Conventional diagnosis of breast cancer involves the histological and immunohistochemical analysis of tissue sections obtained through clinical biopsy. For surgical margin assessment within the operating room, the standard technique is frozen section examination, which takes between 30 min to two hours to give results. Technologies for rapid and label-free diagnosis of malignancies from breast tissues thus have significant potential for application in pathology labs and operating rooms. An IISc team led by Annapoorni Rangarajan and Hardik J Pandya along with researchers from Assam Medical College, reports the design, development, and clinical validation of a MEMS-based platform for characterisation of ex vivo breast biopsy tissues to classify them as either tumour or normal.
Their RapidET system integrates silicon microchips with interdigitated electrodes, a microheater, resistance temperature detectors, and onboard electronics for control, actuation, and data acquisition. Measurements performed on deparaffinised and formalin-fixed breast biopsy tissues show a higher surface and bulk electrical resistivity and lower thermal conductivity for tumours compared to the adjacent normal tissues. The study also presents a novel method of using changes in electrical resistivity with temperature and combining it with thermal conductivity measurements as a metric for classifying tissues as tumour or normal.