The term photonic crystals appears because of the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures. During the recent years the investigation of one-, two-and three-dimensional periodic structures has attracted a widespread attention of the world optics community because of great potentiality of such structures in advanced applied optical fields. The interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.

http://ieeexplore.ieee.org/iel5/6354/16969/00781867.pdf

Photonic crystals

Chitosan—A versatile semi-synthetic polymer in biomedical applications

Fibroblasts can condense a hydrated collagen lattice to a tissue-like structure 1/28th the area of the starting gel in 24 hr. The rate of the process can be regulated by varying the protein content of the lattice, the cell number, or the con- centration of an inhibitor such as Colcemid. Fibroblasts of high population doubling level propagated in vitro, which have left the cell cycle, can carry out the contraction at least as efficiently as cycling cells. The potential uses of the system as an immu- nologically tolerated "tissue" for wound hea ing and as a model for studying fibroblast function are discussed.

Production of a tissue-like structure by contraction of collagen lattices by human fibroblasts of different proliferative

Utilization of polymers as biomaterials has greatly impacted the advancement of modern medicine. Specifically, polymeric biomaterials that are biodegradable provide the significant advantage of being able to be broken down and removed after they have served their function. Applications are wide ranging with degradable polymers being used clinically as surgical sutures and implants. In order to fit functional demand, materials with desired physical, chemical, biological, biomechanical and degradation properties must be selected. Fortunately, a wide range of natural and synthetic degradable polymers has been investigated for biomedical applications with novel materials constantly being developed to meet new challenges. This review summarizes the most recent advances in the field over the past 4 years, specifically highlighting new and interesting discoveries in tissue engineering and drug delivery applications.

/pdf/biomedical-applications-of-biodegradable-polymers-2db9gcyzxw.pdf

Biomedical Applications of Biodegradable Polymers

Polysaccharides-based nanoparticles as drug delivery systems

http://www.falloplastica.net/fp/pdf/prp03.pdf

Autologous preparations rich in growth factors promote proliferation and induce VEGF and HGF production by human tendon cells in culture.

Chitosan-based nanostructures: a delivery platform for ocular therapeutics.

Purpose Gene therapy offers a promising alternative for the treatment of ocular diseases. However, the implementation of this type of therapy is actually hampered by the lack of an efficient ocular gene delivery carrier. The main objective of the present work was to assess the effectiveness and investigate the mechanism of action of a new type of nanoparticle made of two bioadhesive polysaccharides, hyaluronic acid (HA) and chitosan (CS), intended for the delivery of genes to the cornea and conjunctiva. Methods The nanoparticles were obtained by a very mild ionotropic gelation technique. They were loaded with either the model plasmid pEGFP or pbeta-gal. Transfection and toxicological studies were conducted in human corneal epithelial (HCE) and normal human conjunctival (IOBA-NHC) cell lines. The mechanism of internalization of the nanoparticles by the corneal and conjunctival cells was investigated by using fluorescence confocal microscopy. Results The nanoparticles had a size in the range of 100 to 235 nm and a zeta-potential of -30 to +28 mV. The results of the transfection studies showed that HA-CS nanoparticles were able to provide high transfection levels (up to 15% of cells transfected), without affecting cell viability. The confocal images indicated that HA-CS nanoparticles were internalized by fluid endocytosis and that this endocytic process was mediated by the hyaluronan receptor CD44. Conclusions The results give evidence of the potential of HA-CS nanoparticles for the targeting and further transfer of genes to the ocular surface.

/pdf/novel-hyaluronic-acid-chitosan-nanoparticles-for-ocular-gene-1awu4as61v.pdf

Novel Hyaluronic Acid-Chitosan Nanoparticles for Ocular Gene Therapy

The use of autologous fibrin matrices has been proposed as a therapeutic strategy for the local and physiological delivery of growth factors in the treatment of several clinical conditions requiring tendon healing or tendon graft remodelling. In the present work, we investigated the proliferation, synthesis of type-I collagen and angiogenic factors by tendon cells seeded on platelet-rich (PR) and platelet-poor (PP) matrices. Furthermore, in vivo cellular and vascular effects of each treatment were examined after infiltration in Achilles tendon in sheep. Results showed that the presence of platelets within the fibrin matrices increased significantly the proliferation of tendon cells. Additionally, cultured tendon cells synthesised type I collagen and angiogenic factors such as VEGF and HGF. The synthesis of VEGF, but not of HGF, was significantly higher when platelets were present within the matrix. In the sheep model, the injection of pre-clotted plasma within tendons increased cellular density and promoted neovascularization. These results indicate that administration of fibrin matrices is a safe and easy strategy that may open new avenues for enhancing tissue healing and remodelling and influences the process of regeneration in clinical situations characterised by a poor healing outcome.

Autologous fibrin matrices: a potential source of biological mediators that modulate tendon cell activities.

Background:Autologous platelet-rich matrices can be an aid in surgery by promoting and accelerating tissue healing because of the release of growth factors including transforming growth factor (TGF)-β1 and platelet-derived growth factor (PDGF) from platelet α-granules.Methods:PDGF and TGF-β1 were qu

Maria de la Fuente

Papers

Autologous preparations rich in growth factors promote proliferation and induce VEGF and HGF production by human tendon cells in culture.

Chitosan-based nanostructures: a delivery platform for ocular therapeutics.

Novel Hyaluronic Acid-Chitosan Nanoparticles for Ocular Gene Therapy

Autologous fibrin matrices: a potential source of biological mediators that modulate tendon cell activities.

Reciprocal actions of platelet-secreted TGF-beta1 on the production of VEGF and HGF by human tendon cells.