The Chen lab specializes in developing new methods for computer-assisted, light-based 3D nanopatterning of hydrogels for tissue engineering. Such patterning methods enable precise control over the arrangement of component cell types and physical properties. This precise control allows the Chen group to examine the interactions of stem cells with a range of nanoarchitectures; their long-term goal is to develop clinically translatable biomimetic scaffolds.
A recent key advance by the Chen lab was the introduction of dynamic optical projection stereolithography (DOPsL), which allows rapid fabrication of complex structures because it manipulates images using a million pixels rather than one focused point. This advantage makes it more suitable than other emerging nanofabrication technologies, e.g. scanning electron-beam lithography and focused ion-beam lithography, for manufacturing large structured hydrogels. The group has shown that this method is capable of producing a variety of microwell structures and complex vasculature (see image below); the ease of varying these structures could enable high-throughput screening to identify hydrogel architectures that maximize desired cellular behaviors.
The Chen group has also introduced a digital method of manufacturing biomaterial hydrogels with deformational responses to stretching (Poisson’s ratios) that mimic those of specific tissues. Specifically, they have produced hydrogels that do not deform in the axial direction upon stretching (Poisson’s ratio of zero) and that expand axially upon stretching (negative Poisson’s). Non-deformation upon stretching is typical of many tissues, including brain, cartilage, and ligaments, while axial expansion occurs in arterial endothelium; accurately modeling this physical property could be crucial for engineering functional tissue replacements or inducing efficient differentiation of stem cells into desired cell types. Towards clinical translation of these methods, Chen’s team is collaborating with stem cell biologists and liver physiologists to develop a 3D bioprinted liver-on-a-chip. Their expertise in the creation of precise 3D nanoarchitectures will allow them to create a construct that closely matches normal human liver. Encapsulation of pre-differentiated iPSCs from patients with liver disorders into these constructs could lead to a more accurate system for drug screening.
Gou M, Qu X, Zhu W, Xiang M, Yang J, Zhang K, Wei Y, Chen S. Bio-inspired detoxification using 3D-printed hydrogel nanocomposites. Nat Commun 2014;5:3774.
Hribar KC, Soman P, Warner J, Chung P, Chen S. Light-assisted direct-write of 3D functional biomaterials. Lab Chip 2014; 14(2): 268-75.
AP Zhang, X Qu, P Soman, KC Hribar, JW Lee, S Chen, S He. Rapid fabrication of complex 3D extracellular microenvironments by dynamic optical projection stereolithography. Adv Mater 2012; 24 (31): 4266-70.