title: Rapid detection of aflatoxigenic Aspergillus sp. in herbal specimens by a simple, bendable, paper-based lab-on-a-chip.
abstract: Postharvest herbal product contamination with mycotoxins and mycotoxin-producing fungi represents a potentially carcinogenic hazard. Aspergillus flavus is a major cause of this issue. Available mold detection methods are PCR-based and rely heavily on laboratories; thus, they are unsuitable for on-site monitoring. In this study, a bendable, paper-based lab-on-a-chip platform was developed to rapidly detect toxigenic Aspergillus spp. DNA. The 3.0-4.0 cm(2) chip is fabricated using Whatman™ filter paper, fishing line and a simple plastic lamination process and has nucleic acid amplification and signal detection components. The Aspergillus assay specifically amplifies the aflatoxin biosynthesis gene, aflR, using loop-mediated isothermal amplification (LAMP); hybridization between target DNA and probes on blue silvernanoplates (AgNPls) yields colorimetric results. Positive results are indicated by the detection pad appearing blue due to dispersed blue AgNPls; negative results are indicated by the detection pad appearing colorless or pale yellow due to probe/target DNA hybridization and AgNPls aggregation. Assay completion requires less than 40 min, has a limit of detection (LOD) of 100 aflR copies, and has high specificity (94.47%)and sensitivity (100%). Contamination was identified in 14 of 32 herbal samples tested (43.75%). This work demonstrates the fabrication of a simple, low-cost, paper-based lab-on-a-chip platform suitable for rapid-detection applications.
authors.affiliation: Laboratory of Plant Transgenic Technology and Biosensor, Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok, Thailand. piyasakcha@yahoo.com.
authors.forename: Piyasak
authors.initials: P
authors.lastname: Chaumpluk
authors.affiliation: Integration of Health and Beauty Section, Faculty of Applied Science, Dhurakij Pundit University, Bangkok, Thailand.
authors.forename: Pattra
authors.initials: P
authors.lastname: Plubcharoensook
authors.affiliation: Plant Biomass Utilization Research Unit, Department of Botany, Faculty of Science, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Sehanat
authors.initials: S
authors.lastname: Prasongsuk
mesh_terms: D000348:Aflatoxins / Q000235:genetics*; D001230:Aspergillus / Q000235:genetics*; D002152:Calorimetry, Differential Scanning / Q000379:methods; D005516:Food Microbiology; D005800:Genes, Fungal; D056656:Lab-On-A-Chip Devices / Q000382:microbiology; D057230:Limit of Detection; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D021141:Nucleic Acid Amplification Techniques / Q000295:instrumentation / Q000379:methods*; D012834:Silver / Q000737:chemistry
chemical_list: D000348:Aflatoxins; D012834:Silver
keywords: Aspergillus detection; Blue silver nanoplate; Colorimetric detection; LAMP; PNA probe; Paper-based Lab-on-a-chip