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Halloysite is a natural nanotubular clay mineral (HNTs, Halloysite Nano Tubes) chemically identical to kaolinite and, due to its good biocompatibility, is an attractive nanomaterial for a vast range of biological applications. Chitosan oligosaccharides are homo- or heterooligomers of N-acetylglucosamine and D-glucosamine, that accelerate wound healing by enhancing the functions of inflammatory and repairing cells. The aim of the work was the development of a nanocomposite based on HNTs and chitosan oligosaccharides, to be used as pour powder to enhance healing in the treatment of chronic wounds. A 1:0.05 wt ratio HTNs/chitosan oligosaccharide nanocomposite was obtained by simply stirring the HTNs powder in a 1% w/w aqueous chitosan oligosaccharide solution and was formed by spontaneous ionic interaction resulting in 98.6% w/w HTNs and 1.4% w/w chitosan oligosaccharide composition. Advanced electron microscopy techniques were considered to confirm the structure of the hybrid nanotubes. Both HTNs and HTNs/chitosan oligosaccharide nanocomposite showed good in vitro biocompatibility with normal human dermal fibroblasts up to 300 μg/ml concentration and enhanced in vitro fibroblast motility, promoting both proliferation and migration. The HTNs/chitosan oligosaccharide nanocomposite and the two components separately were tested for healing capacity in a murine (rat) model. HTNs/chitosan oligosaccharide allowed better skin reepithelization and reorganization than HNTs or chitosan oligosaccharide separately. The results suggest to develop the nanocomposite as a medical device for wound healing. Statement of Significance The present work is focused on the development of halloysite and chitosan oligosaccharide nanocomposite for wound healing. It considers a therapeutic option for difficult to heal skin lesions and burns. The significance of the research considers two fundamental aspects: the first one is related to the development of a self-assembled nanocomposite, formed by spontaneous ionic interaction, while the second one is related to the possibility to find an effective treatment for cutaneous non healing lesions. The characterization of this hybrid system involves a multidisciplinary approach considering integrated techniques of solid state investigation and advanced electron microscopies, and in vitro/in vivo models to understand biocompatibility and proliferation properties (enhancement of in vitro fibroblast motility, proliferation and migration, and of in vivo burn healing), to understand safety and effectiveness of the developed nanocomposite. [ABSTRACT FROM AUTHOR]

Platelet lysate (PL) was loaded into dressings based on chitosan glutamate (CSG) low and high molecular weight, sericin (Ser), and glycine (Gly). A synergic effect of Ser and PL on fibroblast proliferation was proved in vitro . Two different PL loading approaches were considered: the first provided to prepare dressings by freeze-drying a mixture of PL and CSG/Gly/Ser solution, the second approach consisted in the extemporarily loading of PL in the CSG/Gly/Ser freeze-dried dressings. As for the first approach, PL loading did not produce any variation in dressing mechanical properties. Such dressings absorbed a high amount (about 8-fold of dry weight) of phosphate-buffered saline (fluid mimicking wound exudate), forming a gel with pseudoplastic and elastic properties. Platelet-derived growth factor AB assay indicated that neither freeze-drying nor the excipients alter PL growth factor content. As for the second approach, mechanical and rheological properties of the gel formed upon PL absorption enabled to choose a PL loading of about 90 μL/cm 2 . Upon contact with fibroblasts, all PL loaded formulations increased the number not only of viable cells but also of those in the proliferative phase. Histological studies effected on human skin strips pointed out the positive effect of PL loaded dressings on dermal matrix reconstruction. [ABSTRACT FROM AUTHOR]

The aim of the present work was the development of sponge-like dressings based on chitosan glutamate (high molecular weight) and sericin for the treatment of chronic skin ulcers. Dressings were prepared by freeze-drying and glycine was added as cryoprotectant agent. Dressing development was assisted by design of experiments, using a simplex centroid design. Mechanical resistance, hydration propensity, viscous, and viscoelasticity properties of dressings were considered as response variables. The superimposition of the contour plots, calculated by the best fit model for each response variable, permitted to individuate a region of the factor space where the dressing of optimized quantitative composition was chosen. Such a dressing was able to absorb high amount of phosphate-buffered saline forming a gel characterized by rheological properties enabling both a lubricant and a protective effect. The optimized formulation was characterized by optimal mechanical properties and by cell proliferation and antioxidant activity on human fibroblast cell line. [ABSTRACT FROM AUTHOR]

