Lab-on-a-chip for analysis of triglycerides based on a replaceable enzymecarrier using magnetic beads
In this paper an enzyme-carrier-based microfluidic chip coupled with a gold nanoband microelectrode as electrochemical detector for Triglyceride (TG) determination was developed by co-immobilized lipase, Glycerokinase (GK) and glycerol-3-phosphate oxidase (GPOx) on chitosan/Fe3O4 composite nanoparticles with a shell-core structure, which combined the advantageous features of microfluidic chips technology with magnetic beads. This procedure enabled the easy renewal of the microchip enzymecarrier after each determination in a highly reproducible manner. Several operational parameters such as working potential, buffer pH, adenosine triphosphate concentrations (ATP, mM), separation voltage and temperature were evaluated and optimized. The performance of enzyme-carrier-based microfluidic chip for TG determination was modulated by changing the length of enzymecarrier from 1.0 to 3.0 cm, and the linear ranges were changed from 0–4.0 mM to 0–10.0 mM with the detection limits from 15 μM to 6.0 μM. The enzymecarrier remained its 70% activity after 40 days storage. This system was successfully employed for on-line detection of TG in serums. The experimental results demonstrated that this enzymecarrier using magnetic beads based microfluidic chip provided a relatively simple, sensitive, miniature, and replaceable means for the accurate determination of TG in serum.