I-Ming Chu

National Tsing Hua University, Hsin-chu-hsien, Taiwan, Taiwan

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Publications (84)197.68 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Curcumin is a naturally occurring compound that has been shown to have anti-oxidant, anti-inflammatory, and anti-carcinogenic activities. However, its pharmaceutical potential has been limited due to its low solubility in water. The use of amphiphilic nanocarriers is an attractive and simple method to solubilize curcumin. In this study, we modified Pluronic F-127 [poly(ethylene glycol)100-block-poly(propylene glycol)65-block-poly(ethylene glycol)100] (PF-127) with oligomers of alanine, an amino acid, to increase the drug entrapment efficiency of curcumin through core stabilization. Alanine-modified PF-127 exhibited lower critical micelle concentration and decreased molecular motion in both the hydrophilic and hydrophobic segments ((1)H NMR). Nanocarriers in the size range of 54.2-68.4 nm were observed. Entrapment efficiency of curcumin increased by at most 66% (from 25.3 to 91.3%) and the difference in solubility was clearly visualized by increased transparency of the nanocarrier solutions. Curcumin was released continuously up to 120 h from modified carriers, while drug release from unmodified carriers plateaued within 24 h. These modified nanocarriers exhibited no cytotoxicity and more efficiently delivered drugs to HeLa cells as confirmed by fluorescent microscopy. This study demonstrated that alanine modification of FDA-approved PF-127 affects copolymer nanoassembly and has a profound impact on curcumin loading and possibly on other hydrophobic drugs as well.
    Journal of biomaterials science. Polymer edition. 06/2014;
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    ABSTRACT: Parkinson's disease is known to result from the loss of dopaminergic neurons. Direct intracerebral injections of high doses of recombinant glial cell line-derived neurotrophic factor (GDNF) have been shown to protect adult nigral dopaminergic neurons. Because GDNF does not cross the blood-brain barrier, intracerebral gene transfer is an ideal option. Chitosan (CHI) is a naturally derived material that has been used for gene transfer. However, the low water solubility often leads to decreased transfection efficiency. Grafting of highly water-soluble polyethylene imines (PEI) and polyethylene glycol onto polymers can increase their solubility. The purpose of this study was to design a non-viral gene carrier with improved water solubility as well as enhanced transfection efficiency for treating Parkinsonism. Two molecular weights (Mw =600 and 1,800 g/mol) of PEI were grafted onto CHI (PEI600-g-CHI and PEI1800-g-CHI, respectively) by opening the epoxide ring of ethylene glycol diglycidyl ether (EX-810). This modification resulted in a non-viral gene carrier with less cytotoxicity. The transfection efficiency of PEI600-g-CHI/deoxyribonucleic acid (DNA) polyplexes was significantly higher than either PEI1800-g-CHI/DNA or CHI/DNA polyplexes. The maximal GDNF expression of PEI600-g-CHI/DNA was at the polymer:DNA weight ratio of 10:1, which was 1.7-fold higher than the maximal GDNF expression of PEI1800-g-CHI/DNA. The low toxicity and high transfection efficiency of PEI600-g-CHI make it ideal for application to GDNF gene therapy, which has potential for the treatment of Parkinson's disease.
