Cell-sized mold makes gelatin gels (jelly) 10 times stiffer

Micro-sized gels are indispensable for biomedical, cosmetic and food materials. Researchers therefore seek to control the mechanical properties of a single microgel for application usages. Here, it was shown that space sizes for gelation change mechanical properties of gelatin gels. Detailed analysis in the microgel structure revealed that changes in secondary structures of gelatin protein induced the increase of elasticity. These findings shed light on the ability of space-size as a controller of mechanical properties of gels.

The strength and stability of single microgels are important for controlling functions. However, their mechanical properties are not well understood. Miho Yanagisawa and Atsushi Sakai at Tokyo University of Agriculture and Technology and their colleagues succeeded in measuring the elasticity of single microgels by pulling the with a microcapillary and quantifying deformation and pressure during aspiration.

Through analysis of size dependence on elasticity of gelatin microgels formed inside cell-mimicked small mold (1/10th to 1/1000th of a millimeter), they discovered that Cell-sized mold makes gelatin gels 10 times stiffer. Detailed analysis of molecular structure in the gelatin microgels revealed that increase of β sheet from interaction with lipid membrane covering the cell-mimicked mold is the factor for the higher stiffness.

These findings indicate mechanical properties of gels can be controlled by modulating space sizes for gelation. By application of these findings, development of novel functionalization methods for various biopolymer gels and elucidation of mechanical properties of biopolymer gels in living cells such as cytoskeletal gels are expected.

More information:
Atsushi Sakai et al, Increasing Elasticity through Changes in the Secondary Structure of Gelatin by Gelation in a Microsized Lipid Space, ACS Central Science (2018). DOI: 10.1021/acscentsci.7b00625

Provided by Tokyo University of Agriculture and Technology