BACKGROUND: Polydimethylsiloxane (PDMS) is widely used in the basic research on cell biology because of its good biocompatibility and ability to be processed at the micro/nano level. However, cell culture on PDMS has been generally compromised by its strong hydrophobicity.OBJECTIVE: To perform a comparative investigation on the influences of different surface modifications as well as stiffness of PDMS on cellular behaviors.METHODS: PDMS films with varying stiffnesses were subjected to various surface modifications, including serum incubation, type I collagen deposition and air plasma treatment. Bovine articular chondrocytes were seeded on PDMS films and cell adhesion, proliferation and matrix production were characterized using F-actin staining, cell counting kit-8,microscopic examination, Sirius red/Safranin-O staining and quantitative determination of glycosaminoglycans,respectively.RESULTS AND CONCLUSION: Serum incubation, type I collagen deposition and air plasma treatment were all found to promote adhesion and proliferation of bovine articular chondrocytes from the results of F-actin staining and cell prolifereration curve, with air plasma treatment the best. Total amount of glycosaminoglycans (GAG) secretion was only increased by air plasma treatment and GAG/DNA was decreased by all modifications. Stiffness also played roles in cell adhesion, proliferation and GAG production, which was found to be dependent on surface modifications. This study would provide guidance for applying PDMS in cell culture.

Objective:A genome-wide molecular characterization of FJ21351116, a strain of G3P[8]-E2 2021 collected in Fujian, China, was performed.Methods:Whole genome sequencing of FJ21351116 was performed using a high-sensitivity group A rotavirus whole genome sequencing method. Genomic characteriza-tion of the virus was assessed by nucleic acid sequence analysis using MEGA 11.0, Geneious 9.0.2 and DNASTAR software. Neutralization epitopes of VP7 and VP4 (VP8*) were analyzed using BioEdit v. 7.0.9.0 and PyMOL v. 2.5.2.Results:In this study, FJ21351116 was shown to be a G3-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2 genotype, and the result of phylogenetic tree showed that the VP7, VP4, VP3, and NSP2-NSP5 genes of the FJ21351116 strain were related to the equine-like DS-1-like G3P[8] genes that have been detected in Japan in recent years. VP6, VP1, VP2, and NSP1 genes are closely related to G2P[4] in most countries, especially in Singapore, suggesting that this strain was formed by genetic reassortment during the evolution of equine-like G3P[8] and G2P[4]. Evolutionary relationships between the VP7/VP4 genes of FJ21351116 and Rotarix and RotaTeq vaccines suggest that the multiple mutations in both VP7 and VP4 (VP8*) neutralizing antigenic epitopes and vaccine amino acid sites. It is hypothesized that the Rotarix and RotaTeq vaccines may be less effective against equine DS-1-like G3P[8] RVA, and the sequence differences with Rotarix are higher than those with RotaTeq.Conclusions:In this study, we found a rare case of DS-1-like G3P [8] RVA strain in China. Currently, horse-like DS-1-like G3P [8] RVA is relatively rare in China and may be poorly protected by vaccine strains, emphasizing the importance of continuous monitoring of RVA strains and the development of efficient and full-coverage RVA vaccines.