(635d) A Microfluidic Platform With Continuous Rapid Cell Trapping and Micro/Nano Electroporation for Single Living Cell Study

A microfluidic platform with continuous rapid cell trapping and micro/nano electroporation for single living cell study

Li-Ju Wang, Lei Li, Junyu Ma, Yun Wu, Daniel Gallego-Perez, James L. Lee

Nanoscale Science and Engineering Center for Affordable Nanoengineering of Polymeric Biomedical Devices, the Ohio State University,

Columbus, Ohio, 43210, United States

     Biomedical micro devices have shown incomparable advantages on single living cell study in recent years. Compared to traditional methods, micro chips provide better manipulation of individual cells. Micro devices also show dynamical mimics and precise control of biochemical cellular microenvironment. For single cell study, except for individual cell manipulation and biocompatible micro environment control, efficient and safe delivering of biomolecules is also very important. Single cell micro-electroporation (MEP) has been used to delivery gene/drug into cells. By placing a cell next to a micro aperture or a microchannel, focused electric fields can create temporary pores in cell membranes. Furthermore, nanochannel electroporation (NEP) technology has been developed recently. NEP technology can directly deliver biomolecules into the cell cytosol across nanochannels with highly concentrated electrical fields and much smaller generated pores on cell membranes. Micro/nano electroporation devices has been reported to have superiorities of lower poration voltages, better transfection efficiency, and lower cell mortality comparing to conventional bulk electroporation (BEP) especially for single cell analysis.

      MEP/NEP is a highly effective tool to directly delivery gene/drug into single living cells. However, current MEP/NEP devices require complicated operation to place single cells to the electroporation locations, for example, by using optical tweezers or magnetic tweezers. The long-time manipulation increases cell mortality rate. The process is not only time and cost consuming but also has limited throughput at a time. This greatly limits the scale-up and applications of MEP/NEP technologies.  Although there are a lot of researches working on microfluidic cell-trapping devices, it is still a challenge to integrate microfluidic cell trapping with micro/nano electroporation in the micro devices.

    In this work, an easy-to-use and affordable microfluidic platform combining continuous rapid hydrodynamic cell trapping and micro/nano electroporation gene/drug delivery is presented. The novel device design integrated cell trapping and electroporation channels and was fabricated using soft lithography and was prepared with bio-functionalized surface treatment. A maximum 90% cell trapping rate was achieved by using this device. Each trapped single cell was positioned on the tip of a single microchannel for sequential micro/nano electroporation. After MEP/NEP gene delivery, these cells were able to be incubated inside this biocompatible microenvironment for in vitro growth or moved out for further analysis. This newly developed platform was fist tested for human alveolar basal epithelial cells (HBEC) and mouse embryonic fibroblast (MEF) cells by delivering fluorescent-labeled DNA. Image analysis showed high transfection efficiency as well as the higher cell viability which exhibited by calcein AM staining.