Effects of Gelatin Methacrylate Bio-ink Concentration on Mechano-Physical Properties and Human Dermal Fibroblast Behavior.

Ming-You Shie,Yi-Wen Chen,Hooi Yee Ng,Ssu-Yin Yen,Chia-Che Ho,Jian-Jr Lee

doi:10.3390/polym12091930

Abstract

Gelatin-methacryloyl (GelMa) is a very versatile biomaterial widely used in various biomedical applications. The addition of methacryloyl makes it possible to have hydrogels with varying mechanical properties due to its photocuring characteristics. In addition, gelatin is obtained and derived from natural material; thus, it retains various cell-friendly motifs, such as arginine-glycine-aspartic acid, which then provides implanted cells with a friendly environment for proliferation and differentiation. In this study, we fabricated human dermal fibroblast cell (hDF)-laden photocurable GelMa hydrogels with varying physical properties (5%, 10%, and 15%) and assessed them for cellular responses and behavior, including cell spreading, proliferation, and the degree of extracellular matrix remodeling. Under similar photocuring conditions, lower concentrations of GelMa hydrogels had lower mechanical properties than higher concentrations. Furthermore, other properties, such as swelling and degradation, were compared in this study. In addition, our findings revealed that there were increased remodeling and proliferation markers in the 5% GelMa group, which had lower mechanical properties. However, it was important to note that cellular viabilities were not affected by the stiffness of the hydrogels. With this result in mind, we attempted to fabricate 5–15% GelMa scaffolds (20 × 20 × 3 mm3) to assess their feasibility for use in skin regeneration applications. The results showed that both 10% and 15% GelMa scaffolds could be fabricated easily at room temperature by adjusting several parameters, such as printing speed and extrusion pressure. However, since the sol-gel temperature of 5% GelMa was noted to be lower than its counterparts, 5% GelMa scaffolds had to be printed at low temperatures. In conclusion, GelMa once again was shown to be an ideal biomaterial for various tissue engineering applications due to its versatile mechanical and biological properties. This study showed the feasibility of GelMa in skin tissue engineering and its potential as an alternative for skin transplants.

Highlights

Burn injuries are one of the most common types of cutaneous wounds in the world
Gelatin has a polypeptide backbone with multiple available functional groups, such as amino, hydroxyl, and carboxyl groups, which can serve as grafting sites for additional molecules (Figure 1A)
GelMa is synthesized via modification with a methacryloyl group (Ma), and the degree of methacrylation can be adjusted using different ratios of gelatin to MA to produce scaffolds with different mechanical properties

Summary

Introduction

Burn injuries are one of the most common types of cutaneous wounds in the world. Wounds typically first undergo re-epithelization before dermis regeneration. For patients with burn injuries, sufficient re-epithelization enhances tissue regeneration, but it acts as a barrier to prevent soft tissue infections and moisture loss. The current gold standard for the repair of burn injuries is in good agreement with the above-mentioned rule. Covering a burn wound with autologous skin grafts harvested from a non-injured site is the currently accepted standard for burn injuries. Various types of tissue-engineered scaffolds have been developed since the past decade, and there are currently several skin substitute products on the market [2]

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