posted on 2022-01-11, 17:34authored byYong Wang, Xiaoxia Liu, Chang Chen, Yuduo Chen, Yang Li, Heng Ye, Bo Wang, Huaying Chen, Jinhong Guo, Xing Ma
As
a typical, classical, but powerful biochemical sensing technology
in analytical chemistry, enzyme-linked immunosorbent assay (ELISA)
shows excellence and wide practicability for quantifying analytes
of ultralow concentration. However, long incubation time and burdensome
laborious multistep washing processes make it inefficient and labor-intensive
for conventional ELISA. Here, we propose rod-like magnetically driven
nanorobots (MNRs) for use as maneuverable immunoassay probes that
facilitate a strategy for an automated and highly efficient ELISA
analysis, termed nanorobots enabled ELISA (nR-ELISA). To prepare the
MNRs, the self-assembled chains of Fe3O4 magnetic
particles are chemically coated with a thin layer of rigid silica
oxide (SiO2), onto which capture antibody (Ab1) is grafted
to further achieve magnetically maneuverable immunoassay probes (MNR-Ab1s).
We investigate the fluid velocity distribution around the MNRs at
microscale using numerical simulation and empirically identify the
mixing efficiency of the actively rotating MNRs. To automate the analysis
process, we design and fabricate by 3-D printing a detection unit
consisting of three function wells. The MNR-Ab1s can be steered into
different function wells for required reaction or wishing process.
The actively rotating MNR-Ab1s can enhance the binding efficacy with
target analytes at microscale and greatly decrease incubation time.
The integrated nR-ELISA system can significantly reduce the assay
time, more importantly during which process manpower input is greatly
minimized. Our simulation of the magnetic field distribution generated
by Helmholtz coils demonstrates that our approach can be scaled up,
which proves the feasibility of using current strategy to construct
high throughput nR-ELISA detection instrument. This work of taking
magnetic micro/nanobots as active immunoassay probes for automatic
and efficient ELISA not only holds great potential for point-of-care
testing (POCT) in future but also extends the practical applications
of self-propelled micro/nanorobots into the field of analytical chemistry.