Multiplexed microfluidic fluorescence immunoassay with photodiode array signal acquisition for sub-minute and point-of-need detection of mycotoxins

Abstract

Portable, rapid, cost effective and simple analytical tools are in increasing demand to facilitate the routine monitoring of target chemical/biological compounds at the point-of-need. Such devices are highly relevant within the context of food safety, particularly concerning the screening of highly toxic and strictly regulated mycotoxins. To achieve ultrarapid detection of mycotoxins, namely aflatoxin B1, ochratoxin A and deoxynivalenol, at the point-of-need, a novel multiplexed bead-based microfluidic competitive immunosensor, coupled with an array of a-Si:H thin-film photodiodes for integrated fluorescence signal acquisition, is reported. Simultaneously measuring the initial binding rate for each analyte of the sample under analysis against an internal reference, this device provided limits of detection below 1 ng mL-1 for all mycotoxins in a single-step assay and within 1 minute after mixing the sample under analysis with a fluorescent conjugate. The compatibility of the device with the analysis of mycotoxins spiked in corn samples was further demonstrated after performing a sample preparation procedure based on aqueous two-phase extraction. The short times of analysis and sensitivities in the low ng mL-1 range make these devices potentially competitive with the lateral flow devices that are currently the standard for this application. Furthermore, this device architecture and concept is amenable of being expanded to other analytes in food safety, biomedical and other applications.

Optimizing the Performance of Chromatographic Separations Using Microfluidics: Multiplexed and Quantitative Screening of Ligands and Target Molecules

“…This hypothesis is also supported by previous reports, where microchambers significantly longer than the bead bed height of the device discussed here (equivalent to three columns of 400 µm each) still provided a homogeneous signal. Similarly, other reports on a higher number of bead chambers in series also highlight a lack of molecular depletion at high flow rates . This evaluation was essential to support the subsequent multiplexed analysis of different types of beads, in which each chamber must be subjected to the same concentration of target molecules in solution under the same operating conditions.…”

Multiplex Immunoassay Techniques for On-Site Detection of Security Sensitive Toxins

“…The authors combined a novel immunization strategy to generate high-affinity monoclonal and polyclonal antibodies against the proteotoxins together with Luminex xMAP ® technology. The obtained LODs (2 pg/mL for ricin, 3 pg/mL for SEB, 21 pg/mL for BoNT/A, 73 pg/mL for BoNT/B as well as 546 pg/mL for abrin within 210 min assay time) demonstrate the feasibility to detect biothreat Soares et al [121] developed a new portable fluorescent immunoassay to detect the low molecular weight toxins aflatoxin B1, ochratoxin A and deoxynivalenol. For the multiplex, bead-based microfluidic competitive immunosensor Si:H thin film photodiodes are applied to detect fluorescence signals.…”

“…. Soares et al [121] developed a new portable fluorescent immunoassay to detect the low molecular weight toxins aflatoxin B1, ochratoxin A and deoxynivalenol. For the multiplex, beadbased microfluidic competitive immunosensor Si:H thin film photodiodes are applied to detect fluorescence signals.…”

Biofunctionalization of Glass‐ and Paper‐Based Microfluidic Devices: A Review

“…Microfluidic devices and lab‐on‐a‐chip technology have been distinguished as a promising platform for ultrasensitive bioanalytical devices, point‐of‐care (POC) diagnostics and health monitoring systems, investigation of cell biology and tissue engineering, mixing and separation of biospecies, drug discovery, biohazard detection, as well as automating synthetic biology to create micro‐organism and DNA foundries . Incorporating microfluidics in different bioanalytical systems such as those based on fluorescence, colorimetric, electrochemical, and chemiluminescence readout, as well as mass spectrometry has significantly enhanced the limit of detection (LOD) of these assays . In cell biology, microfluidics enables the integration of multiple cell lines to mimic “organs‐on‐chips” with the desired physiological conditions and hemodynamic forces.…”