Infectious pathogens are a prominent threat to human health in the world. There is a ubiquitous need for safe and reliable pathogen inactivation in the entire health care sector and pharmaceutical industry. Unfortunately, existing chemical treatment methods for virus inactivation have shortcomings as they introduce toxic chemicals or alter the structure of the products, which often pose significant side effects. Furthermore, considering the alarming growth of antibiotic resistances and hospital associated microbial infections, there is an urgent need for alternative pathogen inactivation strategies. Femtosecond (fs) pulsed laser irradiation technique is a promising solution free of added toxic chemicals and does not require the invention of new antibiotics for inactivation of virus contaminations in biological samples. Conventional pulsed laser techniques require relatively long irradiation times to achieve a significant viral inactivation. This thesis is focused on developing a novel photonic inactivation approach that is selective to pathogens, doesn’t compromise the protein-based pharmaceuticals, and is obtained without specific targeting to the pathogens. In our study, we report comparative studies using femtosecond laser pulses generated using Chirped Pulse Amplification (CPA) centered at either 800 nm or frequency-doubled 400 nm wavelengths, on the model bacteriophage φX174. We show that photonic inactivation is wavelength dependent and a Log Reduction Value (LRV) of > 6 in a 2 ml bacteriophage sample volume is achieved with less than 1 min of 400 nm laser exposure. Traditional methods for assaying viral inactivation require cell culture studies that can take up to 48–72 hours. We describe a solid-state nanopore technique that can monitor the effect of this optical viral therapy in under 10 minutes. By developing a statistical model based on the probability distribution function obtained from nanopore data, we monitor the survival fraction of viruses with low sample volume, high precision and fast assay time. Lastly, the purely photonic virus inactivation requires UV fs laser irradiation, which can risk photodamage to biologics. In our research, we introduce a novel inactivation approach that takes advantage of the strong light-matter interactions provided by noble metal nanoparticle (NP) structures that sustain plasmons. We report a plasmonically enhanced virus inactivation of Murine Leukemia Virus (MLV) via 10 s laser exposure with 800 nm fs pulses through gold nanorods, with LRV>3.7. We demonstrate that this NP-enhanced, physical inactivation approach is effective against a diverse group of pathogens, including both enveloped and non-enveloped viruses, and a variety of bacteria and mycoplasma. Importantly, the fs-pulse induced inactivation was selective to the pathogens and did not induce any measurable damage to co-incubated antibodies, or to large mammalian cells. Based on the observations, a model of selective pathogen inactivation based on plasmon enhanced cavitation is proposed.

<p>Vertically aligned nanocomposite (VAN) thin films are a promising thin-film platform that allows the combination of a highly desired material with another complementary oxide. Traditionally, VANs have been limited to combining an oxide with another oxide which has shown a wide range of functionality, and, by adjusting the different growth parameters, it has led to the tuning of their physical properties. While VANs have already shown to be an effective platform with immense potential, further enhancement of physical properties can be performed by replacing one of the oxides with a metal forming metal-oxide VANs. </p> <p>In this dissertation, by the inclusion of the 3d transition metals, e.g., Fe and Co, into various oxide matrices, such as La_0.5Sr_0.5FeO₃, BaZrO₃, and BaTiO₃, strong, highly anisotropic, ferromagnetic properties have been achieved. By varying the growth parameters, tunable physical properties, mainly coercivity and anisotropic ratio, have been demonstrated. Furthermore, in the case of Co-BaZrO₃, a multi-layer stack has been successfully grown and demonstrated a tailorable magnetoresistance. Additionally, a novel system by combining Fe pillars into a BaTiO₃ matrix has been demonstrated. This new system allows for the combination of the room temperature Fe ferromagnetic properties with the ferroelectric properties of BaTiO₃, allowing for coupling between the two with coercivity tuning and tailorable ferromagnetic properties. </p> <p>Lastly, it has been shown a possible framework by adding additional metals into the existing metal-oxide VAN platform. By adding the third phase, another metal, it opens up a new avenue to induce additional functionality while creating a method to introduce coupling between the different metals and physical properties. </p> <br>

