Stretchable and Electroactive Crosslinked Gelatin for Biodevice and Cell Culture Applications.

Biomimetic substrates that incorporate functionality such as electroactivity and mechanical flexibility, find utility in a variety of biomedical applications. Toward these uses, nature-derived materials such as gelatin offer inherent biocompatibility and sustainable sourcing. However, issues such as high swelling, poor mechanical properties, and lack of stability at biological temperatures limit their use. The enzymatic crosslinking of gelatin via microbial transglutaminase (mTG) yields flexible and robust large area substrates that are stable under physiological conditions. Here, we demonstrate the fabrication and characterization of strong, stretchable, conductive mTG crosslinked gelatin thin films. Incorporation of the conductive polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate in the gel matrix with a bioinspired polydopamine surface coating is used to enable conductivity with enhanced mechanical properties such as extensibility and flexibility, in comparison to plain gelatin or crosslinked gelatin films. The electroconductive substrates are conducive to cell growth, supporting myoblast cell adhesion, viability, and proliferation and could find use in creating active cell culture systems incorporating electrical stimulation. The substrates are responsive to motion such as stretching and bending while being extremely handleable and elastic, making them useful for applications such as electronic skin and flexible bioelectronics. Overall, this work presents facile, yet effective development of bioinspired conductive composites as substrates for bio-integrated devices and functional tissue engineering.

Flexible Sensing Systems for Cancer Diagnostics.

Practical screening tools and ultrasensitive technologies can play pivotal roles in precision cancer profiling for early diagnosis at asymptomatic stages, as well as for monitoring prognosis, risk stratification, and disease recurrence. While a number of sensors and diagnostic tools continue to be developed for ultrasensitive detection and off-site analysis, there has been an increasing interest in point-of-care devices, particularly those that are mechanically flexible and potentially wearable by the patient. In this chapter, we present a critical insight into the integrated engineering approaches involved in such flexible systems. We consider various aspects in the design of flexible devices, the biomarkers of interest, and the different transduction mechanisms by which mechanically flexible devices can be used in the area of cancer monitoring. We then discuss the different types of flexible biosensing platforms that have been developed to date, including wearables on skin and on clothing, and exhaled breath and implantable sensors. Finally, we discuss the design challenges and future outlook in the development of flexible platforms that can provide comprehensive cancer biomarker panels for patients and clinicians.