A Versatile Biomimic Nanotemplating Fluidic Assay for Multiplex Quantitative Monitoring of Viral Respiratory Infections and Immune Responses in Saliva and Blood

Abstract

The last pandemic exposed critical gaps in monitoring and mitigating the spread of viral respiratory infections at the point‐of‐need. A cost‐effective multiplexed fluidic device (NFluidEX), as a home‐test kit analogous to a glucometer, that uses saliva and blood for parallel quantitative detection of viral infection and body's immune response in an automated manner within 11 min is proposed. The technology integrates a versatile biomimetic receptor based on molecularly imprinted polymers in a core–shell structure with nano gold electrodes, a multiplexed fluidic‐impedimetric readout, built‐in saliva collection/preparation, and smartphone‐enabled data acquisition and interpretation. NFluidEX is validated with Influenza A H1N1 and SARS‐CoV‐2 (original strain and variants of concern), and achieves low detection limit in saliva and blood for the viral proteins and the anti‐receptor binding domain (RBD) Immunoglobulin G (IgG) and Immunoglobulin M (IgM), respectively. It is demonstrated that nanoprotrusions of gold electrodes are essential for the fine templating of antibodies and spike proteins during molecular imprinting, and differentiation of IgG and IgM in whole blood. In the clinical setting, NFluidEX achieves 100% sensitivity and 100% specificity by testing 44 COVID‐positive and 25 COVID‐negative saliva and blood samples on par with the real‐time quantitative polymerase chain reaction (p < 0.001, 95% confidence) and the enzyme‐linked immunosorbent assay.

Recent development of nanotechnology-empowered antigen assay methods for the control of infectious diseases

“…72 The latest lab-on-a-chip technology enables the integration of multiple parallel but spatially separated recognition reactions on a single small chip for multiplexed assays in a small volume of sample. [73][74][75] And, the combination of these technologies with artificial intelligence (AI) would further enhance the accuracy of recognition. 39 In summary, the cutting-edge antigen assay methods mentioned in this review have their own advantages and limits.…”

Rational In Silico Design of Molecularly Imprinted Polymers: Current Challenges and Future Potential

“…Currently, polymer simulations are performed in simple solvents but can be innovatively extended to modelled fluids based on their intrinsic components. For instance, it is necessary to test MIPs for their ability to ultimately bind in human saliva (as such or diluted) when they are developed as artificial antibodies to target an oral biomarker/antigen [ 146 , 147 , 148 ]. Before actually proceeding to in situ testing, an experimentally simulated artificial saliva can be used [ 149 , 150 ] composed mainly of buffer ions, tween 20, xanthan gum, mucin, and amylase proteins [ 151 ], and this in turn can be computationally mimicked by adding the respective atomic and crystal structures to the MD simulation box along with the modelled MIP.…”

Microfluidic-based colorimetric nucleic acid detection of pathogens

“…2 While polymerase chain reaction (PCR) remains the gold standard technique, next generation and advanced pathogen sensing platforms have been recently reported. 3,4 Among these, colorimetric detection has gained attention for its ability to deliver results on the order of minutes, as well as for its user-friendly and cost-effective methods. Colorimetric detection can be combined with nucleic acid assays for rapid and accurate detection of disease biomarkers.…”