Point-of-care assay platform for quantifying active enzymes to femtomolar levels using measurements of time as the readout

Gregory G. Lewis, Jessica S. Robbins, Scott T. Phillips

Research output: Contribution to journalArticlepeer-review

68 Scopus citations

Abstract

This Article describes a strategy for quantifying active enzyme analytes in a paper-based device by measuring the time for a reference region in the paper to turn green relative to an assay region. The assay requires a single step by the user, yet accounts for variations in sample volume, assay temperature, humidity, and contaminants in a sample that would otherwise prevent a quantitative measurement. The assay is capable of measuring enzymes in the low to mid femtomolar range with measurement times that range from ∼30 s to ∼15 min (lower measurement times correspond to lower quantities of the analyte). Different targets can be selected in the assay by changing a small molecule reagent within the paper-based device, and the sensitivity and dynamic range of the assays can be tuned easily by changing the composition and quantity of a signal amplification reagent or by modifying the configuration of the paper-based microfluidic device. By tuning these parameters, limits-of-detection for assays can be adjusted over an analyte concentration range of low femtomolar to low nanomolar, with dynamic ranges for the assays of at least 1 order of magnitude. Furthermore, the assay strategy is compatible with complex fluids such as serum.

Original languageEnglish (US)
Pages (from-to)10432-10439
Number of pages8
JournalAnalytical Chemistry
Volume85
Issue number21
DOIs
StatePublished - Nov 5 2013

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry

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