Glycan-Based Flow-Through Device for the Detection of SARS-COV-2

Abstract

The COVID-19 pandemic, and future pandemics, require diagnostic tools to track disease spread and guide the isolation of (a)symptomatic individuals. Lateral-flow diagnostics (LFDs) are rapid and of lower cost than molecular (genetic) tests, with current LFDs using antibodies as their recognition units. Herein, we develop a prototype flow-through device (related, but distinct to LFDs), utilizing N- acetyl neuraminic acid-functionalized, polymer-coated, gold nanoparticles as the detection/capture unit for SARS-COV-2, by targeting the sialic acid-binding site of the spike protein. The prototype device can give rapid results, with higher viral loads being faster than lower viral loads. The prototype’s effectiveness is demonstrated using spike protein, lentiviral models, and a panel of heat-inactivated primary patient nasal swabs. The device was also shown to retain detection capability toward recombinant spike proteins from several variants (mutants) of concern. This study provides the proof of principle that glyco-lateral-flow devices could be developed to be used in the tracking monitoring of infectious agents, to complement, or as alternatives to antibody-based systems.

Lateral Flow Glyco‐Assays for the Rapid and Low‐Cost Detection of Lectins–Polymeric Linkers and Particle Engineering Are Essential for Selectivity and Performance

“…It was not possible to find a commercially available BSA-glycoconjugate with sufficient affinity for RCA 120 to generate a test line. Therefore, an alternative approach, a “flow-through assay,” [ 40 , 52 , 53 ] was used based on direct deposition of the target (RCA 120 at 5 mg mL −1 ) onto the test line, followed by running the dipstick. Whilst unconventional, we have previously used this methodology in S1 spike protein detection.…”

“…[ 36 ] This clearly demonstrated that lateral flow glyco-assays, LFDs that use glycans as capture agents (on the test line and particle) for an analyte, have potential applications in rapid diagnostics, surveillance, and as accessible research tools for evaluating glycan-binding protein function. Further work utilizing a flow-through glyco-assay demonstrated that glycans could be used as capture agents to sense for the SARS-COV-2 virus in patient samples and that these tests were thermally robust, [ 40 ] which could be an advantage of glycan-based devices versus antibody-based devices. [ 41 ] To advance the study of glyco-LFD technology, LFDs that use glycans as capture agents on test lines and/or particles, it is crucial to understand how each component (particle, surface) impacts performance.…”

Glycosylated gold nanoparticles in point of care diagnostics: from aggregation to lateral flow

“…13A). 242 Controlled radical polymerisation (RAFT) was employed to undertake a detailed structure-function study exploring how the polymeric glyco tether impacted the performance of a lectin-detecting lateral flow system. 243 Using galactose as the glyco-ligand, the delicate balance between polymer chain length to give specificity, but avoid non-specific binding was revealed, demonstrated by differential binding profiles to SBA and RCA120 using the same glycan on different polymers (Fig.…”

“…Fig.13Representative lateral flow glyco-assay and flow through glycoassay for sensing for SBA243 (A) and SARS-COV-2242 (B) respectively.…”

Polymer-tethered glycosylated gold nanoparticles recruit sialylated glycoproteins into their protein corona, leading to off-target lectin binding

“…20,21 Polymer-tethered sialic acidfunctionalised gold nanoparticles have been designed to bind the N-terminal domain of the SARS-CoV-2 spike protein, allowing for detection in lateral flow or liquid phase assays. [22][23][24] Similarly, lateral flow devices using heparin (which targets a different domain of the spike protein) have been demonstrated. 25 In these specific examples the glycosylated nanomaterials are exposed to nasal swab elutions, which have been diluted and hence components of the biological matrix (mucins etc.)…”