Self-healing properties of augmented injectable hydrogels over time

Abstract

Injectable polymers offer great benefits compared to other types of implants; however, they tend to suffer from increased mechanical wear and may need a replacement implant to restore these mechanical properties. The purpose of this experiment is to investigate an injectable hydrogel's self-healing ability to augment itself to a previously molded implant. This was accomplished by performing a tensile strength test to examine potential diminishing mechanical properties with increasing time, as well as dye penetration tests to examine the formation of interfacial bonds between healed areas of hydrogels. There were several time points in between injections that were explored, from 0 min between injections all the way up to 48 h in between injections. The tests showed no statistical differences of the increased injection times compared to the single injection for the tensile test. However, our results showed an increase of mechanical breaks at self-healed joints, as well as a linear regression test showed a decrease in dye diffusion rate as time between injections increase. These results show that the hydrogel has strong self-healing abilities, and as time between injections increase, they mechanical properties will slowly decrease. Based on this, the tests can be applied to other injectable implants and a noninvasive solution to a worn-down implant, as well as show scientific backing to a possibly unique and beneficial self-healing property.