Ultra-sensitive and ultra-fast detection of whole unlabeled living cancer cell responses to paclitaxel with a graphene-based biosensor

It has been challenging to measure responses of unlabeled, live whole cells. In this work, we designed a graphene-based optical biosensor with a detection depth of greater than 2 mm, a high sensitivity of 1.2 x 10(8) mV/RIU, and a fast response time of 260 ns. This novel biosensor enables fast and highly accurate label-free detection of drug responses in live cells at the cell height level, and can even sense cancer cell responses to anti-cancer drugs. Unexpected early responses to paclitaxel were observed in cancer cells using this biosensor. Two colorectal cancer cell lines, HCT116 and LoVo, were used for measurement. By combining the results from conventional biological assays, including MTT, western blot and immunofluorescence assays, these novel responses were examined in detail. This facile biosensor shows promise to be widely used as a sensor of unlabeled live cell responses for cancer therapy, anti-cancer drug screening and other cell-based research. (C) 2018 Elsevier B.V. All rights reserved.