reported for the detection of drugs, proteins, and oligonucleotides.
For example, an ssDNA-modified porous anodic alumina membrane
has been proposed for the label-free detection of interaction
between DNA on the nanochannel surface (Li et al., 2010). The
sensing strategy was based on the obstruction of nanopore array
after the hybrid of complementary DNA strand. The blockage of
nanopore array was probed by redox species, which can be detected
by gold film electrochemical detector sputtered at the end
of nanochannels. A simple label-free electrochemical biosensor
based on screen-printed carbon electrode (SPCE) modified with
alumina membrane has been developed for the detection of proteins
(de la Escosura, 2010). Mesoporous silicon coated with gold
layer was also exploited as a switchable electro-biosensor in our
group (Feng and Wu, 2012). Screening of antisense oligonucleotides
drug based on the switchable biosensor was demonstrated
(Feng and Wu, 2012). Biosensor based on nanopore array is not
designed to detect single molecule because the sensing signal
come from the pore array is averaged. Despite its lower sensitivity
compared with single nanopore sensor, the application of nanopore
array is promising, since the nanopore array is easier to be
available, and usually do not require a strict operational condition.
In this work, we demonstrated that optical sensor based on
silicon nanopore array is a good platform for the detection of
bacteria. The pore array on a membrane can be effectively blocked
by bacteria, which was captured by antibody attached on the
membrane surface. Usually, blockage of the nanopore can be
probed by either measuring the electrochemical current of redox