Rapid prototyping of three-dimensional nanocomposite hydrogel constructs: Effect of silica nanofiller on swelling and solute release behaviors of the nanocomposite hydrogels

Abstract

Three-dimensional (3D) patterning and engineering of biomaterials and biointerfaces have helped bioengineers harness the full potential of cell immobilization for different biomedical applications. However, the bioengineering of an efficient cell immobilized tool, having application in cell biology and tissue engineering, often comes into realization only when a cell friendly immobilization technique is combined with a compatible 3D patterning scheme. We have previously demonstrated the successful blue light induced photopolymerization of poly (ethyleneglycol) diacrylate (PEGDA) based hydrogels for the entrapment of Saccharomyces cerevisiae and NIH 3T3 fibroblast cells. In the present work we have modified rheology of the prepolymer solution by mixing fumed silica nanofiller in different concentrations. Here we demonstrate the rapid prototyping of cell immobilized nanocomposite hydrogels, where S. cerevisiae loaded nanofilled prepolymer solution was directly written in layer-by-layer fashion using solid free form fabrication also known as rapid prototyping technique and was cross-linked into 3D cell loaded construct via blue light induced polymerization. The swelling trend was found to be a function of silica nanofiller concentration and transitioned from decreasing to increasing type at 10% w/v nanofiller concentration. Dynamic swelling profile predicted that the swelling agent transported with in the gels via super case II type transport mechanism irrespective of the crosslink density. In contrast, the mode of transportation of the loaded solute was found to be fickian and nonfickian type respectively for loosely and tightly crosslinked gels. Spatial heterogeneity in the crosslinked network was resulted upon blue light curing, subsequently the 3D growth of the immobilized cells was observed to be a function of crosslink density.

Controlling Shear Stress in 3D Bioprinting is a Key Factor to Balance Printing Resolution and Stem Cell Integrity

“…While traditional TE techniques, such as hydrogel casting, involve three key elements—cells, scaffolds, and growth factors—the dispensing process in bioprinting represents a fourth. According to the latter, most bioprinting technologies can be classified into three categories: robotic dispensing, laser‐based bioprinting (e.g., LIFT), and inkjet printing . LIFT and inkjet represent contactless printing techniques where discrete drops are dispensed one‐by‐one.…”

Highly Conductive, Stretchable, and Cell‐Adhesive Hydrogel by Nanoclay Doping

“…This removes the need for ionic liquids or acid treatment as means of inducing percolation in PEDOT:PSS microgels. We conjecture that similar effects on the conductivity of in‐gel polymerized PEDOT can be achieved in other mineral colloid scaffolds, for example, in gels formed by fumed silica particles …”

“…We conjecture that similar effects on the conductivity of in-gel polymerized PEDOT can be achieved in other mineral colloid scaffolds, for example, in gels formed by fumed silica particles. [40] Using PEDOT:Laponite-PAAM and PEDOT-PAAM hydrogels we conduct cyclic voltammetry experiments, where the hydrogel is immersed in phosphate-buffered saline (PBS) and current is forced to flow out of the hydrogel through the electrolyte ( Figure 2D). [41] This scenario simulates use of the material in stimulation electrodes that require reversible charge injection.…”

Hydrogels for Therapeutic Delivery: Current Developments and Future Directions

“…Although the number of publications on 3D printable hydrogels is rapidly increasing, as reviewed elsewhere, ,, research concerning drug and growth factor delivery from these constructs is still very limited. Mishra et al prepared 3D hydrogels via layer-by-layer “writing” of cell-loaded PEG diacrylate prepolymer formulations using blue light induced photopolymerization . Addition of silica fillers in the prepolymer formulation modified its rheological properties and made it easily dispensable for the fabrication of 3D hydrogels.…”

“…Mishra et al prepared 3D hydrogels via layer-by-layer "writing" of cell-loaded PEG diacrylate prepolymer formulations using blue light induced photopolymerization. 101 Addition of silica fillers in the prepolymer formulation modified its rheological properties and made it easily dispensable for the fabrication of 3D hydrogels. The antibiotic tetracycline hydrochloride was incorporated in the 3D constructs by adding it to the prepolymer formulations prior to cross-linking.…”