Publications by authors named "Marissa E Wechsler"

17 Publications

  • Page 1 of 1

Messenger RNA-based vaccines: Past, present, and future directions in the context of the COVID-19 pandemic.

Adv Drug Deliv Rev 2021 Oct 9;179:114000. Epub 2021 Oct 9.

Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA; Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA; Institute for Biomaterials, Drug Delivery, and Regenerative Medicine, The University of Texas at Austin, Austin, TX, USA; Division of Molecular Pharmaceutics and Drug Delivery, College of Pharmacy, The University of Texas at Austin, Austin, TX, USA; Department of Surgery and Perioperative Care, Dell Medical School, The University of Texas at Austin, Austin, TX, USA. Electronic address:

mRNA vaccines have received major attention in the fight against COVID-19. Formulations from companies such as Moderna and BioNTech/Pfizer have allowed us to slowly ease the social distancing measures, mask requirements, and lockdowns that have been prevalent since early 2020. This past year's focused work on mRNA vaccines has catapulted this technology to the forefront of public awareness and additional research pursuits, thus leading to new potential for bionanotechnology principles to help drive further innovation using mRNA. In addition to alleviating the burden of COVID-19, mRNA vaccines could potentially provide long-term solutions all over the world for diseases ranging from influenza to AIDS. Herein, we provide a brief commentary based on the history and development of mRNA vaccines in the context of the COVID-19 pandemic. Furthermore, we address current research using the technology and future directions of mRNA vaccine research.
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http://dx.doi.org/10.1016/j.addr.2021.114000DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8502079PMC
October 2021

Electrostatic and Covalent Assemblies of Anionic Hydrogel-Coated Gold Nanoshells for Detection of Dry Eye Biomarkers in Human Tears.

Nano Lett 2021 Oct 8. Epub 2021 Oct 8.

Institute for Biomaterials, Drug Delivery, and Regenerative Medicine, The University of Texas at Austin, Austin, Texas 78712, United States.

Although dry eye is highly prevalent, many challenges exist in diagnosing the symptom and related diseases. For this reason, anionic hydrogel-coated gold nanoshells (AuNSs) were used in the development of a label-free biosensor for detection of high isoelectric point tear biomarkers associated with dry eye. A custom, aldehyde-functionalized oligo(ethylene glycol)acrylate (Al-OEGA) was included in the hydrogel coating to enhance protein recognition through the formation of dynamic covalent (DC) imine bonds with solvent-accessible lysine residues present on the surface of select tear proteins. Our results demonstrated that hydrogel-coated AuNSs, composed of monomers that form ionic and DC bonds with select tear proteins, greatly enhance protein recognition due to changes in the maximum localized surface plasmon resonance wavelength exhibited by AuNSs in noncompetitive and competitive environments. Validation of the developed biosensor in commercially available pooled human tears revealed the potential for clinical translation to establish a method for dry eye diagnosis.
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http://dx.doi.org/10.1021/acs.nanolett.1c02941DOI Listing
October 2021

Recent Advancements in Biosensing Approaches for Screening and Diagnostic Applications.

Curr Opin Biomed Eng 2021 Sep 29;19. Epub 2021 Jun 29.

Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA.

Recent advancements in molecular recognition have provided additional diagnostic and treatment approaches for multiple diseases, including autoimmune disorders and cancers. Research investigating how the composition of biological fluids is altered during disease progression, including differences in the expression of the small molecules, proteins, RNAs, and other components present in patient tears, saliva, blood, urine, or other fluids, has provided a wealth of potential candidates for early disease screening; however, adoption of biomarker screening into clinical settings has been challenged by the need for more robust, low-cost, and high-throughput assays. This review examines current approaches in molecular recognition and biosensing for the quantification of biomarkers for disease screening and diagnostic outcomes.
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http://dx.doi.org/10.1016/j.cobme.2021.100318DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8389739PMC
September 2021

Lipid- and Polymer-Based Nanoparticle Systems for the Delivery of CRISPR/Cas9.

J Drug Deliv Sci Technol 2021 Oct 11;65. Epub 2021 Jul 11.

Department of Biomedical Engineering and Chemical Engineering, The University of Texas at San Antonio, San Antonio, TX, USA.

