Development of Rapid In-situ Multi-property Characterization of Biological Materials Using Scanning Probe Microscopy

Abstract

To characterize the physiologies of biological samples the molecular and immunological staining combining optical microscopy for mammalian tissues mammalian cells and microbes are probably the most common techniques Although those conventional methods have been conventionally used the major drawbacks including time-consumed and labor-intensive need to be solved for the effective development of research Believing the physiologies of biological matters influence their physical properties the atomic force microscopy (AFM) is adapted in this work for the in-situ rapid multi-property examination Possessing several advantages such as simple preparation for specimen flexible working environments and nanoscale resolution the examination time could be significantly decreased from couples of days by those conventional ways to few hours by the probe-based technique Here the surface characteristics of a variety kind of biological materials involving mouse skin tissues and multiple strains of two human pathogen Clostridium difficile and Escherichia coli were focused on The resolution of surface morphologies were determined by the sharpness of AFM tip the detailed information of surface components could be revealed by the simultaneous mechanical mapping and the localized mechanical behaviors of the bacteria were found to be specific to each specimen The results gave the hint of the connection between biological physiologies and physical traits and consequently this method was reckoned as the promising way for the rapid examination The tip-based contact mechanism theory which is required for the calculation of the elastic modulus was noticed to result in the high uncertainty in microbial samples and the real stiffness behaviors of those specimens were obscured To obtain a reliable elastic modulus a reference specimen was selected for multiple testing to establish a new formula fitting to such types of materials Our proposed equation successfully improved both the precision and accuracy of sample modulus and the corresponding new deformational mechanism of the hyperelastic matters was suggested

Date of Award	2018 May 29
Original language	English
Supervisor	Bernard Haochih Liu (Supervisor)