Virus Electrodes for Universal Biodetection

Abstract

A dense virus layer, readily tailored for recognition of essentially any biomarker, was covalently attached to a gold electrode surface through a self-assembled monolayer. The resistance of this "virus electrode", Z(Re), measured in the frequency range from 2 to 500 kHz in a salt-based pH 7.2 buffer, increased when the phage particles selectively bound either an antibody or prostate-specific membrane antigen (PSMA), a biomarker for prostate cancer. In contrast to prior results, we show the capacitive impedence of the virus electrode, Z(Im), is both a noisier and a less sensitive indicator of this binding compared to Z(Re). The specificity of antibody and PSMA binding, and the absence of nonspecific binding to the virus electrode, was confirmed using quartz crystal microbalance gravimetry.

Die Anwendung von Viren in Chemo‐ und Biosensoren

“…4) Fertig ist die Viruselektrode, bereit für den Einsatz in der Analyse! [136] Abbildung 10. ¾nderung der ohmschen Impedanz DZ Re mit der Konzentration eines Anti-Phage-Antikörpers (p-Ab) und eines nichtbindenden Antikörpers (n-Ab).…”

“…Ein EIS-Biosensor mit einer CVL aus solchen Phagen eignet sich für den selektiven PSMA-Nachweis. [136] Weil zielspezifische Proteine durch Phagendisplays identifiziert und mithilfe von gentechnischen Methoden auf der Oberflächen von Phagen präsentiert werden können, sollten Phagen für EIS-Biosensoren mit hö-herer Affinität und Spezifität für so gut wie jeden Analyt herstellbar sein. [154] 3.3.…”

The Promise of Phage Display: Customized Affinity and Specificity

“…Our own efforts have culminated in the development of a scheme for covalently attaching M13 phage particles to a gold surface via a SAM of an N-hydroxy succinimide (NHS)-ester- functionalized dithiol, resulting in phage coverage of 10 11 particles/cm 2 ( Figure 4d; 39,40). This covalent virus surface (CVS) retains the affinity of the free M13 phage for the target molecule (an anti-wild-type P8 antibody) and can bind 140 target molecules per phage particle (Table 1).…”

“…Ironically, in this frequency range, the resultant signal, defined as the absolute increase in resistance of the CVS when binding occurs, is the smallest. For example, the resistance of the CVS prepared on a 0.3 cm 2 electrode (200-300 Ω) increased by up to 14 Ω at 3 kHz when the binding sites on this surface were saturated with molecules of prostate-specific membrane antigen (PSMA), a prostate cancer marker (40). The detection limit was 120 nM, which is several orders of magnitude too large to be of clinical relevance.…”

Heightened sense for sensing: recent advances in pathogen immunoassay sensing platforms

“…This approach has recently been demonstrated by Yang and co-workers against cancer biomarkers, in which the prostatespecific membrane antigen (PSA) binding M13 bacteriophage was covalently attached onto gold electrode surfaces. 47 Electrochemical impendence spectroscopy was used to measure specific PSA binding, resulting in a reliable signal-to-noise ratio of ~10 for PSA concentrations down to 100 nM. The "virus-based" sensing chips represent an improvement in both the capacitive impedance and frequencies over other previously reported electrochemical biosensors.…”