Cellular internalization of large therapeutic agents such as proteins or nucleic acids is a challenging task because of the presence of the plasma membrane. One strategy to facilitate intracellular drug uptake is to induce transient pores in the cell membrane through physical delivery strategies. Physical approaches are attractive as they offer more generic applicability compared with viral or biochemical counterparts. Pulsed laser light can induce the endothermic carbon-steam reaction in carbon-nanoparticle suspensions to produce explosive photoacoustic effects in the surrounding medium. In this study, for the first time, these photoacoustic forces were used to transiently permeabilize the cell membrane to deliver macromolecules into cells. Intracellular delivery using this method was demonstrated in multiple cell types for uptake of small molecules, proteins and DNA. At optimized conditions, uptake was seen in up to 50% of cells with nearly 100% viability and in 90% of cells with ≥90% viability, which compared favorably with other physical methods of drug delivery. Cellular bioeffects were shown to be a consequence of laser-carbon interaction and correlated with properties of the carbon and laser, such as carbon concentration and size, laser pulse duration, wavelength, intensity and exposure time. Similar results were observed using two different lasers, a femtosecond Ti: Sapphire laser and a nanosecond Nd: YAG laser. Uptake was also shown in murine skeletal muscles in vivo with up to 40% efficiency compared to non-irradiated controls. This synergistic use of nanotechnology with advanced laser technology could provide an alternative to viral and chemical-based drug and gene delivery.

L'utilisation de techniques de spectroscopie cohérente comme la diffusion Raman anti-Stokes cohérente (DRASC) sont communément utilisées pour l'analyse quantitative de milieux réactifs.Dans le cadre des progrès récents des sources lasers et des détecteurs, ce travail de thèse propose une adaptation de la technique de mesure de température au régime des impulsions ultra-courtes (femtoseconde, picoseconde) à haute cadence.Le développement d'un dispositif expérimental de DRASC en régime hybride fs/ps utilisant un laser femtoseconde et un réseau de Bragg en volume a permis de générer une impulsion de sonde de 30 ps. Dans la configuration choisie pour ce travail, la résolution spectrale est de 0,7 cm-1, ce qui réprésente l'état de l'art. Ce dispositif est appliqué à la spectroscopie ro-vibrationnelle de plusieurs espèces moléculaires.Pour décrire l'interaction dans ce régime temporel, un modèle de simulation des spectres DRASC est implémenté. Cette modélisation prend notamment en compte le profil en amplitude et phase de la sonde ainsi que son retard par rapport à l'excitation femtoseconde. L'influence des collisions moléculaires est discutée dans le cadre du régime hybride.Les ajustements des spectres calculés sur des spectres expérimentaux enregistrés dans l'air ambiant et dans une flamme de prémélange CH4/air, permettent de valider la modélisation proposée dans ce travail. En particulier, la température est mesurée à froid et à chaud à pression atmosphérique, avec une précision comparable à l'état de l'art dans le régime hybride fs/ps.Ce travail permet d'obtenir des résultats probants, et de valider la pertinence du montage développé pour la thermométrie. Fort de ces résultats, des applications en chambre de combustion réelles sont envisagées à court terme à l'ONERA, notamment par l'extrapolation du modèle à haute pression. / Coherent spectroscopy such as Coherent Anti-Stokes Raman Scattering (CARS) is commonly used for the study of reactive media.Following the recent progress encountered in laser sources and detectors, this thesis work proposes an adaptation of the technique for temperature measurements that exploits the ultra-short pulse regime (femtosecond, picosecond) to operate at high repetition-rate.The developed hybrid fs/ps-CARS setup delivers a 30-ps probe pulse using a femtosecond laser source and a Volume Bragg Grating. The obtained spectral resolution is 0,7 cm-1, which represents, within this pulse generation framework, the state of the art. This setup is applied to ro-vibrational spectroscopy of several molecular species.The interaction in the hybrid regime is described through a CARS simulation model that has been implemented. The modelling takes into account both the amplitude and the phase profiles of the probe pulse, and its delay to the femtosecond excitation. Influence of molecular collisions in the hybrid regime is also discussed.This modelling has been validated by fitting calculated spectra on experimental spectra recorded in ambient air, and in a premixed CH4/air flame. Temperature has been then measured at atmospheric pressure in these media. The precision is similar to the hybrid fs/ps-CARS thermometry state of the art.This work validates our N2 thermometry approach based on both the developed CARS setup and simulation model. Short term perspectives of this work are measurements on real combustion chambers at ONERA, by extrapolating our simulation model at high pressure.

