Atomic Force Microscopy for Space Applications

Atomic force microscopy (AFM) analysis of protein fibers and bone tissues will be the focus of this project. Atomic force microscopy will be used to analyze the behavior of protein colloids, their formation, behavior and aggregation. Atomic force microscopy will be used to analyze protein fibers formed by amyloidosis and compared with collagen fibers. Collagen minimization leads to formation of bone tissues whereas calcification of amyloid fibers forming plaques is found to be an early event in dozens of human diseases including Alzheimer's disease, Parkingon's disease, prion disease, and type 2 diabetes. AFM,  TEM, confocal microscopy, MALDI mass spectrometry, dynamic light scattering, microplate reader for high-throughput screening, circular dichroism, and traditional biochemical and molecular biology approaches are used to understand, at the molecular level, the pathway and the energy driving protein fiber formation. Although individual protein monomers are not considered colloids, the spherical aggregates observed as intermediates in amyloid fiber formation are colloidal particles. Formation of chemical colloids is dependent primarily on molecular properties such as charge and hydrophobicity, which are indirectly related to structure, but does not depend directly on structure-specific interaction between molecular groups; this paradigm may apply to protein amyloid aggregation as well.

Additionally, the application of AFM in the analysis of organs and tissues, however, has been limited. In this study, we present a new method for high-resolution atomic force microscopy imaging of compact bone tissue. We performed atomic force microscopy imaging on demineralized compact bone from bovine tibia to obtain structural information about the bone matrix and the lacunar-canalicular network. Knowledge of the dimensions and distributions of the network allows quantitative analysis of the microfluidics of bone tissue.