Determination of Lysozyme Using Microcantilever Sensor Based on Atomic Force Microscopy

A microcantilever sensor was developed to detect lysozyme in a pharmaceutical formulation based on the principle of atomic force microscopy. By measuring the cantilever bending and deflection using the optical reflection technique, the lysozyme adsorption on a dodecanethiol-modified cantilever surface was detected. Under optimal conditions, a good linear relationship between the deflection of the microcantilever and the logarithm of the lysozyme concentration in the range from 10 ng L−1 to 0.1 mg L−1, with a correlation coefficient of 0.998, was established. The limit of detection was 5.0 ng L−1. The lysozyme in the pharmaceutical formulation sample was determined with the desirable results by using the present method.