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Injectable hyaluronic acid (HA) hydrogel plays an important role in dermal filling. However, conventional HA dermal fillers mostly lack bio‐functional diversity and frequently cause adverse reactions because of the chemical stiffness of highly modified degree and crosslinker residues. In this study, polylactic acid (PLA) was embedded into HA hydrogel as a bioactive substance and 1,4‐butanediol diglycidyl ether was used as a crosslinker to prepare the HA/PLA composite hydrogel with enhanced biocompatibility and biological performance. We aimed to investigate the properties of HA/PLA composite hydrogels as dermal fillers by assessing the rheological properties, surface microstructure, enzymolysis stability, swelling ratio, degradation rate, cytotoxicity, and anti‐wrinkle effect on photo‐aged skin. The results showed that the stability and stiffness of the composite hydrogel decreased with an increasing amount of PLA, while the in vivo safety of the HA/PLA hydrogel was enhanced, showing no adverse reactions such as edema, redness, or swelling. Moreover, the composite hydrogel with 2 wt% PLA exhibited excellent anti‐wrinkle effects, showing the highest collagen production. Thus, the PLA‐embedded HA composite hydrogel showed potential as a dermal filler with high safety, easy injectability, and excellent anti‐wrinkle effects. [ABSTRACT FROM AUTHOR]

Macromolecular crowding and confinement are two factors that potentially affect protein structure and function in a complex cellular environment. The confinement effect on the structure and function of holoCaM [Ca2+-loaded calmodulin (CaM)], a two-domain protein involved in many calcium-mediated signaling pathways, has been investigated previously. However, little is known about how macromolecular crowding affects holoCaM structure and function. Here, the structure-function correlations of holoCaM are investigated in macromolecular crowded environments. It was found that macromolecular crowding impacts its structure and function mildly. The major conformational states are still extended conformation with inter-domain separation in crowded environment as well as those in dilute solution, but the population of transiently compact conformation increases compared to dilute solution. Furthermore, macromolecular crowding facilitates the binding of CaM with AcN19 peptide (CaM-bind domain of α- syn). This study provides a direct comparison for macromolecular crowding and confinement effects on protein structure and function, which helps to understand chemistry regulation in living cells. [ABSTRACT FROM AUTHOR]