DNA nanotechnology has shown great promise for biosensing
and molecular
recognition. However, the practical application of conventional DNA
biosensors is constrained by inadequate target stimuli, intricate
design schemes, multicomponent systems, and susceptibility to nuclease
degradation. To overcome these limitations, we present a class of
starlike branched and multiplex embedded system (SBES) with an integrated
functional design and cascade exponential amplification for serum
microRNA (miRNA) detection. The DNA arms can be integrated into an
all-in-one system by surrounding a branch point, with each arm endowed
with specific functionalities by embedding different DNA fragments.
These fragments include a segment complementary to the target miRNA
for the recognition element, palindromic tails for self-primed polymerization,
and a region with the same sequences as the target serving as the
target analogue. Upon exposure to a target miRNA, the DNA arms unwind
in a stepwise manner through palindrome-mediated dimerization and
polymerization. This enables target recycling for subsequent reactions
while releasing the target analogue to generate a secondary response
in a feedback manner. A comparative analysis illustrates that the
signal-to-noise ratio (SNR) of a full SBES with a feedback strategy
is approximately 250% higher than the system without a feedback design.
We demonstrate that the four-arm 4pSBES has the benefits
of multifunctional integration, enhanced sensitivity, and low false-positive
signals, which makes this approach ideally suited for clinical diagnosis.
Moreover, an upgraded SBES with additional DNA arms (e.g., 6pSBES) can be constructed to allow multifunctional extension, offering
unprecedented opportunities to build versatile DNA nanostructures
for biosensing.