Development of quantitative detection and analysis technology of biomolecular interactions for diagnosis of degenerative diseases using atomic force microscopy

Abstract

Mankind has been suffering from various human degenerative disorders such as cardiovascular diseases, cancers, Alzheimer’s disease, and Parkinson’s disease. These diseases are generally related to abnormal molecular behaviors with cascading illness. For example, protein misfolding causes dysfunctions or malfunctions of numerous enzymes in metabolism, and subsequently induces cancerous cells and amyloidosis. Indeed, understanding intrinsic properties of the biomolecules and molecular interactions is critical in diagnosis and cure of the degenerative diseases. The key to insight of biomolecular interactions at the single-molecule level is multidisciplinary studies with spectroscopy, bio- imaging, and stimulus-response tests. Recently, scanning probe microscopy (SPM) including atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM) is utilized as a versatile toolkit to study biological and nanoscale materials. Specifically, SPM is useful in not only sub-micrometer imaging of biological samples with their nature in nanoscale structures, but also nanomechanical detection of DNA-DNA or protein-protein interactions at sub-nano newton forces at sub-nano molar concentration. Moreover, it is possible that the quantitative mapping of physicochemical properties of biomolecules with high resolution and sensitivity. In this study, biomolecular interactions related to various human degenerative diseases such as cancer, metastasis, and amyloidosis are investigated by SPM. Particularly, enzymatic activity is quantitatively measured and analyzed for cancer diagnosis, and protein-protein interactions related to amyloidosis are demonstrated. It is shown that SPM is a powerful tool for characterizing such various biomolecular interactions, ultimately enables early diagnosis of human degenerative diseases at the single-molecule level.