title: Bead-based microarray immunoassay for lung cancer biomarkers using quantum dots as labels.
abstract: In this study, we developed a multiplex immunoassay system that combines the suspension and planar microarray formats within a single layer of polydimethylsiloxane (PDMS) using soft lithography technology. The suspension format was based on the target proteins forming a sandwich structure between the magnetic beads and the quantum dot (QD) probes through specific antibody-antigen interactions. The planar microarray format was produced by fabricating an array of micro-wells in PDMS. Each micro-well was designed to trap a single microbead and eventually generated a microbead array within the PDMS chamber. The resultant bead-based on-chip assay could be used for simultaneously detecting three lung cancer biomarkers-carcinoembryonic antigen (CEA), fragments of cytokeratin 19 (CYFRA21-1) and neuron-specific enolase (NSE)-in 10 μl of human serum, with a wide linear dynamic range (1.03-111 ng/mL for CEA and CYFRA21-1; 9.26-1000 ng/ml for NSE) and a low detection limit (CEA: 0.19 ng/ml; CYFRA21-1: 0.97 ng/ml; NSE: 0.37 ng/ml; S/N=3). Our micro-well chip does not require complex e-beam lithography or the reactive ion etching process as with existing micro-well systems, which rely on expensive focused ion beam (FIB) milling or optical fiber bundles. Furthermore, the current approach is easy to operate without extra driving equipment such as pumps, and can make parallel detection for multiplexing with rapid binding kinetics, small reagent consumption and low cost. This work has demonstrated the importance of the successful application of on-chip multiplexing sandwich assays for the detection of biomarker proteins.
authors: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, PR China.
authors: Lifen
authors: L
authors: Liu
authors: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, PR China.
authors: Simin
authors: S
authors: Wu
authors: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, PR China.
authors: Fengxiang
authors: F
authors: Jing
authors: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, PR China.
authors: Hongbo
authors: H
authors: Zhou
authors: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, PR China. Electronic address: jiachp@mail.sim.ac.cn.
authors: Chunping
authors: C
authors: Jia
authors: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, PR China.
authors: Gang
authors: G
authors: Li
authors: Department of Tumor Chemotherapy, The Affiliated Hospital of Nantong University, No. 20 Xisi Road, Nantong, Jiangsu 226001, China. Electronic address: huicjs@163.com.
authors: Hui
authors: H
authors: Cong
authors: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, PR China.
authors: Qinghui
authors: Q
authors: Jin
authors: State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050, PR China.
authors: Jianlong
authors: J
authors: Zhao
mesh_terms: D000951:Antigens, Neoplasm / Q000097:blood*; D014408:Biomarkers, Tumor / Q000097:blood; D015374:Biosensing Techniques / Q000295:instrumentation*; D002272:Carcinoembryonic Antigen / Q000097:blood*; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D004867:Equipment Design; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation*; D053539:Keratin-19 / Q000097:blood*; D057230:Limit of Detection; D008175:Lung Neoplasms / Q000097:blood* / Q000175:diagnosis; D059346:Magnets / Q000737:chemistry; D010751:Phosphopyruvate Hydratase / Q000097:blood*; D040081:Protein Array Analysis / Q000295:instrumentation; D045663:Quantum Dots / Q000737:chemistry*
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D004129:Dimethylpolysiloxanes; D053539:Keratin-19; C102012:antigen CYFRA21.1; C013830:baysilon; D010751:Phosphopyruvate Hydratase
keywords: Bead-based microchip; Immunoassay; Micro-well; Multiplexing detection; Quantum dots; Tumor biomarker