The discovery of clustered regularly interspaced short palindromic repeat (CRISPR)/ CRISPR-associated (Cas) genome editing systems and their applications in human health and medicine has heralded a new era of biotechnology. However, the delivery of CRISPR therapeutics is arguably the most difficult barrier to overcome for translation to clinical administration. Appropriate delivery methods are required to efficiently and selectively transport all gene editing components to specific target cells and tissues of interest, while minimizing off-target effects. To overcome this challenge, we discuss and critic nanoparticle delivery strategies, focusing on the use of lipid-based and polymeric-based matrices herein.
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http://dx.doi.org/10.1016/j.jddst.2021.102728DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8318345PMC
October 2021

Engineering the MSC Secretome: A Hydrogel Focused Approach.

Adv Healthc Mater 2021 04 17;10(7):e2001948. Epub 2021 Feb 17.

Department of Chemical and Biological Engineering, University of Colorado-Boulder, 3415 Colorado Avenue, Boulder, CO, 80303, USA.

The therapeutic benefits of exogenously delivered mesenchymal stromal/stem cells (MSCs) have been largely attributed to their secretory properties. However, clinical translation of MSC-based therapies is hindered due to loss of MSC regenerative properties during large-scale expansion and low survival/retention post-delivery. These limitations might be overcome by designing hydrogel culture platforms to modulate the MSC microenvironment. Hydrogel systems could be engineered to i) promote MSC proliferation and maintain regenerative properties (i.e., stemness and secretion) during ex vivo expansion, ii) improve MSC survival, retention, and engraftment in vivo, and/or iii) direct the MSC secretory profile using tailored biochemical and biophysical cues. Herein, it is reviewed how hydrogel material properties (i.e., matrix modulus, viscoelasticity, dimensionality, cell adhesion, and porosity) influence MSC secretion, mediated through cell-matrix and cell-cell interactions. In addition, it is highlighted how biochemical cues (i.e., small molecules, peptides, and proteins) can improve and direct the MSC secretory profile. Last, the authors' perspective is provided on future work toward the understanding of how microenvironmental cues influence the MSC secretome, and designing the next generation of biomaterials, with optimized biophysical and biochemical cues, to direct the MSC secretory profile for improved clinical translation outcomes.
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http://dx.doi.org/10.1002/adhm.202001948DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8035320PMC
April 2021

Charged Poly(-isopropylacrylamide) Nanogels for the Stabilization of High Isoelectric Point Proteins.

ACS Biomater Sci Eng 2021 09 9;7(9):4282-4292. Epub 2021 Feb 9.

Storage and transportation of protein therapeutics using refrigeration is a costly process; a reliable electrical supply is vital, expensive equipment is needed, and unique transportation is required. Reducing the reliance on the cold chain would enable low-cost transportation and storage of biologics, ultimately improving accessibility of this class of therapeutics to patients in remote locations. Herein, we report on the synthesis of charged poly(-isopropylacrylamide) nanogels that efficiently adsorb a range of different proteins of varying isoelectric points and molecular weights (e.g., adsorption capacity () = 4.7 ± 0.2 mg/mg at 6 mg/mL initial IgG concentration), provide protection from external environmental factors (i.e., temperature), and subsequently release the proteins in an efficient manner (e.g., 100 ± 1% at 2 mg/mL initial IgG concentration). Both cationic and anionic nanogels were synthesized and selectively chosen based on the ability to form electrostatic interactions with adsorbed proteins (e.g., cationic nanogels adsorb low isoelectric point proteins whereas anionic nanogels adsorb high isoelectric point proteins). The nanogel-protein complex formed upon adsorption increases the stabilization of the protein's tertiary structure, providing protection against denaturation at elevated temperatures (e.g., 84 ± 4% of the protected IgG was stabilized when exposed to 65 °C). The addition of a high molar salt solution (e.g., 40 mM CaCl solution) to protein-laden nanogels disrupts the electrostatic interactions and collapses the nanogel, ultimately releasing the protein. The versatile materials utilized, in addition to the protein loading and release mechanisms described, provide a simple and efficient strategy to protect fragile biologics for their transport to remote areas without necessitating costly storage equipment.
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http://dx.doi.org/10.1021/acsbiomaterials.0c01690DOI Listing
September 2021

Engineering precision nanoparticles for drug delivery.