<p>Advances in additive manufacturing technologies enable the rapid, high-throughput generation of mechanically soft microelectromechanical devices with tailored designs for many applications spanning from optical to biomedical applications. These devices can be softly interfaced with biological tissues and mechanically fragile systems, which enables to open up a whole new range of applications. However, the scalable production of these devices faces a significant challenge due to the complexity of the microfabrication process and the intolerable thermal, chemical, and mechanical conditions of their flexible polymeric substrates. To overcome these limitations, I have developed a set of advanced additive manufacturing technologies enabling (1) mechanics-driven manufacturing of quasi-three-dimensional (quasi-3D) nanoarchitectures with arbitrary substrate materials and structures; (2) repetitive replication of quasi-3D nanoarchitectures for infrared (IR) bandpass filtering; (3) electrochemical reaction-driven delamination of thin-film electronics over wafer-scale; (4) rapid custom printing of soft poroelastic materials for biomedical applications. </p> <p>First, I have developed a new mechanics-driven nanomanufacturing method enabling large-scale production of quasi-3D plasmonic nanoarchitectures that are capable of controlling light at nanoscale length. This method aims to eliminate the need for repetitive uses of conventional nanolithography techniques that are time- and cost-consuming. This approach is innovative and impactful because, unlike any of the conventional manufacturing methods, the entire process requires no chemical, thermal, and mechanical treatments, enabling a large extension of types of receiver substrate to nearly arbitrary materials and structures. Pilot deterministic assembly of quasi-3D plasmonic nanoarrays with imaging sensors yields the most important advances, leading to improvements in a broad range of imaging systems. Comprehensive experimental and computational studies were performed to understand the underlying mechanism of this new manufacturing technique and thereby provide a generalizable technical guideline to the manufacturing society. The constituent quasi-3D nanoarchitectures achieved by this manufacturing technology can broaden considerations further downscaled plasmonic metamaterials suggest directions for future research.</p> <p>Second, I have developed mechanics-driven nanomanufacturing that provides the capability to repetitively replicate quasi-3D plasmonic nanoarchitectures even with the presence of an extremely brittle infrared-transparent spacer, such as SU-8, thereby manipulating IR light (e.g., selectively transmitting a portion of the IR spectrum while rejecting all other wavelengths). Comprehensive experimental and computational studies were performed to understand the underlying nanomanufacturing mechanism of quasi-3D plasmonic nanoarchitectures. The spectral features such as the shape of the transmission spectrum, peak transmission and full width at half maximum (FWHM), etc. were studied to demonstrate the bandpass filtering effect of the assembled quasi-3D plasmonic nanoarchitecture.</p> <p>Third, I have developed an electrochemical reaction-driven transfer printing method enabling a one-step debonding of large-scale thin-film devices. Conventional transfer printing methods have critical limitations associated with an efficient and intact separation process for flexible 3D plasmonic nanoarchitectures or bio-integrated electronics at a large scale. The one-step electrochemical reaction-driven method provides rapid delamination of large-scale quasi-3D plasmonic nanoarchitectures or bio-integrated electronics within a few minutes without any physical contact, enabling transfer onto the target substrate without any defects and damages. This manufacturing technology enables the rapid construction of quasi-3D plasmonic nanoarchitectures and bio-integrated electronics at a large scale, providing a new generation of numerous state-of-art optical and electronic systems.</p> <p>Lastly, I have developed a new printing method enabling the direct ink writing (DIW) of multidimensional functional materials in an arbitrary shape and size to rapidly prototype stretchable biosensors with tailored designs to meet the requirement of adapting the geometric nonlinearity of a specific biological site in the human body. Herein, we report a new class of a poroelastic silicone composite that is exceptionally soft and insensitive to mechanical strain without generating significant hysteresis, which yields a robust integration with living tissues, thereby enabling both a high-fidelity recording of spatiotemporal electrophysiological activity and real-time ultrasound imaging for visual feedback. Comprehensive <i>in vitro</i>, <i>ex vivo</i>, and <i>in vivo</i> studies provide not only to understand the structure-property-performance relationships of the biosensor but also to evaluate infarct features in a murine acute myocardial infarction model. These features show a potential clinical utility in the simultaneous intraoperative recording and imaging on the epicardial surface, which may guide a definitive surgical treatment.</p>