    International Journal of Nanomedicine 01/2014; 9:3163-74. · 4.20 Impact Factor
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    ABSTRACT: We reveal that a slight change in the functional group of the oligopeptide block incorporated into the poloxamer led to drastically different hierarchical assembly behavior and rheological properties in aqueous media. An oligo(l-Ala-co-l-Phe-co-β-benzyl l-Asp)-poloxamer-oligo(β-benzyl-l-Asp-co-l-Phe-co-l-Ala) block copolymer (OAF-(OAsp(Bzyl))-PLX-(OAsp(Bzyl))-OAF, denoted as polymer 1), which possessed benzyl group on the aspartate moiety of the peptide block, was synthesized through ring-opening polymerization. The benzyl group on aspartate was then converted to carboxylic acid to yield oligo(l-Ala-co-l-Phe-co-l-Asp)-poloxamer-oligo(l-Asp-co-l-Phe-co-l-Ala) (OAF-(OAsp)-PLX-(OAsp)-OAF, denoted as polymer 2). Characterization of the peptide secondary structure in aqueous media by circular dichroism revealed that the oligopeptide block in polymer 1 exhibited mainly an α-helix conformation, whereas that in polymer 2 adopted predominantly a β-sheet conformation at room temperature. The segmental dynamics of the PEG in polymer 1 remained essentially unperturbed upon heating from 10 to 50 °C; by contrast, the PEG segmental motion in polymer 2 became more constrained above ca. 35 °C, indicating an obvious change in the chemical environment of the block chains. Meanwhile, the storage modulus of the polymer 2 solution underwent an abrupt increase across this temperature, and the solution turned into a gel. Wet-cell TEM observation revealed that polymer 1 self-organized to form microgel particles of several hundred nanometers in size. The microgel particle was retained as the characteristic morphological entity such that the PEG chains did not experience a significant change of their chemical environment upon heating. The hydrogel formed by polymer 2 was found to contain networks of nanofibrils, suggesting that the hydrogen bonding between the carboxylic acid groups led to an extensive stacking of the β sheets along the fibril axis at elevated temperature. The in vitro cytotoxicity of the polymer 2 aqueous solution was found to be low in human retinal pigment epithelial cells. The low cytotoxicity coupled with the sol-gel transition makes the corresponding hydrogel a good candidate for biomedical applications.
    Langmuir 12/2013; · 4.38 Impact Factor
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    ABSTRACT: Tissue engineering can provide alternatives to current methods for tracheal reconstruction. Here we describe an approach for ectopic engineering of vascularized trachea based on the implantation of co-cultured scaffolds surrounded by a muscle flap. Poly(L-lactic-co-glycolic acid) (PLGA) or poly(ε-caprolactone) (PCL) scaffolds were seeded with chondrocytes, bone marrow stem cells and co-cultured both cells respectively (8 groups), wrapped in a pedicled muscle flap, placed as an ectopic culture on the abdominal wall of rabbits (n = 24), and harvested after two and four weeks. Analysis of the biochemical and mechanical properties demonstrated that the PCL scaffold with co-culture cells seeding displayed the optimal chondrogenesis with adequate rigidity to maintain the cylindrical shape and luminal patency. Histological analysis confirmed that cartilage formed in the co-culture groups contained a more homogeneous and higher extracellular matrix content. The luminal surfaces appeared to support adequate epithelialization due to the formation of vascularized capsular tissue. A prefabricated neo-trachea was transferred to the defect as a tracheal replacement and yielded satisfactory results. These encouraging results indicate that our co-culture approach may enable the development of a clinically applicable neo-trachea.
    Biomaterials 11/2013; · 8.31 Impact Factor
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    ABSTRACT: Chondrocytes (CH) and bone marrow stem cells (BMSCs) are sources that can be used in cartilage tissue engineering. Co-culture of CHs and BMSCs is a promising strategy for promoting chondrogenic differentiation. In this study, articular CHs and BMSCs were encapsulated in PCL-PEG-PCL photocrosslinked hydrogels for 4 weeks. Various ratios of CH:BMSC co-cultures were investigated to identify the optimal ratio for cartilage formation. The results thus obtained revealed that co-culturing CHs and BMSCs in hydrogels provides an appropriate in vitro microenvironment for chondrogenic differentiation and cartilage matrix production. Co-culture with a 1:4 CH:BMSC ratio significantly increased the synthesis of GAGs and collagen. In vivo cartilage regeneration was evaluated using a co-culture system in rabbit models. The co-culture system exhibited a hyaline chondrocyte phenotype with excellent regeneration, resembling the morphology of native cartilage. This finding suggests that the co-culture of these two cell types promotes cartilage regeneration and that the system, including the hydrogel scaffold, has potential in cartilage tissue engineering. Copyright © 2013 John Wiley & Sons, Ltd.
