Colloidal chemotaxis and a biased random walk model with finite mean first-passage time Christin Puthur, Prabha Chuphal, Snigdha Thakur and Auditya Sharma EPL, 128 2 (2019) 20001 Published online: 02 December 2019 DOI: 10.1209/0295-5075/128/20001