots driven by neutrophils and macrophages were able to migrate toward chemoattractants generated by E. coli (83) and tumor cell lysate (80), respectively. Similarly, Park et al. (134) demonstrated the chemotactic motility of S. typhimurium-driven microrobots toward tumor cell lysates and spheroids in a microfluidic setup, as well as the accumulation of microrobots in tumors in a CT-26 tumor mouse model. ...
Article
Biohybrid microrobots, composed of a living organism integrated with an artificial carrier, offer great advantages for the miniaturization of devices with onboard actuation, sensing, and control functionalities and can perform multiple tasks, including manipulation, cargo delivery, and targeting, at nano- and microscales. Over the past decade, various microorganisms and artificial carriers have been integrated to develop unique biohybrid microrobots that can swim or crawl inside the body, in order to overcome the challenges encountered by the current cargo delivery systems. Here, we first focus on the locomotion mechanisms of microorganisms at the microscale, crucial criteria for the selection of biohybrid microrobot components, and the integration of the selected artificial and biological components using various physical and chemical techniques. We then critically review biohybrid microrobots that have been designed and used to perform specific tasks in vivo. Finally, we discuss key challenges, including fabrication efficiency, swarm manipulation, in vivo imaging, and immunogenicity, that should be overcome before biohybrid microrobots transition to clinical use. Expected final online publication date for the Annual Review of Control, Robotics, and Autonomous Systems Volume 2 is May 3, 2019. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
... Several 7 Stem Cells International types of NPs that exhibited good biocompatibility, biodegradability, and capability to load hydrophilic/hydrophobic drugs were widely studied for drug carrying. Liposomes (including unilamellar and multilamellar) enhanced the maximum tolerated dose (MTD) 20-fold in MAs of PTX [71] and 50-200-fold for Dox [30,67]. It was also reported that poly(lactic-co-glycolic acid) (PLGA) NPs were able to enhance 5-fold higher for Dox MTD for MAs [64], yet no obvious change was observed for PTX MTD on MSCs [69]. ...
... RGD is a short peptide that targets αvβ 3 integrinpositive tumors, and modifying RBCs with RGD allowed an obvious attachment in tumors that native RBCs could not achieve [23,48] (iii) For magnetizing modification, cell carriers have internalized magnetic particles, such as Fe 3 O 4 , to follow guidance from electromagnetic fields. This method was widely studied as external assistance to control the cell path, and MA motion and speed were found to be enhanced 29 times that of normal cells [71]. Along with this, it may improve SMAP capability and make a concession to the premise of reducing early leakage risk Enhancing accumulation can reduce drug demands. ...
Article
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Achievement of high targeting efficiency for a drug delivery system remains a challenge of tumor diagnoses and nonsurgery therapies. Although nanoparticle-based drug delivery systems have made great progress in extending circulation time, improving durability, and controlling drug release, the targeting efficiency remains low. And the development is limited to reducing side effects since overall survival rates are mostly unchanged. Therefore, great efforts have been made to explore cell-driven drug delivery systems in the tumor area. Cells, particularly those in the blood circulatory system, meet most of the demands that the nanoparticle-based delivery systems do not. These cells possess extended circulation times and innate chemomigration ability and can activate an immune response that exerts therapeutic effects. However, new challenges have emerged, such as payloads, cell function change, cargo leakage, and in situ release. Generally, employing cells from the blood circulatory system as cargo carriers has achieved great benefits and paved the way for tumor diagnosis and therapy. This review specifically covers (a) the properties of red blood cells, monocytes, macrophages, neutrophils, natural killer cells, T lymphocytes, and mesenchymal stem cells; (b) the loading strategies to balance cargo amounts and cell function balance; (c) the cascade strategies to improve cell-driven targeting delivery efficiency; and (d) the features and applications of cell membranes, artificial cells, and extracellular vesicles in cancer treatment.
... 4−7 However, there are limitations associated with the use of bacteria: (1) bacteria are usually harmful and are quickly cleared from the bloodstream by the immune system; (2) the attachment of the bacteria to the micro/ nanostructures is challenging and ineffective, limiting the therapeutic potential; and (3) the actuation forces generated by the bacteria are quite small, leading to poor targeting of the microrobots to the target site. 8,9 Macrophages (MΦs) can offer an alternative and effective method of carrying payloads and therapeutic agents, serving as cellular microrobots. 10−12 These cells are already part of the immune system and, therefore, when administered into the body would not induce an immune response. ...
... We measured blood circulation time by intravenously injecting DiD labeled 5 × 10 6 MΦs or the microrobots into the mice (n = 3 per group). At each time point of 3 min, 1,2,4,8,24,36,48, and 96 h, 20 μL of blood was collected via capillary tubes with heparinized coatings (Kimble Chase Life Science and Research Products, Vineland, New Jersey, USA) and was immediately mixed with 20 μL of 0.2% ethylenediaminetetraacetic acid (GenDEPOT, Barker, TX, USA) at pH 7.4 for anticoagulation of the blood. After that, the DiD signal from the blood was detected using the IVIS system, from which the relative FI was quantified, as mentioned previously. ...
