Schematic of pH-responsive triplex DNA nanoswitches regulating the release of AuNP-labeled reporter units for dual detection of bladder cancer-associated miRNAs on an SPR platform.
A recent study published in ACS Nano presented a novel biosensor for the isothermal, highly sensitive detection of bladder cancer biomarkers—miRNAs, short non-coding RNAs that regulate gene expression—using programmable pH-responsive triplex DNA nanostructures.
The platform employs triplex DNA nanoswitches (TDNs) designed to respond to specific pH conditions. Two TDNs were engineered to target miR-183 and miR-155, which are overexpressed in bladder cancer. These TDNs are integrated into a surface plasmon resonance (SPR) biosensor, enabling the sequential release of gold nanoparticle-labeled reporters at pH 5.0 and 8.3. The controlled release events generate distinct optical signals, allowing accurate target identification.
This dual-detection system demonstrated detection limits of 0.57 pM and 0.83 pM for miR-183 and miR-155, respectively, and successfully distinguished urine samples from bladder cancer patients and healthy individuals.
Unlike traditional qRT-PCR, this approach avoids complex amplification steps, operates under isothermal conditions, and reduces the assay time to less than one hour.
This assay offers high sensitivity, specificity, and flexibility, making it a robust platform for multiplex biomarker detection.
"Its straightforward design and non-invasive sampling approach make it highly promising for clinical applications—not only in bladder cancer but also in detecting other diseases linked to specific microRNA signatures," said Prof. Ja-an Annie Ho.
Prof. Ja-an Annie Ho’s email address: [email protected]