A quartz crystal biosensor for measurement in liquids

• Published in: Biosensors & bioelectronics 1992, Vol.7 (6), p.397-404
• Main Authors: Kößlinger, Conrad, Drost, Stephan, Aberl, Franz, Wolf, Hans, Koch, Sabine, Woias, Peter
• Format: Article
• Language: English
• Subjects: AIDS/HIV; anti-HIV antibody; Biological and medical sciences; Biosensing Techniques; biosensor; Biosensors; Biotechnology; Crystallization; Electronics; Evaluation Studies as Topic; Fundamental and applied biological sciences. Psychology; HIV Antibodies - analysis; HIV Antigens; human immunodeficiency virus; Humans; Immunoassay - methods; immunosensor; Immunosorbent Techniques; Methods. Procedures. Technologies; Peptides - immunology; piezoelectric crystal; Quartz; Various methods and equipments
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/0956-5663(92)85038-C

The detection of anti-human immunodefficiency virus (HIV) antibodies by means of synthetic HIV peptide immobilized on a piezoelectric quartz sensor is demonstrated. The measurement set-up consists of an oscillator circuit, a suitably modified. AT-cut thickness-shear-mode quartz crystal with gold electrodes, which is housed in a special reaction vessel, and a computer-controlled frequency counter for the registration of the measured frequency values. The quartz crystal is adapted for a steady operation in liquids at a frequency of 20 MHz. In phosphate-buffered saline solution the oscillator reaches a stability of about 0.5 Hz within a few seconds, of about 2 Hz within 10 min and about 30 Hz within 1 h. The frequency shift due to the adsorption of various proteins to the uncoated sensor surface has been investigated. It can be shown that a stable adsorptive binding of proteins to an oscillating gold surface is feasible and can be used for the immobilization of a receptor layer (e.g. HIV peptide). Specific binding of the anti-HIV monoclonal antibody to the HIV peptide immobilized on the quartz sensor is demonstrated. Control experiments show, however, additional unspecific binding. According to the experiments, the Sauerbrey formula gives a sufficienty accurate value for the decrease of the resonant frequency due to adsorption or binding of macromolecular proteins on the quartz crystal surface.