Icy microneedles transport cells across skin

Abstract

A new microneedle patch offers a cool way to deliver therapeutic cells across skin. Microneedles made of ice with suspended cells frozen in the tips penetrate skin before melting and releasing the cells. Microneedles have been successfully used to deliver a variety of drugs, often with their payloads dissolved in liquid that seeps through the skin penetrations made by the needles. Delivering cells with microneedles has required drying and then reconstituting cells, which doesn’t work well for mammalian cells. Or delivery has involved hollow microneedles, which sacrifice some of the advantages of other types of microneedles, says Mark R. Prausnitz, an expert on microneedle drug delivery at the Georgia Institute of Technology. To address these problems, Chenjie Xu of the City University of Hong Kong and coworkers made microneedles of ice to preserve cells and deliver them through skin ( Nat. Biomed. Eng. 2021, DOI: 10.1038/s41551-021-00720-1 ). Such devices could