Oya Tagit

FHNW University of Applied Sciences and Arts | FHNW · Institute of Chemistry and Bioanalytics (ICB)

A simple method for the encapsulation of quantum dots (QDs) in virus-like particle (VLP) nanoassemblies with tuneable structural properties and enhanced biocompatibility is presented. Cowpea chlorotic mottle virus-based capsid proteins assemble around the carboxylated QDs to form QD/VLP nanoassemblies of different capsid size as a function of pH an...

The interplay of photonics, nanotechnology, and biochemistry has significantly improved the identification and characterization of multiple types of biomarkers by optical biosensors. Great achievements in fluorescence-based technologies have been realized, for example by the advancement of multiplexing techniques or the introduction of nanoparticle...

Submicrometer-sized particles of poly(N-isopropylacrylamide) (PNIPAM) are synthesized by surfactant-free radical polymerization. The morphology and nanomechanical properties of individual, isolated PNIPAM microgel particles at the silicon/air and silicon/water interfaces, below and above the PNIPAM volume-phase-transition temperature (VPTT), are pr...

We report on the proof-of-principle of using semiconductor nanorods (quantum rods; QRs) in homogeneous Förster resonance energy transfer (FRET) bioassays. Terbium complexes (Tb) with long photoluminescence lifetimes were used as FRET donors, and biological recognition was accomplished by biotin-QR to Tb-streptavidin binding. Time-resolved and stead...

There is an urgent need to develop new therapeutic approaches for the treatment of severe neurological trauma, such as stroke and spinal cord injuries. However, many drugs with potential neuropharmacological activity, such as adenosine, are inefficient upon systemic administration because of their fast metabolization and rapid clearance from the bl...

Endogenous stimuli‐responsive prodrugs, due to their disease lesion specificity and reduced systemic toxicity, have been widely explored for antitumor therapy. However, reactive oxygen species (ROS) as classical endogenous stimuli in the tumor microenvironment (TME) are not enough to achieve the expected drug release. Herein, a ROS‐activatable hete...

Endogenous androgens are pivotal in the development and progression of prostate cancer (PC). We investigated nanoparticle formulations of curcumin and piperine in modulating steroidogenesis within PC cells. Using multiple PC cell lines (LNCaP, VCaP, DU145 and PC3) we studied the effects of curcumin, piperine, and their nanoparticle formulations, cu...

Endogenous androgens are pivotal in the development and progression of prostate cancer (PC). We investigated nanoparticle formulations of curcumin and piperine in modulating steroidogenesis within PC cells. Using multiple PC cell lines (LNCaP, VCaP, DU145 and PC3) we studied the effects of curcumin, piperine, and their nanoparticle formulations—cur...

Endogenous androgens are pivotal in the development and progression of prostate cancer (PC). We investigated nanoparticle formulations of curcumin and piperine in modulating steroidogenesis within PC cells. Using multiple PC cell lines (LNCaP, VCaP, DU145 and PC3) we studied the effects of curcumin, piperine, and their nanoparticle formulations—cur...

Recently, chemically synthesized minimal mRNA (CmRNA) has emerged as a promising alternative to in vitro transcribed mRNA (IVT-mRNA) for cancer therapy and immunotherapy. CmRNA lacking the untranslated regions and polyadenylation exhibits enhanced stability and efficiency. Encapsulation of CmRNA within lipid-polymer hybrid nanoparticles (LPPs) offe...

Poly(lactic-co-glycolic acid) (PLGA) nanoparticle-based drug delivery systems are known to offer a plethora of potential therapeutic benefits. However, challenges related to large-scale manufacturing, such as the difficulty of reproducing complex formulations and high manufacturing costs, hinder their clinical and commercial development. In this co...

Despite the efficacy and potential therapeutic benefits that poly(lactic-co-glycolic acid) (PLGA) nanomedicine formulations can offer, challenges related to large-scale processing hamper their clinical and commercial development. Major hurdles for the launch of a polymeric nanocarrier product on the market are batch-to-batch variations and lack of...

Objective: The events of the last year have highlighted the complexity of implementing large-scale molecular diagnostic testing for novel pathogens. The purpose of this study was to determine the chemical influences of sample collection media and storage on the stability and detection of viral nucleic acids by qRT-PCR. We studied the mechanism(s) t...

