posted on 2022-12-09, 12:04authored byKota Hirayama, Masaki Kitamura, Nay San Lin, Minh Hieu Nguyen, Binh Duong Le, Anh Tuan Mai, Shigeki Mayama, Kazuo Umemura
We fabricated a micron-sized
biodevice based on the near-infrared
photoluminescence (PL) response of single-walled carbon nanotubes
(SWNTs). Various biosensors using the unique optical responses of
SWNTs have been proposed by many research groups. Most of these employed
either colloidal suspensions of dispersed SWNTs or SWNT films on flat
surfaces, such as electrodes. In this study, we attached DNA-wrapped
SWNTs (DNA-SWNTs) to frustule (micron-sized nanoporous biosilica)
surfaces, which were purified from cultured isolated diatoms. After
the injection of an oxidant and a reductant, the SWNTs on the frustules
showed prominent PL responses. This suggests that the biodevice functions
as a micron-sized redox sensor. Frustules can be easily suspended
in aqueous solutions because of their porous structures and can easily
be collected as pellets by low-speed centrifugation. Thus, the removal
of unbound SWNTs and the recovery of the fabricated DNA-SWNT frustules
for reuse were achieved by gentle centrifugation. Our proposal for
micron-sized SWNT biodevices would be helpful for various biological
applications.