... 在外加磁场的作用下, 生物医用磁 性纳米材料在体内可以产生多种效应, 例如电磁效应、磁 热效应以及磁-机械力效应等等, 从而可以用来控制药物 释放、进行磁热治疗以及磁控制离子通道活化 [30] . 特殊设 计的磁场能够引导超顺磁氧化铁纳米颗粒标记的巨噬细 胞从血液进入肿瘤病灶, 达到抑制或治疗肿瘤的目的 [31] . 此外, 强磁场还可以引导磁性药物载体到达病灶部位浓聚, 达到多种治疗药物增敏及靶向治疗的作用, 也是近期肿瘤 化学治疗领域的新进展之一 [3] . ...
Article
High magnetic fields are unique artificial physical environments. Since 1913, more than 10 Nobel prizes were given to novel findings related to high magnetic fields in the areas of high-temperature superconductivity, new materials, and life sciences. In recent years, progress in superconducting technologies has dramatically enhanced the application of high magnetic fields in scientific research, industry, and healthcare. Many countries have established national-level high magnetic research centers to strengthen scientific research in magnetic fields. The National High Magnetic Field Laboratory at Florida State University in the United States, the Grenoble High Magnetic Field Laboratory in France, the High Field Magnet Laboratory in Nijmegen in Netherlands, the Tsukuba Magnet Laboratory in Japan, and the High Magnetic Field Laboratory of the Chinese Academy of Sciences in China are the most recognized magnetic field research centers worldwide. Of these institutions, the High Magnetic Field Laboratory in China has a unique research team focused on magnetic field life science research. Current progress at Chinese institutions in high-level talent teams, scientific research, and industry applications is significant and has achieved considerable international influence. In April 2018, the 620th session of the Xiangshan Science Conference, "High Magnetic Field and Life Health: New Conditions, New Questions, New Opportunities", was held in Beijing. This conference attracted more than 40 participants from approximately 30 domestic and international institutions. The following central issues were discussed at the conference: (1) the theory and techniques of high magnetic equipment based on novel superconductive materials; (2) fundamental life science research under high magnetic fields; (3) magnetic nanoparticle medication and iron metabolism; and (4) applications of dynamic magnetic fields in human health care and medicine. The present paper offers a comprehensive summary of the opinions, views, and visions collected during this conference. In addition, this paper reviews recent progress in the interdisciplinary field of high magnetic fields and life science and healthcare. For each central issue discussed in the 620th session of the Xiangshan Science Conference, this review gives a brief summary of the current advancements and challenging problems in research. The key scientific questions and application techniques in this field and the strategic thinking and landscape planning of the scientific research are promoted. Several unknown questions and future directions of innovative and featured research are identified in this paper. First, the scientific questions in the field need to be refined. Moreover, it is necessary to consider how to achieve scientific breakthroughs and high-level scientific research results with the scientific and technical advantages that currently exist in China. Second, the translation-oriented interdisciplinary scientific research in this field needs to be one of the primary research directions to produce innovative principles, methods, and technologies for healthcare and medical treatments. Third, the cooperation of the research groups in China needs to be enhanced to advance the fundamental and application research of life sciences, health, and medical care with respect to high magnetic fields.
... The macrophages are recruited to tumors due to electromagnetic fields and the chemoattract properties of macrophages for dual targeting. This dual targeting system is expected to be developed into a potential cancer treatment strategy [148]. ...
Article
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Nanoparticle delivery systems have good application prospects in the treatment of various diseases, especially in cancer treatment. The effect of drug delivery is regulated by the properties of nanoparticles. There have been many studies focusing on optimizing the structure of nanoparticles in recent years, and a series of achievements have been made. This review summarizes the optimization strategies of nanoparticles from three aspects—improving biocompatibility, increasing the targeting efficiency of nanoparticles, and improving the drug loading rate of nanoparticles—aiming to provide some theoretical reference for the subsequent drug delivery of nanoparticles.
... In a recent study, they refined this approach by employing macrophages filled with liposomes of roughly 150 nm diameter filled with Fe 3 O 4 NPs and PTX instead of DTX. 244 The dual-targeting by magnetic and chemotactic (tumortropic) stimuli, as well as chemotherapeutic activity toward breast and colorectal cancer, was assessed in an in vitro model. As discussed earlier, the biocamouflage effect of blood cells is induced by their endogenous nature that allows them to act as "Trojan horses" within the patient's immune system. ...
