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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/Fe(3)O(4) 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 enzyme carrier 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 enzyme carrier 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 enzyme carrier 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 enzyme carrier using magnetic beads based microfluidic chip provided a relatively simple, sensitive, miniature, and replaceable means for the accurate determination of TG in serum.

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This article demonstrates a novel method for multi-parameter detection of diabetes mellitus. We propose an approach for fabrication of a 3-D metal films array with gold and copper using electroless deposition technique on PDMS substrate. The obtained PDMS slices containing metal films are superimposed layer by layer as a sandwich structure to form 3-D metal films array. The cross-sections of the array could be used as nanoband array electrochemical detectors, which are further integrated with a multichannel microchip for simultaneously detecting multi-parameter of diabetes mellitus, including glucose and metabonomics of diabetes containing aldehyde compounds (glyoxal and methylglyoxal) and short organic acids (lactate, urate and 2-hydroxybutyrate). Under optimized separation and detection conditions, glucose, aldehyde compounds and short organic acids respond linearly in the concentration range of 10-2000, 1-500 and 5-600 μM, with the LODs of 4, 0.5 and 3 μM for glucose, aldehyde compounds and short organic acids, respectively. This system is successfully employed to detect these compounds in serums. This study reveals that the electrochemical array detectors with different materials integrated with multichannel microchip provide a flexible and inexpensive approach for routine, simultaneous and direct detection of some metabolites in metabonomics.