Quantitative Fluorescence Assays Using a Self-Powered Paper-Based Microfluidic Device and a Camera-Equipped Cellular Phone.
Fluorescence assays often require specialized equipment and, therefore, are not easily implemented in resource-limited environments. Herein we describe a point-of-care assay strategy in which fluorescence in the visible region is used as a readout, while a camera-equipped cellular phone is used to capture the fluorescent response and quantify the assay. The fluorescence assay is made possible using a paper-based microfluidic device that contains an internal fluidic battery, a surface-mount LED, a 2-mm section of a clear straw as a cuvette, and an appropriately-designed small molecule reagent that transforms from weakly fluorescent to highly fluorescent when exposed to a specific enzyme biomarker. The resulting visible fluorescence is digitized by photographing the assay region using a camera-equipped cellular phone. The digital images are then quantified using image processing software to provide sensitive as well as quantitative results. In a model 30 min assay, the enzyme β-D-galactosidase was measured quantitatively down to 700 pM levels. This Communication describes the design of these types of assays in paper-based microfluidic devices and characterizes the key parameters that affect the sensitivity and reproducibility of the technique.
Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA; ; Tel: 814 867 2502.
Nicole K
NK
Thom
Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA; ; Tel: 814 867 2502.
Gregory G
GG
Lewis
Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA; ; Tel: 814 867 2502.
Kimy
K
Yeung
Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA; ; Tel: 814 867 2502.
Scott T
ST
Phillips