Photocatalysis is an advanced oxidation process for the purification and remediation of contaminated waters and wastewaters, and is advantageous over conventional treatment technologies due to its ability to degrade emerging and recalcitrant pollutants. In addition, photocatalytic disinfection is less chemical-intensive than other methods such as chlorination, and can inactivate even highly resistant microorganisms with good efficacy. Process sustainability and cost-effectiveness may be improved by utilizing solar irradiation as the source of necessary photons for photocatalyst excitation. However, solar-induced activity of the traditionally-used titania is poor due to its inefficient visible light absorption, and recombination of photo-excited species is problematic. Additionally, mass transfer limitations and difficulties separating the catalyst from the post-treatment slurry hinder conversions and efficiencies obtainable in practice. In this research, various strategies were explored to address these issues using novel visible light active photocatalysts. Two classes of carbon-enhanced photocatalytic materials were studied: activated carbon adsorbent photocatalyst composites, and carbon-doped TiO2. Adsorbent photocatalyst composites based on activated carbon and plasmonic silver/silver chloride structures were synthesized, characterized, and experimentally investigated for their photocatalytic activity towards the degradation of model organic pollutants (methyl orange dye, phenol) and the inactivation of a model microorganism (Escherichia coli K-12) under visible light. The adsorptive behaviour of the composites towards methyl orange dye was also studied and described according to appropriate models. Photocatalytic bacterial inactivation induced by the prepared composites was investigated, and the inactivation mechanisms and roles of incorporated antimicrobial silver on disinfection were probed and discussed. These composites were extended towards magnetic removal strategies for post-use separation through the incorporation of magnetic nanoparticles to prepare Ag/AgCl-magnetic activated carbon composites, and the effect of nanoparticles addition on the properties and photoactivities of the resulting materials was explored. Another silver/silver halide adsorbent photocatalyst composite based on activated carbon and Ag/AgBr exhibiting visible light absorption due to both localized surface plasmon resonance and optical band gap absorption was synthesized and its photocatalytic activity towards organics degradation and microbial inactivation was studied. Carbon-doped mixed-phase titania was also prepared and experimentally investigated.

L’utilisation de micromembranes suspendues chauffées par effet Joule comme source de rayonnement infrarouge est une piste prometteuse pour la réalisation de détecteurs de gaz compacts, basse consommation et à bas coût. Afin d’améliorer l’efficacité de ces dispositifs récemment introduits, il est nécessaire d’optimiser ceux-ci à la fois du point de vue optique et thermique.En ajoutant des résonateurs plasmoniques frustrés sur les membranes, il est possible de modifier l’émissivité de ces dernières, afin de contrôler spectralement et angulairement le rayonnement émis. De cette façon, la puissance utile est augmentée, tandis que la consommation électrique diminue. D’autre part, l’étude en profondeur des rôles des différents canaux thermiques conduit à relier rayon de la membrane, temps de chauffe et énergie disponible par mesure et de définir un régime optimal de fonctionnement dynamique.Finalement les membranes sont fabriquées en salle blanche et caractérisées électriquement, optiquement et mécaniquement afin d’estimer les gains en performances. La réalisation d’un prototype de capteur de CO2 à 4,26 µm à partir de ces sources indique des précisions de l’ordre de la vingtaine de ppm pour une consommation d’un milliwatt, en compétition favorable avec l’état de l’art mondial dans ce domaine. / Joule-heated suspended microhotplates can be used as infrared sources in cheap, low-consumption spectroscopic gas sensors. To enhance the very low efficiency of first generation structures, both their thermal and optical designs have to be optimized.The implementation of frustrated plasmonic resonators on top of the membrane grants both spectral and angular control of its emissivity. It is thus possible to make it radiate only at the frequencies absorbed by the gas under study, and in the solid angle of the detector. This leads to an increase in useful radiated power while the overall electrical consumption is decreased. Dynamical studies of membrane heating provide welcome insight on the relationship between membrane radius, heating time and energy consumption per measurement. The existence of a compromise is demonstrated in order to maximize the radiative efficiency, and its physical interpretation is detailed.Eventually, membranes fabricated in LETI’s clean room were characterized to measure their electrical, optical and mechanical properties. The implementation of such sources in a CO2 prototype sensor led to state-of-the-art results, with a few dozen ppm sensitivity with a power consumption of only one milliwatt.

