Purpose: Circulating tumor DNA (ctDNA) is more representative and accurate than biopsy and is also conducive to dynamic monitoring, facilitating accurate diagnosis and prognosis of glioma. Therefore, the present study aimed to establish and validate a novel amplified method for the detection of IDH1 R132H and BRAF V600E, which were associated with the genetic diagnosis of glioma.
Patients and Methods: A dual-signal amplification method based on magnetic aggregation and catalytic hairpin assembly (CHA) was constructed for the simultaneous detection of ctDNAs. When target ctDNAs are present, the CHA reaction is initiated and leads to the assembly of Au-Ag nanoshuttles (Au-Ag NSs) onto magnetic beads (MBs). Further enrichment of MBs under an external magnetic field facilitated the dual-signal amplification of SERS.
Results: The limit of detection (LOD) for IDH1 R132H and BRAF V600E in serum was as low as 6.01 aM and 5.48 aM. The reproducibility and selectivity of the proposed SERS analysis platform was satisfactory. Finally, the platform was applied to quantify IDH1 R132H and BRAF V600E in the serum of subcutaneous-tumor-bearing nude mice, and the results obtained by SERS were consistent with those from quantitative real-time polymerase chain reaction (qRT-PCR).
Conclusion: The present study showed that the dual-signal amplification method is a simple and ultrasensitive strategy for gliomas-associated ctDNAs detection, which is crucial for early diagnosis and dynamic monitoring.
Keywords: circulating tumor DNA, Au-Ag nanoshuttles, magnetic beads, catalytic hairpin assembly, surface-enhanced Raman spectroscopy