June 2021
Vol 7, Issue 23

About The Cover

Cover image expansion

ONLINE COVER Hydrogel coatings have shown enormous potential as surface treatments for biomedical devices and ship hulls. However, it has proven challenging to adhere these coatings to the surfaces of biomedical devices and to apply them to ship hulls using existing technologies. To overcome these limitations, Yang et al. established a scalable method called renatured hydrogel painting (RHP), which firmly adheres hydrogel layers onto a variety of solid surfaces. The strategy involves adhering dehydrated xerogel (a solid that forms when a gel dries) to a given surface using glue, then forming a hydrogel layer after the xerogel has been rehydrated. Yang et al. tested the RHP technique on metal panels, a porcelain bowl, wood boards, elastomer, poly(vinyl chloride), and Teflon. They also successfully applied it to an artificial femur head in order to reduce friction, a serious complication of partial hip replacement surgeries. The hydrogel coating protected the cartilage from abrasion, suggesting that RHP may be used to lubricate joints. The authors also found that RHP can withstand mechanical friction under 50 kilopascals (equivalent to the pressure of almost three adults) and hydrodynamic shearing under a water jet rate of 14 meters per second (about the speed of an ocean cargo ship). [CREDIT: ZHAOXIANG YANG ET AL/RENMIN UNIVERSITY OF CHINA]