title: Development of a microchip Europium nanoparticle immunoassay for sensitive point-of-care HIV detection.
abstract: Rapid, sensitive and specific diagnostic assays play an indispensable role in determination of HIV infection stages and evaluation of efficacy of antiretroviral therapy. Recently, our laboratory developed a sensitive Europium nanoparticle-based microtiter-plate immunoassay capable of detecting target analytes at subpicogram per milliliter levels without the use of catalytic enzymes and signal amplification processes. Encouraged by its sensitivity and simplicity, we continued to miniaturize this assay to a microchip platform for the purpose of converting the benchtop assay technique to a point-of-care test. It was found that detection capability of the microchip platform could be readily improved using Europium nanoparticle probes. We were able to routinely detect 5 pg/mL (4.6 attomoles) of HIV-1 p24 antigen at a signal-to-blank ratio of 1.5, a sensitivity level reasonably close to that of microtiter-plate Europium nanoparticle assay. Meanwhile, use of the microchip platform effectively reduced sample/reagent consumption 4.5 fold and shortened total assay time 2 fold in comparison with microtiter plate assays. Complex matrix substance in plasma negatively affected the microchip assays and the effects could be minimized by diluting the samples before loading. With further improvements in sensitivity, reproducibility, usability, assay process simplification, and incorporation of portable time-resolved fluorescence reader, Europium nanoparticle immunoassay technology could be adapted to meet the challenges of point-of-care diagnosis of HIV or other health-threatening pathogens at bedside or in resource-limited settings.
authors.affiliation: Laboratory of Molecular Virology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA. Electronic address: Jikun.Liu@fda.hhs.gov.
authors.forename: Jikun
authors.initials: J
authors.lastname: Liu
authors.affiliation: Laboratory of Molecular Virology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA.
authors.forename: Bingchen
authors.initials: B
authors.lastname: Du
authors.affiliation: Laboratory of Molecular Virology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA.
authors.forename: Panhe
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Laboratory of Molecular Virology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA.
authors.forename: Mohan
authors.initials: M
authors.lastname: Haleyurgirisetty
authors.affiliation: Laboratory of Molecular Virology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA.
authors.forename: Jiangqin
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Laboratory of Molecular Virology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA.
authors.forename: Viswanath
authors.initials: V
authors.lastname: Ragupathy
authors.affiliation: Laboratory of Molecular Virology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA.
authors.forename: Sherwin
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Mechanical Engineering, University of Maryland, College Park, MD 20842, USA.
authors.forename: Don L
authors.initials: DL
authors.lastname: DeVoe
authors.affiliation: Laboratory of Molecular Virology, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD 20892, USA. Electronic address: Indira.Hewlett@fda.hhs.gov.
authors.forename: Indira K
authors.initials: IK
authors.lastname: Hewlett
mesh_terms: D000956:Antigens, Viral / Q000032:analysis* / Q000097:blood; D015374:Biosensing Techniques / Q000295:instrumentation*; D005063:Europium / Q000737:chemistry*; D015658:HIV Infections / Q000097:blood / Q000175:diagnosis*; D015497:HIV-1 / Q000302:isolation & purification*; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation; D053758:Nanoparticles / Q000737:chemistry*; D019095:Point-of-Care Systems; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D000956:Antigens, Viral; D005063:Europium
keywords: Europium nanoparticles; HIV; Microchip; Point-of-care diagnostics; Resource-limited settings