Study Of Squeezing Based Intracellular Delivery On Microfluidic

Intracellular delivery,also known as cell transfection,is considered an essential process in medical applications such as cell therapy,gene editing,and the biomanufacturing industry.It involves the successful delivery and expression of exogenous substances at the nanoscale,such as genes,proteins,and biomacromolecules,into target cells.Cell squeezing refers to the significant deformation and formation of numerous nanopores on the cell membrane when cells pass through microfluidic channels approximately half their diameter.The squeezing process of cells through narrow microchannels is a topic worthy of exploration.Currently,there is limited systematic research on the numerical relationship between microfluidic chip parameters and the efficiency of mechanical squeezing transfection,as well as the transfection mechanisms of exogenous substances.The aim of this study is to investigate the mechanical mechanisms of the squeezing transfection method and design and fabricate a microfluidic chip for cell squeezing.The main objectives are as follows:1.Introducing a droplet model to simulate the mechanical deformation behavior of cells,analyzing and establishing the transfection mechanism of exogenous substances entering the cell body,and the regulatory mechanism of cell membrane damage repair.A critical energy model for cell membrane porosity is established,and an exogenous substance delivery model is used to simulate the process of exogenous substances entering cells after squeezing.The correlations between cells driven at different speeds and different geometric shapes,lengths,and widths of microchannels are analyzed,leading to the following conclusions:(1)Circular microchannels with restricted space can provide uniform compression,which is more suitable for cell squeezing;(2)Longer and narrower microchannels can induce higher transfection efficiency;(3)Increasing the driving fluid velocity significantly increases cell deformation in the microchannels.2.Establishing a microfluidic platform for cell transfection based on mechanical squeezing.Microfluidic channel substrates are fabricated using photolithography,and flexible microfluidic chips are created using PDMS.The structure and dimensions of the microfluidic chip are designed.In vitro experiments are conducted on the mechanical squeezing cell transfection system,successfully delivering propidium iodide(PI)dye into the cell body.The transfection efficiency remains satisfactory across different-sized microfluidic chips.A piezoelectric impact squeezing platform is constructed,and the impact frequency and amplitude of the piezoelectric film on transfection efficiency are analyzed.