MilliporeSigma
  • Tutorial: design and fabrication of nanoparticle-based lateral-flow immunoassays.

Tutorial: design and fabrication of nanoparticle-based lateral-flow immunoassays.

Nature protocols (2020-10-25)
Claudio Parolo, Amadeo Sena-Torralba, José Francisco Bergua, Enric Calucho, Celia Fuentes-Chust, Liming Hu, Lourdes Rivas, Ruslan Álvarez-Diduk, Emily P Nguyen, Stefano Cinti, Daniel Quesada-González, Arben Merkoçi
ABSTRACT

Lateral-flow assays (LFAs) are quick, simple and cheap assays to analyze various samples at the point of care or in the field, making them one of the most widespread biosensors currently available. They have been successfully employed for the detection of a myriad of different targets (ranging from atoms up to whole cells) in all type of samples (including water, blood, foodstuff and environmental samples). Their operation relies on the capillary flow of the sample throughout a series of sequential pads, each with different functionalities aiming to generate a signal to indicate the absence/presence (and, in some cases, the concentration) of the analyte of interest. To have a user-friendly operation, their development requires the optimization of multiple, interconnected parameters that may overwhelm new developers. In this tutorial, we provide the readers with: (i) the basic knowledge to understand the principles governing an LFA and to take informed decisions during lateral flow strip design and fabrication, (ii) a roadmap for optimal LFA development independent of the specific application, (iii) a step-by-step example procedure for the assembly and operation of an LF strip for the detection of human IgG and (iv) an extensive troubleshooting section addressing the most frequent issues in designing, assembling and using LFAs. By changing only the receptors, the provided example procedure can easily be adapted for cost-efficient detection of a broad variety of targets.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Hydrochloric acid, ACS reagent, 37%
Sigma-Aldrich
Sodium hydroxide, BioXtra, ≥98% (acidimetric), pellets (anhydrous)
Sigma-Aldrich
Sucrose, BioUltra, for molecular biology, ≥99.5% (HPLC)
Sigma-Aldrich
Anti-Human IgG (γ-chain specific)-Biotin antibody produced in goat, affinity isolated antibody, buffered aqueous solution
Sigma-Aldrich
Bovine Serum Albumin, heat shock fraction, protease free, pH 7, ≥98%
Sigma-Aldrich
IgG from human serum, reagent grade, ≥95% (HPLC), buffered aqueous solution
Sigma-Aldrich
TWEEN® 20, viscous liquid
Sigma-Aldrich
Anti-Human IgG (whole molecule) antibody produced in goat, IgG fraction of antiserum, buffered aqueous solution
Sigma-Aldrich
Phosphate buffered saline, tablet