Red light-triggerable nanohybrids of graphene oxide, gold nanoparticles and thermo-responsive polymers for combined photothermia and drug release effects.

The development of multifunctional nanohybrid systems for combined photo-induced hyperthermia and drug release is a challenging topic in the research of advanced materials for application in the biomedical field. Here, we report the first example of a three-component red-light-responsive nanosystem consisting of graphene oxide, gold nanoparticles and poly-N-isopropylacrylamide (GO-Au-PNM). The GO-Au-PNM nanostructures were characterized by spectroscopic techniques and atomic force microscopy. They exhibited photothermal conversion effects at various wavelengths, lower critical solution temperature (LCST) behaviour, and curcumin (Curc) loading capacity. The formation of GO-Au-PNM/Curc adducts and photothermally controlled drug release, triggered by red-light excitation (680 nm), were demonstrated using spectroscopic techniques. Drug-polymer interaction and drug-release mechanism were well supported by modelling simulation calculations. The cellular uptake of GO-Au-PNM/Curc was imaged by confocal laser scanning microscopy. In vitro experiments revealed the excellent biocompatibility of the GO-Au-PNM that did not affect the viability of human cells.

Green Light-Triggerable Chemo-Photothermal Activity of Cytarabine-Loaded Polymer Carbon Dots: Mechanism and Preliminary In Vitro Evaluation.

Carbon-based nanostructures are attracting a lot of attention because of their very low toxicity, excellent visible light-triggered optical and photothermal properties, and intriguing applications. Currently, the development of multifunctional carbon-based nanostructures for a synergistic chemo-photothermal approach is a challenging topic for the advancement of cancer treatment. Here, we report an unprecedented example of photoresponsive carbon-based polymer dots (CPDs-PNM) obtained by a one-pot thermal process from poly(N-isopropylacrylamide) (PNIPAM) without using organic solvent and additional reagents. The CPDs-PNM nanostructures were characterized by spectroscopic techniques, transmission electron microscopy, and atomic force microscopy. The CPDs-PNM exhibited high photothermal conversion efficiency, lower critical solution temperature (LCST) behavior, and good cytarabine (arabinosyl cytosine, AraC) loading capacity (62.3%). The formation of a CPDs-PNM/AraC adduct and photothermal-controlled drug release, triggered by green light excitation, were demonstrated by spectroscopic techniques, and the drug-polymer interaction and drug release mechanism were well supported by modeling simulation calculations. The cellular uptake of empty and AraC-loaded CPDs-PNM was imaged by confocal laser scanning microscopy. In vitro experiments evidenced that CPDs-PNM did not affect the viability of neuroblastoma cells, while the CPDs-PNM/AraC adduct under light irradiation exhibited significantly higher toxicity than AraC alone by a combined chemo-photothermal effect.

Topical Delivery of Curcumin by Choline-Calix[4]arene-Based Nanohydrogel Improves Its Therapeutic Effect on a Psoriasis Mouse Model.

Curcumin (CUR) has shown remarkable efficacy in the treatment of skin diseases, but its effective transdermal delivery is still a major challenge and stimulates interest in the design of novel systems for CUR dispersion, preservation, and delivery facilitation to the deeper layers of the skin. The present work aimed to investigate the potential of a nanohydrogel, formed by a micellar choline-calix[4]arene amphiphile (CALIX) and CUR, in the treatment of skin diseases through an imiquimod (IMQ)-induced psoriasis model. Psoriasis plaques are associated with aberrant keratinization, abnormal distribution of tight junctions (TJs) proteins, and enhanced expression of inflammatory markers. The nanohydrogel restored the normal distribution of TJs proteins ZO1 and occludin and reduced the expression of TNF-α and inducible nitric oxide synthetase (iNOS) compared to the untreated IMQ group. The novelty lies in the calix[4]arene-based nanohydrogel as a potential new soft material for the topical skin delivery of CUR. The nanohydrogel, due to its physicochemical and mechanical properties, enhances the drug water-solubility, preserves CUR from rapid degradation, and eases the local skin administration and penetration.

Hydroxycinnamic acids loaded in lipid-core nanocapsules.

Ferulic, caffeic, sinapic, and coumaric acids, belonging to the class of hydroxycinnamic acids (HAs), are bioactive polyphenols widespread in the plant kingdom and present in the human diet. Due to their biological properties and effects in the prevention of various diseases associated with oxidative stress, HAs can be exploited for attractive nutraceutical applications. Starting from this and in order to increase bioaccessibility, we encapsulated HAs in lipid-core nanocapsules (NCs) based on a biodegradable and biocompatible poly(ε-caprolactone) polymer. The results showed that nanoparticles loaded with hydroxycinnamic acids (HA-NCs) have diameter of 224-253 nm, encapsulation efficiency of 53-78%, and are stable over time (30 days). In vitro tests evidenced that NCs are able to preserve HAs in the gastric simulated fluid and release them in the intestinal simulated fluid. The delivery system developed could be employed to create novel functional foods.