Unravelling biotoxicity of graphdiyne:Molecular dynamics simulation of the interaction between villin headpiece protein and graphdiyne

Recently,there has been a growing prevalence in the utilization of graphdiyne(GDY)in the field of biomedicine,attributed to its distinctive physical structure and chemical properties.Additionally,its biocompatibility has garnered increasing attention.However,there is a lack of research on the biological effects and physical mechanisms of GDYprotein interactions at the molecular scale.In this study,the villin headpiece subdomain(HP35)served as a representative protein model.Molecular dynamics simulations were employed to investigate the interaction process between the HP35 protein and GDY,as well as the structural evolution of the protein.The data presented in our study demonstrate that GDY can rapidly adsorb HP35 protein and induce denaturation to one of the a-helix structures of HP35 protein.This implies a potential cytotoxicity concern of GDY for biological systems.Compared to graphene,GDY induced less disruption to HP35 protein.This can be attributed to the presence of natural triangular vacancies in GDY,which prevents p–p stacking action and the limited interaction of GDY with HP35 protein is not conducive to the expansion of protein structures.These findings unveil the biological effects of GDY at the molecular level and provide valuable insights for the application of GDY in biomedicine.

Methods for measuring pre-,intra-,and postoperative skin thickness for cochlear implants

Objective:This study was conducted to determine whether there is a reliable method for measuring the thickness of the retroauricular skin before,during,and after cochlear implantation,which allows the assessment of the optimal force of the external magnet of the cochlear implant(CI).Methods:The retroauricular skin thickness of 83 patients who received a CI was measured using three different methods.The thickness was measured on pre-and postoperative CT images,as well as intraoperatively.The magnet category chosen by the surgeon was recorded when the implant was switched on and during the first follow-up visit.Correlation analyses were performed on the different skin thickness measurements and between the skin thickness and magnet strength categories.Results:Only six patients required an exchange of the magnet until the follow-up.Although the median absolute thickness differed significantly between the three measures(p<0.0001),their thickness values showed highly significant correlations(Pearson’s r=0.457-0.585;p<0.01).In addition,magnet strength,was significantly correlated with the flap thickness determined pre-,post-,and during surgery.The lowest correlation with magnet strength was found in the intraoperative needle method.Conclusion:All three measurements methods provided a suitable base for determining the ideal magnetic force.However,of particular interest were the pre-and postoperative CT measurements.The first enabled the early assessment of the required magnetic strength and thus a timely postoperative supply,whereas the latter helped to estimate the need for magnetic strength reduction during follow-up care and the feasibility of an early swith-on.