Photodynamic toluidine blue-gold nanoconjugates as a novel therapeutic for biofilms.

are among the most frequent bacteria known to cause biofilm-related infections. Pathogenic biofilms represent a global healthcare challenge due to their high tolerance to antimicrobials. In this study, water soluble polyethylene glycol (PEG)-coated gold nanospheres (28 ppm) and nanostars (15 ppm) with electrostatically adsorbed photosensitizer (PS) Toluidine Blue O (TBO) ∼4 μM were successfully synthesized and characterized as PEG-GNPs@TBO and PEG-GNSs@TBO.

Association of Indocyanine Green with Chitosan Oleate Coated PLGA Nanoparticles for Photodynamic Therapy.

Indocyanine green (ICG) is a safe dye widely used in the biomedical field. Its photodynamic effect (PDT), originating from laser irradiation at 803 nm, opens interesting perspectives in theranostic applications. To overcome its low water stability, ICG can be shielded with nanoparticles (NPs).

Multi-frequency passive and active microrheology with optical tweezers.

Optical tweezers have attracted significant attention for microrheological applications, due to the possibility of investigating viscoelastic properties in vivo which are strongly related to the health status and development of biological specimens. In order to use optical tweezers as a microrheological tool, an exact force calibration in the complex system under investigation is required. One of the most promising techniques for optical tweezers calibration in a viscoelastic medium is the so-called active-passive calibration, which allows determining both the trap stiffness and microrheological properties of the medium with the least a-priori knowledge in comparison to the other methods.

Yield stress "in a flash": investigation of nonlinearity and yielding in soft materials with an optofluidic microrheometer.

Yield stress materials deform as elastic solids or flow as viscous liquids, depending on the applied stress, which also allows them to trap particles below a certain size or density threshold. To investigate the conditions for such a transition at the microscale, we use an optofluidic microrheometer, based on the scattering of an infrared beam onto a microbead, which reaches forces in the nN scale. We perform creep experiments on a model soft material composed of swollen microgels, determining the limits of linear response and yield stress values, and observe quantitative agreement with bulk measurements.