Brain cancer has a high mortality rate, partly due to late diagnosis and reliance on invasive diagnostic methods. Circulating microRNAs, small noncoding RNAs (~21–25 nucleotides) involved in gene regulation, offer a minimally invasive alternative within liquid biopsy, which analyzes body fluids to capture tumor-related molecular signatures. However, these biomarkers are present at extremely low concentrations and are affected by complex sample backgrounds and detection interferences. Their very low abundance makes sensitive and simple detection challenging. Current methods, such as northern blotting, microarrays, and reverse transcription quantitative PCR (RT-qPCR), require large sample volumes, are time-consuming and low-throughput, and are limited by variability, bias, and mainly relative quantification. Here, we present a PCR amplification-free, plasmonic platform that combines gold nanoparticles (AuNPs) and enzymatic extension for hsa-miR-497 analysis and quantification in the serum of brain cancer patients. Target miR-497 longed with a Poly(A) tail bridges a PNA surface-immobilized capture probe and a Poly(T) tail on AuNPs to form a sandwich. Using this capture interface, the signal of target miR-497 was accurately quantified using the standard addition method by compensating for sample handling and matrix effect. We selected miR-497 based on prior evidence linking it to early tumor detection. The developed platform can measure miRNA concentrations as low as 0.5 fM while requiring only a minimal sample volume of 40 μL of unextracted and not PCR amplified serum from glioblastoma patients. The entire assay can be completed in 2 hours. The amount of miR-497 measured using our method was comparable to that obtained by RT-qPCR.
Quantification of circulating microRNA brain cancer biomarkers in patient sera using a surface plasmon resonance imaging (SPRI) biosensing platform
Federica Di Padua;Alessia Finotti;
2026
Abstract
Brain cancer has a high mortality rate, partly due to late diagnosis and reliance on invasive diagnostic methods. Circulating microRNAs, small noncoding RNAs (~21–25 nucleotides) involved in gene regulation, offer a minimally invasive alternative within liquid biopsy, which analyzes body fluids to capture tumor-related molecular signatures. However, these biomarkers are present at extremely low concentrations and are affected by complex sample backgrounds and detection interferences. Their very low abundance makes sensitive and simple detection challenging. Current methods, such as northern blotting, microarrays, and reverse transcription quantitative PCR (RT-qPCR), require large sample volumes, are time-consuming and low-throughput, and are limited by variability, bias, and mainly relative quantification. Here, we present a PCR amplification-free, plasmonic platform that combines gold nanoparticles (AuNPs) and enzymatic extension for hsa-miR-497 analysis and quantification in the serum of brain cancer patients. Target miR-497 longed with a Poly(A) tail bridges a PNA surface-immobilized capture probe and a Poly(T) tail on AuNPs to form a sandwich. Using this capture interface, the signal of target miR-497 was accurately quantified using the standard addition method by compensating for sample handling and matrix effect. We selected miR-497 based on prior evidence linking it to early tumor detection. The developed platform can measure miRNA concentrations as low as 0.5 fM while requiring only a minimal sample volume of 40 μL of unextracted and not PCR amplified serum from glioblastoma patients. The entire assay can be completed in 2 hours. The amount of miR-497 measured using our method was comparable to that obtained by RT-qPCR.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