    Journal of Tissue Engineering and Regenerative Medicine 11/2013; · 4.43 Impact Factor
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    ABSTRACT: Human embryonic stem cells (hESCs), due to their self-renewal capacity and pluripotency, have become a potential source of transplantable β-cells for the treatment of diabetes. However, it is imperative that the derived cells fulfill the criteria for clinical treatment. In this study, we replaced common Matrigel with a synthetic peptide-acrylate surface (Synthemax) to expand undifferentiated hESCs and direct their differentiation in a defined and serum-free medium. We confirmed that the cells still expressed pluripotent markers, had the ability to differentiate into three germ layers, and maintained a normal karyotype after 10 passages of subculture. Next, we reported an efficient protocol for deriving nearly 86% definitive endoderm cells from hESCs under serum-free conditions. Moreover, we were able to obtain insulin-producing cells within 21 days following a simple three-step protocol. The results of immunocytochemical and quantitative gene expression analysis showed that the efficiency of induction was not significantly different between the Synthemax surface and the Matrigel-coated surface. Thus, we provided a totally defined condition from hESC culture to insulin-producing cell differentiation, and the derived cells could be a therapeutic resource for diabetic patients in the future.
    Stem cells and development 10/2013; · 4.15 Impact Factor
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    ABSTRACT: Thermosensitive micelles composed of a copolymer of methoxy polyethylene glycol (mPEG), polylactic acid (PLA), and 1,6-bis (p-carboxyphenoxy) hexane (CPH), namely methoxy polyethylene glycol-co-polylactic acid-co-aromatic anhydride (mPEG-PLCPHA), were fabricated for application as a promising hydrophilic drug carrier. The copolymer can self-assemble into micelles in PBS by hydrophobic interaction. The diameters of these micelles increased as the environmental temperature increased. An increase in viscosity with sol-to-gel transition occurred as temperature increased from room temperature to body temperature. During the in vitro degradation process, hydrogels demonstrated a more stable degradation rate. Both in vitro and in vivo cytotoxicity results showed that the materials had excellent biocompatibility due to less acidic products formation. In vitro cefazolin release profiles showed a stable release for 30 days. The hydrogel encapsulated cefazolin exhibited a good antibacterial effect. Based on these results, mPEG-PLCPHA can serve as an injectable depot gel for drug delivery.
    Nanomedicine: nanotechnology, biology, and medicine 10/2013; · 6.93 Impact Factor
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    ABSTRACT: Temperature-sensitive hydrogels are attractive alternatives to porous cell-seeded scaffolds and is minimally invasive through simple injection and in situ gelling. In this study, we compared the performance of two types of temperature-sensitive hydrogels on chondrocytes encapsulation for the use of tissue engineering of cartilage. The two hydrogels are composed of methoxy poly(ethylene glycol)- poly(lactic-co-valerolactone) (mPEG-PVLA), and methoxy poly(ethylene glycol)-poly(lactic- co-glycolide) (mPEG-PLGA). Osmolarity and pH were optimized through the manipulation of polymer concentration and dispersion medium. Chondrocytes proliferation in mPEG-PVLA hydrogels was observed as well as accumulation of GAGs and collagen. On the other hand, chondrocytes encapsulated in mPEG-PLGA hydrogels showed low viability and chondrogenesis. Also, mPEG-PVLA hydrogel, which is more hydrophobic, retained physical integrity after 14 days while mPEG-PLGA hydrogel underwent full degradation due to faster hydrolysis rate and more pronounced acidic self-catalyzed degradation. The mPEG-PVLA hydrogel can be furthered tuned by manipulation of molecular weights to obtain hydrogels with different swelling and degradation characteristics, which may be useful as producing a selection of hydrogels compatible with different cell types. Taken together, these results demonstrate that mPEG-PVLA hydrogels are promising to serve as three-dimensional cell carriers for chondrocytes and potentially applicable in cartilage tissue engineering. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2013.
    Journal of Biomedical Materials Research Part A 08/2013; · 2.83 Impact Factor
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    ABSTRACT: The acinus-mimicking microfluidic chip, which simulates the in vivo condition of the liver, was developed and reported in this paper. The gradient microenvironment of the liver acinus is replicated within this proposed microfluidic chip. The advantage of this acinus-mimicking chip is capable of adjusting the concentration gradient in a relatively short period of time at around 10 s. At the same instance the non-linear concentration gradient can be presented in the various zones within this microfluidic chip. The other advantage of this proposed design is in the convenience of allowing the direct injection of the cells into the chip. The environment within the chip is multi-welled and gel-free with high cell density. The multi-row pillar microstructure located at the entrance of the top and bottom flow channels is designed to be able to balance the pressure of the perfusion medium. Through this mechanism the shear stress experienced by the cultured cells can be minimized to reduce the potential damage flow from the perfusion process. ((3))The fluorescence staining and the observations of the cell morphology verify the life and death of the cells. The shear stress experienced by the cells in the various zones within the chip can be effectively mapped. The serum glutamic oxaloacetic transaminase (SGOT) collected from the supernatants was used to determine the effects of the degassing process and the shear stress of the medium flow on the cultured cells.
