Multifunctional polymeric coatings containing drug delivery vehicles can play a key role in preventing/reducing biofilm formation on implant surfaces. Their requirements are biocompatibility, good adhesion, and controllable drug release. Although cellulose acetate (CA) films and membranes are widely studied for scaffolding, their applications as a protective coating and drug delivery vehicle for metal implants are scarce. The reason is that adhesion to stainless steel (SS) substrates is non-trivial. Grinding SS substrates enhances the adhesion of dip-coated CA films while the adhesion of electrospun CA membranes is improved by an electrosprayed chitosan intermediate layer. PMMA microcapsules containing daptomycin have been successfully incorporated into CA films and fibres. The released drug concentration of 3 x10-3 mg/mL after 120 minutes was confirmed from the peak luminescence intensity under UV radiation of simulated body fluid (SBF) after immersion of the fibres.

The present paper regards the preparation and characterization of Pluronic F127 + F68/water/poly (ε-caprolactone) microcapsules (MCs) composite systems for tissue repair. The first part of the work relates to the production of poly(ε-caprolactone) (PCL) MCs via water-in-oil-in-water (W/O/W) double emulsion system combined with solvent evaporation method. The study of different process parameters in the final MCs characteristics and their drug release profile is herein reported. Different percentages of PCL, emulsion stabilizer, and volume proportions of the emulsion constituents have been tested, leading to considerable differences in the MCs size distributions. The selected MCs, containing an aqueous solution of methylene blue (MB) as a model drug, were then used to fill a Pluronic F127 + F68/water system leading to the final composite system (5 and 10 wt % MB loaded PCL MCs). The composite systems were characterised in the second part of the work in terms of its rheological behaviour and drug release performance. They were found to gellify at 30 °C, and present an extended drug release to a total of 18 days. The models that best define the release profiles were also studied, with the release of MB occurring mostly by Fick diffusion and polymer chain relaxation. Pluronic F127 + F68/water/poly (ε-caprolactone) MCs composite system is shown to be a promising injectable system, with two different drug release rates, for tissue repair.

The unique properties of electrospun nanofibers combined with functional compounds allow the preparation of novelty materials that can be employed in a wide range of applications. Among a vast number of polymers, Cellulose Acetate (CA) it is considered easy to electrospun and it was employed as the polymeric matrix, where free and iridium-porphyrins were incorporated. Two different solvent systems were employed according to the porphyrin used, and the best dispersion level on both the electrospun solution and the membranes, was achieved with the iridium porphyrin. The nanofibers with this porphyrin also exhibited electrical properties, while the fluorescence was quenched by the presence of specific axial ligands.

Fast-dissolving delivery systems (FDDS) have received increasing attention in the last years. Oral drug delivery is still the preferred route for the administration of pharmaceutical ingredients. Nevertheless, some patients, e.g. children or elderly people, have difficulties in swallowing solid tablets. In this work, gelatin membranes were produced by electrospinning, containing an encapsulated therapeutic deep-eutectic solvent (THEDES) composed by choline chloride/mandelic acid, in a 1:2 molar ratio. A gelatin solution (30% w/v) with 2% (v/v) of THEDES was used to produce electrospun fibers and the experimental parameters were optimized. Due to the high surface area of polymer fibers, this type of construct has wide applicability. With no cytotoxicity effect, and showing a fast-dissolving release profile in PBS, the gelatin fibers with encapsulated THEDES seem to have promising applications in the development of new drug delivery systems.

Nanometric and sub-micrometric monodispersed hydroxyapatite (HAp) particles with different morphologies (spheres and rods) were synthesized via a simple solvothermal method using Ca(NO3)2·4H2O and P2O5 as starting materials without any requirement to use organic templates. The growth, evolution and purity of the nanoparticles were investigated by controlling the synthesis conditions, including the alkalinity and the temperature of the solvothermal treatment. The increasing of the alkaline ratio results in a great change of the elaborated particles’ morphology that evolved from anisotropic forms (nanorods, sub-micrometric rod) at pH 9, short rod particles at pH 9.5 to spherical ones at higher pH (pH≥10).
Powder X-Ray diffractometry (XRD), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and Nitrogen adsorption and desorption studies (BET) were used to characterize the structure and composition of the as-prepared samples.
The thermal analysis of the synthesized particles conducted by differential scanning calorimetry (DSC) shows a good stability for all morphologies with a degradation temperature reaching 1300 °C.

