Conductive gelatin methacrylate-poly(aniline) hydrogel for cell encapsulation

Abstract

New conductive hydrogels with superior biocompatibility continue to be developed in order to serve as bioactive scaffolds capable of modulating cellular functionality for tissue engineering applications. We developed an electrically conductive gelatin methacrylate-poly(aniline) (GelMA-PANi) hydrogel that is permissive of matrix mineralization by encapsulated osteoblast-like cells. Incorporation of PANi clusters within the GelMA matrix increases the electro-conductivity of the composite gel, while maintaining the osteoid-like soft mechanical properties that allows three-dimensional encapsulation of living cells. Viability of human osteogenic cells encapsulated within GelMA-PANi hydrogels was similar to that of GelMA. Cells within GelMA-PANi also demonstrated the capability of depositing mineral within the hydrogel matrix after being chemically induced for two weeks, although the total mineral content was lower as compared to GelMA. Additionally, we demonstrated that the GelMA-PANi-composite hydrogel could be printed in complex, user-defined geometries using digital projection stereolithography.

Perfusion-based co-culture model system for bone tissue engineering

“…The addition of HUVECS alongside the Saos-2 cells in the bulk matrix resulted in the deposition of mineral within the center of our constructs between the two perfusable channels. Previous studies with Saos-2 cells encapsulated within GelMA hydrogels have shown that there is a diffusion limitation at the center of the hydrogel that inhibits mineral deposition [ 58 , 59 ]. This previously observed inhibition is reinforced by observation of in vivo tissue architecture that shows most cells reside within 100–200 μm of a nutrient supply, which allows for normal physiologic function [ 15 , 60 ].…”

Measuring Changes in Electrical Impedance During Cell-Mediated Mineralization

“…GelMA, a denatured form of collagen, was chosen as model hydrogel due to its widespread use in the field and due to established synthesis, fabrication, and material characterization techniques. 12,35,36 Saos-2, an osteoblast-like cell line, was chosen as it is a widely used cell line that deposits mineral within hydrogel matrix when chemically stimulated, mimicking the process of mineral deposition occurring in vivo. 9,12,35 Bright-field images taken on day 7 showed that the initial deposition of mineral resulted in the formation of isolated aggregates that merged and formed a continuous and partially connected unit with increasing culture durations (days 14, 21, and 28).…”

“…12,35,36 Saos-2, an osteoblast-like cell line, was chosen as it is a widely used cell line that deposits mineral within hydrogel matrix when chemically stimulated, mimicking the process of mineral deposition occurring in vivo. 9,12,35 Bright-field images taken on day 7 showed that the initial deposition of mineral resulted in the formation of isolated aggregates that merged and formed a continuous and partially connected unit with increasing culture durations (days 14, 21, and 28). This provides an explanation of why mineralized constructs on day 7 had compressive moduli closer to the day 1 constructs, as isolated mineral deposits randomly within the GelMA matrix were unable to provide additional resistance against compressive loading.…”

“…A custom-made impedance testing chip was designed and developed. 35,36 The measurement chip was configured with planar electrodes that are adhered to an FR-4 fiberglass printed circuit board substrate. The chip electrodes were constructed of etched copper 17 lm thick, and subsequently plated with nickel and gold on the surface.…”

Generation of cell-laden hydrogel microspheres using 3D printing-enabled microfluidics

“…20,21 Furthermore, GelMA is capable of being UV crosslinked with minimal negative side effects to the encapsulated cells and their properties have shown consistency between batches. 5,[24][25][26][27] B. Optimization of process parameters…”