Production of high-quality extremely-thin histological sections by ultrasonically assisted cutting

Abstract

Modern-day histology of biological tissues requires precision cutting of a wide variety of tissue samples for histological analyses. Lots of common problems can be identified at the conventional microtome sectioning including creation of curling sections and sections stick to the blade, which made high-quality sections hard to obtain. This paper deals with the development of next generation of microtomes employing introduction of a controlled ultrasonic vibration to process biological tissues. Based on a combination of advanced experimental and numerical studies of a novel cutting system with multi-body dynamics, this study investigated effects of cutting parameters and characteristics of ultrasonic excitation with the aim to design and manufacture an ultrasonically assisted cutting device (UACD) for microtomy. The cutting mechanism was detailed to show the advantages of the ultrasonically assisted cutting in the creation of high quality, thin sections. The novel prototype was designed and developed to conduct conventional cutting (CC) and ultrasonically assisted cutting (UAC) of biological tissues embedded in wax. Cutting forces, blade wear, blade damage and section quality for these cutting processes were assessed. It was found that the efficiency and quality of cutting were dependent on the level of cutting forces, which were lower in UAC compared with CC. The quality of cut samples with a thickness of 4 μm was better in UAC than CC. The developed ultrasonically assisted cutting device also enables successfully sectioning of the thin biological samples with high precision, reduced blade wear and less blade damage. This will increase the blade life making both environmental and economic impacts.