Functionalized electrospun fibers are of great interest for biomedical applications such as in the design of drug delivery systems. Nevertheless, in some cases the molecules of interest have poor solubility in water or have high melting temperatures. These drawbacks can be overcome using deep eutectic solvents. In this work, poly(vinyl alcohol) (PVA), a common biodegradable biopolymer, was used to produce new functionalized fibers with the eutectic mixture choline chloride:citric acid in a molar ratio of (1:1) ChCl:CA (1:1), which was used as a model system. Fibers were produced from an aqueous solution with 7.8% (w/v) and 9.8% (w/v) of 95% hydrolyzed PVA and a 2% (v/v) of ChCl:CA (1:1). Smooth, uniform fibers with an average diameter of 0.4 μm were obtained with a content of 19.8 wt % of ChCl:CA (1:1) encapsulated.

The thermally stimulated discharge current, the final thermally stimulated discharge current, DC conductivity and the final thermally stimulated discharge current with partially blocking electrode measures were used to analyze electrical behavior of Nylon 11. The objective was to discriminate between dipole related effects and space charge related effects. The space charge effects are dominant in the temperature range from room temperature to 170 °C. By using a Teflon-FEP partially blocking electrode, the space charge injected in the sample is diminished and the effects related to dipole movement can be observed. Beside the two known relaxations for Nylon 11, one associated with the glass transition around 60 °C and a second one associated with a molecular motion in the rigid-amorphous phase at 96 °C, a weak relaxation was observed around 168 °C. The peak around 96 °C is quite broad been composed of two narrow peaks. The final thermally stimulated discharge current method allows a better selection of the experimental conditions for sample charging (polarization) to have only a partial overlap between the nearby peaks. The peak's maximum current and temperature are dependent on the ratio between the charging and discharging time and temperature given a possibility to discriminate between dipolar and space charge effects. A pyroelectric current changes sign around 140 °C indicating that the amidegroup dipoles are frozen in opposite directions when the sample temperature is below 140 °C (amorphous and rigid-amorphous phase) or above (crystalline phase). The conductivity is controlled by the competition between n(E,T) and μ(E,T) indicating a space charge controlled conductivity mechanism.

We report a method to obtain electrospun fibers based on ionic liquids and gelatin, exhibiting antimicrobial properties.

Osteosarcoma is the most common primary bone tumor in children and adolescents, with a 5-year disease free survival rate of 70%. Current chemotherapy regimens comprise a group of chemotherapeutic agents in which doxorubicin is included. However, tumor resistance to anthracyclines and cardiotoxicity are limiting factors for its usage. Liposomal formulations of doxorubicin improve its anti-cancer effects but are still insufficient. The research in this area has lead to the production of anthracyclines analogues, such as ladirubicin, the leading compound of alkylcyclines. This new anticancer agent has shown promising results in vivo and in vitro, being effective against osteosarcoma cell lines, including those with a multidrug resistant phenotype. In phase I clinical trials, this molecule caused mild side effects and did not induce significant cardiotoxicity at doses ranging from 1 to 16 mg/m2, resulting in a peak plasma concentration (Cmax) ranging from 0.5 to 1.5 μM. The recommended doses for phase II studies were 12 and 14 mg/m2 in heavily and minimally pretreated/non-pretreated patients, respectively. Phase II clinical trials in ovary, breast, colorectal cancer, NSCLC and malignant melanoma are underway. Given the improved molecular targeting efficacy of these new compounds, ongoing approaches have sought to improve drug delivery systems, to improve treatment efficacy while reducing systemic toxicity. The combination of these two approaches may be a good start for the discovery of new treatment for osteosarcoma.