QCM–FIA with PGMA coating for dynamic interaction study of heparin and antithrombin III

Electrochemical impedance spectroscopy as a highly sensitive tool for a dynamic interaction study between heparin and antithrombin: a novel antithrombin sensor

Specific recognition between two biological partners is widely exploited in biosensors nowadays. To explore this avenue, a novel biosensor for antithrombin (AT) detection was constructed. Heparin was used as the affinity ligand. A well-known acrylic monomer (butyl methacrylate) was polymerized and grafted onto the heparin polysaccharide by the use of ceric ammonium nitrate as a redox initiator in aqueous nitric acid medium. Polymers were deposited as a thin layer onto surface of stainless steel electrode (SS316L). The obtained polymers were studied by Fourier transform infrared spectroscopy (FTIR) and analyzed by differential scanning calorimetry (DSC). Moreover, the films were characterized by electrochemical impedance spectroscopy (EIS), contact-angle measurements and AFM. EIS was used to study the biosensor affinity to AT and the relationship between functionalization growth of modified electrode and the response of the sensor. The proposed approach appears to be simple, sensitive and correlated with methods that analyse the detection of antithrombin.

A survey of the 2001 to 2005 quartz crystal microbalance biosensor literature: applications of acoustic physics to the analysis of biomolecular interactions

The widespread exploitation of biosensors in the analysis of molecular recognition has its origins in the mid-1990s following the release of commercial systems based on surface plasmon resonance (SPR). More recently, platforms based on piezoelectric acoustic sensors (principally 'bulk acoustic wave' (BAW), 'thickness shear mode' (TSM) sensors or 'quartz crystal microbalances' (QCM)), have been released that are driving the publication of a large number of papers analysing binding specificities, affinities, kinetics and conformational changes associated with a molecular recognition event. This article highlights salient theoretical and practical aspects of the technologies that underpin acoustic analysis, then reviews exemplary papers in key application areas involving small molecular weight ligands, carbohydrates, proteins, nucleic acids, viruses, bacteria, cells and lipidic and polymeric interfaces. Key differentiators between optical and acoustic sensing modalities are also reviewed.

Acoustic microsensors—the challenge behind microgravimetry

Acoustic microsensors are commonly known as high-resolution mass-sensitive devices. This is a restricted view in many chemical and biosensor applications, especially in liquids. Sensitivity to non-gravimetric effects is a challenging feature of acoustic sensors. In this review we give an overview of recent developments in resonant sensors including micromachined devices and also list recent activity relating to the (bio)chemical interface of acoustic sensors. Major results from theoretical analysis of quartz crystal resonators, descriptive for all acoustic microsensors are summarized, and non-gravimetric contributions to the sensor signal from viscoelasticity and interfacial effects are discussed. We finally conclude with some future perspectives.