    Biomedical Microdevices 04/2013; · 2.72 Impact Factor
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    ABSTRACT: Human embryonic stem cells (hESCs), due to their self-renewal capacity and pluripotency, are an important source of cells for regenerative medicine. The immediate obstacles that need to be addressed are the poor cell survival rate of hESCs and their cell quality after cryopreservation. In this study, we used the Cell Alive System (CAS) which combines a programmed freezer with an oscillating magnetic field to reduce cryo-injury during the freezing process. The hESC clumps suspended in freezing medium were divided into three groups: (i) cells frozen by a conventional freezing container, Mr. Frosty and kept in a -80°C freezer (MF); (ii) cells frozen to -32°C by CAS, and then transferred to a -80°C freezer (CAS); (iii) cells frozen to -32°C by CAS, and then transferred to a pre-cooled Mr. Frosty and kept in a -80°C freezer (CAS-MF) for overnight. All cryovials were placed in liquid nitrogen for one week, and hESCs were then thawed and cultured on feeder for 7 days. The results of alkaline phosphatase (AP) staining showed that the attachment efficiency of the cells cryopreserved by CAS and CAS-MF was significantly higher (29.0% and 44.0%) than in the MF method (7.0%). Furthermore, we confirmed the cells cryopreserved using CAS-MF could be subcultured while expressing pluripotent markers, differentiate into three germ layers, and maintain a normal karyotype. These results demonstrate that the use of CAS-MF offers an efficient method of hESC banking.
    Cryobiology 03/2013; · 2.14 Impact Factor
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    ABSTRACT: This paper reports a gel-free multi-well microfluidic chip for cell cultures. Polydimethylsiloxane (PDMS) material was used because of its hydrophobic and gas-permeable features. Surface tension and fluidic channel resistance simplified the procedure of cell injection into the system. The shear stress and the mass-transfer perfusion medium reached a balance through the multi-row square-pillar microstructure and the driven pressure. The cell seeding was completed in 10-mm scaled culture wells in less than 6 s using the microstructure composed of PDMS. The adjustable initial cell density and length of the culture area facilitate its use in desired biological experiments. To verify whether the operation caused cell damage or not, the biological index of supernatants with glutamic oxaloacetic transaminase (GOT) and blood urea nitrogen (BUN) were monitored for 4 days. The 1–4-mm-long multi-rows square-pillar microstructure can sustain HA22T cells for 5 days and still maintain cell viability for up to 90% of seeded cells.
    Sensors and Actuators B Chemical 02/2013; Volume 177:Pages 295–307. · 3.84 Impact Factor
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    ABSTRACT: The long term in vivo biocompatibility is an essential feature for the design and development of sustained drug release carriers. In the recent intraocular drug delivery studies, hydrogels were suggested as sustained release carriers. The biocompatibility test for these hydrogels, however, was commonly performed only through in vitro cell culture examination, which is insufficient before the clinical applications. We compared three thermosensitive hydrogels that have been suggested as the carriers for drugs by their gel-solution phase-change properties. A new block terpolymer (PEOz-PCL-PEOz, ECE) and two commercial products (Matrigel® and Pluronic F127) were studied. The results demonstrated that the ocular media remained translucent for ECE and Pluronic F127 in the first 2 weeks, but cataract formation for Matrigel occurred in 2 weeks and for Pluronic F127 in 1 month, while turbid media was observed for both Matrigel and Pluronic F127 in 2 months. The electrophysiology examinations showed significant neuroretinal toxicity of Matrigel and Pluronic F127 but good biocompatibility of ECE. The neuroretinal toxicity of Matrigel and Pluronic F127 and superior biocompatibility of ECE hydrogel suggests ECE as more appropriate biomaterial for use in research and potentially in intraocular application.
