Integrated microfluidic system for electrochemical sensing of glycosylated hemoglobin

Abstract

This article reports a new miniature electrochemical detection system integrating a sample pretreatment device for fast detection of glycosylated hemoglobin (HbA 1C ), which is a common indicator for diabetes mellitus. In this system, circular micropumps, normally closed microvalves, dielectrophoretic (DEP) electrodes, and electrochemical sensing electrode are integrated to perform several crucial processes. These processes include separation of red blood cells (RBCs), sample/reagent transportation, mixing, cell lysis, and electrochemical sensing. For the HbA 1C measurement, the RBCs are separated and are collected from whole human blood by using a positive DEP force generated by the DEP electrodes. The collected RBCs are then lysed to release HbA 1C for the subsequent electrochemical detection processes. Experimental data show that the RBCs are successfully separated and are collected using the developed system with a RBCs capture rate of 84.2%. The subsequent detection of HbA 1C is automatically completed by utilizing electrochemical sensing electrode. The microfluidic system only consumes a sample volume of 200 ll. The entire process is automatically performed within a short period of time (10 min). The development of this integrated microfluidic system may be promising for the clinical monitoring of diabetes mellitus.

Simultaneous separation and concentration of micro- and nano-particles by optically induced electrokinetics

“…Automated and parallel manipulation, separation, concentration, and assembly of micro-/nano-entities, such as biological objects, micro-/nano-particles, carbon nanotubes (CNTs), and graphene, are essential for a variety of applications, including electrochemical sensing of hemoglobin [1], assembly of gold nanoparticle-based sensors [2], CNT-based [3] and graphene-based field effect transistors [4]. Targets of interest are usually expected to be first separated from other micro-/nano-entities that may interfere with later detection or assembly process by characteristics such as their sizes, electrical or other physical properties.…”

Adsorption Kinetics of Glycated Hemoglobin on Aptamer Microarrays with Antifouling Surface Modification

“…19 The limitations of standard methods, as well as the need for frequent measurements of HbA1c and other glycated blood proteins to improve patients' glycemic control, have highlighted the development of simpler, cheaper, and faster methods for measuring glycated blood proteins, such as aptamer-based methods. Several aptamer-based methods for measuring HbA1c have been developed including electrochemical aptamer sensors 20 and fluorescent aptamer sensors. 14 For example, Chang et al 21 developed hemoglobin (Hb)-and glycated hemoglobin (gHb)-specific aptamers, applied them to a microfluidic chemiluminescence sensor array, and successfully determined the concentrations of Hb and gHb.…”

Rapid and Label-Free Separation of Burkitt's Lymphoma Cells from Red Blood Cells by Optically-Induced Electrokinetics

“…In addition, dielectrophoresis (DEP) force, generated by the interaction between an applied non-uniform electric field and the dielectric objects in the field, can be used to induce motions of different directions on the objects, reflecting the differential inherent properties (e.g., dielectric properties and sizes) of the objects. Accordingly, this technique is a label-free manner and has been applied to separate cancerous cells [11] – [13] . Nevertheless, the DEP-based separation technique requires unique conductive electrodes fabricated by micro-lithographic techniques to be integrated with a microfluidic system, and, hence, this technology lacks the flexibility of allowing for dynamic and reconfigurable manipulation once the electrodes are fabricated.…”