Intracellular fate and impact on gene expression of doxorubicin/cyclodextrin-graphene nanomaterials at sub-toxic concentration

The graphene road in nanomedicine still seems very long and winding because the current knowledge about graphene/cell interactions and the safety issues are not yet sufficiently clarified. Specifically, the impact of graphene exposure on gene expression is a largely unexplored concern. Herein, we investigated the intracellular fate of graphene (G) decorated with cyclodextrins (CD) and loaded with doxorubicin (DOX) and the modulation of genes involved in cancer-associated canonical pathways. Intracellular fate of GCD@DOX, tracked by FLIM, Raman mapping and fluorescence microscopy, evidenced the efficient cellular uptake of GCD@DOX and the presence of DOX in the nucleus, without graphene carrier. The NanoString nCounter™ platform provided evidence for 34 (out of 700) differentially expressed cancer-related genes in HEp-2 cells treated with GCD@DOX (25 µg/mL) compared with untreated cells. Cells treated with GCD alone (25 µg/mL) showed modification for 16 genes. Overall, 14 common genes were differentially expressed in both GCD and GCD@DOX treated cells and 4 of these genes with an opposite trend. The modification of cancer related genes also at sub-cytotoxic G concentration should be taken in consideration for the rational design of safe and effective G-based drug/gene delivery systems. The reliable advantages provided by NanoString® technology, such as sensibility and the direct RNA measurements, could be the cornerstone in this field

Controlling the Luminescence of Carboxyl-Functionalized CdSe/ZnS Core–Shell Quantum Dots in Solution by Binding with Gold Nanorods

Plasmonic nanostructures offer promising routes toward artificial control of the photoluminescence properties of various emitters. Here, we investigated the photoluminescence of carboxyl-functionalized CdSe/ZnS core–shell quantum dots (c-QDs) localized near gold nanorods (AuNRs) as a function of c-QDs–AuNRs distance using the cetyltrimethylammonium bromide (CTAB) surfactant and Bovine Serum Albumin (BSA) protein layers over coating metal surface as spacer. The direct binding of negatively charged c-QDs to positively charged CTAB (3–4 nm thickness) caused close contact with the metal, resulting in an efficient metal-induced energy transfer (quenching). We found that quenching is modulated by the degree of spectral overlap between the photoluminescence band of c-QDs (620 nm) and longitudinal localized surface plasmon resonance (LSPR) of AuNRs (637 and 733 nm). Deposition of BSA layer over CTAB coated-AuNRs and subsequent decoration with c-QDs yielded an increase in photoluminescence signal when exciting in resonance with the transverse LSPR of AuNRs. On the basis of experimental studies using steady-state and time-resolved fluorescence measurements as well as finite-difference time-domain calculations, we report over 70% quenching efficiency for all investigated AuNRs along with a 4.6-fold in photoluminescence enhancement relative to free c-QDs (39-fold enhancement relative to c-QDs loaded AuNRs) after BSA deposition

Personalized reusable face masks with smart nano-assisted destruction of pathogens for COVID-19. A visionary road

The Coronavirus disease 2019 (COVID-19) emergency has demonstrated that the utilization of face masks plays a critical role in limiting the outbreak. Healthcare professionals utilize masks all day long without replacing them very frequently, thus representing a source of cross-infection for patients and themselves. Nanotechnology is a powerful tool with the capability to produce nanomaterials with unique physicochemical and antipathogen properties. Here, how to realize non-disposable and highly comfortable respirators with light-triggered self-disinfection ability by bridging bioactive nanofiber properties and stimuli-responsive nanomaterials is outlined. The visionary road highlighted in this Concept is based on the possibility of developing a new generation of masks based on multifunctional membranes where the presence of nanoclusters and plasmonic nanoparticles arranged in a hierarchical structure enables the realization of a chemically driven and on-demand antipathogen activities. Multilayer electrospun membranes have the ability to dissipate humidity present within the mask, enhancing the wearability and usability. The photothermal disinfected membrane is the core of these 3D printed and reusable masks with moisture pump capability. Personalized face masks with smart nano-assisted destruction of pathogens will bring enormous advantages to the entire global community, especially for front-line personnel, and will open up great opportunities for innovative medical applications

Plasmonic bipyramids for fluorescence enhancement and protection against photobleaching

International audienceA great number of studies focus their interest on the photophysical properties of fluorescent hybrid gold nanoparticles for potential applications in biotechnologies such as imaging and/or treatment. Spherical gold nanoparticles are known to quench a chromophore fluorescent signal, when moieties are located in their close vicinity. The use of a polymer spacer on such a system allowed only partial recovery of the dye emission by controlling the surface to dye distance. Gold-based anisotropic sharp nanostructures appear to exhibit more interesting features due to the strong electric field generated at their edges and tips. In this paper, a complete study of hybrid fluorescent bipyramidal-like gold nanostructures is presented. We describe the chemical synthesis of gold bipyramids functionalized with fluorescent water-soluble polymers and their photophysics both in solution and on a single object. We show that the use of a bipyramidal shape instead of a spherical one leads to total recovery of the fluorescence and even to an enhancement of the emission of the dyes by a factor of 1.4