Reagentless Bidirectional Lateral Flow Bioactive Paper Sensors for Detection of Pesticides in Beverage and Food Samples

Abstract

A reagentless bioactive paper-based solid-phase biosensor was developed for detection of acetylcholinesterase (AChE) inhibitors, including organophosphate pesticides. The assay strip is composed of a paper support (1 x 10 cm), onto which AChE and a chromogenic substrate, indophenyl acetate (IPA), were entrapped using biocompatible sol-gel derived silica inks in two different zones (e.g., sensing and substrate zones). The assay protocol involves first introducing the sample to the sensing zone via lateral flow of a pesticide-containing solution. Following an incubation period, the opposite end of the paper support is placed into distilled deionized water (ddH(2)O) to allow lateral flow in the opposite direction to move paper-bound IPA to the sensing area to initiate enzyme catalyzed hydrolysis of the substrate, causing a yellow-to-blue color change. The modified sensor is able to detect pesticides without the use of any external reagents with excellent detection limits (bendiocarb approximately 1 nM; carbaryl approximately 10 nM; paraoxon approximately 1 nM; malathion approximately 10 nM) and rapid response times (approximately 5 min). The sensor strip showed negligible matrix effects in detection of pesticides in spiked milk and apple juice samples. Bioactive paper-based assays on pesticide residues collected from food samples showed good agreement with a conventional mass spectrometric assay method. The bioactive paper assay should, therefore, be suitable for rapid screening of trace levels of organophosphate and carbamate pesticides in environmental and food samples.

Paper-based diagnostic devices for clinical paraquat poisoning diagnosis

“…[42][43][44] PADs as pesticide detection devices may use photoelectrochemical or colorimetric assay platforms to indicate the presence of organophosphorus or carbamate pesticides to secure food quality. [45][46][47] Notably, we, and others, have developed PADs to analyze serum organophosphate level for organophosphate poisoning in patients. 48 To the best of our knowledge, few previous studies have examined the use of PADs for clinically diagnostic PQ detection.…”

A perspective on paper-based microfluidics: Current status and future trends

“…One proposal is combining assay reagents with sol-gel materials to immobilize reagents on paper. [64][65][66] In this way, Hossain et al developed a paper-based sensor which can detect organophosphate pesticides of nanomolar quantities in milk or lettuce by color changing. 65 Another proposal is using gold nanoparticle (AuNP) based colorimetric detection which can dramatically improve both the sensitivity and the specificity of detection.…”

“…[64][65][66] In this way, Hossain et al developed a paper-based sensor which can detect organophosphate pesticides of nanomolar quantities in milk or lettuce by color changing. 65 Another proposal is using gold nanoparticle (AuNP) based colorimetric detection which can dramatically improve both the sensitivity and the specificity of detection. 67 Zhao et al applied a AuNP colorimetric probe to paper-based assays for detecting Deoxyribonuclease I and adenosine.…”

Defining microchannels and valves on a hydrophobic paper by low-cost inkjet printing of aqueous or weak organic solutions

“…Additionally, fluids can wick through (hydrophilic) cellulose through capillary actions, thereby eliminating the necessity for using external fluid pumps. As a result, lPADs have emerged as a promising platform for point-of-care analytical applications in clinical diagnostics, [1][2][3] food safety control, 4,5 and environmental testing. 6,7 Various techniques have been used to fabricate lPADs, including photolithography, 8,9 wax printing, [10][11][12] inkjet printing, [13][14][15] laser etching, 16,17 plasma treatment, 18 and use of metal/paper masks.…”