ABSTRACT
We describe an automated, self-powered chip based on lateral flow immunoassay for rapid, quantitative, and multiplex protein detection from pinpricks of whole blood. The device incorporates on-chip purification of blood plasma by employing inertial forces to focus blood cells away from the assay surface, where plasma proteins are captured and detected on antibody "barcode" arrays. Power is supplied from the capillary action of a piece of adsorbent paper, and sequentially drives, over a 40 minute period, the four steps required to capture serum proteins and then develop a multiplex immunoassay. An 11 protein panel is assayed from whole blood, with high sensitivity and high reproducibility. This inexpensive, self-contained, and easy to operate chip provides a useful platform for point-of-care diagnoses, particularly in resource-limited settings.
Subject(s)
Blood Proteins/analysis , Microfluidic Analytical Techniques/instrumentation , Blood Proteins/metabolism , DNA/chemistry , Enzyme-Linked Immunosorbent Assay/instrumentation , Enzyme-Linked Immunosorbent Assay/methods , Humans , Image Processing, Computer-Assisted , Immunoassay/methods , Microfluidic Analytical Techniques/methods , Oligonucleotide Array Sequence Analysis , Point-of-Care Systems , Reproducibility of Results , Sensitivity and Specificity , Spectrometry, FluorescenceABSTRACT
Electrolyte transport through an array of 20 nm wide, 20 microm long SiO(2) nanofluidic transistors is described. At sufficiently low ionic strength, the Debye screening length exceeds the channel width, and ion transport is limited by the negatively charged channel surfaces. At source-drain biases >5 V, the current exhibits a sharp, nonlinear increase, with a 20-50-fold conductance enhancement. This behavior is attributed to a breakdown of the zero-slip condition. Implications for energy conversion devices are discussed.
