(217ek) 3D Scaffolds With Inverted Colloidal Crystal Geometry From Expandable Cationic Poly(DMAA-co-AMTAC) Hydrogel for Well-Plate Format

Bahng, J. H. - Presenter, University of Michigan
Yeom, B., University of Michigan
Kotov, N., University of Michigan

Importance of cell studies in 3D culture evidenced in academics as well as in industries lead to significant growth in the development of 3D tissue culture scaffolds. Amongst the varieties, hydrogel have been one of the most popular choices as scaffolding material due to its chemical versatility as well as its mechanical similarity to living tissues. In this study, we introduce a positively charged polyelectrolyte hydrogel scaffold for tissue culture. The hydrogel is made by free radical copolymerization of N,N-Dimethylacrylamide (DMAA) and (3-Acrylamidopropyl)-trimethylammonium chloride (AMTAC) chemically cross-linked by N,N-Methylenebisacrylamide (NMBA) for the manufacture of scaffolds with inverted colloidal crystal (ICC) geometry. The poly(DMAA-co-AMTAC) was found biocompatible through cell studies and its chemical properties demonstrated following features: (1) cationic nature promoted cell-adhesive interface between various tissue types, (2) high transparency allowed for optical-based evaluation protocols, (3) homogenous gel formation avoided lot-to-lot variability . As a 3D tissue support scaffold, the ICC poly(DMAA-co-AMTAC) demonstrated numerous advantages due to its unique topology:  unique manufacturing process rendered (i) simplicity in its manufacture, (ii) highly-ordered array structure (iii) high porosity allowing efficient nutrient delivery and metabolite diffusion, (iv) facile cell inoculation of adherent cell types, (v) structural resemblance of several in vivo organs. Combination of benefits and consistencies in material properties and geometrical features enabled standardization to our 3D ICC scaffold, which is critical in the experimental reproducibility. Moreover, the poly(DMAA-co-AMTAC) hydrogel was found to undergo volume transition where the degree of the swelling was dependent on the contents of the cross-linking agent, charged monomer, and ionic strength of the external environment. This property was utilized to control the physical dimensions of ICC geometry (cavity size and interconnecting channels) significant for many tasks of ex-vivo tissue engineering and for tight fitting the ICC scaffolds into a well-plate. Along with the standardized feature, easy integration into current infrastructure deployed in the current pharmaceutical industries makes ICC poly(DMAA-co-AMTAC) hydrogel scaffold a practical 3D tissue culture and in vitro early stage assay platform for the future drug discovery and development.