Objective: The present study investigates viscoelastic properties of human autopsy brain tissue via nanoindentation to find feasible biomarkers for Alzheimer's Disease (AD) in ex vivo condition and to understand the mechanics of the human brain better, especially on the difference before and after progression of AD.Methods: Viscoelastic properties of paraformaldehyde-fixed, paraffin-embedded thin (8 μm) sectioned normal and AD affected human autopsy brain tissue samples are investigated via nanoindentation with a combined loading profile of a linear preloading and a sinusoidal loading at various loading frequencies from 0.01 -10 Hz. In 1,200 indentation tests for 10 human autopsy brain tissue samples from 10 different subjects (5 AD cases and 5 normal controls), viscoelastic properties such as Young's modulus, storage modulus, loss modulus, and loss factor of both gray and white matter brain tissues samples from normal and AD affected tissues were measured experimentally. Results:We found that the normal brain tissues have higher Young's modulus values than the AD affected brain tissues by 23.5 % and 27.9 % on average for gray and white matter, respectively, with statistically significant differences (p < 0.0001) between the normal and AD affected brain tissues. Additionally, the AD affected brain tissues have much higher loss factor than the normal brain tissues on lower loading frequencies.

Research in the field of underwater (UW) robotic applications is rapidly developing. The emergence of coupling the newest technologies on submersibles, different types of telecommunication devices, sensors, and soft robots is transforming the rigid approach to robotic design by providing solutions that bridge the gap between accuracy and adaptability in an environment where there is so much fluctuation in object targeting and environmental conditions. In this paper, we represent a review of the history, development, recent research endeavors, and projected outlook for the area of soft robotics technology pertaining to its use with tactile sensing in the UW environment.

The use of flexible micro-electro-mechanical systems (MEMS) based device provides a unique opportunity in bio-medical robotics such as characterization of normal and malignant tissues. This paper reports on design and development of a flexible MEMS-based sensor array integrating mechanical and electrical sensors on the same platform to enable the study of the change in electro-mechanical properties of the benign and cancerous breast tissues. In this work, we present the analysis for the electrical characterization of the tissue specimens and also demonstrate the feasibility of using the sensor for mechanical characterization of the tissue specimens. Eight strain gauges acting as mechanical sensors were fabricated using poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) conducting polymer on poly(dimethylsiloxane) (PDMS) as the substrate material. Eight electrical sensors were fabricated using SU-8 pillars on gold (Au) pads which were patterned on the strain gauges separated by a thin insulator (SiO2 1.0μm). These pillars were coated with gold to make it conducting. The electromechanical sensors are integrated on the same substrate. The sensor array covers 180μm × 180μm area and the size of the complete device is 20mm in diameter. The diameter of each breast tissue core used in the present study was 1mm and the thickness was 8μm. The region of interest was 200μm × 200μm. Microindentation technique was used to characterize the mechanical properties of the breast tissues. The sensor is integrated with conducting SU-8 pillars to study the electrical property of the tissue. Through electro-mechanical characterization studies using this MEMS-based sensor, we were able to measure the accuracy of the fabricated device and ascertain the difference between benign and cancer breast tissue specimens.

Goal The objective of this study is to design and develop a portable tool consisting of a disposable biochip for measuring electro-thermo-mechanical (ETM) properties of breast tissue. Methods A biochip integrated with a microheater, force sensors and electrical sensors is fabricated using microtechnology. The sensor covers the area of 2mm and the biochip is 10mm in diameter. A portable tool capable of holding tissue and biochip is fabricated using 3D printing. Invasive ductal carcinoma (IDC) and normal tissue blocks are selected from cancer tissue bank in Biospecimen Repository Service at Rutgers Cancer Institute of New Jersey. The ETM properties of the normal and cancerous breast tissues (3mm thickness and 2mm diameter) are measured by indenting the tissue placed on the biochip integrated inside the 3D printed tool. Results Integrating microengineered biochip and 3D printing we have developed a portable cancer diagnosis device. Using this device, we have shown a statistically significant difference between cancerous and normal breast tissues in mechanical stiffness, electrical resistivity, and thermal conductivity. Conclusion The developed cancer diagnosis device is capable of simultaneous ETM measurements of breast tissue specimens and can be a potential candidate for delineating normal and cancerous breast tissue cores. Significance The portable cancer diagnosis tool could potentially provide a deterministic and quantitative information about the breast tissue characteristics, as well as the onset and disease progression of the tissues. The tool can be potentially used for other tissue-related cancers.

The increase in collagen density in breast tissue is an objective and reproducible characteristic of breast cancer. Although characterization of mechanical tissue property has been shown to be useful for differentiating cancerous tissue from normal tissue, using a single parameter may not be sufficient for practical usage due to inherent variation among biological samples. The portable breast cancer diagnostic tool reported in this manuscript shows the feasibility of measuring multiple parameters of breast tissue allowing for practical application.