Highlights: [•] Development of MT/CS nanocomposites loaded with silver sulfadiazine (AgSD) as a powder or dressing for cutaneous application. [•] Nanocomposites protect fibroblasts from the cytotoxic action of AgSD, enabling their proliferation in vitro and gap closure. [•] AgSD loaded nanocomposites improve antimicrobial properties of the drug especially against Pseudomonas aeruginosa. [•] Nanocomposite is a promising treatment of skin lesions. [ABSTRACT FROM AUTHOR]

The aim of the present work was to evaluate the mucoadhesive and penetration enhancement properties via the buccal and vaginal mucosae of four different chitosan derivatives: 5-methyl-pyrrolidinone chitosan (MPC), two low molecular weight chitosans (DC1 and DC2) and a partially reacetylated chitosan (RC). Chitosan HCl was used as a reference. Polymer solutions (4% w/w) were prepared in media simulating the buccal (pH 6.4 buffer or water) and the vaginal (pH 5.0 buffer) environments and subjected to rheological characterization. Acyclovir was added to the polymer solutions at 5% (w/w) concentration. The mucoadhesive properties of the polymer solutions were measured using excised porcine cheek or vaginal mucosa and mucin dispersions to simulate the buccal or vaginal environments, respectively. Drug permeation and penetration tests were carried out using porcine cheek and vaginal mucosae as model membranes. Acyclovir aqueous suspensions prepared in pH 6.4 and 5.0 buffers were used as blanks. Drug release measurements were also carried out in the same conditions employed for the permeation and penetration tests. Methyl-pyrrolidinone chitosan shows the best mucoadhesive and penetration enhancement properties in both buccal and vaginal environments. The capability to enhance the permeation/penetration of acyclovir was decreased by partial depolymerization of chitosan and disappeared after partial reacetylation. [Copyright &y& Elsevier]

• Electrospun chitosan/glycosaminoglycan scaffolds for skin reparation were developed. • The scaffolds were insoluble in aqueous fluids after crosslinking by heating. • Chondroitin sulfate renders the scaffold best suited to heal lesions in murine model. • Chondroitin sulfate provides system flexibility for optimal preclinical performance. Burns and chronic wounds, often related to chronic diseases (as diabetes and cancer), are challenging lesions, difficult to heal. The prompt and full reconstitution of a functional skin is at the basis of the development of biopolymer-based scaffolds, representing a 3D substrate mimicking the dermal extracellular matrix. Aim of the work was to develop scaffolds intended for skin regeneration, according to: fabrication by electrospinning from aqueous polysaccharide solutions; prompt and easy treatment to obtain scaffolds insoluble in aqueous fluids; best performance in supporting wound healing. Three formulations were tested, based on chitosan (CH) and pullulan (P), associated with glycosaminoglycans (chondroitin sulfate - CS or hyaluronic acid – HA). A multidisciplinary approach has been used: chemico-physical characterization and preclinical evaluation allowed to obtain integrated information. This supports that CS gives distinctive properties and optimal features to the scaffold structure for promoting cell proliferation leading tissue reparation towards a complete skin restore. [ABSTRACT FROM AUTHOR]

In healthy individuals, wound healing is a highly efficient process. However, interruptions of normal healing give rise to chronic wounds, characterized by inflammation with impaired angiogenesis and re-epithelialization. The aim of this work was the design and the development of electrospun nanofibrous scaffolds based on sodium alginate (SA) and pullulan (PUL) and loaded with human platelet lysate (PL) intended for skin reparation, to take the advantage of nanofibrous scaffolds (with improved physical structure) and of SA as biopolymer. Two preparation approaches have been used to load PL in the scaffolds: as component of the PUL/SA matrix, to be electrospun, or as coating component, to cover the previously prepared electrospun PUL based membranes. A preformulation study to assess pullulan entanglement concentration and alginate or citric acid critical concentration, to obtain electrospun nanofibers, has been performed. The preparation process allowed to obtain insoluble systems starting from aqueous solutions and these were able to act as scaffolds for tissue engineering with suitable mechanical properties and PL release. PL loading in PUL/SA matrix nanofibers did not substantially modify the nanofiber morphology before crosslinking, while the crosslinking process, in presence of PL, determined less sharp nanofibers probably due to an increase in hydrophilicity caused by PL proteins. On the contrary, the coated nanofibers showed an increase in diameters due to PL loading. The two different approaches affected the fiber dimension and scaffold elasticity, especially for PL loaded systems. Anyhow, these differences were not crucial for fibroblast adhesion and proliferation which were mainly influenced by PL loading. In particular, fibroblasts presented different conformation and orientation mainly due to the presence of PL. This caused a cell random orientation compatible to a fibroblast-to-myofibroblast transition that could enhance wound healing. [ABSTRACT FROM AUTHOR]

