Detection of human T-lymphocytes with a piezoelectric immunosensor

Advancements in Biosensor Technologies for Medical Field and COVID-19 Pandemic

World health organization (WHO) has declared the COVID-19 outbreak as a public health emergency of international concern and then as a pandemic on 30th of January and 11th of March 2020, respectively. After such concern, the world scientific communities have rushed to search for solutions to bring down the disease’s spread, fast-paced vaccine development, and associated medical research using modern technologies. Biosensor technologies play a crucial role in diagnosing various medical diseases, including COVID-19. The present paper describes the major advancement of biosensor-based technological solutions for medical diagnosis, including COVID-19. This review-based work covers the biosensors and their working principles in the context of medical applications. The paper also discusses different biosensors and their applications to tackle medical issues, including this ongoing pandemic.

Uncoated quartz resonator as a universal biosensor

We studied dynamic processes in drying drops of model protein-salt solutions, using an uncoated quartz resonator as a biosensor. To measure these processes we developed a method based on recording the dynamics of the Acoustic-Mechanical Impedance (AMI) of a drop as it dried on the surface of a quartz resonator oscillating at a resonant frequency of 60 kHz. The aim of this work was to highlight the role of some components of serum in self-organization processes. Human serum albumin (HSA), fibronectin (Fn), immunoglobulin G (IgG), immunoglobulin M (IgM), bovine serum albumin (BSA), sodium chloride (NaCl), Potassium Chloride (KCl), and nonionic surfactant O(CH(2)CH(2))(n)CH(2)CH(2)OH were used as components of the tested solutions. It was shown that dynamics of the AMI in drying drops were closely related to liquid composition. This approach allowed us to distinguish with good accuracy solutions in which one or more components (proteins or salts) were replaced by other components with the same mass concentration. We assumed that these differences were due to different surface properties and native functions of proteins, and different positions of salts in the Hofmeister line. Our preliminary work demonstrated that the dynamics of phase transitions in drying drops of serum could be used as an informative parameter for medical diagnostics. In this study, we highlight some positions in this cause-effect chain.

Immunosensors: electrochemical sensing and other engineering approaches

This article overviews the engineering approaches and the recent trends in the development of alternative immunoassay systems. A brief description of the main principles and limitations of conventional immunoassay is given. Immunosensing approaches overcoming these limitations are discussed. Alternatives to traditional immunoassay systems are discussed in terms of the enhancement of immunointeraction processes and in terms of the various detection principles. Applications of flow-injection techniques to the development of immunosensing systems are presented. Immunosensors are categorized based on the detection principle employed, as immunoelectrodes (electrochemical immunosensors), piezoelectric immunosensors, or as sensors based on optical detection of the immunointeraction. The discussion focuses on electrochemical immunosensors. In conclusion, the engineering issues involved in immunosensor development are outlined and trends towards practical applications are discussed.

A novel method of immobilizing antibodies on a quartz crystal microbalance using plasma-polymerized films for immunosensors

A novel method of immobilizing antibodies on quartz crystals for use in immunosensors was developed using an ethylenediamine plasma-polymerized film matrix. The films formed on the quartz crystals are extremely thin and homogeneous, and they incorporate amino groups. Sensors produced using this method are more reproducible from sample to sample and exhibit lower noise and higher sensitivity than sensors made using conventional immobilization methods, e.g., via polyethylenimine and (gamma-aminopropyl)trimethoxysilane. This is, to our knowledge, the first reported application of plasma-polymerized films to quartz crystal microbalance immunosensors. Results on orientation-controlled immobilization of anti-bodies, reusability and calibration tests are also presented.