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Blood is an attractive carrier for plasmid and RNA based medicine in cell therapy. Electroporation serves as its favorable delivery tool for simple operation, quick internalization, minimum cell culture involvement, and low contamination risk. However, the delivery outcomes of electroporation heavily depend on the treated cells such as their type, size, and orientation to the electric field, not ideal for highly heterogeneous blood samples. Herein a new electroporation system was developed towards effective transfection to cells in blood regardless their large diversity. By coupling replica molding and infiltration coating processes, we successfully configured a three-dimensional electrode comprised of a polymer micropillar array on which carbon nanotubes (CNTs) are partially embedded. During electroporation, cells sag between micropillars and deform to form conformal contact with their top and side surface. The implanted CNTs not only provide a robust conductive coating for the polymer micropattern, but also have their protruded ends face the cell membrane vertically everywhere with maximum transmembrane potential. Regardless their largely varied sizes and random dispersion, both individual blood cell type and whole blood samples were effectively transfected with plasmid DNA (85% after 24 hrs and 95% after 72 hrs, or 2.5-3.0 folds enhancement). High-dose RNA probes were also introduced which regulate better the expression levels of exogenous and endogenous genes in blood cells. Besides its promising performance on non-viral delivery route to cell-related studies and therapy, the invovled new fabrication method also provides a convenient and effective way to construct flexible electronics with stable micro/nanofeatures on the surface. 

The commercialization of high‐energy Li‐metal batteries is impeded by Li dendrites formed during electrochemical cycling and the safety hazards it causes. Here, a novel porous copper current collector that can effectively mitigate the dendritic growth of Li is reported. This porous Cu foil is fabricated via a simple two‐step electrochemical process, where Cu‐Zn alloy is electrodeposited on commercial copper foil and then Zn is electrochemically dissolved to form a 3D porous structure of Cu. The 3D porous Cu layers on average have a thickness of ≈14 um and porosity of ≈72%. This current collector can effectively suppress Li dendrites in cells cycled with a high areal capacity of 10 mAh cm⁻²and under a high current density of 10 mA cm⁻². This electrochemical fabrication method is facile and scalable for mass production. Results of advanced in situ synchrotron X‐ray diffraction reveal the phase evolution of the electrochemical deposition and dealloying processes.