Disposable Passive Electrochemical Microfluidic Device for Diagnosis of Congenital Disorders of Glycosylation

Abstract

A disposable pump-free electrochemical microfluidic device made by using a multilayer lamination technique is proposed for diagnosis of glycosylation disorders. Thanks to the stacking of polyethylene terephthalate (PET) films and double adhesive layers, it is possible to create a geometry that allows the filling of the tailored channels in a fixed time. In the main channel of this passive microfluidic device, the necessary steps to perform the electrochemical determination of transferrin are performed: labeling of the protein with Os (VI) complex (electrochemical tag), washing with water of the osmium residues and electrochemical detection by adsorptive transfer stripping square wave voltammetry. Electrochemical detection released two electrochemical signals: one from Os (VI) complex due to carbohydrates at −0.9 V, and other from the intrinsic electrochemical signal of glycoprotein due to the amino acids at +0.8 V. The ratio between them establishes an indicator of the degree of glycosylation (called electrochemical index of glycosylation). The method was successfully applied to the analysis of clinical samples from patients with congenital disorders of glycosylation.