Bleeding control plays an important role to increase survival in the early phase after a traumatic event. The aim of present work was the development of hemostatic sponge-like dressings based on chitosan, in association with glycosaminoglycans (GAG) (chondroitin sulfate or hyaluronic acid) and the improvement of their hemostatic performance by loading tranexamic acid (TA). The dressings were prepared by lyophilizazion and were characterized for mechanical, hydration, bioadhesion properties and morphology. Moreover, FTIR analysis was performed to understand the interactions between the different polyelectrolytes present in the dressings. Clotting was investigated in vitro by using rat whole blood. Moreover, in vitro biocompatibility and proliferation were evaluated towards fibroblasts. Ex vivo proliferation properties were assessed by using human skin. All the dressings were characterised by mechanical, hydration and bioadhesion properties suitable to be applied on bleeding wounds and to absorb bleeding or wound exudate, avoiding tissue dehydration. TA release was fast; TA and chitosan showed a synergic effect to speed up clotting. The dressings were biocompatible and able to sustain cell proliferation in vitro and ex vivo in human skin. In conclusion, sponge-like dressings based on chitosan and GAG and loaded with TA are an effective tool to enhance hemostasis and healing in bleeding wounds. [ABSTRACT FROM AUTHOR]

The aim of the present work was the development of a powder formulation for the delivery of manuka honey (MH) bioactive components in the treatment of chronic skin ulcers. In particular pectin (PEC)/chitosan glutamate (CS)/hyaluronic acid (HA) mini-capsules were obtained by inverse ionotropic gelation in presence of calcium chloride and subsequently freeze-dried. Optimization of unloaded (blank) formulation was performed using DoE approach. In a screening phase, the following three factors were investigated at two levels: CS (0.5–1% w/w), PEC (0.5–1% w/w) and HA (0.3–0.5% w/w) concentrations. For the optimization phase a “central composite design” was used. The response variables considered were: particle size, buffer (PBS) absorption and mechanical resistance. In a previously work two different MH fractions were investigated, in particular MH fraction 1 (Fr1), rich in polar substances (sugars, methylglyoxal (MGO), dicarbonyl compounds, …), was able to enhance human fibroblasts in vitro proliferation. In the present work, the loading of MH Fr1 into mini-capsules of optimized composition determined a significant increase in cell proliferation in comparison with the unloaded ones. Loaded particles showed antimicrobial activity against Staphylococcus aureus and Streptococcus pyogenes ; they were also able to improve wound healing in vivo on a rat wound model. [ABSTRACT FROM AUTHOR]

Solid Lipid Nanoparticles (SLNs) composed of biodegradable physiological lipids have been widely proposed as efficient drug delivery systems, also for ophthalmic administration. Recently, chitosan-associated-SLNs have been developed to further improve the residence time of these colloidal systems in the precorneal area by means of mucoadhesive interaction. In the present study, a one-step preparation protocol was used aiming both at scale-up ease and at stronger coupling between chitosan and SLNs. The resulting particles were chitosan associated-SLNs (CS-SLNs). These nanoparticles were characterized, as compared to both the chitosan-free and the usual chitosan-coated ones, by applying a multi-technique approach: light, neutron and X-ray scattering, Zeta-potential, AFM, calorimetry. It was assessed that, while keeping the features of nano-size and surface-charge required for an efficient vector, these new nanoparticles display a strong and intimate interaction between chitosan and SLNs, far more settled than the usual simple coverage. Moreover, this one-step preparation method allows to obtain a strong and intimate interaction between chitosan and SLNs, firmer than the usual simple coating. This confers to the CS-SLNs an improved mucoadhesion, opening the way for a high-performing ophthalmic formulation. [ABSTRACT FROM AUTHOR]

