New graphene-containing pharmaceutical formulations for infrared lamps-based phototherapy of skin cancer: In vitro validation and ex-vivo human skin permeation.

Basal cell carcinoma (BCC) is the most common form of human cancer, and treatment usually involves surgery, with alternative strategies being needed. We propose the use of carbopol hydrogels (HG) for topical administration of nanographene oxide (GOn) and partially-reduced nanographene oxide (p-rGOn) for photothermal therapy (PTT) of BCC. GOn and p-rGOn incorporated into the HG present lateral sizes ∼200 nm, being stable for 8 months. After 20 min irradiation with an infrared (IR) photothermal therapy lamp (15.70 mW cm-2), GOn-HG increased temperature to 44.7 °C, while p-rGOn-HG reached 47.0 °C. Human skin fibroblasts (HFF-1) cultured with both hydrogels (250 µg mL-1) maintained their morphology and viability. After 20 min IR irradiation, p-rGOn HG (250 µg mL-1) completely eradicated skin cancer cells (A-431). Ex vivo human skin permeability tests showed that the materials can successfully achieve therapeutic concentrations (250 µg mL-1) inside the skin, in 2.0 h for GO HG or 0.5 h for p-rGOn HG.

Effect of Lignosulphonates on the Moisture Resistance of Phenol-Formaldehyde Resins for Exterior Plywood.

Phenol-formaldehyde (PF) resins remain the preferred adhesive for exterior plywood, as they confer these boards their extreme weather resistance. However, their high price and toxicity has made phenol alternatives, such as technical lignins, increasingly more attractive. While many works report the use of kraft lignin, the most commercially available form are lignosulphonates (LS). However, these lack industrial success and are associated with low moisture resistance. In the current study, lignosulphonate-phenol-formaldehyde (LPF) resoles were synthesized considering a phenol replacement of 30% (w/w). Two LS samples of softwood (SLS) and hardwood (HLS) origin were compared. These samples were previously methylolated to increase their reactivity. The effectiveness of the treatment was confirmed through the Automated Bonding Evaluation System. Plywood was manufactured and tested according to EN 314 class 3 for exterior conditions, which is seldom found in the literature. Although a 35% increase in shear strength is still necessary to comply with the standard, methylolated SLS was the most promising substitute, as it resulted in the highest board performance. Notably, when this sample was used without previous methylolation, the plywood boards suffered delamination during immersion in boiling water prior to shear testing. These results reinforce the need for the methylolation of LS to increase the weather resistance of plywood.

New MoS2/Tegafur-Containing Pharmaceutical Formulations for Selective LED-Based Skin Cancer Photo-Chemotherapy.

Non-melanoma skin cancer (NMSC) is one of the most common types of cancer worldwide. Despite the low mortality rate, rising incidence and recurrence rates are a burden on healthcare systems. Standard treatments such as chemotherapy, radiotherapy, and surgery are either invasive or toxic to healthy tissues; therefore, new, alternative, selective treatments are needed. In this work, a combined photothermal and chemotherapeutic approach is proposed. MoS2 was used as photothermal agent. It was prepared by a liquid-phase exfoliation and intercalation method using polyvinylpyrrolidone (PVP), followed by recirculation through a custom-built high-power ultrasonication probe. After 6 h of ultrasonication treatment, the average particle size was 165 ± 170 nm. Near-infrared (NIR) irradiation assays (810 nm, 0.1 W/cm2, 30 min, 180 J/cm2) confirmed that MoS2 nanosheets can efficiently convert NIR light into heat and reach 52 °C. The therapeutic doses of MoS2 (125 µg/mL) and Tegafur (50 µg/mL) were optimized and both were simultaneously incorporated into a Carbopol hydrogel. The cells were brought into contact with the hydrogel and irradiated with a custom-built NIR LED system. In HFF-1 cells (normal human fibroblasts), the metabolic activity was 78% (above the 70% toxicity limit-ISO 10993-5:2009(E)), while in A-431 skin cancer cells, it was 28%. In addition, the MoS2 + Tegafur hydrogels led to a 1.9-fold decrease in A-431 cancer cell metabolic activity, 72 h after irradiation, in comparison to MoS2 hydrogels, indicating a combined effect of photothermal and chemotherapy.

Pharmaceutical Formulations Containing Graphene and 5-Fluorouracil for Light-Emitting Diode-Based Photochemotherapy of Skin Cancer.

Nonmelanoma skin cancer (NMSC) is the most common cancer worldwide, among which 80% is basal cell carcinoma (BCC). Current therapies' low efficacy, side effects, and high recurrence highlight the need for alternative treatments. In this work, a partially reduced nanographene oxide (p-rGOn) developed in our laboratory was used. It has been achieved through a controlled reduction of nanographene oxide via UV-C irradiation that yields small nanometric particles (below 200 nm) that preserve the original water stability while acquiring high light-to-heat conversion efficiency. The latter is explained by a loss of carbon-oxygen single bonds (C-O) and the re-establishment of sp2 carbon bonds. p-rGOn was incorporated into a Carbopol hydrogel together with the anticancer drug 5-fluorouracil (5-FU) to evaluate a possible combined PTT and chemotherapeutic effect. Carbopol/p-rGOn/5-FU hydrogels were considered noncytotoxic toward normal skin cells (HFF-1). However, when A-431 skin cancer cells were exposed to NIR irradiation for 30 min in the presence of Carbopol/p-rGOn/5-FU hydrogels, almost complete eradication was achieved after 72 h, with a 90% reduction in cell number and 80% cell death of the remaining cells after a single treatment. NIR irradiation was performed with a light-emitting diode (LED) system, developed in our laboratory, which allows adjustment of applied light doses to achieve a safe and selective treatment, instead of the standard laser systems that are associated with damages in the healthy tissues in the tumor surroundings. Those are the first graphene-based materials containing pharmaceutical formulations developed for BCC phototherapy.