Characterisation of particle-surface interactions via anharmonic acoustic transduction

Abstract

Most transduction methods for measuring particle-surface interactions are unable to differentiate the strength of interaction and largely reliant on extensive washing to reduce the ubiquitous non-specific background. Label-based methods, in particular, are limited in wide applicability due to their inherent operational complexity. On the other hand, label-free force-spectroscopic methods that can differentiate particlesurface interaction strength are skill-demanding and time-consuming. Here, we present a label-free anharmonic (nonlinear) acoustic transduction method employing the quartz crystal resonator that reads out ligand-receptor binding based on the interaction strength. We show that while stronger specific interactions are transduced more strongly, and in linear proportionality to the ligand concentration on microparticles, non-specific interactions are significantly attenuated. This allows ligand quantification with high specificity and sensitivity in realtime under flow without separate washing steps. Constructing an analytical model of a quartz resonator, we can relate the number and type (specific vs. non-specific) of ligandreceptor interactions with the change in characteristic nonlinearity coefficient of the resonator. The entirely-electronic and microfluidic-integrable transduction method could potentially allow a simple, fast and reliable way for characterising particlesurface interactions with economy of scale.

Simpler and faster quartz crystal microbalance for macromolecule detection using fixed frequency drive

“…1c) allowed a controlled surface functionalisation process and monitoring of the same using the QCR. Moreover, the D17.4 anti-hIgE aptamer employed here was thoroughly validated in our earlier work for sensitive hIgE detection with low cross-reactivity [105].…”

“…Among these, we noted different versions of D17.4 anti-hIgE aptamer to be well characterised and validated for label-free human IgE detection [73,89]. We employed one version of D17.4 anti-hIgE aptamer in this work [105]. Human immunoglobulin-G (hIgG) was used as a negative control.…”

“…Human immunoglobulin-E (hIgE) (ab65866) and human immunoglobulin-G (hIgG) (ab91102) were procured from Abcam (Cambridge, UK). D17.4 biotinylated anti-hIgE aptamer (MW=19.0234 kDa) with a base sequence of 5'-GGG GCA CGT TTA TCC GTC CCT CCT AGT GGC GTG CCC CTT TTT TTT TTT TTT TTT TTT TTT T/3Bio/-3' was synthesised by Integrated DNA Technologies (IDT) [105]. Thiolated alkanes, HS-(CH2)11-EG6-Biotin and HS-(CH2)11-EG3-OCH3, were purchased from ProChimia (Poland).…”

“…A custom-built network analyser with PC-based graphical user interface control and a facility to drive at a wide range of frequency and amplitude was employed for actuating and sensing the QCR [105,108]. Wolfram Mathematica 10 was used for processing the experimental data.…”