RapidET: a MEMS-based platform for label-free and rapid demarcation of tumors from normal breast biopsy tissues

The rapid and label-free diagnosis of malignancies in ex vivo breast biopsy tissues has significant utility in pathology laboratories and operating rooms. We report a MEMS-based platform integrated with microchips that performs phenotyping of breast biopsy tissues using electrothermal sensing. The microchip, fabricated on a silicon substrate, incorporates a platinum microheater, interdigitated electrodes (IDEs), and resistance temperature detectors (RTDs) as on-chip sensing elements. The microchips are integrated onto the platform using a slide-fit contact enabling quick replacement for biological measurements. The bulk resistivity (ρb), surface resistivity (ρs), and thermal conductivity (κ) of deparaffinized and formalin-fixed paired tumor and adjacent normal breast biopsy samples from N = 8 patients were measured. For formalin-fixed samples, the mean ρb for tumors showed a statistically significant fold change of 4.42 (P=0.014) when the tissue was heated from 25 °C to 37 °C compared to the adjacent normal tissue, which showed a fold change of 3.47. The mean ρs measurements also showed a similar trend. The mean κ of the formalin-fixed tumor tissues was 0.309 ± 0.02 W m^-1 K^-1 compared to a significantly higher κ of 0.563 ± 0.028 W m^-1 K^-1 for the adjacent normal tissues. A similar trend was observed in ρb, ρs, and κ for the deparaffinized tissue samples. An analysis of a combination of ρb, ρs, and κ using Fisher's combined probability test and linear regression suggests the advantage of using all three parameters simultaneously for distinguishing tumors from adjacent normal tissues with higher statistical significance.

Anil Vishnu G. K, Gayatri Gogoi, Bhagaban Behera, Saeed Rila, Annapoomi Rangarajan, Hardik J. Pandya