Ce travail porte sur la réalisation de nanostructures d'or sur substrat de verre afin d’en étudier les propriétés plasmoniques et de les optimiser pour des applications dans le domaine des biocapteurs. L'objectif principal a été de démontrer la faisabilité de combiner sur une même biopuce, les biocapteurs à résonance de plasmon de surface propagatif (SPR) et ceux basés sur la diffusion Raman exaltée de surface (SERS). Nous montrons que la présence d’un film d’or sous les nanostructures est très favorable pour une double caractérisation SPR-SERS. Afin d’étudier plus en détails les couplages entre les différents modes plasmoniques existants dans ces substrats et ainsi pouvoir déterminer la structure optimale, l’essentiel des échantillons a été réalisé par lithographie électronique. La nanoimpression assistée par UV (UV-NIL) a aussi été développé au cours de cette thèse afin de réaliser un nombre important d'échantillons et répondre aux futurs besoins de l'industrie des biocapteurs. Les performances de ces échantillons réalisés par UV-NIL ont été comparées avec ceux fabriqués par lithographie électronique. Les diamètres des nanodisques d'or varient de 40 nm à 300 nm et les périodes de 80 nm à 600 nm en fonction de la technique de fabrication. En SERS, des facteurs d’exaltation de 10^6 à 10^8 ont été obtenus grâce à la présence du film d’or continu sous le réseau de nanodisques. Ce gain est fonction de l’épaisseur du film d’or, de la longueur d’onde d’excitation utilisée et du taux de remplissage des nanostructures. En SPR, nous avons démontré expérimentalement et théoriquement la possibilité de couplage entre les modes localisés et propagatifs donnant lieu à un nouveau mode hybride, potentiellement plus sensible car plus confiné. Les calculs numériques développés pour simuler le comportement de structures réelles (présence d’arrondi, de flanc ou de couche d’accroche) confirment les résultats obtenus. L’ensemble de ce travail a permis de manière expérimentale et théorique d’apporter une meilleure compréhension des propriétés plasmoniques aux échelles nanométriques sur des structures constituées de réseaux de nanostructures d'or, notamment sur film d’or. Par ailleurs, une étude précise des différentes étapes technologiques a permis de comprendre quels éléments impactent significativement les propriétés plasmoniques des échantillons et donc améliorent ou dégradent les performances de ces substrats en tant que biocapteur. Au final, les échantillons réalisés ont été testés et validés en tant que biocapteur au sein d'un appareil bimodal SPR-SERS. / This thesis is focused on gold nanostructuration on glass substrate in order to study and optimize their plasmonic properties for biosensing applications. The main goal was to demonstrate the feasibility of combining on a single biochip, Surface Plasmon Resonance Imaging (SPRI) and Surface Enhanced Raman Scattering (SERS) measurements. We have demonstrated that adding a gold film under the nanostructures was highly beneficial for a dual SPRI-SERS characterization. In order to optimize the geometry of the nanostructures and understand the various plasmonic modes, most of the samples were first made by electron beam lithography. Nanoimprinting assisted by UV (UV-NIL) was also developed during this thesis to manufacture samples in large quantities and reply to the future industrial needs for biosensing applications. Performances of these UV-NIL samples were compared with those produced by e-beam lithography. Diameters and periods of gold nanodisks range respectively from 40 nm to 300 nm and 80 nm to 600 nm, depending on the manufacturing technique used. In SERS, enhancement factor of 10^6 to 10^8 were obtained thanks to the presence of the continuous gold film under the nanodisks array. We found that this gain is a function of the thickness of the gold film, the excitation wavelength used and the nanostructures filling factor. In SPRI, we have demonstrated experimentally and theoretically the existence of a coupling between the propagating and localized plasmonic modes, resulting in a new hybrid mode, potentially more sensitive due to its high confinement. Numerical models confirm these results, taking into account the defects found in real samples (rounded edges, imperfect lateral side, adhesion layer). The whole work proposes a better understanding, both experimentally and theoretically, of the plasmonic properties at nanoscale of gold nanostructures with and without an underlying gold film. Moreover, a detailed study of the different technological processes helps to understand which steps significantly impact the plasmonic properties of the samples and their performance as a biosensor. Finally, these samples were characterized and validated on a bimodal instrument SPRI-SERS.

