title: Electrochemiluminescence analysis of folate receptors on cell membrane with on-chip bipolar electrode.
abstract: In this paper we report a transparent bipolar electrode based microfluidic chip-electrochemiluminescence (ECL) system for sensitive detection of folate receptors (FR) on cell membranes. This integrated system consists of a poly(dimethylsiloxane) (PDMS) layer containing a microchannel and a glass bottom sheet with indium tin oxide (ITO) strips as bipolar detectors. The ITO strips are fabricated using a PDMS micromold with carbon ink as a protective layer in place of traditional photoresist. The configuration of the bipolar electrode has great influence on the ECL intensity of Ru(bpy)(3)(2+)/tripropylamine(TPA) system. Further studies show that folic acid (FA) can strongly inhibit the ECL of the Ru(bpy)(3)(2+)/TPA system. Based on specific recognition between FA and FR on cell membrane, this microfluidic chip-ECL system is successfully applied for detecting the level of FR on human cervical tumor (HL-60) cells and MEF cells. It is found that the ECL intensity increases with the number of HL-60 cells in the range of 21 to 3.28 × 10(4) cells/mL. The average level of FR on HL-60 cells is calculated to be 8.05 ± 0.75 × 10(-18) mol/cell. While for MEF cells, it shows a much slower ECL increment than HL-60 cells due to the much lower FR level on MEF cells (5.30 ± 0.61 × 10(-19) mol/cell). Moreover, exocytosis of FA after FR mediated endocytosis was observed according to the change of the ECL signal with the incubation time of HL-60 cells in the FA- Ru(bpy)(3)(2+)/TPA system.
authors: Key Laboratory of Analytical Chemistry for Life Science (Ministry of Education of China), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, PR China.
authors: Mei-Sheng
authors: MS
authors: Wu
authors: Bi-Yi
authors: BY
authors: Xu
authors: Hai-Wei
authors: HW
authors: Shi
authors: Jing-Juan
authors: JJ
authors: Xu
authors: Hong-Yuan
authors: HY
authors: Chen
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000737:chemistry*; D002478:Cells, Cultured; D004563:Electrochemistry; D004566:Electrodes; D005347:Fibroblasts / Q000166:cytology; D058973:Folate Receptors, GPI-Anchored / Q000032:analysis*; D005492:Folic Acid / Q000737:chemistry; D018922:HL-60 Cells; D006801:Humans; D049449:Luminescence; D051379:Mice; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods*; D012680:Sensitivity and Specificity
chemical_list: D058973:Folate Receptors, GPI-Anchored; D005492:Folic Acid