The Development of Visually Identifiable Bio-sensor using Magnetic Nanoclusters (MNCs) with High Viscous Polyethylene glycol (PEG) Solution.

Abstract

We develop the new method for a facile and sensitive analytical detection of biomarkers in short time, don’t need any bulk instruments, just with naked eye using magnetic nanoclusters (MNCs) and high viscous polyethylene glycol solution. We named this detection method, magnetophoretic chromatography that uses precision pipette for visually identifiable detection. Antibody-conjugated MNCs are used to capture the biomarker (in case, alpha fetoprotein (AFP) closely related with liver cancer) from buffer solution. When biomarker induced agglutination of MNCs are occurred in the solution, magnetophoretic chromatography can separate agglutinated MNCs from remained free MNCs. This new method is only using precision pipette, pipette tip, and permanent magnet. Agglutinated MNCs and remained free MNCs solution is sucked into a precision pipette tip, then viscous polymer solution is sucked follow. Every magnetophoretic chromatography process carried out within 10 min. We determine the concentration of AFP below 0.1 ng/ml with naked eyes. This is 10 times better than conventional ELISA. In addition to that, MNC has intrinsic biomimetic property to make 3,3’,5,5’-Tetramethylbenzidine (TMB) color formation that act as horse radish peroxidase (HRP). After magnetophoretic chromatography, agglutinated MNCs are gathering at bottom side of pipette tip. Collect this part and add to TMB and H2O2 solutions. The performance of this method was evaluated by using dynamic light scattering and light absorption spectroscopy. The detection limit of this case is 0.01 ng/ml, 100 times superior to the sensitivity of conventional ELISA.