Figure 1.

Conceptual illustration of three generations of the NanoVelcro CTC Assays developed by the UCLA team to achieve different clinical utilities. 1^st-Gen NanoVelcro Chip ⁹, ⁸⁰, composed of a silicon nanowire substrate (SiNS) and an overlaid microfluidic chaotic mixer, was created for CTC enumeration. In conjunction with the use of the laser capture microdissection (LCM) technique, 2^nd-gen NanoVelcro-LMD technology ¹⁶, ⁸¹, ⁸², was developed for single-CTC isolation. The individually isolated CTCs can be subjected to single-CTC genotyping. By grafting thermoresponsive polymer brushes onto SiNS, 3^rd-gen Thermoresponsive NanoVelcro CTC Chips ⁸³, ⁸⁴ were developed for purification of CTCs via capture and release of CTCs at 37°C and 4°C, respectively. The surface-grafted polymer brushes were responsible for altering the accessibility of the capture agent on NanoVelcro substrates, allowing for rapid CTC purification with desired viability and molecular integrity. (Reprinted with permission from Tseng 2014, Copyright, American Chemical Society). We compare the performance and differences of the three generations of NanoVelcro CTC Assays in a table.