Article
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Micromotors are devices that operate at the microscale and convert energy to motion. Many micromotors are microswimmers, i.e., devices that can move freely in a liquid at a low Reynolds number, where viscous drag dominates over inertia. Hybrid biomicromotors are microswimmers that consist of both biological and artificial components, i.e., one or several living microorganisms combined with one or many synthetic attachments. Initially, living microbes were used as motor units to transport synthetic cargo at the microscale, but this simple allocation has been altered and extended gradually, especially considering hybrid biomicromotors for biomedical in vivo applications, i.e., for non-invasive microscale operations in the body. This review focuses on these applications, where other properties of the microbial component, for example, the capability of chemotaxis, biosensing, and cell-cell interactions, have been exploited in order to realize tasks like localized diagnosis, drug delivery, or assisted fertilization in vivo. In the biohybrid approach, biological and artificially imposed functionalities act jointly through a microrobotic device that can be controlled or supervised externally. We review the development and state-of-the-art of such systems and discuss the mastery of current and future challenges in order to evolve hybrid biomicromotors from apt swimmers to adapted in vivo operators.
... Recent studies reported that TAMs are recruited to the tumors and can form up to 70% of tumor mass. The characteristic enables macrophages to become valuable biocarriers that can ferry therapeutic agents deep into the tumors [17]. Recently, many research groups have adopted macrophages as transporters to deliver therapeutic agents and proved the effectiveness of these systems in animal models. ...
Conference Paper
In this study, we prepare and evaluate a novel cellbased micro-platform (microrobot) for active tumor therapy. The microrobots are fabricated utilizing the engulfment activity of immune cells (macrophages) with drug-loaded magnetic liposomes via phagocytosis. First, we synthesize magnetic nanoparticles (MNP) with superparamagnetic properties and high energy absorbance to near-infrared (NIR) light, and load the MNPs to liposomes (MNP-DLs). Then, we prepare the microrobots by incubating the MNP-DLs with the macrophages. After that, we characterize the tumor targeting ability of the microrobots using electromagnetic actuating (EMA) system and a transwell chemotactic assay. Experiment results show that the microrobots can be controlled by an external magnetic field to reach the average velocity of approximately 11 μm/second, and they can cross the membranes mimicking the blood barrier to tumor chemo-attractants with the infiltration rate up to 74%. Therefore, the study proposes an innovative approach for active tumor targeting and NIR light triggered drug delivery using the developed cellular microrobots.
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Near-infrared persistent luminescence nanoparticles (NIR-PLNPs) are promising imaging agents due to deep tissue penetration, high signal-to-noise ratio, and repeatedly charging ability. Here, we report liposome-coated NIR-PLNPs (Lipo-PLNP) as a novel persistent luminescence imaging guided drug carrier for chemotherapy. The Lipo-PLNP nanocomposite shows the advantages of superior persistent luminescence and high drug loading efficiency, and enables autofluorescence-free and long-term tracking of drug delivery carriers with remarkable therapeutic effect.
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Recent advances in the versatility and sophistication of design, fabrication, and control methods of mobile microrobots could have a transforming impact on future healthcare technologies. Self‐propelled or remotely actuated, synthetic, or biohybrid microrobots can navigate to difficult‐to‐reach regions in the human body to deliver therapeutics for microscopically localized medical interventions. Here, recent progress in the design of microrobotic systems concerning therapeutic delivery of drugs, cells, and genetic materials is reported. This perspective prioritizes the design aspects of microrobots for medical cargo loading, navigation in biologically relevant environments, and controlled cargo release. In the final section, future prospects and a discussion on the critical shortcomings for the benchside‐to‐bedside translation of medical microrobots are provided.
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Reprogramming the immunosuppressive tumor microenvironment by modulating macrophages holds great promise in tumor immunotherapy. As a class of professional phagocytes and antigen‐presenting cells in the innate immune system, macrophages can not only directly engulf and clear tumor cells, but also play roles in presenting tumor‐specific antigen to initiate adaptive immunity. However, the tumor‐associated macrophages (TAMs) usually display tumor‐supportive M2 phenotype rather than anti‐tumor M1 phenotype. They can support tumor cells to escape immunological surveillance, aggravate tumor progression, and impede tumor‐specific T cell immunity. Although many TAMs‐modulating agents have shown great success in therapy of multiple tumors, they face enormous challenges including poor tumor accumulation and off‐target side effects. An alternative solution is the use of advanced nanostructures, which not only can deliver TAMs‐modulating agents to augment therapeutic efficacy, but also can directly serve as modulators of TAMs. Another important strategy is the exploitation of macrophages and macrophage‐derived components as tumor‐targeting delivery vehicles. Herein, we summarize the recent advances in targeting and engineering macrophages for tumor immunotherapy, including (1) direct and indirect effects of macrophages on the augmentation of immunotherapy and (2) strategies for engineering macrophage‐based drug carriers. The existing perspectives and challenges of macrophage‐based tumor immunotherapies are also highlighted. Modulating macrophages for tumor immunotherapy holds great promise to improve anti‐tumor efficacy. Inhibition of macrophage recruitment, depleting tumor‐associated macrophages (TAMs), repolarizing TAMs, and regulating macrophage‐mediated phagocytosis of tumor cells are the four major strategies for manipulating macrophage‐mediated tumor immunotherapy.
