title: Ultrasensitive microfluidic analysis of circulating exosomes using a nanostructured graphene oxide/polydopamine coating.
abstract: Exosomes are cell-derived nano-sized vesicles that have been recently recognized as new mediators for many cellular processes and potential biomarkers for non-invasive disease diagnosis and the monitoring of treatment response. To better elucidate the biology and clinical value of exosomes, there is a pressing need for new analytical technologies capable of the efficient isolation and sensitive analysis of such small and molecularly diverse vesicles. Herein, we developed a microfluidic exosome analysis platform based on a new graphene oxide/polydopamine (GO/PDA) nano-interface. To the best of our best knowledge, we report for the first time, the GO-induced formation of a 3D nanoporous PDA surface coating enabled by the microfluidic layer-by-layer deposition of GO and PDA. It was demonstrated that this nanostructured GO/PDA interface greatly improves the efficiency of exosome immuno-capture, while at the same time effectively suppressing non-specific exosome adsorption. Based on this nano-interface, an ultrasensitive exosome ELISA assay was developed to afford a very low detection limit of 50 μL(-1) with a 4 log dynamic range, which is substantially better than the existing methods. As a proof of concept for clinical applications, we adapted this platform to discriminate ovarian cancer patients from healthy controls by the quantitative detection of exosomes directly from 2 μL plasma without sample processing. Thus, this platform could provide a useful tool to facilitate basic and clinical investigations of exosomes for non-invasive disease diagnosis and to aid precision treatment.
authors.affiliation: Department of Chemistry, University of Kansas, Lawrence, KS 66045, USA. yongz@ku.edu.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Department of Biological and Agricultural Engineering, Kansas State University, Manhattan, KS 66506, USA and Terry C. Johnson Cancer Research Center, Kansas State University, Manhattan, KS 66506, USA.
authors.forename: Mei
authors.initials: M
authors.lastname: He
authors.affiliation: Department of Chemistry, University of Kansas, Lawrence, KS 66045, USA. yongz@ku.edu and University of Kansas Cancer Center, Kansas City, KS 66160, USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zeng
mesh_terms: D018070:Biological Specimen Banks; D015415:Biomarkers / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay / Q000295:instrumentation; D004867:Equipment Design; D055354:Exosomes / Q000737:chemistry / Q000378:metabolism*; D005260:Female; D006108:Graphite / Q000737:chemistry*; D006801:Humans; D055767:Immobilized Proteins / Q000378:metabolism; D007211:Indoles / Q000737:chemistry*; D057230:Limit of Detection; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation; D049329:Nanostructures / Q000737:chemistry*; D009363:Neoplasm Proteins / Q000097:blood / Q000737:chemistry; D010051:Ovarian Neoplasms / Q000097:blood* / Q000175:diagnosis; D011108:Polymers / Q000737:chemistry*; D000075082:Proof of Concept Study; D013499:Surface Properties
chemical_list: D015415:Biomarkers; D055767:Immobilized Proteins; D007211:Indoles; D009363:Neoplasm Proteins; D011108:Polymers; C568283:polydopamine; D006108:Graphite