Dans ce travail de thèse, la texturation de surface d‟alliages de titane a été étudiée en utilisant un procédé d'écriture directe par laser femtoseconde dans le but d'améliorer la mouillabilité d‟implants dentaires et orthopédiques par les fluides biologiques et la minéralisation de la matrice (formation osseuse) tout en réduisant l'adhésion bactérienne et la formation de biofilmes. Des surfaces de titane (Ti-6Al-4Vet cp Ti) ont été micro-, nano-texturées par laser femtoseconde et une biofonctionnalisation de ces surfaces a été ajoutée ou non par greffage de peptides d'adhésion cellulaire (peptides RGD) en surface de ces différents matériaux. Les textures de surface peuvent être classées comme suit: (a) structures périodiques de surface induites par laser (LIPSS); (b) étalage de nanopiliers (NP); (c) étalage de micro colonnes recouvertes de LIPSS (MC-LIPSS) formant une distribution bimodale de rugosité. Nous avons montré que la texturation de surface par laser améliore la mouillabilité des surfaces avec de l'eau ainsi qu‟une solution saline tamponnée Hank's (HBSS) et amène une anisotropie de mouillage. Une minéralisation cellulaire est observée pour toutes les surfaces des deux alliages de titane lorsque des Cellules Souches Mésenchymateuses humaines (hMSC) sont cultivées dans un milieu ostéogénique. La minéralisation de la matrice et la formation de nodules osseux sont considérablement améliorées sur les surfaces texturées LIPSS et NP. Parallèlement,l'adhésion de Staphylococcus aureus et la formation de biofilmes sont considérablement réduites pour les surfaces texturées LIPSS et NP. La biofonctionnalisation des différentes surfaces texturées (cp Ti) par laser a été réalisée et caractérisée par spectroscopie de photoélectrons (XPS) et par microscopie à fluorescence en utilisant des peptides fluorescents. L‟ensemble des résultats obtenus suggèrent que la texturation de surface d'alliages de titane (Ti-6Al-4V et cp Ti) en utilisant une technique d‟écriture directe par laser femtoseconde est un procédé prometteur pour l'amélioration de la mouillabilité de la surface d'implants dentaires et orthopédiques par les fluides biologiques et leur ostéointégration (différenciation ostéoblastique et minéralisation de la matrice), tout en réduisant l‟adhésion de Staphylococcus aureus et la formation de biofilmes. Enfin, la combinaison de la texturation par laser et du greffage covalent d‟un principe actif (ici un peptide d‟adhésion cellulaire comme le peptide RGD) amènera indéniablement une bioactivité utile pour favoriser l'adhésion des hMSC et faciliter laformation osseuse. / In the present thesis the surface texturing of Ti alloys using femtosecond laser direct writing method is explored as a potential technique to enhance the wettability of dental and orthopaedic implants by biological fluids and matrix mineralisation (bone formation), while reducing bacteria adhesion and biofilmformation. The surface texture was combined with biofunctionalisation by covalent grafting of a RGD peptide sequence as well. The surface textures can be classified as follows: (a) Laser-Induced Periodic Surface Structures-LIPSS; (b) nanopillars arrays(NP); (c) arrays of microcolumns covered with LIPSS (MC-LIPSS), forming a bimodal roughness distribution. Laser texturing enhances surface wettability by water andHank‟s balanced salt solution (HBSS) and introduces wetting anisotropy, crucial incontrolling the wetting behaviour. Matrix mineralisation is observed for all surfaces of both Ti alloys when human mesenchymal stem cells (hMSCs) are cultured in osteogenic medium. Matrix mineralisation and formation of bone-like nodules are significantly enhanced on LIPSS and NP textured surfaces. On the contrary, Staphylococcus aureusadhesion and biofilm formation are significantly reduced for LIPSS and NP textured surfaces. The biofunctionalisation of the laser textured surfaces of cp Ti is sucessfully achieved. In general, these results suggest that surface texturing of Ti alloys using femtosecond laser direct writing is a promising method for enhancing surface wettability of dental and orthopaedic implants by biological fluids and their osseointegration (osteoblastic differentiation and matrix mineralisation), while reducing Staphylococcus aureus adhesion and biofilm formation. Finally, the combination of laser texturing and covalent grafting of a RGD peptide sequence may be potentially useful for increasing cell adhesion and facilitating bone formation.

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Human immunodeficiency virus type 1 (HIV-1) still causes a chronic infection that affects millions of individuals worldwide. The infection remains incurable and presents a huge challenge for treatment, as it tends to disable a patient’s immune system. Although the current HIV-1 treatment regime possesses the ability to reduce the viral load to undetectable limits, complete eradication of the virus cannot be achieved while latent HIV-1 reservoirs go unchallenged. These viral reservoirs are established early on during HIV-1 infection and are a major hurdle since they remain unaffected by antiretroviral drugs and have the ability to replenish systemic infections once treatment is interrupted. Further ailments with the highly active antiretroviral therapy (HAART) include issues such as the cumbersome lifelong treatment, development of drug resistant strains of HIV-1 and adverse side effects. Contrarily, early diagnosis of the HIV-1 infection and HIV-1 treatment is a major challenge in resource-limited countries. The current available diagnostic tools for HIV-1 infection have shown to be highly accurate in monitoring CD4+ T lymphocyte count and viral load measurements. However, these tests such as enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) which are highly efficient, are usually very expensive with complex operation, time consuming, require skilled personnel and training that makes them incompatible for the application in resource-limited areas. Therefore, this raises the urgent need for developing an HIV point of care (POC) diagnostic tool that is label-free, highly specific and sensitive as well as therapeutic modalities, which can be used to address the previously mentioned challenges. Much research has been conducted to resolve these problems but to date, there has not been application of laser and/or photonics in HIV research. Therefore, in this thesis a femtosecond laser was used in HIV infected cells for targeted antiretroviral drug delivery while preserving their viability. For the first time according to our knowledge, antiretrovirals (ARVs) that target all the life stages of the HIV-1 life cycle were utilized and they proved to be significant in reducing HIV-1 infection. Furthermore, through the employment of a continuous wave laser at 640 nm, for the first time, surface plasmon resonance was conducted to facilitate label-free detection of HIV-1. Success of these laser based technologies will open doors for incorporation in POC HIV diagnostic tools for the detection and treatment monitoring of HIV in resource-limited settings. / Physics / Ph. D. (Physics)