Modeling and Experimental Validation of Microbial Transfer via Surface Touch

Surface touch spreads disease-causing microbes, but the measured rates of microbial transfer vary significantly. Additionally, the mechanisms underlying microbial transfer via surface touch are unknown. In this study, a new physical model was proposed to accurately evaluate the microbial transfer rate in a finger-surface touch, based on the mechanistic effects of important physical factors, including surface roughness, surface wetness, touch force, and microbial transfer direction. Four surface-touch modes were distinguished, namely, a single touch, sequential touches (by different recipients), repeated touches (by the same recipient), and a touch with rubbing. The tested transfer rates collated from 26 prior studies were compared with the model predictions based on their experimental parameters, and studies in which the transfer rates were more consistent with our model predictions were identified. New validation experiments were performed by accurately controlling the parameters involved in the model. Four types of microbes were used to transfer between the naked finger and metal surface with the assistance of a purpose-made touch machine. The measured microbial transfer rate data in our new experiments had a smaller standard deviation than those reported from prior studies and were closer to the model prediction. Our novel predictive model sheds light on possible future studies.

接触传播可扩散致病微生物，但现有测得的微生物转移率差异显著。此外，经由表面接触实现的微生物转移背后的作用机制仍未明确。本研究提出了一种全新的物理模型，可基于表面粗糙度、表面湿度、接触力、微生物转移方向等关键物理因素的力学效应，精准评估手指与表面接触时的微生物转移率。本研究区分了四种接触模式：单次接触、不同受体依次接触、同一受体重复接触，以及伴随摩擦的接触。本研究将26项既往研究中整理得到的实测转移率，结合其实验参数与模型预测结果进行比对，筛选出了转移率与本模型预测结果吻合度更高的相关研究。本研究通过精准控制模型涉及的各项参数，开展了全新的验证实验。借助定制的接触实验装置，本研究使用四种微生物开展裸指与金属表面间的转移实验。本研究新实验中测得的微生物转移率数据，相较于既往研究报道的数据，具有更小的标准差，且与模型预测结果更为接近。本研究提出的新型预测模型可为未来相关研究提供新思路。