Nat Rev Drug Discov 2021 02 4;20(2):101-124. Epub 2020 Dec 4.

Department of Chemical Engineering and Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA, USA.

In recent years, the development of nanoparticles has expanded into a broad range of clinical applications. Nanoparticles have been developed to overcome the limitations of free therapeutics and navigate biological barriers - systemic, microenvironmental and cellular - that are heterogeneous across patient populations and diseases. Overcoming this patient heterogeneity has also been accomplished through precision therapeutics, in which personalized interventions have enhanced therapeutic efficacy. However, nanoparticle development continues to focus on optimizing delivery platforms with a one-size-fits-all solution. As lipid-based, polymeric and inorganic nanoparticles are engineered in increasingly specified ways, they can begin to be optimized for drug delivery in a more personalized manner, entering the era of precision medicine. In this Review, we discuss advanced nanoparticle designs utilized in both non-personalized and precision applications that could be applied to improve precision therapies. We focus on advances in nanoparticle design that overcome heterogeneous barriers to delivery, arguing that intelligent nanoparticle design can improve efficacy in general delivery applications while enabling tailored designs for precision applications, thereby ultimately improving patient outcome overall.
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http://dx.doi.org/10.1038/s41573-020-0090-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7717100PMC
February 2021

Nanogel receptors for high isoelectric point protein detection: influence of electrostatic and covalent polymer-protein interactions.

Chem Commun (Camb) 2020 Jun 4;56(45):6141-6144. Epub 2020 May 4.

Institute for Biomaterials, Drug Delivery, and Regenerative Medicine, The University of Texas at Austin, Austin, TX, USA.

An aldehyde acrylate-based functional monomer was incorporated into poly(N-isopropylacrylamide-co-methacrylic acid) nanogels for use as protein receptors. The aldehyde component forms dynamic imines with surface exposed lysine residues, while carboxylic acid/carboxylate moieties form electrostatic interactions with high isoelectric point proteins. Together, these interactions effect protein adsorption and recognition.
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http://dx.doi.org/10.1039/d0cc02200dDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7377432PMC
June 2020

Developing a Multidisciplinary Approach for Engineering Stem Cell Organoids.

Ann Biomed Eng 2020 Jul 28;48(7):1895-1904. Epub 2019 Oct 28.

Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA.

Recent advances in stem cell biology, synthetic biology, bioengineering, and biotechnology have included significant work leading to the development of stem cell-derived organoids. The growing popularity of organoid research and use of organoids is widely due to the fact that these three-dimensional cellular structures better model human physiology compared to traditional in vitro and in vivo methods by recapitulating many biologically relevant parameters. Organoids show great promise for a wide range of applications, such as for use in disease modeling, drug discovery, and regenerative medicine. However, many challenges associated with reproducibility and scale up still remain. Identification of the conditions which generate a robust environment that predictably promotes cellular self-assembly and organization leading to organoid formation is critical and requires a multidisciplinary approach. To accomplish this we need to identify a cellular source, engineer a matrix to stimulate cell-cell and cell-matrix interactions, and provide the biochemical and biophysical cues which mimic that of the in vivo environment. Discussion of the components needed for organoid development and formation is reviewed herein, as well as specific organoid examples and the promise of this research for the future.
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http://dx.doi.org/10.1007/s10439-019-02391-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7186139PMC
July 2020

Engineered microscale hydrogels for drug delivery, cell therapy, and sequencing.

Biomed Microdevices 2019 03 23;21(2):31. Epub 2019 Mar 23.

Department of Biomedical Engineering, The University of Texas at Austin, Austin, TX, USA.

