A bioactive paper is a paper that can detect, capture and deactivate water and airborne pathogens. In this project, we presented a model "bioactive paper" made by attaching T4 bacteriophages to a cellulose substrate. T4 bacteriophages can be genetically engineered to possess copies of cellulose-binding modules (CBM) on their capsids. This allows them to bind specifically onto cellulose surfaces. Our model surface is a thin film of regenerated cellulose made by spin coating a glass or quartz substrate with a cellulose triacetate and subsequently hydrolyzing the surface back to cellulose. We successfully demonstrated the attachment of the CBM-T4 bacteriophages onto cellulose substrates by the phage viability test. The deposition kinetics were measured using an impinging jet apparatus combined with an evanescent wave light scattering (EWLS) system. We first tested the apparatus by using amidine latex particles deposited on the cellulose at different flow rates and found them to be in a good agreement with the constant potential double-layer model. The adhesion experiments were also performed in an impinging jet apparatus in which the CBM-T4 bacteriophages and the unassembled protein complexes from a suspension of 4.08 x 10 8 PFU/mL were allowed to diffuse to the cellulose surface, The competitive diffusion kinetics were again studied by the EWLS technique. For CBM-T4, the blocking time was found to be around 58 minutes and the maximum surface number density of phages was 5.9 x 1010 per m 2. / Key phrases: bioactive paper, cellulose film, cellulose binding module, bacteriophage T4, evanescent wave light scattering, unassembled protein complex, diffusion kinetics

The work reported in this thesis is motivated by the need for wireless powering of a miniaturized implantable device for neurophysiological research and possible clinical applications. The antenna used in such applications must be studied in the context of biological tissue media. In this thesis, we perform a preliminary study of antenna behaviour in the complex tissue environment. Our test cases are the wire dipole antenna chosen for its structural simplicity and the spiral antenna, selected for its wide bandwidth. The simulation tool SEMCAD-X, is based on the Finite-Difference Time-Domain (FDTD) method and is used throughout this work. To have an in-depth understanding of the characteristics of different solvers implemented in SEMCAD-X and relevant for our applications, we first simulate the antenna structures in the free-space region using both SEMCAD-X and HFSS (a Finite-Element Method (FEM) simulation software). The cross-platform comparison between these two simulation tools helps us identify the advantages of using conformal FDTD solver over the conventional staircase FDTD solver in SEMCAD-X. We then embed the antennas in tissue-like non-homogeneous lossy media to observe the terminal voltages induced by an impinging plane-wave. These numerical experiments will help us with the assessment of the following: variations of antenna properties with the in-tissue locations, and more importantly the dependence of the induced voltage on the depth of the implant.

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<p dir="ltr">The gastrointestinal tract harbors a diverse range of microorganisms, collectively constituting the gut microbiome. <a href="" target="_blank">The maintenance of a symbiotic relationship between the host and these microorganisms is essential to gastrointestinal health. Disruption of the ecological balance within the gut microbiome can result in discomfort or pathological conditions.</a> <a href="" target="_blank">This dissertation explores these alterations within the gastrointestinal tract as potential indicators for specific gastrointestinal diseases.</a> <a href="" target="_blank">In pursuit of this, I collaborated with others to develop a smart ingestible capsule that offers a non-invasive method for enhancing the effectiveness of differential diagnosis and treatment strategies for Inflammatory Bowel Disease (IBD). </a>My contributions encompassed conducting <i>in vitro</i> protein sampling and extraction experiments, as well as enteric coating dissolution tests. Following thorough characterization of the capsule, I advanced to <i>ex vivo</i> sampling experiments. As a proof of concept, the capsule's sampling capabilities have been rigorously validated both <i>in vitro</i> and <i>ex vivo</i> using calprotectin, a key biomarker for monitoring and managing IBD. Future research may explore integrating this technology with other sensors for diverse chemical and gas sensing capabilities, aiming to refine the differential diagnostics of Irritable Bowel Syndrome (IBS) and IBD.</p><p dir="ltr">Simultaneously, the potential transmission of pathogenic microorganisms from the gastrointestinal tract to the environment through fecal matter can lead to substantial public health implications if adequate surveillance is not in place. These pathogens can contaminate water and food sources from various origins, exacerbating the problem. Furthermore, conventional laboratory-based assays, while effective, have extensive turnaround times and require skilled scientists to operate them. In response to this challenge, I have undertaken the development of point-of-care assays, aiming to streamline the detection of fecal contamination. This innovation is designed to mitigate the limitations associated with traditional methods by offering a more rapid and user-friendly approach. The primary objective is to enhance the accessibility of these assays, enabling on-site personnel with varying levels of expertise to utilize them effectively. Through the widespread adoption of these point-of-care assays, the overarching goal is to ensure the consistent provision of safe and reliable water and food supplies to the public.</p>