With the advent of novel immunotherapies, interest in ex vivo autologous cell labeling for in vivo cell tracking has revived. However, current clinically available labeling strategies have several drawbacks, such as release of radiolabel over time and cytotoxicity. Poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) are clinically used biodegrad...

Supplementary Information

The events of the last year have highlighted the complexity of implementing large-scale molecular diagnostic testing for novel pathogens. The purpose of this study was to determine the chemical influences of sample collection media and storage on the stability and detection of viral nucleic acids by qRT-PCR. We studied the mechanism(s) through whic...

Nanomedicines based on poly(lactic-co-glycolic acid) (PLGA) carriers offer tremendous opportunities for biomedical research. Although several PLGA-based systems have already been approved by both the Food and Drug Administration (FDA) and the European Medicine Agency (EMA), and are widely used in the clinics for the treatment or diagnosis of diseas...

This study demonstrated a drug-delivery system with anionic beta cyclodextrin (β-CD) complexes to retain tetracycline (TC) and control its release from multilayers of poly(acrylic acid) (PAA) and poly(l-lysine) (PLL) in a ten double layers ([PAA/PLL]10) coating onto titanium. The drug-delivery capacity of the multilayer system was proven by control...

Poly(lactic-co-glycolic acid) (PLGA)-based drug delivery systems are among the most commonly studied materials due to excellent biocompatibility, tuneable degradation characteristics and long clinical history of PLGA. Size and surface functionality of PLGA particles are main parameters that dictate their fate in vivo. Fluorescence labeling and imag...

Perfluorocarbons hold great promise both as imaging agents, particularly for ¹⁹F MRI, and in therapy, such as oxygen delivery. ¹⁹F MRI is unique in its ability to unambiguously track and quantify a tracer while maintaining anatomic context, and without the use of ionizing radiation. This is particularly well-suited for inflammation imaging and quan...

Nanovaccines, co-delivering antigen and invariant natural killer T (iNKT) cell agonists, proved to be very effective in inducing anti-tumor T cell responses due to their exceptional helper function. However, it is known that iNKT cells are not equally present in all lymphoid organs and nanoparticles do not get evenly distributed to all immune compa...

Polymeric particles made up of biodegradable and biocompatible polymers such as poly(lactic-co-glycolic acid) (PLGA) are promising tools for several biomedical applications including drug delivery. Particular emphasis is placed on the size and surface functionality of these systems as they are regarded as the main protagonists in dictating the part...

Endogenous extracellular Galectins constitute a novel mechanism of membrane protein organization at the cell surface. Although Galectins are also highly expressed intracellularly, their cytosolic functions are poorly understood. Here, we investigated the role of Galectin-9 in dendritic cell (DC) surface organization and function. By combining funct...

Unraveling the mechanisms that govern the formation and function of invadopodia is essential towards the prevention of cancer spread. Here, we characterize the ultrastructural organization, dynamics and mechanical properties of collagenotytic invadopodia forming at the interface between breast cancer cells and a physiologic fibrillary type I collag...

Polymeric particles made up of biodegradable and biocompatible polymers such as poly(lactic-co-glycolic acid) (PLGA) are promising tools for several biomedical applications including drug delivery. Particular emphasis is placed on the size and surface functionality of these systems as they are regarded as the main protagonists in dictating the part...

Extracellular Galectins constitute a novel mechanism of membrane protein organisation at the cell surface. Although Galectins are also highly expressed intracellularly, their cytosolic functions are poorly understood. Here, we investigated the role of Galectin-9 in dendritic cell (DC) surface organisation and function. By combining functional, supe...

Percutaneous medical devices are prone to bacterial contamination that causes dramatic clinical conditions. At the percutaneous level of dental implant systems, microbial pathogens induce biofilm formation that may result in bone resorption and dental implant loss. In view of peri-implantitis caused by bacterial inflammation at the percutaneous abu...

Introduction The knowledge of in vitro and in vivo stability of polymeric nanoparticles is vital for the development of clinical formulations for drug delivery and cell labeling applications. Fӧrster resonance energy transfer (FRET)-based fluorescence labeling approaches are promising tools to study nanoparticle stability under different physiologi...

Although common in biology, controlled stiffening of hydrogels in vitro is difficult to achieve; the required stimuli are commonly large and/or the stiffening amplitudes small. Here, we describe the hierarchical mechanics of ultra-responsive hybrid hydrogels composed of two synthetic networks, one semi-flexible and stress-responsive, the other flex...

