TiO2-Alginate-Chitosan-Based Composites for Skin Tissue Engineering Applications.

The UV-B component of sunlight damages the DNA in skin cells, which can lead to skin cancer and premature aging. Therefore, it is necessary to use creams that also contain UV-active substances. Many sunscreens contain titanium dioxide due to its capacity to absorb UV-B wavelengths. In the present study, titan dioxide was introduced in alginate and chitosan-alginate hydrogel composites that are often involved as scaffold compositions in tissue engineering applications. Alginate and chitosan were chosen due to their important role in skin regeneration and skin protection. The composites were cross-linked with calcium ions and investigated using FT-IR, Raman, and UV-Vis spectroscopy. The stability of the obtained samples under solar irradiation for skin protection and regeneration was analyzed. Then, the hydrogel composites were assayed in vitro by immersing them in simulated body fluid and exposing them to solar simulator radiation for 10 min. The samples were found to be stable under solar light, and a thin apatite layer covered the surface of the sample with the two biopolymers and titanium dioxide. The in vitro cell viability assay suggested that the anatase phase in alginate and chitosan-alginate hydrogel composites have a positive impact.

Healing of Skin Wounds in Rats Using Creams Based on Symphytum Officinale Extract.

Rosmarinic acid is a well-known natural antioxidant and anti-inflammatory compound, and it is one of the polyphenolic compounds found in comfrey plants. Comfrey root also contains allantoin, which helps with new skin regeneration. This study aimed to investigate the healing and skin regeneration process of skin wounds in Wistar rats using creams based on comfrey extract and to correlate the results with active compounds in the extract. The obtained results showed that comfrey root is rich in bioactive compounds, including allantoin, salvianolic acid, and rosmarinic acid, which are known for their great free radical scavenging activity, and the high antioxidant activity of the extract may be mainly due to these compounds. The obtained extract has an antimicrobial effect on Staphylococcus aureus (1530.76/382.69), Escherichia coli (6123.01/6123.01), and Pseudomonas aeruginosa (6123.01/6123.01). The macroscopic evaluation and the histological analysis of the skin defects 14 days after the intervention showed faster healing and complete healing in the skin excisions treated with oil-in-water cream with 20% extract of comfrey as the active ingredient.

Gelatin-assisted fabrication of reduced nanographene oxide for dual-modal imaging of melanoma cells.

In this work we report a gelatin-based, simple two-steps approach for fabrication of reduced graphene oxide (rGO-GEL) possessing high stability and biocompatibility, as novel label-free intracellular contrast agents. Gelatin, a biopolymer that is known for its versatility, was employed not only to biocompatibilize the rGO, but also to prevent the aggregation of the GO nanosheets during the reduction process. To confirm the successful reduction process and the attachment of the gelatin to the rGO nanosheets, we employed multiple spectroscopic analyses such as FT-IR, Raman, UV-VIS and photoluminescence, while the morphology and the lateral dimensions of the resulting hybrid rGO-GEL were investigated by Scanning-Transmission Electron Microscopy (STEM). Cellular toxicity test proved that the rGO-GEL nanoflakes are nontoxic for melanoma B16-F10 cells, even at high concentrations. Finally, the intracellular tracking after 24 h of treatment was performed by non-invasive Super-resolution re-scan confocal microscopy as well as Confocal Raman imaging, thus implementing our nanoflakes as a suitable contrast agent candidate for cellular imaging of interest.

Multi-analyses of gallstones and correlation between their properties with the laboratory results.

This study explores the morpho-structure of gallstones (GSs) removed from 36 patients in NW Romania and correlate it with the laboratory results of the patients. GSs were analyzed by SEM-EDS, X-ray diffraction and IR, UV-Vis and X-ray photoelectron spectroscopy. The laboratory studies consisted in hematological, coagulation, biochemistry, immunological and tumor markers tests. The morphological and structural investigations allowed to classify the GS in five different types and to establish their mechanism of formation. Only macroscopic evaluation, SEM microscopy, FTIR and UV-Vis spectroscopy give different easily noticeable information for each GS type. EDS, XPS and XRD diffraction are recommended to distinguish pigment and carbonate stones from the other GS types and a carefully examination is needed to establish the differences between the pure cholesterol, the mixed cholesterol and the composite cholesterol stones, due to the high similarities. The variation of specific markers cannot differentiate the patients with pure cholesterol GS from those with mixed cholesterol and pigment GS and those with mixed cholesterol from those with composite cholesterol stones. Seven laboratory parameters (RDW-CV, MPV, PCT, GLUC-HK, WBC, PT, GPT) are the key indicators for the GS disease and trend to present generally higher values than normal.

Intracellular Dynamic Disentangling of Doxorubicin Release from Luminescent Nanogold Carriers by Fluorescence Lifetime Imaging Microscopy (FLIM) under Two-Photon Excitation.

There is still a lack of available techniques to follow noninvasively the intracellular processes as well to track or disentangle various signals from the therapeutic agents at the site of action in the target cells. We present here the assessment of the intracellular kinetics of doxorubicin (DOX) and gold nanoparticle (AuNP) carriers by mapping simultaneously fluorescence and photoluminescence signals by fluorescence lifetime imaging microscopy under two-photon excitation (TPE-FLIM). The new nano-chemotherapeutic system AuNPs@gelatin-hyd-DOX has been fabricated by DOX loading onto the surface of gelatin-biosynthesized AuNPs (AuNPs@gelatin) through a pH-sensitive hydrazone bond. The successful loading of DOX onto the AuNPs was studied by spectroscopic methods and steady-state fluorescence, and the nanosystem pH-responsive character was validated under simulated biological conditions at different pH values (i.e., pH 4.6, 5.3, and 7.4). Considering that the fluorescence lifetime of DOX molecules at a specific point in the cell is a reliable indicator of the discrimination of the different states of the drug in the internalization path, i.e., released versus loaded, the kinetics of AuNPs@gelatin-hyd-DOX cellular uptake and DOX release was compared to that of free DOX, resulting in two different drug internalization pathways. Finally, cell viability tests were conducted against NIH:OVCAR-3 cell line to prove the efficiency of our chemotherapeutic nanosystem. TPE-FLIM technique could be considered promising for noninvasive, high-resolution imaging of cells with improved capabilities over current one-photon-excited FLIM.