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(k)of deparaffinized and formalin-fixed paired tumor and adjacent normal breast biopsy samples from N=8 patients were measured.For formalin-fixed samples,the meanρB 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 meanρS measurements also showed a similar trend.The mean k of the formalinfixed tumor tissues was 0.309±0.02Wm^(-1)K^(-1)compared to a significantly higher k of 0.563±0.028 Wm^(-1)K^(-1)for the adjacent normal tissues.A similar trend was observed inρB,ρS,and k for the deparaffinized tissue samples.An analysis of a combination ofρ_(B,)ρ_(S,)and k 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.