Engineered microscale hydrogels have emerged as promising therapeutic approaches for the treatment of various diseases. These microgels find wide application in the biomedical field because of the ease of injectability, controlled release of therapeutics, flexible means of synthesis, associated tunability, and can be engineered as stimuli-responsive. While bulk hydrogels of several length-scale dimensions have been used for over two decades in drug delivery applications, their use as microscale carriers of drug and cell-based therapies is relatively new. Herein, we critically summarize the fundamentals of hydrogels based on their equilibrium and dynamics of their molecular structure, as well as solute diffusion as it relates to drug delivery. In addition, examples of common microgel synthesis techniques are provided. The ability to tune microscale hydrogels to obtain controlled release of therapeutics is discussed, along with microgel considerations for cell encapsulation as it relates to the development of cell-based therapies. We conclude with an outlook on the use of microgels for cell sequencing, and the convergence of the use of microscale hydrogels for drug delivery, cell therapy, and cell sequencing based systems.
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http://dx.doi.org/10.1007/s10544-019-0358-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6615733PMC
March 2019

110 Anniversary: Nanoparticle mediated drug delivery for the treatment of Alzheimer's disease: Crossing the blood-brain barrier.

Ind Eng Chem Res 2019 23;58(33):15079-15087. Epub 2019 Jul 23.

Institute for Biomaterials, Drug Delivery, and Regenerative Medicine, The University of Texas at Austin, Austin, TX, 78712, United States.

Alzheimer's disease is an irreversible neurodegenerative disorder affecting approximately 6 million Americans, 90% of which are over the age of 65. The hallmarks of the disease are represented by amyloid plaques and neurofibrillary tangles. While the neuronal characteristics of Alzheimer's disease are well known, current treatments only provide temporary relief of the disease symptoms. Many of the approved therapeutic agents for the management of cognitive impairments associated with the disease are based on neurotransmitter or enzyme modulation. However, development of new treatment strategies is limited due to failures associated with poor drug solubility, low bioavailability, and the inability to overcome obstacles present along the drug delivery route. In addition, treatment technologies must overcome the challenges presented by the blood-brain barrier. This complex and highly regulated barrier surveys the biochemical, physicochemical, and structural features of nearby molecules at the periphery, only permitting passage of select molecules into the brain. To increase drug efficacy to the brain, many nanotechnology-based platforms have been developed. These methods for assisted drug delivery employ sophisticated design strategies and offer serveral advantages over traditional methods. For example, nanoparticles are generally low-cost technologies, which can be used for non-invasive administrations, and formulations are highly tunable to increase drug loading, targeting, and release efficacy. These nanoscale systems can facilitate passage of drugs through the blood-brain barrier, thus improving the bioavailability, pharmacokinetics, and pharmacodynamics of therapeutic agents. Examples of such nanocarriers which are discussed herein include polymeric nanoparticles, dendrimers, and lipid-based nanoparticles.
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http://dx.doi.org/10.1021/acs.iecr.9b02196DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7518412PMC
July 2019

Label-Free Detection of Tear Biomarkers Using Hydrogel-Coated Gold Nanoshells in a Localized Surface Plasmon Resonance-Based Biosensor.

ACS Nano 2018 09 14;12(9):9342-9354. Epub 2018 Sep 14.

The dependence of the localized surface plasmon resonance (LSPR) of noble-metal nanomaterials on refractive index makes LSPR a useful, label-free signal transduction strategy for biosensing. In particular, by decorating gold nanomaterials with molecular recognition agents, analytes of interest can be trapped near the surface, resulting in an increased refractive index surrounding the nanomaterial, and, consequently, a red shift in the LSPR wavelength. Ionic poly( N-isopropylacrylamide- co-methacrylic acid) (PNM) hydrogels were used as protein receptors because PNM nanogels exhibit a large increase in refractive index upon protein binding. Specifically, PNM hydrogels were synthesized on the surface of silica gold nanoshells (AuNSs). This composite material ([email protected]) was used to detect changes in the concentration of two protein biomarkers of chronic dry eye: lysozyme and lactoferrin. Both of these proteins have high isoelectric points, resulting in electrostatic attraction between the negatively charged PNM hydrogels and positively charged proteins. Upon binding lysozyme or lactoferrin, [email protected] exhibits large, concentration-dependent red shifts in LSPR wavelength, which enabled the detection of clinically relevant concentration changes of both biomarkers in human tears. The LSPR-based biosensor described herein has potential utility as an affordable screening tool for chronic dry eye and associated conditions.
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http://dx.doi.org/10.1021/acsnano.8b04348DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6156935PMC
September 2018

Vision for Functionally Decorated and Molecularly Imprinted Polymers in Regenerative Engineering.

Regen Eng Transl Med 2017 Sep 20;3(3):166-175. Epub 2017 Mar 20.

