Improving hydrogel properties for better cell survival for transplantation

The free radical formation and resulting oxidative stress formed during cell transplantation can cause cellular damage, leading to prolonged healing times and reduction in efficacy of the implant. Depending on the site of transplantation and its distance from vasculature, cells may experience low oxygen concentrations, which can affect the proliferation and differentiation potential. To improve cell survival and cellular behavior for transplantation, gallic acid (GA) incorporated hyaluronic acid hydrogel (HA-GA) was formulated and its properties were compared to hyaluronic acid (HA) hydrogels without gallic acid (HA-HA). Further, human mesenchymal stem cells (hMSCs) were cultured under hypoxia to observe effect of hypoxia on osteogenic differentiation. The results obtained during this study suggest that HA-GA gels showed improved adhesive and antioxidant properties as compared to HA-HA gels. Both gels showed high elastic property during rheological studies and could maintain viability of hMSCs for 21 days of culture. Moreover, HA-GA gels also possessed immunomodulatory properties, and might reduce inflammation and damaging immune response at the transplantation site. Thus, the incorporation of gallic acid moieties into HA gels could be a viable strategy to combat oxidative stress encountered during transplantation procedures, while improving adhesiveness to the target tissue, thus reducing wound healing time and promoting better quality of healing. This may especially be useful for individuals with reduced wound healing capacity, for example, diabetic individuals. Hydrogels can increase the osteogenic differentiation potential of hMSCs and as such could be applied as transplants for treating bony injury. Furthermore, the application of hypoxic conditions to MSC cell culture may improve cell viability and cell number upon transplantation, which may help to overcome limitations of low cell numbers currently restricting tissue engineering applications and promote understanding and development of functional tissue constructs. En masse, the results obtained during the study could lead towards improvement of cellular behavior and survival in hydrogels for cell transplantatio

Improving hydrogel properties for better cell survival for transplantation

The free radical formation and resulting oxidative stress formed during cell transplantation can cause cellular damage, leading to prolonged healing times and reduction in efficacy of the implant. Depending on the site of transplantation and its distance from vasculature, cells may experience low oxygen concentrations, which can affect the proliferation and differentiation potential. To improve cell survival and cellular behavior for transplantation, gallic acid (GA) incorporated hyaluronic acid hydrogel (HA-GA) was formulated and its properties were compared to hyaluronic acid (HA) hydrogels without gallic acid (HA-HA). Further, human mesenchymal stem cells (hMSCs) were cultured under hypoxia to observe effect of hypoxia on osteogenic differentiation. The results obtained during this study suggest that HA-GA gels showed improved adhesive and antioxidant properties as compared to HA-HA gels. Both gels showed high elastic property during rheological studies and could maintain viability of hMSCs for 21 days of culture. Moreover, HA-GA gels also possessed immunomodulatory properties, and might reduce inflammation and damaging immune response at the transplantation site. Thus, the incorporation of gallic acid moieties into HA gels could be a viable strategy to combat oxidative stress encountered during transplantation procedures, while improving adhesiveness to the target tissue, thus reducing wound healing time and promoting better quality of healing. This may especially be useful for individuals with reduced wound healing capacity, for example, diabetic individuals. Hydrogels can increase the osteogenic differentiation potential of hMSCs and as such could be applied as transplants for treating bony injury. Furthermore, the application of hypoxic conditions to MSC cell culture may improve cell viability and cell number upon transplantation, which may help to overcome limitations of low cell numbers currently restricting tissue engineering applications and promote understanding and development of functional tissue constructs. En masse, the results obtained during the study could lead towards improvement of cellular behavior and survival in hydrogels for cell transplantatio

Polystyrene Pocket Lithography - Sculpting Plastic with Light

Tissue culture ware polystyrene is the gold standard for in vitro cell culture. While microengineering techniques can create advanced cell microenvironments in polystyrene, they require specialized equipment and reagents, which hinder their accessibility for most biological researchers. We developed and validated an economical and easily accessible method for fabricating microstructures directly in polystyrene with sizes approaching subcellular dimensions while requiring minimal processing time. The process involves deep ultraviolet irradiation through a shadow mask or ink pattern using inexpensive, handheld devices followed by selective chemical development with common reagents to generate micropatterns with depths/heights between 5-10 μm, which can be used to guide cell behavior. The remarkable straightforwardness of the process enables this class of microengineering techniques to be broadly accessible to diverse research communities. This article is protected by copyright. All rights reserved

Direct deep UV lithography to micropattern PMMA for stem cell culture

Microengineering is increasingly being used for controlling the microenvironment of stem cells. Here, a novel method for fabricating structures with subcellular dimensions in commonly available thermoplastic poly(methyl methacrylate) (PMMA) is shown. Microstructures are produced in PMMA substrates using Deep Ultraviolet lithography, and the effect of different developers is described. Microgrooves fabricated in PMMA are used for the neuronal differentiation of mouse embryonic stem cells (mESCs) directly on the polymer. The fabrication of 3D, curvilinear patterned surfaces is also highlighted. A 3D multilayered microfluidic chip is fabricated using this method, which includes a porous polycarbonate (PC) membrane as cell culture substrate. Besides directly manufacturing PMMA-based microfluidic devices, an application of the novel approach is shown where a reusable PMMA master is created for replicating microstructures with polydimethylsiloxane (PDMS). As an application example, microchannels fabricated in PDMS are used to selectively expose mESCs to soluble factors in a localized manner. The described microfabrication process offers a remarkably simple method to fabricate for example multifunctional topographical or microfluidic culture substrates outside cleanrooms, thereby using inexpensive and widely accessible equipment. The versatility of the underlying process could find various applications also in optical systems and surface modification of biomedical implants