However, all cell types suffered from a massive loss in viability 24 hours after encapsulation and polymerization into 10 wt% PEGDA microgels, indicating cells may have initiated apoptosis upon polymerization due to the intense oxidative stress posted on them during ROS conversion (Fig. and macro- length scales. We found PEGNB provides excellent cellular tolerance and supports long-term cell survival by mitigating the deleterious effects of acrylate photopolymerization, which are exacerbated at diminishing volumes. PEGNB, therefore, is an excellent candidate for hydrogel miniaturization. PEGNB hydrogel properties, however, were found to have variable effects on encapsulating different cell candidates. This study could provide guidance for cell encapsulation practices in tissue engineering and regenerative medicine research. environment, allowing the elucidation of cellular mechanisms in a well-defined, tunable environment[16,17]. (±)-WS75624B Previous attempts have demonstrated the bulk encapsulation of stem cells[18], fibroblasts[19], and pancreatic -cells[20,21] into hydrogel scaffolds for tissue engineering, repair, and regenerative medicine, respectively. Chondrogenesis of stem cells[22], migration and activation of fibroblasts[23], and survival and cytokine secretion of pancreatic -cells[24] have been successfully achieved via dynamic control over hydrogel properties, along with understanding of fundamental cell-cell or cell-matrix interactions. Although bulk cell encapsulation and subsequent implantation has shown promising clinical outcomes[25,26], bulk gels are limited by relatively low diffusivity[27] and a lack of control over individual cell behavior and response to encapsulation, which can result in wide and unpredictable experimental variability. Moreover, the screening and identification of improved matrix formulations is hindered by low experimental throughput and analysis in bulk gels. The clinical and translational potential (±)-WS75624B for bulk gels is also limited by the need to surgically implant large, cellularized hydrogels. Accordingly, forming injectable hydrogels have been widely studied[28,29]. The miniaturization of bulk hydrogel scaffolds into microscale injectable cell carriers has also been more recently demonstrated in combination with a variety of approaches to overcome design constraints inherent to bulk hydrogels[30,31]. These efforts, including liquid bridging[32], stop flow lithography[33], and bioprinting [34,35], have successfully reduced the physical size of individual hydrogels, and therefore decreased diffusion lengths. By coupling these fabrication methods with custom materials chemistry, the functionality of the microgels may be engineered, as with programmed degradation[33,36], directed microgel assembly[37], or controlled cell interactions[38,39] for studies. The production and collection of microgels by these techniques, however, is considerably constrained by the fabrication approach, which dramatically hinders their translational potential. To increase injectable microgel fabrication throughput, while retaining precise control over microgel size and shape, microfluidic-based droplet forming RB1 techniques have introduced the capability to produce monodisperse cell-laden hydrogel-forming droplets at kHz rates[40-45]. Combined with inertial focusing for precise control over intervals between cells[46-48], microfluidic droplet platforms have enabled high throughput single cell encapsulation and subsequent molecular analysis, such as screening and sorting[49-51]. These techniques provide new high throughput methods to explore the heterogeneity of encapsulated cell populations, and thus understand the complex regulatory pathways contributing to the functionality of tissues[52,53]. Post-encapsulation cell viability has been considered (±)-WS75624B as a critical factor allowing for either cell studies, or functional tests. Previous attempts to encapsulate cells into microgels have produced high initial viability, however a dramatic decrease in viability is typically seen over longer time periods[54,55]. Previous studies have considered encapsulation procedures and materials chemistry independently and have determined that (±)-WS75624B microfluidic handling and encapsulation are cell friendly, thus identifying materials chemistry as the primary factor determining postencapsulation viability. As such, polymer and hydrogel chemistry must be further investigated to understand its role in optimizing live cell encapsulation, supporting long-term high cell viability, and providing a salubrious environment for cell growth and tissue elaboration. Pioneering work has demonstrated cell microencapsulation using.