Figure 18.4 — Controlled vesicle fusion in optical tweezers Figure 18.4 — Controlled vesicle fusion in optical tweezers. The top row shows a schematic of the fusion and mixing process: (a) chemical reagents A and B are contained in two separate liposomes; (b) the liposomes are brought into contact using optical tweezers; (c) disruption of the membrane in the region of contact is initiated by a pulsed UV laser; (d) a single large liposome is formed in which the reagents can mix. The bottom row reproduces photographs from the experiment demonstrating controlled vesicle fusion at times (a) t = 0 ms, (b) t = 132 ms, (c) t = 264 ms and (d) t = 528 ms.Reprinted with permission from Kulin et al., Langmuir 19, 8206–10. Copyright (2003) American Chemical Society.