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Paclitaxel (PTX) is a potent drug for treating advanced solid carcinomas; however, its clinical utility is limited by its poor water solubility. Despite the promise of using nanoparticles to deliver hydrophobic PTX, achieving sufficient drug loading while maintaining small particle size and stability in biological media remains a challenge. Here, a PTX nanoparticle (NP) formulation with small size and great stability is presented that targets breast cancer cells and enables controlled release of PTX. This NP formulation (NP‐PTX‐FA) comprises a superparamagnetic iron oxide core coated with short‐ and long‐chain polyethylene glycol: the former for conjugation of hydrophobic PTX and folic acid (FA), and the latter as an outer layer for improved hydrophilicity. The NP‐PTX‐FA has a uniform size distribution (averaging 28.2 ± 0.64 nm) and high drug loading capacity of 22.8 wt% (vs <10 wt% normally). NP‐PTX‐FA releases the drug under conditions mimicking the acidic intracellular pH of breast cancer cells and the FA conjugation leads to higher NP uptake by target cells, enhancing the cytotoxicity to target cells compared to free PTX. This NP formulation holds great promise to improve breast cancer therapy and potential to deliver other hydrophobic drugs for treating various cancer types. A nanoparticle that exhibits small particle size, great stability, high drug loading, and enables the controlled release of paclitaxel (PTX) for targeted treatment of breast cancer cells is developed. This targeted magnetic nanoparticle, functionalized with pH‐cleavable paclitaxel, significantly enhances the cytotoxicity toward tumor cells as compared to free paclitaxel.
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Monocyte-derived macrophages orchestrate tissue regeneration by homing to sites of injury, phagocytosing pathological debris, and stimulating other cell types to repair the tissue. Accordingly, monocytes have been investigated as a translational and potent source for cell therapy, but their utility has been hampered by their rapid acquisition of a pro-inflammatory phenotype in response to the inflammatory injury microenvironment. To overcome this problem, we designed a cell therapy strategy where monocytes are exogenously reprogrammed by intracellularly loading the cells with biodegradable microparticles containing an anti-inflammatory drug in order to modulate and maintain an anti-inflammatory phenotype over time. To test this concept, poly(lactic-co-glycolic) acid microparticles were loaded with the anti-inflammatory drug dexamethasone (Dex) and administered to primary human monocytes for four hours to facilitate phagocytic uptake. After removal of non-phagocytosed microparticles, microparticle-loaded monocytes differentiated into macrophages and stored the microparticles intracellularly for several weeks in vitro, releasing drug into the extracellular environment over time. Cells loaded with intracellular Dex microparticles showed decreased expression and secretion of inflammatory factors even in the presence of pro-inflammatory stimuli up to 7 days after microparticle uptake compared to untreated cells or cells loaded with blank microparticles, without interfering with phagocytosis of tissue debris. This study represents a new strategy for long-term maintenance of anti-inflammatory macrophage phenotype using a translational monocyte-based cell therapy strategy without the use of genetic modification. Because of the ubiquitous nature of monocyte-derived macrophage involvement in pathology and regeneration, this strategy holds potential as a treatment for a vast number of diseases and disorders. Statement of significance We report a unique and translational strategy to overcome the challenges associated with monocyte- and macrophage-based cell therapies, in which the cells rapidly take on inflammatory phenotypes when administered to sites of injury. By intracellularly loading monocytes with drug-loaded microparticles prior to administration via phagocytosis, we were able to inhibit inflammation while preserving functional behaviors of human primary macrophages derived from those monocytes up to seven days later. To our knowledge, this study represents the first report of reprogramming macrophages to an anti-inflammatory phenotype without the use of genetic modification.
Chapter
Thanks to millions of years of evolution, living beings have developed complex mechanisms for sensing, actuation, and adaptation to the surrounding environment. Biohybrid robots exploit these mechanisms by embedding living components and combining them with nonliving elements. This allows overcoming some of the issues affecting entirely artificial devices, such as difficult scalability to small scales, inability to self-heal, and possible immunogenicity. In this chapter, biohybrid microrobots based on bacteria or other single cells (e.g., sperm cells, erythrocytes, neutrophils) are described. The most relevant examples reported in the state-of-the-art are analyzed, focusing on their specific sensing and actuation mechanisms. Relying on the use of a complete and autonomous living organism, they must be considered examples of a top-down approach, which needs to find ways of adequately controlling them. Specific applications of these systems are also described, with a particular focus on clinical ones. Then, muscle-based multicellular robots are introduced. Such systems are based on a bottom-up approach, through which single contractile units (skeletal muscle cells, cardiomyocytes, or insect-derived cells) are assembled and integrated with materials supporting them, to achieve effective locomotion and other functions. The main applications and challenges related to multicellular biohybrid microrobots are described, mentioning among others, modeling issues and the need for implementing multiple degrees of freedom, yet keeping high controllability by an external user.
