Three dimensional live cell lithography.

We investigate holographic optical trapping combined with step-and-repeat maskless projection stereolithography for fine control of 3D position of living cells within a 3D microstructured hydrogel. C2C12 myoblast cells were chosen as a demonstration platform since their development into multinucleated myotubes requires linear arrangements of myoblasts. C2C12 cells are positioned in the monomer solution with multiple optical traps at 1064 nm and then encapsulated by photopolymerization of monomer via projection of a 512x512 spatial light modulator illuminated at 405 nm. High 405 nm sensitivity and complete insensitivity to 1064 nm was enabled by a lithium acylphosphinate (LAP) salt photoinitiator. These wavelengths, in addition to brightfield imaging with a white light LED, could be simultaneously focused by a single oil immersion objective. Large lateral dimensions of the patterned gel/cell structure are achieved by x and y step-and-repeat process. Large thickness is achieved through multi-layer stereolithography, allowing fabrication of precisely-arranged 3D live cell scaffolds with micron-scale structure and millimeter dimensions. Cells are shown to retain viability after the trapping and encapsulation procedure.

Team Red, White & Blue: a community-based model for harnessing positive social networks to enhance enrichment outcomes in military veterans reintegrating to civilian life.

Military service assimilates individuals into a socially cohesive force to address dangerous and traumatic situations that have no counterpart in civilian life. Upon leaving active duty, many veterans experience a "reverse culture shock" when trying to reintegrate into civilian institutions and cultivate supportive social networks. Poor social reintegration is associated with greater morbidity and premature mortality in part due to adoption of risky health behaviors, social isolation, and inadequate engagement in health care services. Although institutions like the Veterans Health Administration (VA) do much to address the complex psychosocial and health care needs of veterans and their families with evidence-based care, only 61% of Operations Enduring and Iraqi Freedom (OEF/OIF) Veterans are enrolled in VA care and there are numerous perceived barriers to care for enrollees. To address this gap, a community-based nonprofit organization, Team Red, White & Blue (RWB), was created to help veterans establish health-enriching social connections with communities through the consistent provision of inclusive and locally tailored physical, social, and service activities. This article provides an overview of the development and refinement of a theory-based framework for veteran health called the Enrichment Equation, comprised of three core constructs: health, people, and purpose. By operationalizing programming activities and roles, we describe how theoretical components were translated into a social networking implementation package that enabled rapid national spread of Team RWB. We conclude with future opportunities to partner with researchers and other organizations to understand program impact, and to identify effective intervention components that could be adapted for similar vulnerable groups.

Capillary-like network formation by human amniotic fluid-derived stem cells within fibrin/poly(ethylene glycol) hydrogels.

A major limitation in tissue engineering strategies for congenital birth defects is the inability to provide a significant source of oxygen, nutrient, and waste transport in an avascular scaffold. Successful vascularization requires a reliable method to generate vascular cells and a scaffold capable of supporting vessel formation. The broad potential for differentiation, high proliferation rates, and autologous availability for neonatal surgeries make amniotic fluid-derived stem cells (AFSC) well suited for regenerative medicine strategies. AFSC-derived endothelial cells (AFSC-EC) express key proteins and functional phenotypes associated with endothelial cells. Fibrin-based hydrogels were shown to stimulate AFSC-derived network formation in vitro but were limited by rapid degradation. Incorporation of poly(ethylene glycol) (PEG) provided mechanical stability (65%±9% weight retention vs. 0% for fibrin-only at day 14) while retaining key benefits of fibrin-based scaffolds-quick formation (10±3 s), biocompatibility (88%±5% viability), and vasculogenic stimulation. To determine the feasibility of AFSC-derived microvasculature, we compared AFSC-EC as a vascular cell source and AFSC as a perivascular cell source to established sources of these cell types-human umbilical vein endothelial cells (HUVEC) and mesenchymal stem cells (MSC), respectively. Cocultures were seeded at a 4:1 endothelial-to-perivascular cell ratio, and gels were incubated at 37°C for 2 weeks. Mechanical testing was performed using a stress-controlled rheometer (G'=95±10 Pa), and cell-seeded hydrogels were assessed based on morphology. Network formation was analyzed based on key parameters such as vessel thickness, length, and area, as well as the degree of branching. There was no statistical difference between individual cultures of AFSC-EC and HUVEC in regard to these parameters, suggesting the vasculogenic potential of AFSC-EC; however, the development of robust vessels required the presence of both an endothelial and a perivascular cell source and was seen in AFSC cocultures (70%±20% vessel length, 90%±10% vessel area, and 105%±10% vessel thickness compared to HUVEC/MSC). At a fixed seeding density, the coculture of AFSC with AFSC-EC resulted in a synergistic effect on network parameters similar to MSC (150% vessel length, 147% vessel area, 150% vessel thickness, and 155% branching). These results suggest that AFSC-EC and AFSC have significant vasculogenic and perivasculogenic potential, respectively, and are suited for in vivo evaluation.