Ho Nam Chan

Engineering a Freestanding Biomimetic Cardiac Patch Using Biodegradable Poly(lactic‐co‐glycolic acid) (PLGA) and Human Embryonic Stem Cell‐derived Ventricular Cardiomyocytes (hESC‐VCMs)

Microgrooved thin PLGA film (≈30 μm) is successfully fabricated on a Teflon mold, which could be readily peeled off and is used for the construction of a biomimetic cardiac patch. The contraction of it is studied with optical mapping on transmembrane action potential. Our results suggest that steady-state contraction could be easily established on it under regular electrical stimuli. Besides, the biomimetic cardiac patch recapitulates the anisotropic electrophysiological feature of native cardiac tissue and is much more refractory to premature stimuli than the random one constructed with non-grooved PLGA film, as proved by the reduced incidence of arrhythmia. Considering the good biocompatibility of PLGA as demonstrated in our study and the biodegradability of it, our biomimetic cardiac patch may find applications in the treatment of myocardial infarction. Moreover, the Teflon mold could be applied in the fabrication of various scaffolds with fine features for other tissues.

Replicating 3D printed structures into hydrogels

Fabricating complicated three-dimensional (3D) hydrogel structures are important in biological studies. Herein, stereolithographic printed acrylate-based masters with different complicated 3D geometry (e.g. dodecahedron and a trifurcating network) were replicated into alginate and gelatin. Alginate was further used as a sacrificial template to fabricate a perfusable microfluidic network in cell-seeded agarose to sustain the cell viability in a large slab of agarose scaffold. With the replication approach, 3D alginate (a photo-insensitive material) constructs with stereolithographic (a photolithographic technology) grade resolution and structural complexity were fabricated.

Facile formation of a microporous chitosan hydrogel based on self-crosslinking

A facile approach for the formation of microporous (chitosan) hydrogel scaffolds based on self-crosslinking is presented. It is simple and does not require any sacrificial porogen, toxic initiator/catalyst, harmful irradiation, or sophisticated equipment. The pore size, porosity, and mechanical properties of our hydrogels can be readily tuned.