Engineering bio/non-bio interfaces for biomedical applications

Together with the rapid development of several bioengineering fields, among which those related to implantable medical devices, bio/non-bio interfaces have become of primary interest. In fact, in all those situations in which a biological component is in contact with an artificial one, a considerable number of mechanisms and pathways establish and lead to a biological response that may cause effects also on the artificial counterpart. This is the principle exploited in bio-hybrid sensors, for example, whose measures derive from sensing some changes in the properties of the biological elements. This bio/non-bio response is also a key aspect that boosts the integration between an implanted device and the host's organism, or to promote specific tissue responses (e.g. regeneration). Hence bio/non-bio interfaces are crucial for a considerable number of applications, in fields such as implantable biomedical devices, biomechatronics, tissue engineering and regenerative medicine. The aim of this research study was investigating bio/non-bio interfaces, engineering their bidirectional responsivity and exploiting them for applications in different bioengineering fields. In the introduction we will identify the three main players in a bio/non-bio interface that are (1) the biological component the material is in contact with, (2) the man-made material/biomaterial and (3) the external environment/stimuli. The mail goal of this thesis is the attempt to face different aspects of bio/non-bio interfaces. In particular, applications concern bio-hybrid tactile sensors and derived tools, interfaces with peripheral nerves, remote cell/material stimulation by means of ultrasound and triggerable drug delivery system. Considering the bio-hybrid sensing approach, the exploitation of a kidney derived cell line to achieve a mechanotransduction system will be presented, laying the foundation for an ever deeper interaction between artifacts and biocomponents. From this developed technology, we will present a fluidic mechanotransducer following the recent trend of creating flexible force sensors by using non toxic filling material, normally employed for cell culture routines. Then the thesis will focus on the direct stimulation that can be provided to the biological component by a bio/non-bio interface, in particular by the chemical and physical properties of a hydrogel soft coating designed for peripheral nerve interfaces, or by one of the most attractive external stimuli, i.e ultrasound, applied in this case directly to muscle cells. Finally an ultrasound triggered drug release system, i.e. poly(2-oxazoline) micelles, will be analyzed for the dexamethasone administration with possible future application inside anti-inflammatory matrix. Although the presented research will differ in the topic treated and the application, the common scope is to find novel solutions going beyond the state-of-the-art, providing as much as possible a systematic investigation.