Background Paclitaxel (PTX) has been clinically used for several years due to its good therapeutic effect against cancers. Its poor water-solubility, non-selectivity, high cytotoxicity to normal tissue and worse pharmacokinetic property limit its clinical application. Objective To review the recent progress on the PTX delivery systems. Methods In recent years, the copolymeric nano-drug delivery systems for PTX are broadly studied. It mainly includes micelles, nanoparticles, liposomes, complexes, prodrugs and hydrogels, etc. They were developed or further modified with target molecules to investigate the release behavior, targeting to tissues, pharmacokinetic property, anticancer activities and bio-safety of PTX. In the review, we will describe and discuss the recent progress on the nano-drug delivery system for PTX since 2011. Results The water-solubility, selective delivery to cancers, tissue toxicity, controlled release and pharmacokinetic property of PTX are improved by way of its encapsulation into the nano-drug delivery systems. In addition, its activities against cancer are also comparable or high when compared with commercial formulation. Conclusion Encapsulating PTX into nano-drug carriers should be helpful to reduce its toxicity to human, keep or enhance its activity and improve its pharmacokinetic property.
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One of the challenges to adopt photothermal ablation clinically is optimization of the agent delivery in vivo. Herein, a cell-mediated delivery and therapy system by employing macrophage vehicles to transport 7 nm diameter Au nanorods (sAuNRs) is described. Owing to the small size, the sAuNRs exhibit much higher macrophage uptake and negligible cytotoxicity in comparison with commonly used 14 nm diameter AuNRs to achieve healthy BSA-coated sAuNRs-laden-macrophages. By delivering BSA-coated sAuNRs to the entire tumor after intratumoral injection, the BSA-coated sAuNRs-laden-macrophages show greatly improved photothermal conversion almost everywhere in the tumor, resulting in minimized tumor recurrence rates compared to free BSA-coated sAuNRs. Our findings not only provide a desirable approach to improve the photothermal therapy efficiency by optimizing the intratumoral distribution of the agents, but also expedite clinical application of nanotechnology to cancer treatment.
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In this paper, we propose a new concept for a hybrid actuated microrobot for tumor-targeting therapy. For drug delivery in tumor therapy, various electromagnetic actuated microrobot systems have been studied. In addition, bacteria-based microrobot (so-called bacteriobot), which use tumor targeting and the therapeutic function of the bacteria, has also been proposed for solid tumor therapy. Compared with bacteriobot, electromagnetic actuated microrobot has larger driving force and locomotive controllability due to their position recognition and magnetic field control. However, because electromagnetic actuated microrobot does not have self-tumor targeting, they need to be controlled by an external magnetic field. In contrast, the bacteriobot uses tumor targeting and the bacteria's own motility, and can exhibit self-targeting performance at solid tumors. However, because the propulsion forces of the bacteria are too small, it is very difficult for bacteriobot to track a tumor in a vessel with a large bloodstream. Therefore, we propose a hybrid actuated microrobot combined with electromagnetic actuation in large blood vessels with a macro range and bacterial actuation in small vessels with a micro range. In addition, the proposed microrobot consists of biodegradable and biocompatible microbeads in which the drugs and magnetic particles can be encapsulated; the bacteria can be attached to the surface of the microbeads and propel the microrobot. We carried out macro-manipulation of the hybrid actuated microrobot along a desired path through electromagnetic field control and the micro-manipulation of the hybrid actuated microrobot toward a chemical attractant through the chemotaxis of the bacteria. For the validation of the hybrid actuation of the microrobot, we fabricated a hydrogel microfluidic channel that can generate a chemical gradient. Finally, we evaluated the motility performance of the hybrid actuated microrobot in the hydrogel microfluidic channel. We expect that the hybrid actuated microrobot will be utilized for tumor targeting and therapy in future. Biotechnol. Bioeng. 2015;9999: 1-9. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.
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The biomimetic delivery system (BDS) based on special type of endogenous cells like macrophages and T cells, has been emerging as a novel strategy for cancer therapy, due to its tumor homing property and biocompatibility. However, its development is impeded by complicated construction, low drug loading or negative effect on the cell bioactivity. The present report constructed a BDS by loading doxorubicin (DOX) into a mouse macrophage-like cell line (RAW264.7). It was found that therapeutically meaningful amount of DOX could be loaded into the RAW264.7 cells by simply incubation, without significantly affecting the viability of the cells. Drug could release from the BDS and maintain its activity. RAW264.7 cells exhibited obvious tumor-tropic capacity towards 4T1 mouse breast cancer cells both in vitro and in vivo, and drug loading did not alter this tendency. Importantly, the DOX loaded macrophage system showed promising anti-cancer efficacy in terms of tumor suppression, life span prolongation and metastasis inhibition, with reduced toxicity. In conclusion, it is demonstrated that the BDS developed here seems overcome some of the main issues related to a BDS. The DOX loaded macrophages might be a potential BDS for targeted cancer therapy. Copyright © 2015. Published by Elsevier B.V.
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Biocompatibility, sensing, and self-actuation are very important features for a therapeutic biomedical microrobot. As a new concept for tumor theragnosis, this paper proposes a monocyte-based microrobots, which are combining the phagocytosis and engulfment activities containing human acute monocytic leukemia cell line (THP-1) with various sized polystyrene microbeads are engulfed instead of a therapeutic drug. For the validation of the blood vessel barrier-penetrating activity of the monocyte-based microrobot, we fabricate a new cell migration assay with monolayer-cultured endothelial cell (HUVEC), similar with the blood vessels. We perform the penetrating chemotactic motility of the monocyte-based microrobot using various types of the chemo-attractants, such as monocyte chemotactic protein (MCP)-1, human breast cancer cell lines (MCF7)-cell lysates, and -contained alginate spheroids. The monocyte-based microrobot show chemotactic transmigrating motilities similar with what an actual monocyte does. This new paradigm of a monocyte-based microrobot having various useful properties such as biocompatibility, sensing, and self-actuation can become the basis of a biomedical microrobot using monocytes for diagnosis and therapy of various diseases. Biotechnol. Bioeng. © 2014 Wiley Periodicals, Inc.
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Cellular hitchhiking leverages the use of circulatory cells to enhance the biological outcome of nanoparticle drug delivery systems, which often suffer from poor circulation time and limited targeting. Cellular hitchhiking utilizes the natural abilities of circulatory cells to: (i) navigate the vasculature while avoiding immune system clearance, (ii) remain relatively inert until needed and (iii) perform specific functions, including nutrient delivery to tissues, clearance of pathogens, and immune system surveillance. A variety of synthetic nanoparticles attempt to mimic these functional attributes of circulatory cells for drug delivery purposes. By combining the advantages of circulatory cells and synthetic nanoparticles, many advanced drug delivery systems have been developed that adopt the concept of cellular hitchhiking. Here, we review the development and specific applications of cellular hitchhiking-based drug delivery systems.
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A bacteria-based microrobot (bacteriobot) was proposed and investigated as a new type of active drug delivery system because of its useful advantages, such as active tumor targeting, bacteria-mediated tumor diagnosis, and therapy. In this study, we fabricated a bacteriobot with enhanced motility by selective attachment of flagellar bacteria (Salmonella typhimurium). Through selective bovine serum albumin (BSA) pattering on hydrophobic polystyrene (PS) microbeads, many S. typhimurium could be selectively attached only on the unpatterned surface of PS microbead. For the evaluation of the chemotactic motility of the bacteriobot, we developed a microfluidic chamber which can generate a stable concentration gradient of bacterial chemotactic chemicals. Prior to the evaluation of the bacteriobot, we first evaluated the directional chemotactic motility of S. typhimurium using the proposed microfluidic chamber, which contained a bacterial chemo-attractant (L-aspartic acid) and a chemo-repellent (NiSO 4), respectively. Compared to density of the control group in the microfluidic chamber without any chemical gradient, S. typhimurium increased by about 16% in the L-aspartic acid gradient region and decreased by about 22% in the NiSO 4 gradient region. Second, we evaluated the bacteriobot's directional motility by using this microfluidic chamber. The chemotactic directional motility of the bacteriobot increased by 14% and decreased by 13% in the concentration gradients of L-aspartic acid and NiSO 4 , respectively. These results confirm that the bacteriobot with selectively patterned S. typhimurium shows chemotaxis motility very similar to that of S. typhimurium. Moreover, the directional motilities of the bacteria and bacteriobot could be demonstrated quantitatively through the proposed micro-fluidic chamber.
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Many people proposed living things as actuators, for example microbes, cell and protein molecules. To address these problems for biomedical application, especially drug delivery system, a novel, miniature, and energy-efficient propulsion concept is proposed in this paper. Some bacteria have flagellar motor for swimming in water environment. The bacterial flagellar motor is a molecular machine that converts ion-motive force into mechanical force. Liposome is well known component for drug delivery. This vesicle can contain biologically active compounds. We proposed a new integration method of these two functions, bacteria motility and liposome carrier. Bacteria and liposome are combined through antibody binding technique and we have created a bacteria-driven liposome easily. Consequently, the effect of antibody when bacteria attached to liposome is studied experimentally. Furthermore, the stochastic nature of bacterial bio propulsion of liposome is investigated. It is shown that the mobility of liposome with bacteria was higher than that of liposome without bacteria and demonstrate potential for highly-functional drug delivery system.
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We proposed a new bacteria patterning method on the restricted region of microbeads, using the submerged property of polystyrene microbeads on various concentrations of agarose gel. Moreover, we fabricated a bacterial microrobot using attenuated Salmonella typhimurium through the new patterning methods. We controlled the submerged degree of polystyrene microbeads through the regulation of the hardness of the agarose gel. The polystyrene microbeads on agarose gel were transferred onto a poly-dimethylsiloxane (PDMS) surface for easy manipulation of the microbeads. Then, we treated the polystyrene microbeads on the PDMS surface with antibacterial adherent factors, such as O2 plasma and bovine serum albumin (BSA). The Salmonella typhimurium was attached to the entire surface of the untreated polystyrene microbeads, whereas Salmonella typhimurium were only attached to the restricted surface region of the treated polystyrene microbeads through the proposed patterning method. The bacteria-attached microbeads gain motility by the propulsion of the attached bacteria, and the selective-bacteria-attached microbeads showed enhanced motility. Compared with whole-bacteria-attached polystyrene microbeads (1.74 ± 1.62 μm/s), the selective bacteria-attached polystyrene microbeads, using O2 plasma and BSA, showed 9.18 ± 1.88 μm/s and 14.65 ± 8.66 μm/s faster moving velocities, respectively. Through the results, we expected that the proposed patterning methodology of microbeads could contribute to the development of biomedical bacterial microrobots.
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Drug targeting to tumors with limited toxicity and enhanced efficacy of drug is one of the important goals for cancer treatment pharmaceutics. Monocytes/macrophages are able to migrate to tumor sites across the blood barriers by acting as Trojan horses carrying drug cargoes. Taking this advantage, we have intended to develop an efficient administration system using a biologically active carrier of mouse peritoneal macrophage bearing liposomal doxorubicin (macrophage-LP-Dox). We expect that this system could improve the cancer therapeutic efficacy through deeper penetration into tumor even hypoxic region behind tumor blood vessel. We first confirmed that macrophages containing iron oxides could migrate and infiltrate into tumors effectively by MR imaging. Next, we showed that doxorubicin (Dox) encapsulated with liposomes (LP-Dox) was successfully loaded into macrophages, in which the biological activity of macrophage and cytotoxicity of Dox against tumor cells were well preserved. Delivery of Dox into tumor tissue by systemic administration of macrophage-LP-Dox was verified in both subcutaneous and metastasis xenograft tumor models. Importantly, the effective inhibition of in vivo tumor growth was proved with this system. Our results provide the feasibility of macrophages-LP-drug as an active biocarrier for the enhancement of therapeutic effects in cancer treatment and open new perspectives for the active delivery of drugs.
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Nanobots - tiny robots that can be injected into the body to perform medical procedures - are the stuff of science fiction. Swimming microrobots propelled by artificial flagella bring that fantasy closer to reality.
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The diffusion of univalent cations and anions out of spontaneously formed liquid crystals of lecithin is remarkably similar to the diffusion of such ions across biological membranes. If the unit structure of the liquid crystal is accepted as being that of a bimolecular leaflet, then these leaflets have been shown to be many orders of magnitude more permeable to anions than to cations. The diffusion rate for cations is very significantly controlled by the sign and magnitude of the surface charge at the water/lipid interface. There is a decrease of the diffusion rate for cations as the negative charge on the lipid structure decreases—which diminishes to zero for a positively charged membrane—the diffusion rate of anions remaining very high. The exchange diffusion rate of Cl− and I− was greater than that of F−, NO3−, SO42− and HPO42− but no significant differences were detectable for the cation series, Li+, Na+, K+, Rb+ and choline. The membranes are very permeable to water.Because the diffusion rate of cations is low, the phospholipid liquid crystalline structures appear to “bind” or “capture” cations. It is found that as the surface charge of the lipid lamellae is increased, the amount of cation per μmle of lipid increases. It is argued that if the cation is sequestered in aqueous compartments between the bimolecular leaflets, and if the thickness of the aqueous compartments is determined by the surface charge density of the lipid head groups and by the ionic strength of the aqueous phase in accordance with double-layer theory, the amount of cation trapped would also be expected to vary.