Abstract: Corneal lesions cause significant pain and visual impairment and, in many cases, are unresponsive to conventional treatments. Platelet lysate (PL) is an haemoderivative rich in growth factors (GFs) that are released by platelets after freeze-thawing destruction of platelet rich plasma (PRP). The aim of the present work was to develop thermosensitive and mucoadhesive eyedrops to maintain and prolong the contact of platelet lysate (PL) with cornea ulcers. A sterile vehicle based on chondroitin sulphate sodium (CS) and hydroxypropylmethyl cellulose (HPMC) was developed. An extemporaneous loading of the vehicle with PL was performed and the obtained formulation was able to quickly thermogelify at about 32°C and was characterized by good mucoadhesive properties. ELISA evidenced that the growth factor PDGF AB was compatible with the vehicle and stable in the formulation up to 15 days of storage at 2–8°C. In vitro wound healing and proliferation test (performed using rabbit corneal epithelial cells (RCE)) showed that the formulation enhanced cell growth and put in evidence a synergistic effect of CS and PL in stimulating cell proliferation. The overall results indicate that PL loaded in thermosensitive and mucoadhesive eyedrops can be profitably employed to treat corneal lesions. [Copyright &y& Elsevier]

Abstract: Cyclosporine A (CsA) loaded solid lipid nanoparticles (SLNs) for topical ophthalmic applications were prepared by high shear homogenization and ultrasound method using Compritol 888 ATO, Poloxamer 188 and Tween 80, to investigate the cellular uptake of rabbit corneal epithelial cells (RCE) and to evaluate the cytotoxicity. The size of the optimized formulation was 225.9±5.5nm with a polydispersity index of 0.253±0.05. The zeta potential and entrapment efficiency was detected as −16.9±0.7mV and 95.6%, respectively. The CsA release was found to be enzyme (lipase/co-lipase complex) dependent. SLNs were sterilized at 110 and 121°C. The cytotoxicity was evaluated in vitro by means of RCE cells and was higher at 121°C sterilization temperature, probably due to a supposed leakage of Tween 80 following lipid re-crystallization. The permeation and penetration of CsA across/into the corneal cells were evaluated using in vitro and ex vivo experiments. The cellular uptake was investigated by replacing CsA with the fluorescent dye Rhodamine B. The penetration enhancement properties were supported by confocal laser scanning microscopy analysis. The internalization of SLNs in cornea and in RCE cell lines was confirmed, pointing out the possibility of CsA targeting to the cornea. [Copyright &y& Elsevier]

Fucoxanthin (FUCO) is a marine carotenoid characterized by antiproliferative properties against hyperproliferative cells. The aim of this work was to design and develop nanostructured lipidic carriers (NLCs) based on bacuri butter and tucumã oil and loaded with FUCO, intended for skin application to prevent skin hyperproliferative diseases and in particular psoriasis. The presence of FUCO should control the hyperproliferation of skin diseased cells and the lipids forming the NLC core, rich in antioxidants and characterized by wound healing properties, should favor the restoring of skin integrity. NLCs were coated with chitosan (CS) to improve their biopharmaceutical properties (bio/mucoadhesion and wound healing) and to combine the advantages of lipidic nanoparticles with the biological properties of CS. Chitosan coated and non-coated NLC were prepared by means of high shear homogenization and characterized for chemico-physical and biopharmaceutical properties (in vitro biocompatibility and cell uptake towards normal dermal human fibroblasts). Moreover, the pharmacological activity of FUCO loaded in NLCs was assessed in psoriatic-like cellular model. NLCs were characterized by dimensions ranging from about 250 to 400 nm. Moreover, the CS coating and FUCO loading determined an increase of size. Moreover, TEM and zeta potential analysis confirmed the presence of CS coating on nanoparticle surface, thus conferring to nanoparticle good bioadhesion properties. NLCs uptake in fibroblasts was observed and NLC-FUCO-CS caused a reduction of cell viability with a less marked effect in fibroblasts rather than in psoriatic cells, highlighting the capability of this system to control skin hyperproliferation and inflammation. The loading of NLC-FUCO-CS in pullulan film should render NLCs application easy, without impair prompt interaction of the drug with the skin. Considering the overall results skin application of CS coated NLCs loaded with FUCO seems a promising approach to control skin hyperproliferation and to preserve skin integrity in psoriatic skin. [ABSTRACT FROM AUTHOR]