Glucose diffusivity and porosity in silica hydrogel based on organofunctional silanes

Quercetin encapsulated polycaprolactone-polyvinylpyrrolidone electrospun membranes as a delivery system for wound healing applications

The present work focuses on the production of electrospun membranes based on Poly(ε-caprolactone) (PCL) and Polyvinylpyrrolidone (PVP) for the topical release of Quercetin (Q). Membranes were prepared at 0.5, 1.0, 3.0, 7.0 and 15 % wt of Quercetin and studied from a morphological, physical, and biological point of view. The scanning electron microscopy (SEM) evidences micrometric dimensions of the fibres with a good dispersion of the functional molecule. The retention degree of liquids was evaluated by testing four different liquid media while the radical scavenging activity of Quercetin-loaded membranes was evaluated through DPPH analysis. The release kinetics of Quercetin highlights the presence of an initial burst followed by slower release up to attaining an equilibrium state, after roughly 50 h, showing the possibility of a fine-tuning of drug release. Diffusion coefficients were then evaluated by using Fick's law. Finally, to verify the actual biocompatibility of the systems produced and the possible application in the repair of tissue injury, the biological activity of Quercetin released from drug-loaded membranes was analysed in an immortalized human keratinocyte cell line HaCaT by a wound healing assay. So, the reported preliminary data confirm the possibility of applying the electrospun Quercetin-loaded PCL-PVP membranes for wound healing applications.

Quercetin-Loaded Polycaprolactone-Polyvinylpyrrolidone Electrospun Membranes for Health Application: Design, Characterization, Modeling and Cytotoxicity Studies

Fibrous membranes of polycaprolactone (PCL)-polyvinylpyrrolidone (PVP) encapsulating 15% wt of quercetin are fabricated by a uniaxial electrospinning technique. Morphological analysis of the electrospun systems proved the fabrication of micrometric fibers (1.58 µm for PCL/PVP and 2.34 µm for quercetin-loaded membrane). The liquid retention degree of the electrospun membranes is evaluated by testing four different liquid media. The contact angle estimation is performed by testing three liquids: phosphate buffer solution, basic solution (pH = 13) and acidic solution (pH = 3), showing high hydrophobicity degree (contact angles > 90°) in all cases. The release of quercetin from the nanofibers in PBS (phosphate buffer solution) and pH = 3 medium, modeled through different models, shows the possibility of a fine tuning of drug release (up to 7 days) for the produced materials. The release profiles attained a plateau regime after roughly 50 h up to 82% and 71% for PBS and pH = 3 media, respectively. Then, since quercetin is known to undergo photooxidation upon UV radiation, release tests after different UV treatment times are carried out and compared with the untreated membrane, demonstrating that the release of the active drug changes from 82% for no-irradiated sample up to 57% after 10 h of UV exposure. The biology activity of released quercetin is evaluated on two human cell lines. The reported results demonstrate the ability of the quercetin-loaded membranes to reduce cell viability of human cell lines in two different conditions: direct contact between cells and quercetin-loaded membranes and cells treatment with culture medium previously conditioned with quercetin-loaded membranes. Therefore, the reported preliminary data confirm the possibility of applying the electrospun quercetin-loaded PCL-PVP membranes for health applications.

A colon-specific delivery system for quercetin with enhanced cancer prevention based on co-axial electrospinning

The antioxidant quercetin (Q) is a bioactive compound that can inhibit colon cancer. However, its poor stability in the upper gastro-intestinal tract and low bioavailability compromised its benefits. In this study, a biopolymer-based colon-specific delivery system for Q was constructed by co-axial electrospinning. Quercetin-loaded chitosan nanoparticles (QCNP) were firstly prepared and characterized. Then, a Q-loaded electrospun fiber mat (Q-loaded EFM) containing prebiotics (galactooligosaccharide, GOS) was fabricated using sodium alginate as the shell layer and the abovementioned QCNP and prebiotics as the core layer. The DPPH assay showed that the antioxidant activity of Q was maintained in the obtained film. Owing to the addition of prebiotic GOS, the obtained fiber mat exhibited good prebiotic effects. In vitro release kinetics showed a sustained and targeted colon-specific release of Q from the Q-loaded EFM containing GOS, and the release rate of Q was enhanced by the presence of GOS. The obtained film also exhibited inhibition effects on Caco-2 cells in a dose- and time-dependent manner. Flow cytometry and fluorescence microscopy analysis indicated that the Q-loaded EFM containing GOS exerted its activity on colonic cancer cells by arresting the cell cycle in the G0/G1 phase and triggering apoptotic cell death. This study demonstrates the potential of the obtained film as an oral delivery system for encapsulation, protection, and release of Q at the colon for the oral therapy of colon disorders.

Inorganic polymerization: an attractive route to biocompatible hybrid hydrogels

The sol–gel process is one of the main techniques leading to hybrid hydrogels that can be used in a wide scope of applications, especially in the biomedical field.

Preparation and Characterization of Protein-Loaded Electrospun Fiber Mat and Its Release Kinetics

For the enhancement of protein's bioavailability, a specific delivery system was developed by coaxial electrospinning. Bovine serum albumin (BSA) was used as protein model, and the core-sheath fiber mat was fabricated using sodium alginate as shell layer and the BSA-loaded chitosan nanoparticle that was prepared previously as core layer. By optimizing electrospinning parameters, uniform fibers with diameters ranging from 200-600 nm were obtained, and transmission electron microscopy and confocal laser scanning microscopy revealed their core-sheath structures. Fourier transform infrared spectroscopy (FTIR) analysis demonstrated that there existed molecular interaction between components, which enhanced the mat's thermal stability and mechanic property. It was found that the predominant release mechanism of BSA from fiber mat was erosion, and little change occurred in the secondary structure of encapsulated BSA indicated by FTIR and circular dichroism analysis. The study shows that the obtained fiber mat is a potential delivery system for protein.

A polysulfobetaine hydrogel for immobilization of a glucose-binding protein

A hydrogel based on sulfobetaine methacrylate monomer and crosslinker was investigated as a potential material for fluorescent glucose biosensor applications.