Hyaluronic acid and beta cyclodextrins films for the release of corneal epithelial cells and dexamethasone

In this work we prepared hydrogels based on hyaluronic acid and β-cyclodextrins to sustain the release of both corneal epithelial cells and dexamethasone. This steroid is administered as eye drops several times per day to reduce the risk of rejection in the post operative period after the cornea transplantation and cell release techniques. Hydrogels were produced by crosslinking an amino derivative of hyaluronic acid, with the divinyl sulfone derivative of β-cyclodextrins, this last employed as a crosslinker and solubilizing agent. Drug release studies revealed that dexamethasone containing samples are able to extend the release of this drug for at least five days. Biological studies, conducted with human corneal epithelial cells, showed that it is possible to employ the hydrogels for the temporary seeding of the cells and their potential release onto the cornea.

Double-Network-Structured Graphene Oxide-Containing Nanogels as Photothermal Agents for the Treatment of Colorectal Cancer

Here, we reported the production of hyaluronic acid/polyaspartamide-based double-network nanogels for the potential treatment of colorectal carcinoma. Graphene oxide, thanks to the huge aromatic surface area, allows to easily load high amount of irinotecan (33.0% w/w) and confers to the system hyperthermic properties when irradiated with a near-infrared (NIR) laser beam. We demonstrate that the release of antitumor drug is influenced both by the pH of the external medium and the NIR irradiation process. In vitro biological studies, conducted on human colon cancer cells (HCT 116), revealed that nanogels are uptaken by the cancer cells and, in the presence of the antitumor drug, can produce a synergistic hyperthermic/cytotoxic effect. Finally, 3D experiments demonstrate that it is possible to conduct thermal ablation of solid tumors after the intratumoral administration of nanogels.

Uptake of silica covered Quantum Dots into living cells: Long term vitality and morphology study on hyaluronic acid biomaterials

Quantum Dots (QDs) are promising very bright and stable fluorescent probes for optical studies in the biological field but water solubility and possible metal bio-contamination need to be addressed. In this work, a simple silica-QD hybrid system is prepared and the uptake in bovine chondrocytes living cells without any functionalization of the external protective silica shield is demonstrated. Moreover, long term treated cells vitality (up to 14days) and the transfer of silica-QDs to the next cell generations are here reported. Confocal fluorescence microscopy was also used to determine the morphology of the so labelled cells and the relative silica-QDs distribution. Finally, we employ silica-QD stained chondrocytes to characterize, as proof of concept, hydrogels obtained from an amphiphilic derivative of hyaluronic acid (HA-EDA-C18) functionalized with different amounts of the RGD peptide.

Interpenetrated 3D porous scaffolds of silk fibroin with an amino and octadecyl functionalized hyaluronic acid

A functionalized HA derivative (HA–EDA–C₁₈) was processed with silk fibroin via a salt leaching procedure to produce stable porous scaffolds for biomedical applications. The HA derivative was able to induce β-sheet transitions on fibroin.

Injectable in situ forming hydrogels based on natural and synthetic polymers for potential application in cartilage repair

Injectable hydrogels based on hyaluronic acid, elastin and a biocompatible polyaspartamide are optimal scaffolds of viable chondrocytes for potential cartilage repair.

In-situ forming gel-like depot of a polyaspartamide-polylactide copolymer for once a week administration of sulpiride

Objectives

An in-situ forming gel-like depot, prepared by using an appropriate polyaspartamide-polylactide graft copolymer, has been employed to release in a sustained way sulpiride.

Methods

α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide-g-polylactic acid (PHEA-g-PLA) has been used as a polymer component. Its physicochemical properties make possible to dissolve it in N-methyl-2-pyrrolidone, with the obtainment of a solution able to form a gel-like depot once injected into a physiological medium. Cell compatibility of PHEA-g-PLA depot has been investigated, using murine dermal fibroblasts as cell model. 3-(4,5-Dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt assay and fluorescence microscopy have been employed to evaluate cell viability and morphology after contact with PHEA-g-PLA depot. Pharmacokinetic parameters of sulpiride released from depot have been determined following subcutaneous administration to rabbits and compared with corresponding parameters following administration of free sulpiride solution.

Key findings

It has been demonstrated that the system does not affect significantly the viability of fibroblasts and is able to sustain the release of sulpiride until a week, with a burst effect dependent on the initial weight ratio polymer/drug.

Conclusion

In-vivo release profiles and pharmacokinetic parameters suggest that PHEA-g-PLA depot could have interesting clinical applications for a once a week administration of poorly soluble drugs to humans or animals.