The process of spontaneous emission can be dramatically modified by optical micro- and nanostructures. We studied the modification of fluorescence dynamics using a polymer spacer layer fabricated through layer-by-layer (LbL) self-assembly. The advantages of this method are numerous: The self-assembled spacers can possess exceptional smooth surface morphology; The thickness of the spacer can be controlled with nanometer accuracy; And depending on fabrication conditions, the spacer layer is stimuli responsive and its thickness can be dynamically tuned. This thesis contains three interlinked components. First, we vary LbL spacer layer thickness and explore the change in fluorescence lifetime induced by the modified photonic density of states (PDOS), i.e., Purcell effects. Our experimental results agree well with theoretical predictions based on a classical dipole model, which also yields consistent values for the fluorophores' intrinsic fluorescence lifetime and quantum yield near a dielectric as well as a plasmonic interface. Based on this observation, we further demonstrate that self-assembled fluorophores can be used to probe the modified PDOS near optical micro- and nano-structures. These results naturally lead to the second component of our research. In particularly, based on the PDOS-induced changes in fluorescent lifetime, we develop a non-contact method that can measure morphological changes with nanoscale resolution. Our method relies on quantitatively linking fluorophore position with PDOS, and is validated through direct comparison with ellipsometry and atomic force microscopy (AFM) measurements. To demonstrate the potential application of this method, we investigated the swelling/deswelling of LbL films induced by pH changes. Our results indicate significant difference between a LbL film composed of a single polymer monolayer and a LbL film with 3 monolayers. Such stimuli-responsive polymers can be used to construct active and tunable plasmonic nano-devices. As a proof-of-principle demonstration, we experimentally confirm that it is possible to utilize the swelling/deswelling behavior of stimuli-responsive films to dynamically control the separation between Au nanoparticles and Texas Red (TR) dyes. This result is based on the strong correlation of TR fluorescence lifetime and nanoparticles-TR separation. Finally, we investigate the impact of different lithography processes on the fluorescence properties of self-assembled fluorophores. We consider three methods: direct fluorophore patterning through ultraviolet (UV) ablation, focused ion beam (FIB) milling of self-assembled fluorophores, and self-assembly of fluorescent materials over plasmonic nano-patterns. / Ph. D.

No description available.

Tato disertační práce pojednává o plazmonických anténách. Rezonanční vlastnosti plazmonických antén jsou studovány teoreticky i experimentálně. Teoretické výpočty jsou prováděny v programu Lumerical FDTD Solutions užitím numerické metody konečných diferencí v časové doméně. Pro experimentální studium byly antény vyrobeny pomocí elektronové litografie. Rezonanční vlastnosti vyrobených antén jsou studovány fourierovskou infračervenou spektroskopií. Práce se zaměřuje na studium rezonančních vlastností antén vyrobených na vrstvě nanokrystalického diamantu. Dále zkoumá možnost využití antén jako plazmonického senzoru funkcionalizovaného k detekci streptavidinu. Nakonec je představena anténa tvaru písmene V, u které dochází v důsledku porušení symetrie antény ke směrovému rozptylu dopadajícího světla. Tato směrovost se ovšem projevuje jen na vlnových délkách blízkých kvadrupólovému módu antény.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18284号 / 工博第3876号 / 新制||工||1595(附属図書館) / 31142 / 京都大学大学院工学研究科電子工学専攻 / (主査)教授 野田 進, 教授 川上 養一, 教授 藤田 静雄 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM