Tetronic^®-based composite hydrogel scaffolds seeded with rat bladder smooth muscle cells for urinary bladder tissue engineering applications

Abstract

Natural hydrogels such as collagen offer desirable properties for tissue engineering, including cell adhesion sites, but their low mechanical strength is not suitable for bladder tissue regeneration. In contrast, synthetic hydrogels such as poly (ethylene glycol) allow tuning of mechanical properties, but do not elicit protein adsorption or cell adhesion. For this reason, we explored the use of composite hydrogel blends composed of Tetronic (BASF) 1107-acrylate (T1107A) in combination with extracellular matrix moieties collagen and hyaluronic acid seeded with bladder smooth muscle cells (BSMC). This composite hydrogel supported BSMC growth and distribution throughout the construct. When compared to the control (acellular) hydrogels, mechanical properties (peak stress, peak strain, and elastic modulus) of the cellular hydrogels were significantly greater. When compared to the 7-day time point after BSMC seeding, results of mechanical testing at the 14-day time point indicated a significant increase in both ultimate tensile stress (4.1–11.6 kPa) and elastic modulus (11.8–42.7 kPa) in cellular hydrogels. The time-dependent improvement in stiffness and strength of the cellular constructs can be attributed to the continuous collagen deposition and reconstruction by BSMC seeded in the matrix. The composite hydrogel provided a biocompatible scaffold for BSMC to thrive and strengthen the matrix; further, this trend could lead to strengthening the construct to match the mechanical properties of the bladder.

Keywords:

• composite hydrogel
• bladder smooth muscle cell
• collagen synthesis
• Tetronic 1107 Acrylate
• tissue engineering

Acknowledgments

The authors thank Dr Terri Bruce of the Clemson light imaging facility (CLIF) for assistance with confocal microscopy, and Dr Ken Webb and Mr Atanu Sen for assistance with T1107 acrylation. The authors wish to thank Porvair plc (Norfolk, UK) for donating the Bio-Vyon used in the present study. The funding for this research was provided by NIH COBRE Grant # 8P20GM103444.

Additional information

Funding

This work was supported by the NIH COBRE under 8P20GM103444.