Dexamethasone dipropionate loaded nanoparticles of α-elastin-g-PLGA for potential treatment of restenosis

A graft copolymer of α-elastin with poly(lactic-co-glycolic) acid (PLGA) has been synthesized and successfully employed to produce nanoparticles. Exploiting the known biological activity of α-elastin to promote the maintenance of smooth muscle cells (SMCs) contractile phenotype and the antiproliferative effect of glucocorticoids, the aim of this research was to produce drug-loaded nanoparticles suitable for potential treatment of restenosis. In particular, nanoparticles of α-elastin-g-PLGA with a mean size of 200 nm have been produced and loaded with dexamethasone dipropionate (10% w/w), chosen as a model drug that inhibits proliferation of vascular SMCs. These nanoparticles are able to prolong the drug release and show a pronounced sensibility to elastase. Drug unloaded nanoparticles stimulate the differentiation of human umbilical artery smooth muscle cells (HUASMCs) toward the contractile phenotype as demonstrated by immunofluorescence, flow cytofluorimetric, and western blotting analyses. Finally, drug-loaded nanoparticles efficiently reduce viability of HUASMCs as evidenced by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2- (4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay.

Polymeric nanocarriers for magnetic targeted drug delivery: preparation, characterization, and in vitro and in vivo evaluation

In this paper the preparation of magnetic nanocarriers (MNCs), containing superparamagnetic domains, is reported, useful as potential magnetically targeted drug delivery systems. The preparation of MNCs was performed by using the PHEA-IB-p(BMA) graft copolymer as coating material through the homogenization-solvent evaporation method. Magnetic and nonmagnetic nanocarriers containing flutamide (FLU-MNCs) were prepared. The prepared nanocarriers have been exhaustively characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), and magnetic measurements. Biological evaluation was performed by in vitro cytotoxicity and cell uptake tests and in vivo biodistribution studies. Magnetic nanocarriers showed dimensions of about 300 nm with a narrow size distribution, an amount of loaded FLU of 20% (w/w), and a superparamagnetic behavior. Cell culture experiments performed on prostate cancer cell line LNCaP demonstrated the cytotoxic effect of FLU-MNCs. In vivo biodistribution studies carried out by the application of an external magnetic field in rats demonstrated the effect of the external magnet on modifying the biodistribution of FLU-MNCs. FLU-MNCs resulted efficiently internalized by tumor cells and susceptible to magnetic targeting by application of an external magnetic field. The proposed nanocarriers can represent a very promising approach to obtain an efficient magnetically targeted anticancer drug delivery system.

Heparin functionalized polyaspartamide/polyester scaffold for potential blood vessel regeneration

An interesting issue in tissue engineering is the development of a biodegradable vascular graft able to substitute a blood vessel and to allow its complete regeneration. Here, we report a new scaffold potentially useful as a synthetic vascular graft, produced through the electrospinning of α,β-poly(N-2-hydroxyethyl) (2-aminoethylcarbamate)-D,L-aspartamide-graft-polylactic acid (PHEA-EDA-g-PLA) in the presence of polycaprolactone (PCL). The scaffold degradation profile has been evaluated as well as the possibility to bind heparin to electrospun fibers, being it a known anticoagulant molecule able to bind growth factors. In vitro cell compatibility has been investigated using human vascular endothelial cells (ECV 304) and the ability of heparinized PHEA-EDA-g-PLA/PCL scaffold to retain basic fibroblast growth factor has been evaluated in comparison with not heparinized sample.

Medicated hydrogels of hyaluronic acid derivatives for use in orthopedic field

Physical hydrogels have been obtained from hyaluronic acid derivatized with polylactic acid in the presence or in the absence of polyethylene glycol chains. They have been extemporarily loaded with antibacterial agents, such as vancomycin and tobramycin. These medicated hydrogels have been used to coat titanium disks (chosen as simple model of orthopedic prosthesis) and in vitro studies in simulated physiological fluid have been performed as a function of time and for different drug loading and polymer concentration values. Sterilization process performed on the hydrogels does not change their rheological behavior and release properties as well as the chemical structure of starting copolymers. A preliminary test has been performed by coating with the hydrogel a prosthesis that has been inserted in a seat of a lyophilized human femur, to confirm the ability of the hydrogel to adhere to the prosthesis surface also after its insertion in the implant seat. Cell compatibility of obtained hydrogels has been confirmed in vitro by using human dermal fibroblasts chosen as a model cell line. Obtained results suggest the potential use of these hydrogels in the orthopedic field, in particular for the production of antibacterial coatings of prostheses for implant in the human or animal body in the prevention and/or treatment of post surgical infections.