A Straightforward Method to Produce Multi-Nanodrug Delivery Systems for Transdermal/Tympanic Patches Using Electrospinning and Electrospray

The delivery of drugs through the skin barrier at a predetermined rate is the aim of transdermal drug delivery systems (TDDSs). However, so far, TDDS has not fully attained its potential as an alternative to hypodermic injections and oral delivery. In this study, we presented a proof of concept of a dual drug-loaded patch made of nanoparticles (NPs) and ultrafine fibers fabricated by using one equipment, i.e., the electrospinning apparatus. Such NP/fiber systems can be useful to release drugs locally through the skin and the tympanic membrane. Briefly, dexamethasone (DEX)-loaded poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) fiber meshes were decorated with rhodamine (RHO)-loaded poly(lactic-co-glycolic acid) (PLGA) NPs, with RHO representing as a second drug model. By properly tuning the working parameters of electrospinning, DEX-loaded PHBHV fibers (i.e., by electrospinning mode) and RHO-loaded PLGA NPs (i.e., by electrospray mode) were successfully prepared and straightforwardly assembled to form a TDDS patch, which was characterized via Fourier transform infrared spectroscopy and dynamometry. The patch was then tested in vitro using human dermal fibroblasts (HDFs). The incorporation of DEX significantly reduced the fiber mesh stiffness. In vitro tests with showed that HDFs were viable for 8 days in contact with drug-loaded samples, and significant signs of cytotoxicity were not highlighted. Finally, thanks to a beaded structure of the fibers, a controlled release of DEX from the electrospun patch was obtained over 4 weeks, which may accomplish the therapeutic objective of a local, sustained and prolonged anti-inflammatory action of a TDDS, as is requested in chronic inflammatory conditions, and other pathological conditions, such as in sudden sensorineural hearing loss treatment

Electrospun Poly(3-Hydroxybutyrate-Co-3-Hydroxyvalerate)/Olive Leaf Extract Fiber Mesh as Prospective Bio-Based Scaffold for Wound Healing

Polyhydroxyalkanoates (PHAs) are a family of biopolyesters synthesized by various microorganisms. Due to their biocompatibility and biodegradation, PHAs have been proposed for biomedical applications, including tissue engineering scaffolds. Olive leaf extract (OLE) can be obtained from agri-food biowaste and is a source of polyphenols with remarkable antioxidant properties. This study aimed at incorporating OLE inside poly(hydroxybutyrate-co-hydroxyvalerate) (PHBHV) fibers via electrospinning to obtain bioactive bio-based blends that are useful in wound healing. PHBHV/OLE electrospun fibers with a size of 1.29 ± 0.34 µm were obtained. Fourier transform infrared chemical analysis showed a uniform surface distribution of hydrophilic -OH groups, confirming the presence of OLE in the electrospun fibers. The main OLE phenols were released from the fibers within 6 days. The biodegradation of the scaffolds in phosphate buffered saline was investigated, demonstrating an adequate stability in the presence of metalloproteinase 9 (MMP-9), an enzyme produced in chronic wounds. The scaffolds were preliminarily tested in vitro with HFFF2 fibroblasts and HaCaT keratinocytes, suggesting adequate cytocompatibility. PHBHV/OLE fiber meshes hold promising features for wound healing, including the treatment of ulcers, due to the long period of durability in an inflamed tissue environment and adequate cytocompatibility

Sintesi controllate di precursori colloidali per membrane nanocomposite sensibili al pH

In questo lavoro di tesi è stata studiata la sintesi di nanocompositi colloidali, precursori di film elettroresistivi sensibili al pH. Il nanocomposito comprende tre componenti: una matrice polimerica ottenuta da un lattice di un copolimero di butil acrilato e metil metacrilato denominato BM, in grado di fornire film continui e non porosi per semplice deposizione a temperatura ambiente ed in assenza di solventi coadiuvanti; un polimero pH-sensibile, cioè acido acrilico (AA) copolimerizzato con 2-etilesil acrilato (EEA); nanotubi di carbonio a parete multipla (MWNT), per impartire caratteristiche conduttive al materiale

Simultaneous sensing of the chemical and physical environment with smart nanocomposites prepared from hybrid colloids

Sensing environmental parameters such as temperature, volatile organic molecules, relative humidity, ionic strength or pH can be achieved in many different ways with devices exploiting the sensing capability of materials resulting from their solid state properties (e.g. of semiconductors, fluorescent probes, etc.) or from wet chemistry. However, there is a growing demand for cheap, miniaturized, adaptable sensors, in particular for packaging, garment and biomedical applications. Selectivity and multifunctionality are additional issues that cannot generally be met by the current state-of-the art sensors, unless using relatively sophisticated techniques or equipment. In particular, sensing pH with solid state devices is a sought after alternative to conventional pH sensing by membrane electrodes requiring calibration and relatively large volumes of solution to be analysed. An attractive option with a broad range of potential applications involves using a resistive device in which the pH sensing mechanism relies on the modification of the dielectric properties of the coating of an electrode, allowing fast pH measurements even from microliter-sized samples. As a general strategy for the fabrication of single-use, disposable sensing devices, possibly capable of simultaneous sensing of multiple environmental physical and chemical parameters we are investigating a sensor architecture based on a resistive electrode coated with a smart polymer nanocomposite as the sensing material

Grafting of Hindered Phenol Groups onto Ethylene/α-Olefin Copolymer by Nitroxide Radical Coupling

The covalent immobilization of hindered phenol groups, with potential antioxidant activity, onto an ethylene/α-olefin (EOC) copolymer was carried out by the nitroxide radical coupling (NRC) reaction performed in the melt with a peroxide and the 3,5-di-tert-butyl-4-hydroxybenzoyl-2,2,6,6-tetramethylpiperidine-1-oxyl radical (BHB-T). Functionalized EOC (EOC-g-(BHB-T)) was exposed to photo- and thermo-oxidation. By comparison with some model compounds bearing the (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) moiety or the hindered phenol unit, it was observed that the grafted BHB-T could effectively help the stabilization of the polymer matrix both under photo- and thermo-oxidation. In addition, the immobilization of BHB-T can effectively increase the service life of the functionalized polymers when polymer films were put in contact with ethanol solution thus simulating a possible application of the modified polymer

Grafting of hindered phenol groups onto Ethylene/α-Olefin copolymer by nitroxide radical coupling

The covalent immobilization of hindered phenol groups, with potential antioxidant activity, onto an ethylene/α-olefin (EOC) copolymer was carried out by the nitroxide radical coupling (NRC) reaction performed in the melt with a peroxide and the 3,5-di-tert-butyl-4-hydroxybenzoyl-2,2,6,6-tetramethylpiperidine-1-oxyl radical (BHB-T). Functionalized EOC (EOC-g-(BHB-T)) was exposed to photo- and thermo-oxidation. By comparison with some model compounds bearing the (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) moiety or the hindered phenol unit, it was observed that the grafted BHB-T could effectively help the stabilization of the polymer matrix both under photo- and thermo-oxidation. In addition, the immobilization of BHB-T can effectively increase the service life of the functionalized polymers when polymer films were put in contact with ethanol solution thus simulating a possible application of the modified polymer