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Antibody or ligand-mediated targeting of liposomal anticancer drugs to antigens expressed selectively or over-expressed on tumor cells is increasingly being recognized as an effective strategy for increasing the therapeutic indices of anticancer drugs. This review summarizes some recent advances in the field of ligand-targeted liposomes (LTLs) for the delivery of anticancer drugs. New approaches used in the design and optimization of LTLs is discussed and the advantages and potential problems associated with their therapeutic applications are described. New technologies are widening the spectrum of ligands available for targeting and are allowing choices to be made regarding affinity, internalization and size. The time is rapidly approaching where we will see translation of anticancer drugs entrapped in LTLs to the clinic.
Article
A novel liposomal formulation of paclitaxel targeting the folate receptor (FR) was synthesized and characterized. This formulation was designed to overcome vehicle toxicity associated with the traditional Cremophor EL-based formulation and to provide the added advantages of prolonged systemic circulation time and selective targeting of the FR, which is frequently overexpressed on epithelial cancer cells. The formulation had the composition of dipalmitoyl phosphatidylcholine/dimyristoyl phosphatidylglycerol/monomethoxy-polyethylene glycol (PEG)2000-distearoyl phosphatidylethanolamine/folate-PEG3350-distearoyl phosphatidylethanolamine (DPPC/DMPG/mPEG-DSPE/folate-PEG-DSPE) at molar ratios of (85.5:9.5:4.5:0.5) and a drug-to-lipid molar ratio of 1:33. The liposomes were prepared by polycarbonate membrane extrusion. The mean particle size of the liposomes was 97.1 nm and remained stable for at least 72 h at 4 degrees C. FR-targeted liposomes of the same lipid composition entrapping calcein were shown to be efficiently taken up by KB oral carcinoma cells, which are highly FR+. FR-targeted liposomes containing paclitaxel showed 3.8-fold greater cytotoxicity compared to non-targeted control liposomes in KB cells. Plasma clearance profiles of paclitaxel in the liposomal formulations were then compared to paclitaxel in Cremophor EL formulation. The liposomal formulations showed much longer terminal half-lives (12.33 and 14.23 h for FR-targeted and non-targeted liposomes, respectively) than paclitaxel in Cremophor EL (1.78 h). In conclusion, the paclitaxel formulation described in this study has substantial stability and favorable pharmacokinetic properties. The FR-targeted paclitaxel formulation is potentially useful for treatment of FR+ tumors and warrants further investigation.
Article
This paper describes the use of a simple microfluidic device for studying T cell chemotaxis. The microfluidic device is fabricated in poly(dimethylsiloxane) (PDMS) using soft-lithography and consists of a "Y" type fluidic channel. Solutions are infused into the device by syringe pumps and generate a concentration gradient in the channel by diffusion. We show that the experimentally measured gradient profiles agree nicely with theoretical predictions and the gradient is stable in the observation region for cell migration. Using this device, we demonstrate robust chemotaxis of human T cells in response to single and competing gradients of chemokine CCL19 and CXCL12. Because of the simplicity of the device, it can flexibly control gradient generation in space and time, and would allow generation of multiple gradient conditions in a single chip for highly parallel chemotaxis experimentation. Visualization of T cell chemotaxis has previously been limited to studies in 3D matrices or under agarose assays, which do not allow precise control or variation in conditions. Acknowledging the importance of lymphocyte homing in the adaptive immune response, the ability to study T cell chemotaxis in microfluidic devices offers a new approach for investigating lymphocyte migration and chemotaxis in vitro.
Article
Destruction of hypoxic regions within tumors, virtually inaccessible to cancer therapies, may well prevent malignant progression. The tumor's recruitment of monocytes into these regions may be exploited for nanoparticle-based delivery. Monocytes containing therapeutic nanoparticles could serve as "Trojan Horses" for nanoparticle transport into these tumor regions. Here we report the demonstration of several key steps toward this therapeutic strategy: phagocytosis of Au nanoshells, and photoinduced cell death of monocytes/macrophages as isolates and within tumor spheroids.
  • T Lin-Ai
  • T Pi-Ju
  • W Yu-Chao
  • W Yu-Jing
  • L Leu-Wei
  • Y Chung-Shi
T. Lin-Ai, T. Pi-Ju, W. Yu-Chao, W. Yu-Jing, L. Leu-Wei, Y. Chung-Shi, Thermosensitive liposomes entrapping iron oxide nanoparticles for controllable drug release, Nanotechnology 20 (2009) 135101.
Selective uptake of single-walled carbon nanotubes by circulating monocytes for enhanced tumour delivery
  • B R Smith
  • H Eid
  • J A Rallapalli
  • T Prescher
  • L A Larson
  • Herzenberg
B.R. Smith, B. GhosnEliver Eid, H. Rallapalli, J.A. Prescher, T. Larson, L.A. Herzenberg, et al., Selective uptake of single-walled carbon nanotubes by circulating monocytes for enhanced tumour delivery, Nat. Nano 9 (2014) 481-487.