Ultrasensitive detection of biomolecules based on bio-barcode DNA coupled with MALDI-TOF mass spectrometry

Abstract

We have devised a novel, highly sensitive, and selective approach for thrombin detection based on bio-barcode DNA (bio-bcDNA) by utilizing matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Firstly, the target (thrombin) was captured by aptamer15 functionalized magnetic beads (MBs-apt15) and sandwich complex was formed with thrombin through the bio-bcDNA and aptamer29 (apt29) functionalized gold nanoparticles (apt15-MB/thrombin/apt29-AuNPs-bio-bcDNA) interaction. The sandwich complex was treated with potassium cyanide (KCN) to dissolve the AuNPs. The released bio-bcDNAs were collected by magnetic separation and analyzed by using MALDI-TOF MS. Under optimized conditions, this strategy exhibited a wide linear detection range from 1 nM to 1 aM with detection limit of 0.478 aM and also showed acceptable recovery for thrombin detection in complex biological matrices.