Figure 9.

a) Photo‐thermal effect of laser irradiated Au‐nano rods, causing localized collapse of hydrogel. White arrow indicates position of Au‐nano rods and laser irradiation. Reproduced with permission.57 Copyright 2007, American Chemical Society. b) T‐junction of a microfluidic device with Au‐colloid hydrogel (right valve) and Au nano shell hydrogel (left valve) with 100 μM wide channels i) When the device is illuminated with 532nm green light the left valve opened ii) when the device is illuminated with 832nm IR light the right valve opened. iii) The absorption spectra of gold nano particles and gold nano shells. Adapted and reproduced with permission.50