New oligoethylene glycol linkers for the surface modification of an ultra-high frequency acoustic wave biosensor

Abstract

This work describes the application of acoustic wave technology for the real-time and label-free detection of biotin-avidin interactions. Biosensing surfaces are constructed onto unelectroded piezoelectric quartz discs as functionalizable mixed self-assembled monolayers (SAM) produced from previously unreported linker and diluent molecules. Biotinthiol can subsequently be immobilized for detection purposes in a straightforward and coupling-free manner. Specific and non-specific adsorptions of avidin are measured at ultra-high frequencies (1.06 and 0.82 GHz) with an electromagnetic piezoelectric acoustic sensor (EMPAS) using micromolar avidin-spiked buffer solutions. These biosensing surfaces, especially the oligoethylene glycol SAM-based variety, display high specificity for avidin, with moderate to excellent reproducibility. This preliminary work constitutes the first application of SAM chemistry and EMPAS technology in the bioanalytical field.

A true theranostic approach to medicine: Towards tandem sensor detection and removal of endotoxin in blood

“…The EMPAS is a relatively new, built in-house piezoelectric system that belongs to the larger family of bulk acoustic wave (BAW) devices and, unlike its BAW predecessors, operates through the remote instigation of acoustic resonance within electrode-free quartz discs by an external electromagnetic field (Ballantyne and , at ultra-high frequencies up to 1.06 GHz (Sheikh et al, 2010(Sheikh et al, , 2011. These features allow in practice the EMPAS to offer superior analytical sensitivity compared to the more conventional BAW piezoelectric sensors (Ballantyne and Thompson, 2004).…”

“…Borosilicate glass beads (d ¼1 mm) were purchased from Sigma-Aldrich. Silanization reactions (mixed adlayer formation) with OEG-TTTA and MEG-TFA trichlorosilanes (Sheikh et al, 2010) were prepared in a glovebox maintained under inert (N 2 ) and anhydrous (P 2 O 5 ) atmosphere, using glassware pre-treated overnight with a 1/20 (v/v) solution of octadecyltrichlorosilane in anhydrous toluene. Quartz discs were systematically handled with thoroughly pre-cleaned stainless steel tweezers to avoid external contamination.…”

“…Both diagnostic and therapeutic platforms adopt the same proprietary surface chemistry, which relies on the covalent attachment of PMB to silica substrates through organosiloxane mixed adlayer coatings constructed from a binary mixture of mono-and oligoethylene glycol (MEG and OEG) trichlorosilane surface modifiers (Thompson et al, 2013;Sheikh et al, 2010) (Fig. 2).…”

Ultra-high frequency piezoelectric aptasensor for the label-free detection of cocaine

“…The coil and piezoelectric substrate are located in a sample cell, wherein a running buffer is flowed, hence the EMPAS operates in an online and real-time detection format. In practice, the sensor has been successfully applied for the detection of proteins (Sheikh et al, 2011(Sheikh et al, , 2010, and lipopolysaccharide pathogens (Thompson et al, 2015), as well as for the evaluation of surface fouling (Sheikh et al, 2013. Functionalization of the EMPAS sensor platforms is generally achieved through the use of conditioning organic adlayers.…”

Rapid Detection of Human Immunodeficiency Virus Types 1 and 2 by Use of an Improved Piezoelectric Biosensor

“…Rupp and colleagues used antibodies in extensive cross-recognition experiments to validate sensitivity and specificity and also reported on the effect of serum on these parameters (26). Similarly, Sheikh and coworkers studied the interactions between biotin and avidin in a real-time and label-free manner on self-assembling monolayers (27). Pertinent to the application reported herein, Sheikh and colleagues have previously reported on the detection of HIV-2 antibodies in serum using a label-free approach on an ultra-highfrequency acoustic wave sensor at 1.06 GHz (28).…”