http://cau.ac.kr/~jjang14/BioMEMS/Ivnitski_BSBE_Bacteria_Detection_Bio_Sensors_Review_1999.pdf

Biosensors for detection of pathogenic bacteria

Commercial quartz crystal microbalances-Theory and applications

Acoustic Wave Sensors

Attachment of biomolecules on gold, silicon or glass surfaces has direct implications for the development of novel biosensors in the context of nanoscale detection of pathogens and other metabolites related to issues of human health. In this critical review, we have highlighted the current developments in various techniques of immobilization of biomolecules, specifically biological macromolecules on surfaces through the modification of a functional self-assembled monolayer. The utility of such immobilized biomolecules in the area of biosensing in nanoscale has been surveyed. Merits and demerits of some of the methods with reference to sensitivity of detection and practical use have been discussed (221 references).

Immobilization of bio-macromolecules on self-assembled monolayers: methods and sensor applications

The immobilization of antibodies on solid-phase materials has been used in many areas such as purification, diagnostic immunoassays and immunosensors. Problems associated with the loss of biological activity of the antibodies upon immobilization have been noticed in many cases. One of the main reasons for such loss is attributed to the random orientation of the asymmetric macromolecules on support surfaces. In this paper, the approaches for achieving oriented coupling of antibodies to increase the antigen binding capacity are reviewed. Some issues such as steric hindrance caused by neighbouring antibody molecules, the distance between an antibody and the support surface and the use of antibody fragments are dealt with. Some applications of the oriented immobilized antibodies in immunoassays and immunosensors are examined.

Tutorial review. Oriented immobilization of antibodies and its applications in immunoassays and immunosensors

A reusable piezoelectric immunosensor has been developed for the detection of viruses and bacteria, playing an important role in acute diarrhea in early childhood. Three different methods for antibody immobilization to the gold electrode were tested. Coating the electrode with protein A gave the best results in terms of stability, sensitivity and reproducibility. Worse results were observed when coating the electrode with γ-amino propyltriethoxy silane and polyethyleneimine. Applying an antibody layer via protein A immobilization onto a 10-MHz AT-cut crystal resulted for 1 × 106 to 1 × 1010 virus cells and for 1 × 106 to 1 × 108 bacteria in a linear frequency change. The modified crystal was stable for six weeks when stored desiccated at +4°C.

Bernd König

Papers

Detection of viruses and bacteria with piezoelectric immunosensors

Development of a piezoelectric immunosensor for the detection of human erythrocytes

A piezoelectric immunosensor for hepatitis viruses

Detection of human T-lymphocytes with a piezoelectric immunosensor

Long-term stability and improved reusability of a piezoelectric immunosensor for human erythrocytes