Gold NanorodNanolayer-Mediated Photothermal TransfectionPromotes DNA Nanomachine Crossing of Cell Membranes for SensitiveCell Imaging

The transmembrane efficiency of DNA nanomachines greatly affects the performance of cell imaging. The current transmembrane methods suffer from long time incubation, low efficiency, and potential cyto-toxicity. Here, we report on a novel gold nanorod <b>n</b>anolayer-<b>m</b>ediated <b>p</b>hotothermal <b>t</b>ransfection (AuNRs-NMPT) method to deliver a DNA nanomachine across the cell membrane. Due to good photothermal effects, AuNRs <b>n</b>anolayer-<b>f</b>unctionalized <b>s</b>lide (AuNRs-NFS) converted light energy into local heat. Local heat disrupted the fluidity of the cell membrane for perforation. The DNA nanomachine penetrates the cell membrane rapidly and efficiently via those holes under the optimal laser power and irradiation time. The AuNRs-NMPT exhibited a 12-fold lower incubation time and 13-fold higher fluorescent intensity compared to that of common direct incubation. The cells also exhibited a high cell viability after being treated with the AuNRs-NMPT, due to cell membrane self-repair. Due to efficient, rapid, and low cytotoxic transmembrane transfection, the AuNRs-NMPT ensures sensitive cell imaging of miRNA-21. The proposed AuNRs-NMPT will promote the application of DNA nanomachines for clinical cancer diagnosis in the future.