Total Capture, Convection-Limited Nanofluidic Immunoassays Exhibiting Nanoconfinement Effects

Abstract

Understanding nanoconfinement phenomena is necessary to develop nanofluidic technology platforms. One example of nanoconfinement phenomena is shifts in reaction equilibria toward reaction products in nanoconfined systems, which have been predicted theoretically and observed experimentally in DNA hybridization. Here we demonstrate a convection-limited nanofluidic immunoassay that achieves total capture of a target analyte and an apparent shift in the antibody-antigen reaction equilibrium due to nanoconfinement. The system exhibits wavefronts of the target analyte that propagate along the length of the nanochannel at a velocity much slower than that of the carrier fluid. We apply an analytical model describing the propagation of these wavefronts to determine the density of capture antibody binding sites in the enclosed nanochannel for a known concentration of the target analyte. We then use this binding site density to estimate the concentration of solutions with 5× and 10× less analyte. Our analysis suggests that nanoconfinement results in a preference toward binding of the target analyte with the surface-grafted capture antibody, as evidenced by an apparent reduction in the equilibrium dissociation constant. Our findings motivate the advancement of new biomedical and chemical synthesis technologies by leveraging nanoconfinement effects, and demonstrate a useful platform for studying the effect of nanoconfinement on chemical systems.

Confinement effects on DNA hybridization in electrokinetic micro‐ and nanofluidic systems

“…As many emerging nanosensing technologies require electric fields for biomolecule transport, separation, and detection, we determined whether nanoconfinement enhances molecular recognition under an applied electric field. We showed that the nanoconfinement effect on molecular recognition observed in in pressure‐driven and stationary‐flow systems also extends to electrophoretic separation systems with application of a high potential . However, in order for this technique to provide truly quantitative results, we must expand the parameter sweep of the model, investigate the impact of injection plug width variation on both experimental and simulated electropherograms, and examine the impact of second‐order reaction kinetics on the robustness of the numerical simulation technique.…”

“…In addition, Galvin et al. observed confinement‐enhanced protein‐antibody association in a nanofluidic immunoassay .…”

“…Rubonovich et al performed further analysis on the experiments of Shon et al, and suggested the results represent a nanoconfinement entropic effect on chemical equilibrium -stabilizing the reaction products and reducing k off [13]. In addition, Galvin et al observed confinement-enhanced protein-antibody association in a nanofluidic immunoassay [14].…”

Piezoelectric and dielectric properties of Bi3TiNbO9 prepared by hot pressing from powders activated using the serial dilution method

“…Studying the applications of UHD technology in biology, it was found that the addition of UHD of antibodies could cause the change in conformation of the target protein 40 . Also, some authors report that a substance may completely change its properties when tightly surrounded by certain structures 41,42 . As mentioned earlier, UHD process leads to formation of nanostructures and nanobubbles [31][32][33] .…”

Nanofluidics Drives Point-of-care Technology for on the Spot Protein Marker Analysis with Rapid Actionable Results

“…Moreover, contrary to polydimethylsiloxane (PDMS) based systems, the MEMS scaffold of the biosensors enables mechanical robustness, cost-effectiveness and capacity for large-scale manufacturing using well-controlled processes, which are all essential for a robust commercial product. Secondly, the fluidic system was developed based on a combination of micro-and nanoscale structures and uses only capillary forces instead of active actuation typically used Several academic works have demonstrated that nanofluidic systems can be used for rapid sensing of biomolecules [16][17][18][19][20] and have provided deep insights, supported by theoretical modelling, into the mechanisms by which biomolecular interactions are enhanced. While differences exist between these systems and the one presented here, notably regarding the fact that we have developed a homogeneous ('no-wash') system without pressuredriven actuation, it is important to point out that the analyte capture behavior observed is in line with the principle of nano-fluidics: efficient mass transfer and nanoconfinement as described in previous studies.…”