    PLoS ONE 01/2013; 8(7):e67495. · 3.53 Impact Factor
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    ABSTRACT: Background/Purpose Durable mechanical strength and biocompatibility are the two major requirements for osteogenic scaffolds. Polyanhydrides are a class of biodegradable polymers characterized by anhydride bonds that connect repeating units of the polymer backbone chain. Hydroxyapatite (HAP) is the main component of human bone and is a good osteoinductive factor that promotes bone mineralization. This work validates the combination of polyanhydrides and HAP for biomedical application. Methods Polyanhydride copolymers were fabricated from sebacic acid (SA) and 1,6-bis(p-carboxyphenoxy)hexane (CPH). HAP was surface-modified by polycaprolactone (PCL), and testing tablets were made using different ratios of copolymers and surface-grafted HAP (g-HAP). Degradation tests were performed to evaluate mechanical strength, pH, and weight loss. Biocompatibility was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and live/dead stain test. Cell affinity was measured using scanning electronic microscopy (SEM). Results The favorable surface erosion property of polyanhydrides prevented marked changes in the mechanical properties over time. In addition, the degradation byproducts of the copolymer did not cause a serious decline in pH and were less harmful to the cells. g-HAP increased cell affinity for the polymer surface. Conclusion The research team synthesized polyanhydride/g-HAP composites with high mechanical strength, slow degradation, and excellent biocompatibility. The result showed that a CPH/SA ratio of 7:3 in combination with 10 wt% g-HAP was optimal as bone substitute.
    Formosan Journal of Musculoskeletal Disorders. 01/2013; 4(1):6–10.
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    ABSTRACT: The composite of methoxy polyethylene glycol (mPEG) and poly(lactic-co-glycolic acid) (PLGA) thermosensitive hydrogel mixed with various portions of hydroxyapatite (HAP) or β-tricalcium phosphate (β-TCP) were used as bone graft substitutes. The physical properties of a series of composite gels, including the critical micelle concentration (CMC), particle sizes, zeta potential, rheological behavior, morphology of composite gels, and sol–gel transition, were characterized in vitro. These composite gels could form a gel at body temperature and could be controlled easily at room temperature, but showed only a small decline in pH, to between 6.33 and 6.66, whereas mPEG–PLGA gel without ceramic exhibited a more significant decrease in pH over a period of 5 days. The dissolution of ceramics results in an increase in the concentration of calcium and phosphate, which can buffer the degradation of mPEG–PLGA. Higher cell viability was observed in the composite gels with more bioceramics, as shown in the MTT assay and the live and dead stain. Mixing mPEG–PLGA with HAP or β-TCP may hold greater promise than mPEG–PLGA alone for repairing bone defects.
    Composites Part B Engineering 12/2012; 43(8):3088–3095. · 2.14 Impact Factor
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    ABSTRACT: mPEG–PLLA (poly l-lactic acid) is synthesized by ring-opening polymerization of lactide and conjugation with mPEG. Sebacic acid is modified with acetic anhydride and condensed with mPEG to form mPEG–PSA (poly sebacic anhydride). The micelles formed by mPEG–PLLA are characterized by slow degradation and low drug encapsulation efficiency; on the contrary, mPEG–PSA micelles are characterized by rapid degradation but high encapsulation efficiency. They can merge into spherical micelles (Φ = 140 nm) by self-assembly in water. The mixed micelles can successfully encapsulate a typical hydrophobic drug (curcumin), and significantly improve its solubility. Experimental results show that the mixed micelles have the features of high encapsulation efficiency and slow degradation.
