Assay of Glomalin Using a Quartz Crystal Microbalance Biosensor

Abstract

AbstractGlomalin is a soil protein abundantly occurring in the soil. In the current time, knowledge about glomalin is limited and there are also missing simple test for the determination of glomalin in the environment. This work is devoted to construction of a biosensor which is expected to be a simple device for the determination of glomalin in extracts from soil samples. The biosensor was constructed using an antibody against glomalin and piezoelectric quartz crystal microbalance (QCM) sensor platform allowing label free assay. Electrodes of QCM were activated using cysteamine and glutaraldehyde and finally, an antibody against glomalin was immobilized. Glomalin was acquired from various soil samples by extraction in an autoclave and its content was determined by a standard spectrophotometric test. Time necessary to bind sufficient amount of glomalin was discovered for the biosensor and four hours incubation interval corresponded with maximal efficacy. Limit of detection for the biosensor based assay was found to be equal to 3.40 μg/g which is enough to cover all the tested soil samples containing glomalin in a concentration from 291 μg/g to 3.47 mg/g. The assay also fully correlated with the standard tests. In a conclusion, the piezoelectric biosensor seems to be a suitable platform for the determination of glomalin in samples of environment origin. The method represents an improvement of the current analytical platforms that are based on measurement of total protein content in soil extract.