In-capillary magnetic separation and enrichment coupled with laser-induced fluorescence for rapid determination of biomolecules

Abstract

Biomolecules are indispensable in the life activities and metabolism of various organisms, and their highly sensitive detection is of great significance for disease diagnosis and food safety. Due to the complexity of the matrix and the low concentration of the target, separation and enrichment of biomolecules prior to detection are necessary and time-consuming. Herein, a novel approach combining in-capillary magnetic separation and enrichment with laser-induced fluorescence detection method was proposed for qualitative and quantitative analysis of biomolecules. Two different sequence aptamers modified with magnetic nanoparticles and labeled with fluorescence were used as capture probes and signal probes to form sandwich structures with target molecules for detection. Under the combined influence of magnetic field force and fluid drag force, the integration of separation, enrichment and on-line detection were finished within 5min. Under optimal conditions, the developed method provided a low limit of detection as 2.7 fmol/L, 0.57 nmol/L, 3 CFU/mL for DNA, thrombin and Staphylococcus aureus, respectively. This proposed method offers a promising platform for the sensitive and rapid determination of biomolecules. It holds significant potential for future applications in fields of environmental and biochemical analysis.