University of Texas at Austin, Austin, TX 78712, USA.

The emerging field of regenerative engineering offers a great challenge and an even greater opportunity for materials scientists and engineers. How can we develop materials that are highly porous to permit cellular infiltration, yet possess sufficient mechanical integrity to mimic native tissues? How can we retain and deliver bioactive molecules to drive cell organization, proliferation, and differentiation in a predictable manner? In the following perspective, we highlight recent studies that have demonstrated the vital importance of each of these questions, as well as many others pertaining to scaffold development. We posit hybrid materials synthesized by molecular decoration and molecular imprinting as intelligent biomaterials for regenerative engineering applications. These materials have potential to present cell adhesion molecules and soluble growth factors with fine-tuned spatial and temporal control, in response to both cell-driven and external triggers. Future studies in this area will address a pertinent clinical need, expand the existing repertoire of medical materials, and improve the field's understanding of how cells and materials respond to one another.
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http://dx.doi.org/10.1007/s40883-017-0028-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6426136PMC
September 2017

Charged poly(N-isopropylacrylamide) nanogels for use as differential protein receptors in a turbidimetric sensor array.

Analyst 2017 Aug;142(17):3183-3193

Institute for Biomaterials, Drug Delivery, and Regenerative Medicine, USA.

Due to the high cost and environmental instability of antibodies, there is precedent for developing synthetic molecular recognition agents for use in diagnostic sensors. While these materials typically have lower specificity than antibodies, their cross-reactivity makes them excellent candidates for use in differential sensing routines. In the current work, we design a set of charge-containing poly(N-isopropylacrylamide) (PNIPAM) nanogels for use as differential protein receptors in a turbidimetric sensor array. Specifically, NIPAM was copolymerized with methacrylic acid and modified via carbodiimide coupling to introduce sulfate, guanidinium, secondary amine, or primary amine groups. Modification of the ionizable groups in the network changed the physicochemical and protein binding properties of the nanogels. For high affinity protein-polymer interactions, turbidity of the nanogel solution increased, while for low affinity interactions minimal change in turbidity was observed. Thus, relative turbidity was used as input for multivariate analysis. Turbidimetric assays were performed in two buffers of different pH (i.e., 7.4 and 5.5), but comparable ionic strength, in order to improve differentiation. Using both buffers, it was possible to achieve 100% classification accuracy of eleven model protein biomarkers with as few as two of the nanogel receptors. Additionally, it was possible to detect changes in lysozyme concentration in a simulated tear fluid using the turbidimetric sensor array.
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http://dx.doi.org/10.1039/c7an00787fDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5570555PMC
August 2017

Molecularly Imprinted Intelligent Scaffolds for Tissue Engineering Applications.

Tissue Eng Part B Rev 2017 02 31;23(1):27-43. Epub 2016 Aug 31.

4 Department of Biomedical Engineering, The University of Texas at Austin , Austin, Texas.

The development of molecularly imprinted polymers (MIPs) using biocompatible production methods enables the possibility to further exploit this technology for biomedical applications. Tissue engineering (TE) approaches use the knowledge of the wound healing process to design scaffolds capable of modulating cell behavior and promote tissue regeneration. Biomacromolecules bear great interest for TE, together with the established recognition of the extracellular matrix, as an important source of signals to cells, both promoting cell-cell and cell-matrix interactions during the healing process. This review focuses on exploring the potential of protein molecular imprinting to create bioactive scaffolds with molecular recognition for TE applications based on the most recent approaches in the field of molecular imprinting of macromolecules. Considerations regarding essential components of molecular imprinting technology will be addressed for TE purposes. Molecular imprinting of biocompatible hydrogels, namely based on natural polymers, is also reviewed here. Hydrogel scaffolds with molecular memory show great promise for regenerative therapies. The first molecular imprinting studies analyzing cell adhesion report promising results with potential applications for cell culture systems, or biomaterials for implantation with the capability for cell recruitment by selectively adsorbing desired molecules.
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http://dx.doi.org/10.1089/ten.TEB.2016.0202DOI Listing
February 2017

Adult Human Mesenchymal Stem Cell Differentiation at the Cell Population and Single-Cell Levels Under Alternating Electric Current.