The knowledge of in vitro and in vivo stability of polymeric nanoparticles is vital for the development of clinical formulations for drug delivery and cell labeling applications. Fӧrster resonance energy transfer (FRET)-based fluorescence labeling approaches are promising tools to study nanoparticle stability under different physiological condition...

The clinical and commercial development of polymeric sub-micron size formulations based on poly(lactic-co-glycolic acid) (PLGA) particles is hampered by the challenges related to their good manufacturing practice (GMP)-compliant, scale-up production without affecting the formulation specifications. Continuous process technologies enable large-scale...

The use of nanotechnologies for the development of highly sensitive and affordable diagnostic assays has significantly improved the ability to detect and characterize multiple types of biomarkers. Semiconductor and metal nanoparticles with unique optical properties have been successfully integrated within biomarker detection schemes for the generat...

Introduction Dendritic cells (DCs) express a variety of cell surface receptors aimed at facilitating recognition, uptake and presentation of tumour antigens, which allows for the initiation of a potent anti-tumour immune response. Galectin-mediated interactions on DC-plasma membrane are emerging as potent modulators of cellular organisation althoug...

Quantum dots (QDs) are not only advantageous for color-tuning, improved brightness, and high stability, but their nanoparticle surfaces also allow for the attachment of many biomolecules. Because IgG antibodies (ABs) are in the same size range of biocompatible QDs and the AB orientation after conjugation to the QD is often random, it is difficult t...

Drug delivery to the brain is one of the major challenges in the treatment of cerebral diseases and implies extensive understanding of nanomedicine transcytosis pathways across the Blood-Brain Barrier (BBB). In this study, we investigated the interaction of squalenoyl-adenosine nanoassemblies (SQAd NAs) with human brain endothelial cells, concernin...

Synthesis and characterization of gold nanoclusters (Au NCs) stabilized by a zwitterion ligand (Zw) at different Au : Zw ratios are demonstrated. Au NCs exhibit photoluminescence (PL) emission which is tunable from the near infrared (805 nm) to the red spectral window (640 nm) and strongly influenced by the ligand shell size. Optical and chemical i...

There is an urgent need to develop new therapeutic approaches for the treatment of severe neurological trauma, such as stroke and spinal cord injuries. However, many drugs with potential neuropharmacological activity, such as adenosine, are inefficient upon systemic administration because of their fast metabolization and rapid clearance from the bl...

Structural and optical characterization of water soluble, thermo-responsive quantum dot/poly(N-isopropyl acrylamide) (QD/PNIPAM) hybrid particles using fluorescence correlation spectroscopy (FCS) and time-correlated single photon counting (TCSPC) measurements performed at temperatures below and above the lower critical solution temperature (LCST) o...

Synthesis, characterization, and applications of novel thermoresponsive polymeric coatings for quantum dots (QDs) are presented. Comb-copolymers featuring hydrophobic alkyl groups, carboxylic groups and poly(N-isopropylacrylamide) (PNIPAM) side chains with molar masses ranging from 1000g/mol to 25,400g/mol were obtained. The amphiphilic comb-copoly...

Quantum dots, QDs, receive growing attention from many research disciplines owing to their advantages as fluorescent probes including their nanoscale size (similar to biomolecules), high quantum yield and molar extinction coefficients, versatility in surface modification, broad excitation spectra (for multicolor imaging) and narrow band emission an...

Semiconductor nanocrystal particles (quantum dots, QDs) exhibit unique electronic and optical properties, which depend on their size and composition, and can be tuned by a controlled variation of the particle dimensions. Due to this tunability, applications of QDs in optoelectronics, sensing, biolabeling and biodiagnostics have attracted great inte...

A thermo-responsive polymer/quantum dot platform based on poly(N-isopropyl acrylamide) (PNIPAM) brushes 'grafted from' a gold substrate and quantum dots (QDs) covalently attached to the PNIPAM layer is presented. The PNIPAM brushes are grafted from the gold surface using an iniferter-initiated controlled radical polymerization. The PNIPAM chain end...

Antibiotic use is a vital method for the treatment of most diseases involving bacterial infections. Unfortunately, in certain cases these agents are not effective in treatments against diseases for either some limitation in antibiotic usage because of the side effects or some distribution problems caused by physiological or pathological barriers in...