Correction to: Microsystems & Nanoengineering (2019)5:10

https://doi.org/10.1038/s41378-019-0049-2

published online: 11 March 2019

The legend in Fig. 4a in the previously published version of this article contained erroneous units. The correct units are given in the caption–that is, 1 µM (black), 500 nM (red), 100 nM (blue), 50 nM (cyan), 10 nM (pink), and 0 nM (1× PBS solution, brown).