Thanks to their giant nonlinear optical response, liquid crystals support the existence of spatial optical solitons called nematicons. These solitons can be experimentally imaged in a microscope thanks to the fluctuation-induced scattering of the laser beam, but the associated microscope images are generally hard to interpret due to the partially incoherent nature of light scattering. In this contribution, we introduce a theoretical framework allowing to simulate microscope images originating from bulk scattering sources. We apply this framework to the visualization of laser beams and bouncing solitons in the weak nonlinear regime, and show that our framework could be the basis for a novel tomography technique of optical fields.

Pancreatic cancer is one of the deadliest cancers with an increasing incidence due to a lack ofearly-stage diagnostics and effective treatment [1]. The RAS/RAF/ MAPK/CDK4 pathway is frequentlydysregulated in pancreatic cancer and CDK4 constitutes an attractive target since several drugs havebeen approved by the FDA to inhibit its activity: Abemaciclib, Ribociclib and Palbociclib [2,3] (Figure1) However these inhibitors are not efficient in monotherapy and have only been approved for breastcancer. In order to propose an efficient therapeutic strategy to target CDK4 in pancreatic cancer, wepropose to deliver Abemaciclib using carbon nanotubes.
Carbon nanotubes are promising materials for nanomedicine applications and especially fordrug delivery. [4] In this project, we adsorb Abemaciclib onto single-walled carbon nanotubes (SWNT)for delivery of the drug into pancreatic cancer cells. In order to study adsorption, we investigate thechanges in the optical signatures of SWNTs in the near-infrared (NIR) by coupling NIR absorption,photoluminescence and Raman spectroscopies. [5] Typical kinetic spectroscopic results, assigned tothe adsorption of Abemaciclib on SWNT, dispersed in water using carbomethylcellulose (CMC), arepresented in Figure 2. We discuss the results in terms of changes of the dielectric environment of thenanotubes, leading to modulation of their excitonic and optical properties. We have furtherinvestigated the inhibitory potential of SWNT-Abemaciclib on proliferation of PANC1 cells comparedto Abemaciclib alone and have determined the toxicthreshold of SWNT dispersed in CMC.

Poly(N-isopropyl acrylamide) (PNIPAM) is a thermo-responsive polymer which undergoes a reversible coil-to-globule transition in water at temperatures close to the human body temperature [1]. Consequently, PNIPAM-based microgels show a volume phase transition (VPT) under heating. Photo-responsive hybrid microgels have been prepared by incorporating gold nanoparticles in PNIPAM microgels [2]. The outstanding photo-thermal and optical properties of single-walled carbon nanotubes (SWNTs) make them promising candidates to prepare multi-responsive hybrid microgels. However, no thorough studies have been reported so far.
In this work, we report the preparation and properties of aqueous dispersions of PNIPAM/SWNTs hybrid microgels (Figure 1a). We study their structure by transmission electron microscopy and dynamic light scattering. We investigate their optical properties and changes when heated at the VPT by near infrared (NIR) absorption, Raman and photoluminescence (PL) spectroscopies [3]. Furthermore, we use optical microscopy (Figure 1b), light scattering and NIR Raman/PL spectroscopy to show that the VPT transition can be triggered by NIR photo-thermal excitation.

We present a phase-shifting digital holographic microscopy technique, where a digital micromirror device enables to perform a precise phase-only shift of the reference wave. By coupling the beam into a monomode fiber, we obtain a laser mode with a constant phase shift, equally acting on all pixels of the hologram. This method has the advantage of being relatively simple and compatible with high frame rate cameras, which makes it of great interest for the observation of fast phenomena. We demonstrate the validity of the technique in an off-axis configuration by imaging living paramecia caudata.

Food transition requires the replacement in human diet of animal-based proteins by alternative sources of proteins including plant-based proteins. This calls for a detailed knowledge of the functional properties of plant-based proteins, including their surface activity. In this framework, we provide here a comparative study of the interfacial properties of two plant proteins, extracted respectively from wheat and sunflower. We combine time- and concentration-dependent measurements of the surface tension and the surface rheology, as measured with a pendant-drop set-up, and of the surface excess concentration, as measured by ellipsometry, of plant protein interfacial films. We demonstrate a time-concentration superposition principle for the surface pressure and surface excess concentration, showing that the kinetics for the building of the interfacial films is essentially governed by the diffusion of the proteins from the bulk to the interface. We find that the rheological and structural properties of the interfacial protein films show markedly different behaviors for the two classes of protein, which is encoded in the structural features of the individual proteins: wheat proteins are more surface active than sunflower proteins, are keen to compress and re-arrange at an air-water interface, whereas sunflower proteins do not. This work provides qualitative and quantitative analysis of the comparative interfacial behavior of flexible and rigid plant proteins extracted respectively from wheat and sunflower, and demonstrates that a combination of several experimental techniques is necessary to obtain insightful information on the interfacial properties of any species.

Mucus is a viscoelastic aqueous fluid that participates in the protective barrier of many mammals' epithelia. In the airways, together with cilia beating, mucus rheological properties are crucial for lung mucociliary function, and, when impaired, potentially participate in the onset and progression of chronic obstructive pulmonary disease (COPD). Samples of human mucus collected in vivo are inherently contaminated and are thus poorly characterized. Human bronchial epithelium (HBE) cultures, differentiated from primary cells at an air–liquid interface, are highly reliable models to assess non-contaminated mucus. In this paper, the viscoelastic properties of HBE mucus derived from healthy subjects, patients with COPD and from smokers are measured. Hallmarks of shear-thinning and elasticity are obtained at the macroscale, whereas at the microscale mucus appears as a heterogeneous medium showing an almost Newtonian behaviour in some extended regions and an elastic behaviour close to boundaries. In addition, we developed an original method to probe mucus adhesion at the microscopic scale using optical tweezers. The measured adhesion forces and the comparison with mucus-simulants rheology as well as mucus imaging collectively support a structure composed of a network of elastic adhesive filaments with a large mesh size, embedded in a very soft gel.