    Reactive and Functional Polymers 11/2012; 72(11):846–855. · 2.51 Impact Factor
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    ABSTRACT: BACKGROUND: Polymethylmethacrylate (PMMA) is commonly used for clinical applications. However, the short handling time increases the probability of a surgeon missing the crucial period in which the cement maintains its ideal viscosity for a successful injection. The aim of this article was to illustrate the effects a reduction in temperature would have on the cement handling time during percutaneous vertebroplasty. METHODS: The injectability of bone cement was assessed using a cement compressor. By twisting the compressor, the piston transmits its axial load to the plunger, which then pumps the bone cement out. The experiments were categorized based on the different types of hypothermic manipulation that were used. In group I (room temperature, sham group), the syringes were kept at 22[degree sign]C after mixing the bone cement. In group 2 (precooling the bone cement and the container), the PMMA powder and liquid, as well as the beaker, spatula, and syringe, were stored in the refrigerator (4[degree sign]C) overnight before mixing. In group 3 (ice bath cooling), the syringes were immediately submerged in ice water after mixing the bone cement at room temperature. RESULTS: The average liquid time, paste time, and handling time were 5.1 +/- 0.7, 3.4 +/- 0.3, and 8.5 +/- 0.8 min, respectively, for group 1; 9.4 +/- 1.1, 5.8 +/- 0.5, and 15.2 +/- 1.2 min, respectively, for group 2; and 83.8 +/- 5.2, 28.8 +/- 6.9, and 112.5 +/- 11.3 min, respectively, for group 3. The liquid and paste times could be increased through different cooling methods. In addition, the liquid time (i.e. waiting time) for ice bath cooling was longer than for that of the precooling method (p < 0.05). CONCLUSIONS: Both precooling (i.e. lowering the initial temperature) and ice bath cooling (i.e. lowering the surrounding temperature) can effectively slow polymerization. Precooling is easy for clinical applications, while ice bath cooling might be more suitable for multiple-level vertebroplasty. Clinicians can take advantage of the improved injectability without any increased cost.
    BMC Musculoskeletal Disorders 10/2012; 13(1):198. · 1.88 Impact Factor
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    ABSTRACT: This study evaluates the crosslinkage effect of chondroitin sulphate C (CSC) and type II collagen (COL II) on chondrogenesis of mesenchymal stem cells (MSCs) in vitro and in vivo. In the in vitro studies, our results show that the weight ratio CSC:COL II that reaches 1.2:100 (CSC(1.2/100) -COL II scaffold) can provide an optimal microenvironment for MSC chondrogenesis. When MSCs are cultured in this CSC(1.2/100) -COL II scaffold, the chondrogenic gene expression of cultured cells is upregulated, while the osteogenic gene expression of these is downregulated. In addition, MSCs cultivated in the CSC(1.2/100) -COL II scaffold are found to express the highest glycosaminoglycans:DNA ratio as compared to those in scaffolds of other CSC:COL II ratios. Histological and immunohistological evidence also supports the result. In the in vivo study, our results show that MSCs cultivated in the CSC(1.2/100) -COL II scaffold demonstrate a better repair ability on cartilage lesions than does the COL II scaffold. After 1 month in vivo, the injected MSCs in the CSC(1.2/100) -COL II scaffold show lacuna structures and stimulate the formation of type II collagen at the defective sites. Six months after transplantation, the generated cells in the CSC(1.2/100) -COL II group show higher gene expressions of type II collagen and aggrecan but lower gene expression of type I collagen at the defective sites than those in the COL II group. The results strongly suggest that CSC(1.2/100) -COL II scaffold can serve as a potential candidate for cartilage repair and improve the chondrogenesis of MSCs in general. Copyright © 2012 John Wiley & Sons, Ltd.
    Journal of Tissue Engineering and Regenerative Medicine 03/2012; · 4.43 Impact Factor
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    ABSTRACT: This paper presents a microfluidic chip platform with electrochemical carbon nanotube electrodes for preclinical evaluation of antibiotics nanocapsules. Currently, there has been an increasing interest in the development of nanocapsules for drug delivery applications for localized treatments of diseases. So far, the methods to detect antibiotics are liquid chromatography (LC), high performance liquid chromatography (HPLC), mass spectroscopy (MS). These conventional instruments are bulky, expensive, not ease of access, and talented operator required. In order to help the development of nanocapsules and understand drug release profile before planning the clinical experiments, it is important to set up a biosensing platform which could monitor and evaluate the real-time drug release profile of nanocapsules with high sensitivity and long-term measurement ability. In this work, a microfluidic chip platform with electrochemical carbon nanotube electrodes has been developed and characterized for rapid detection of antibiotics teicoplanin nanocapsules. Multi-walled carbon nanotubes are used to modify the gold electrode surfaces to enhance the performance of the electrochemical biosensors. Experimental results show that the limit of detection of the developed platform using carbon nanotubes electrodes is 0.1 μg/ml with a linear range from 1 μg/ml to 10 μg/ml. The sensitivity of the developed system is 0.023 mA ml/μg at 37°C. The drug release profile of teicoplanin nanocapsules in PBS shows that the antibiotics nanocapsules significantly increased the release of drug on the 4th day, measuring 0.4858 μg/(ml hr). The release of drug from the antibiotics nanocapsules reached 34.98 μg/ml on the 7th day. The results showed a similar trend compared with the measurement result using the HPLC instrument. Compared with the traditional HPLC measurements, the electrochemical sensing platform we developed measures results with increased flexibility in controlling experimental factors for long-term preclinical measurement of nanocapsules in real time and at low cost.
