Catalin Zaharia

In Vitro Studies of Bacterial Cellulose and Magnetic NanoparticlesSmart Nanocomposites for Efficient Chronic Wounds Healing

The quality of life of patients with chronic wounds can be extremely poor and, therefore, over the past decades, great efforts have been made to develop efficient strategies to improve the healing process and the social impact associated with these conditions. Cell based therapy, as a modern tissue engineering strategy, involves the design of 3D cell-scaffold bioconstructs obtained by preseeding drug loaded scaffolds with undifferentiated cells in order to achieve in situ functional de novo tissue. This paper reports on the development of bionanocomposites based on bacterial cellulose and magnetic nanoparticles (magnetite) for efficient chronic wounds healing. Composites were obtained directly in the cellulose bacterial culture medium by dispersing various amounts of magnetite nanoparticles during the biosynthesis process. After purification and drying, the membranes were characterized by Raman spectroscopy and X-ray diffraction to reveal the presence of magnetite within the bacterial cellulose matrix. Morphological investigation was employed through SEM and TEM analyses on bionanocomposites. The biocompatibility of these innovative materials was studied in relation to human adipose derived stem cells in terms of cellular morphology, viability, and proliferation as well as scaffolds cytotoxic potential.

Poly(HydroxyButyrate-co-HydroxyValerate) (PHBHV) Nanocarriers for Silymarin Release as Adjuvant Therapy in Colo-rectal Cancer

The aim of this study was to address one of the major challenges of the actual era of nanomedicine namely, the bioavailability of poorly water soluble drugs such as Silymarin. We developed new, biodegradable, and biocompatible nanosized shuttles for Silymarin targeted delivery in colon-cancer cells. The design of these 100 nm sized carrier nanoparticles was based on natural polymers and their biological properties such as cellular uptake potential, cytotoxicity and 3D penetrability were tested using a colon cancer cell line (HT-29) as the in vitro culture model. Comparative scanning electron microscopy (SEM) and atomic force microscopy (AFM) measurements demonstrated that the Silymarin loaded Poly(3-HydroxyButyrate-co-3-HydroxyValerate) (PHBHV) nanocarriers significantly decreased HT-29 cells viability after 6 and 24 h of treatment. Moreover, in vivo-like toxicity studies on multicellular tumor spheroids showed that the Silymarin loaded PHBHV nanocarriers are able to penetrate 3D micro tumors and significantly reduce their size.

Silk-Based Hydrogels for Biomedical Applications

Among the naturally occurring fibers, silk occupies a special position due to its properties. Silk fibroins, the unique proteins of silkworm fibers, are highmolecular-weight block copolymers consisting of a heavy (~370 kDa) and a light (~26 kDa) chain with varying amphiphilicity linked by a single disulphide bond. Bombyx mori silk is the most characterized silkworm silk. Researchers have investigated fibroin as one of the promising resources of biotechnology and biomedical materials due to its other unique properties including excellent biocompatibility, favorable oxygen permeability, and outstanding biodegradability, and the degradation product can be readily absorbed by the body with minimal inflammatory reaction. Silk hydrogels have been thoroughly studied for potential biotechnological applications due to their mechanical properties, biocompatibility, controllable degradation rates, and self-assembly into β-sheet networks. Hydrogels made from silk proteins have shown a potential in overcoming limitations of hydrogels prepared from conventional polymers. This chapter offers overview of the recent developments in silk protein-based hydrogels, both of fibroin and sericin proteins. It describes the approaches for obtaining silk hydrogels and ideas to improve the existing properties or to incorporate new features in the hydrogels by making composites. Characterization tools and modern bioapplications of the silk hydrogels for tissue engineering and controlled release are also reviewed. A special focus is given to silk fibroin composite hydrogels for bone tissue engineering applications.

Triiodophenyl acrylate-based microbeads find important use in the medical field

Preparation of polymeric micro- and nanoparticles has significantly become an effective approach for achieving efficient drug targeting to tumour tissues. A promising solution could be the use of a radio-opaque polymeric system carrying iodine groups. In this context, radio-opaque polymeric microparticles based on methyl methacrylate (MMA) and an 2,4,6-triiodophenyl acrylate (TIPA) were synthesised by suspension and emulsion polymerisation techniques. Various compositions of p(MMA-co-TIPA) were physico-chemically and biologically characterised through FTIR-ATR, SEM, EDX, in vitro biocompatibility and X-ray measurements. These copolymers exhibit good in vitro cell compatibility together with good X-ray visibility so they are good candidates for tumour detection and imaging.