Challenges of the Nano–Bio Interface in Lateral Flow and Dipstick Immunoassays

Abstract

Lateral flow assays (LFAs) are highly attractive for point of care diagnostics for infectious disease, food safety, and many other medical uses. The unique optical, electronic and chemical properties that arise from the nanostructured and material characteristics of nanoparticles provide an opportunity to increase LFA sensitivity and impart novel capabilities. However, interfacing to nanomaterials in complex biological environments is challenging and can result in undesirable side effects such as non-specific adsorption, protein denaturation, and steric hindrance. These issues are even more acute in LFAs, where there are many different types of inorganic-biological interfaces, often of complex nature. Therefore, the unique properties of nanomaterials for LFAs must be exploited in a way that addresses these interface challenges.

Sensitivity enhancement in lateral flow assays: a systems perspective

“…The reduction of sensitivity by assay interferents in human clinical sample matrices, such as blood and urine, due to the non-specific immobilization of detection reagents, has been reviewed extensively. [76][77][78][79] Blocking. An almost universal strategy for reducing the impact of non-specific binding or adsorption on signal is to dry passive blocking reagents into an LFA.…”

Radial Flow Assay Using Gold Nanoparticles and Rolling Circle Amplification to Detect Mercuric Ions

“…Recently, paper-based assays (PBAs) have received considerable attention in the area of point-of-care testing (POCT) [ 25 ]. Many PBAs adopt formats with lateral flow assays (LFAs), dipstick assays, and microfluidic paper-based analytical devices (µPADs) [ 26 , 27 , 28 ]. These formats for PBAs have great advantages in terms of their reasonable price, portability, ease of handling, and low sample/reagent consumption [ 29 , 30 , 31 ].…”

Reporter Selection for Nanotags in Multiplexed Surface Enhanced Raman Spectroscopy Assays

“…Even though the nanoparticle concentration was the same for each of the individual nanotags, the SERS signal of each sample can still differ because of other factors 32 such as inherent reporter Raman intensity and reporter concentration on the GNS, as well as the antibody surface density (coverage) on the nanoparticle. 38 SERS measurements of the test area for a strip run with a mixture of all of the nanotags (mix, purple line) resulted in a spectrum exhibiting the different features of each individual reporter, which could be distinguished in the spectrum. SERS measurements of the test areas for tests run with no IgG present showed spectra characteristic of nitrocellulose, with no spectral contributions of the Raman reporters, confirming the negative control ( Supporting Information , Figure S4b).…”