    Biosensors & bioelectronics 02/2011; 26(8):3620-6. · 5.43 Impact Factor
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    ABSTRACT: Chondroitin sulfate C (CSC) is a kind of glycosaminoglycans (GAGs) with molecular weights of 10,000 to 50,000 Da and a high charge density. GAGs are major components in extracellular matrix (ECM), which play important role in the regulation of cell proliferation, migration, and differentiation. In this study, we studied the effects of chondroitin sulfate C (CSC) on the differentiation of human mesenchymal stem cells (MSCs) toward the chondrocyte lineage. The MSCs were either cultured on type II collagen (COL II) scaffolds with high molecular weight CSC addition in the medium (free CSC) or with free oligosaccharide CSC. Special attention was given to the effects of MSCs cultured on CSC cross-linked type II scaffolds (cross-linked CSC). According to the analysis of histology stain, gene expression, and ECM secretion, our results showed that MSCs cultured with free CSC, free oligosaccharides CSC, and on the cross-linked CSC scaffolds all would be induced into chondrocytes. Moreover, free oligosaccharide CSC present in the microenvironment could significantly up-regulate MSC chondrogenesis gene expression and stimulate cartilage ECM accumulation more than free CSC with high molecular weight after 3-week induction. Importantly, cross-linked CSC had the most excellent effects on the MSC chondrogenesis. Thus, we believed that cross-linked CSC in the scaffold would play the similar roles with free oligosaccharide CSC in the medium. Cross-linked CSC would be a potential candidate for cartilage repair in the cell therapy and tissue engineering.
    Journal of Bioscience and Bioengineering 10/2010; 111(2):226-31. · 1.74 Impact Factor
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    ABSTRACT: The feasibility of using genipin cross-linked type II collagen scaffold with rabbit bone marrow mesenchymal stem cells (RBMSCs) to repair cartilage defect was herein studied. Induction of RBMSCs into chondrocytic phenotype on type II collagen scaffold in vitro was conducted using TGF-β 3 containing medium. After 3-weeks of induction, chondrocytic behavior, including marker genes expression and specific extracellular matrix (ECM) secretion, was observed. In the in vivo evaluation experiment, the scaffolds containing RBMSCs without prior induction were autologous implanted into the articular cartilage defects made by subchondral drilling. The repairing ability was evaluated. After 2 months, chondrocyte-like cells with lacuna structure and corresponding ECM were found in the repaired sites without apparent inflammation. After 24 weeks, we could easily find cartilage structure the same with normal cartilage in the repair site. In conclusion, it was shown that the scaffolds in combination of in vivo conditions can induce RBMSCs into chondrocytes in repaired area and would be a possible method for articular cartilage repair in clinic and cartilage tissue engineering.
    Cytotechnology 10/2010; 63(1):13-23. · 1.32 Impact Factor

Publication Stats

537 Citations
197.68 Total Impact Points

Institutions

  • 1989–2014
    • National Tsing Hua University
      • • Department of Chemical Engineering
      • • Department of Power Mechanical Engineering
      Hsin-chu-hsien, Taiwan, Taiwan
  • 2010
    • Kaohsiung Medical University
      • Department of Orthopaedics
      Kao-hsiung-shih, Kaohsiung, Taiwan
  • 2004–2008
    • Food Industry Research and Development Institute
      Hsin-chu-hsien, Taiwan, Taiwan
  • 2007
    • National Taipei University of Technology
      • Department of Chemical Engineering
      Taipei, Taipei, Taiwan