ac5b03722_si_001.pdf (232.74 kB)
Ultrasensitive Detection of Single-Walled Carbon Nanotubes Using Surface Plasmon Resonance
journal contribution
posted on 2016-01-05, 00:00 authored by Daeho Jang, Wonhwi Na, Minwook Kang, Namjoon Kim, Sehyun ShinBecause
single-walled carbon nanotubes (SWNTs) are known to be
a potentially dangerous material, inducing cancers and other diseases,
any possible leakage of SWNTs through an aquatic medium such as drinking
water will result in a major public threat. To solve this problem,
for the present study, a highly sensitive, quantitative detection
method of SWNTs in an aqueous solution was developed using surface
plasmon resonance (SPR) spectroscopy. For a highly sensitive and specific
detection, a strong affinity conjugation with biotin–streptavidin
was adopted on an SPR sensing mechanism. During the pretreatment process,
the SWNT surface was functionalized and hydrophilized using a thymine-chain
based biotinylated single-strand DNA linker (B-ssDNA) and bovine serum
albumin (BSA). The pretreated SWNTs were captured on a sensing film,
the surface of which was immobilized with streptavidin on biotinylated
gold film. The captured SWNTs were measured in real-time using SPR
spectroscopy. Specific binding with SWNTs was verified through several
validation experiments. The present method using an SPR sensor is
capable of detecting SWNTs of as low as 100 fg/mL, which is the lowest
level reported thus far for carbon-nanotube detection. In addition,
the SPR sensor showed a linear characteristic within the range of
100 pg/mL to 200 ng/mL. These findings imply that the present SPR
sensing method can detect an extremely low level of SWNTs in an aquatic
environment with high sensitivity and high specificity, and thus any
potential leakage of SWNTs into an aquatic environment can be precisely
monitored within a couple of hours.