title: Smartphone Detection of UV LED-Enhanced Particle Immunoassay on Paper Microfluidics.
abstract: Use of a smartphone as an optical detector for paper microfluidic devices has recently gained substantial attention due to its simplicity, ease of use, and handheld capability. Utilization of a UV light source enhances the optical signal intensities, especially for the particle immunoagglutination assay that has typically used visible or ambient light. Such enhancement is essential for true assimilation of assays to field deployable and point-of-care applications by greatly reducing the effects by independent environmental factors. This work is the first demonstration of using a UV LED (UVA) to enhance the Mie scatter signals from the particle immunoagglutination assay on the paper microfluidic devices and subsequent smartphone detection. Smartphone's CMOS camera can recognize the UVA scatter from the paper microfluidic channels efficiently in its green channel. For an Escherichia coli assay, the normalized signal intensities increased up to 50% from the negative signal with UV LED, compared with the 4% to 7% with ambient light. Detection limit was 10 colony-forming units/mL. Similar results were obtained in the presence of 10% human whole blood.
authors.affiliation: 1 Department of Agricultural and Biosystems Engineering, University of Arizona, Tucson, AZ, USA.
authors.forename: Tu San
authors.initials: TS
authors.lastname: Park
authors.affiliation: 1 Department of Agricultural and Biosystems Engineering, University of Arizona, Tucson, AZ, USA.
authors.forename: Soohee
authors.initials: S
authors.lastname: Cho
authors.affiliation: 2 Biomedical Engineering Graduate Interdisciplinary Program, University of Arizona, Tucson, AZ, USA.
authors.forename: Tigran G
authors.initials: TG
authors.lastname: Nahapetian
authors.affiliation: 1 Department of Agricultural and Biosystems Engineering, University of Arizona, Tucson, AZ, USA.|2 Biomedical Engineering Graduate Interdisciplinary Program, University of Arizona, Tucson, AZ, USA.
authors.forename: Jeong-Yeol
authors.initials: JY
authors.lastname: Yoon
mesh_terms: D000372:Agglutination Tests / Q000379:methods*; D058491:Bacterial Load / Q000379:methods; D004926:Escherichia coli / Q000276:immunology; D006801:Humans; D044085:Microfluidics / Q000379:methods*; D061848:Optical Imaging / Q000379:methods*; D010209:Paper; D000068997:Smartphone; D014466:Ultraviolet Rays
keywords: CMOS camera; Escherichia coli; UVA; light scatter; whole blood