Delivery of growth factors and control of vascularization are prominent problems in regenerative medicine.Vascular endothelial growth factor (VEGF) has been used both in vitro and in vivo to promote angiogenesis but due to its short half-life its controlled delivery is a sought after method. In this study we present a new concept of degradable drug loaded nanoparticles entrapped into exponentially growing multilayer films.Through hydrolysis of the nanoparticles, the drug can be delivered over long periods in a controlled manner. Poly(3-caprolactone) nanoparticles were loaded with VEGF and in turn the release of VEGF from a surface is controlled by a thick layer-by-layer polyelectrolyte film. Direct loading of VEGF inside the film was not efficient for long-term applications. When VEGF loaded nanoparticles were introduced into the film, the particles were equally distributed inside and were stable after several washes. Moreover, the presence of the film sustained the release of VEGF for 7 days. Addition of the nanoparticles to the film promoted endothelial cell proliferation, mainly due to the presence of VEGF. Mechanical properties of the film (Young's moduli) were also improved by the presence of nanoparticles. However, in the presence of the film loaded with nanoparticles and without any direct contact with this film, endothelial cell growth was also enhanced on polystyrene and on Transwell insert surfaces which demonstrates the effectiveness of the nanoparticles not only to improve the mechanical properties of the film but also to deliver active VEGF. An increase in nitric oxide levels as an indicator of endothelial cell activity was monitored and was correlated with the release of VEGF from the nanoparticle/film platform. Finally, such a system can be used as an auxiliary delivery body within implants to finely control the release of bioactive agent containing nanoparticles.

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The aim of this study was to prepare and characterize highly porous clinoptilolite/poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) composite scaffolds. Scaffolds with different clinoptilolite contents (10% and 20%) were fabricated with reproducible solvent-free powder compression/particulate leaching technique. The scaffolds had interconnective porosity in the range of 55-76%. Clinoptilolite/poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) scaffolds showed negligible degradation within eight weeks and displayed less water uptake and higher bioactivity than poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) scaffolds. The presence of clinoptilolite improved the mechanical properties. Highest compressive strength (5.6 MPa) and modulus (114.84 MPa) were reached with scaffold group containing 20% clinoptilolite. In vitro protein adsorption capacity of the scaffolds was also higher for clinoptilolite/poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) scaffolds. These scaffolds had 0.95 mg protein/g scaffold adsorption capacity and also higher osteoinductivity in terms of enhanced ALP, OSP activities and intracellular calcium deposition. Stoichiometric apatite deposition (Ca/P=1.686) was observed during cellular proliferation analysis with human fetal osteoblasts cells. Thus, it can be suggested that clinoptilolite/poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) composite scaffolds could be promising carriers for enhancement of bone regeneration in bone tissue engineering applications.

The objective of this study was to improve the efficacy of polycaprolactone/bioglass (PCL/BG) bone substitute using demineralized bone matrix (DBM) or calcium sulfate (CS) as a third component. Composite discs involving either DBM or CS were prepared by compression moulding. Bioactivity of discs was evaluated by energy dispersive X-ray spectroscopy (ESCA) and scanning electron microscopy (SEM) following simulated body fluid incubation. The closest Calcium/Phosphate ratio to that of hydroxyl carbonate apatite crystals was observed for PCL/ BG/DBM group (1.53) after 15 day incubation. Addition of fillers increased microhardness and compressive modulus of discs. However, after 4 and 6-week PBS incubations, PCL/BG/DBM discs showed significant decrease in modulus (from 266.23 to 54.04 and 33.45 MPa, respectively) in parallel with its highest water uptakes (36.3 and 34.7%). Discs preserved their integrity with only considerable weight loss (7.5-14.5%) in PCL/BG/DBM group. In vitro cytotoxicity tests showed that all discs were biocompatible.

Herein, an easy one‐pot synthesis method for gold nanoparticles (AuNPs), involving only gold salt and sericin extracted from silkworm cocoon in the presence of ultraviolet C (UVC) radiation, was developed. Nanoparticle formation was confirmed by characteristic surface plasmon resonance peaks at 520–540 nm wavelengths, and the influence of silk sericin on enhancing the colloidal stability of AuNPs was confirmed. Transmission electron microscopy examination showed the average size (<10 nm) and size distribution decreased significantly with higher sericin concentration. No antibacterial activity was observed on Gram‐positive Bacillus subtilis or Gram‐negative Escherichia coli for sole AuNPs (0.065–0.26 mg/ml), but the conjugation of AuNPs with streptomycin antibiotic decreased significantly the required minimum inhibitory concentration doses, as also confirmed with agar plating, Scanning Electron Microscopy and Atomic Force Microscopy analyses. Furthermore, sericin‐capped AuNPs showed high cell viabilities (>100%) and no sign of any detectable apoptosis or necrosis in 1‐day incubation. Also, high real‐time cell proliferation results of AuNPs competitive with positive control groups implied excellent in vitro biocompatibility. These results evidenced that sericin enhanced the colloidal stability of AuNPs and the biological activities of sericin‐capped AuNPs reported here could render them suitable nanoscale vehicles for biomedical applications.