Introduction
Analytical platforms are used in the life sciences for the observation,
identification, and characterization of various biological systems. These
platforms serve applications such as sequencing of deoxyribonucleic acid
(DNA), immunoassays, and gene expression analyses for environmental,
medical, forensics, and biohazard detection [1]–[3]. Biosensors are a
subset of such platforms that can convey biological parameters in terms of
electrical signals. Biosensors are utilized to measure the quantity of
various biological analytes and are often required to be capable of
specifically detecting multiple analytes simultaneously. A goal in biosensor
research is to develop portable, hand-held devices for point-of-care (POC)
use, for example in a physician’s office, an ambulance, or at a
hospital bedside, that could provide time-critical information about a
patient on the spot [4].
The current demand for high-throughput, point-of-care bio-recognition has
introduced new technical challenges for biosensor design and implementation.
Conventional biological tests are highly repetitive, labor-intensive, and
require a large sample volume [2], [5]. The associated biochemical protocols
often require hours or days to perform at a cost of hundreds of dollars per
test. Instrumentation for performing such testing today is bulky, expensive,
and requires considerable power consumption. Problems remain in detecting
and quantifying low levels of biological compounds reliably, conveniently,
safely, and quickly. Solving these problems will require the development of
new techniques and sensors.