Tissue Eng Part C Methods 2016 02 28;22(2):155-164. Epub 2015 Dec 28.

1 Department of Biomedical Engineering, The University of Texas at San Antonio , San Antonio, Texas.

Mesenchymal stem cells, precursors that can differentiate into osteoblasts, chondrocytes, and adipocytes, have tremendous potential for derivation of cells with specific (e.g., osteogenic) phenotypes for tissue engineering and tissue regeneration applications. To date, the predominant strategy to achieve directed differentiation of MSCs into osteoblasts was to recapitulate the normal developmental ontogeny of osteoblasts using growth factors (e.g., bone morphogenetic proteins). In contrast, the effects of biophysical stimuli alone on such outcomes remain, at best, partially understood. This in vitro study examined and optimized the effects of alternating electric current alone on the differentiation of adult human mesenchymal stem cells (hMSCs) at the cell population and single-cell levels. hMSCs, cultured on flat, indium-tin-oxide-coated glass in the absence of supplemented exogenous growth factors were exposed to alternating electric current (5-40 μA, 5-10 Hz frequency, sinusoidal waveform), for 1-24 h daily for up to 21 consecutive days. Compared to results obtained from the respective controls, hMSC populations exposed to the alternating electric current alone (in the absence of exogenous growth factors) expressed genes at various stages of differentiation (specifically, TAZ, Runx-2, Osterix, Osteopontin, and Osteocalcin). Optimal osteogenic differentiation was achieved when hMSCs were exposed to a 10 μA, 10 Hz alternating electric current for 6 h daily for up to 21 days. Exclusive osteodifferentiation was observed since genes for the chondrocyte (Collagen Type II) and adipocyte (FABP-4) lineages were not expressed under all conditions of the biophysical stimulus tested. Single cell mRNAs for 45 genes (indicative of hMSC differentiation) were monitored using Fluidigm Systems. Homogeneous expression of the early osteodifferentiation genes (specifically, TAZ and Runx-2) was observed in hMSCs exposed to the alternating electric current at 7 and 21 days. Heterogeneity for all other genes monitored was observed in hMSCs exposed to alternating electric current and in their respective controls. These results provide the first glimpse of gene expression in differentiating hMSCs at the cell population and single-cell levels and represent novel approaches for stem cell differentiation pertinent to new tissue formation.
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http://dx.doi.org/10.1089/ten.TEC.2015.0324DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4744881PMC
February 2016

Electrochemically Preadsorbed Collagen Promotes Adult Human Mesenchymal Stem Cell Adhesion.

Tissue Eng Part C Methods 2016 Jan 15;22(1):69-75. Epub 2015 Dec 15.

1 Department of Chemistry, Clemson University , Clemson, South Carolina.

The present article reports on the effect of electric potential on the adsorption of collagen type I (the most abundant component of the organic phase of bone) onto optically transparent carbon electrodes (OTCE) and its mediation on subsequent adhesion of adult, human, mesenchymal stem cells (hMSCs). For this purpose, adsorption of collagen type I was investigated as a function of the protein concentration (0.01, 0.1, and 0.25 mg/mL) and applied potential (open circuit potential [OCP; control], +400, +800, and +1500 mV). The resulting substrate surfaces were characterized using spectroscopic ellipsometry, atomic force microscopy, and cyclic voltammetry. Adsorption of collagen type I onto OTCE was affected by the potential applied to the sorbent surface and the concentration of protein. The higher the applied potential and protein concentration, the higher the adsorbed amount (Γcollagen). It was also observed that the application of potential values higher than +800 mV resulted in the oxidation of the adsorbed protein. Subsequent adhesion of hMSCs on the OTCEs (precoated with the collagen type I films) under standard cell culture conditions for 2 h was affected by the extent of collagen preadsorbed onto the OTCE substrates. Specifically, enhanced hMSCs adhesion was observed when the Γcollagen was the highest. When the collagen type I was oxidized (under applied potential equal to +1500 mV), however, hMSCs adhesion was decreased. These results provide the first correlation between the effects of electric potential on protein adsorption and subsequent modulation of anchorage-dependent cell adhesion.
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http://dx.doi.org/10.1089/ten.TEC.2015.0315DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4722606PMC
January 2016
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