Novel approaches to investigate behaviors of bacteria by atomic force microscopy and circulating tumor cells through microfluidics

Abstract

The adaptability and apparent ingenuity of renegade and intruding cells within the human body present formidable challenges in warding off disease. As the longevity of humans increases, cancer will afflict greater numbers, and if bacteria continue to grow resistant to conventional antibiotics, new treatment approaches will need to be identified. Through the use of two types of advanced instrumentation, a high-speed atomic force microscope (AFM) and microfluidic devices, further insights into behaviors of bacteria and cancer cells were sought, respectively. Although involving very different types of cells, the projects were characterized by overarching similarities, including the aim of studying the cells at the individual level and the need to attach the cells to a substrate to accomplish this. Ultimately, these studies uncovered phenomenon that without the AFM and microfluidics may have gone unnoticed. Specifically, a new, possible two-phase response of bacteria to an antimicrobial peptide (AmP) was discovered by high-speed AFM, and very large clusters of circulating tumor cells (CTCs) with platelets were captured on the microfluidic device - albeit the mechanism by which this happens remains to be determined. These insights were the result of seeking to understand the response of E. coli to CM15, a particular AmP, and attempting to isolate platelet-CTC complexes with a herringbone microfluidic device functionalized with antibodies that bind to surface markers on activated platelets.