ABSTRACT
Bioactive polymers represent one of the most promising and adequate classes of materials for the development of devices for tissue engineering and controlled targeted drug delivery applications of drugs and active agents.
In the framework of a long-standing research activity ongoing at the Biomaterial Research Group active at the Department of Chemistry and Industrial Chemistry, the present work was aimed at the preparation and biological evaluation of micro/nanostructured systems in order to develop structures susceptible to be used in pharmacological and biomedical applications.
Three-dimensional polymeric structures were prepared using natural polymers both commercial (Alginate) and directly extracted from renewable sources (Ulvan). The morphological characterization of these scaffolds was performed by Scanning Electron Microscopy (SEM). Swelling degree of the prepared scaffolds was evaluated using PBS and cell growth medium (DMEM) as solvents. Results stemming from these investigations were correlated to the use of different crosslinking agents, employed to produce the above mentioned structures. A careful in-vitro investigation of scaffolds cytotoxicity and bioactivity was performed by using human hepatoblastoma cell line HepG2 as a model of hepatic cell. Cell vitality was investigated by means of three different kinds of tests such as WST-1 tetrazolium salts, Neutral red uptake and LDH release.
In parallel, it was started a study aimed at the development of bioerodible polymeric nanoparticles loaded with haemoglobin as oxygen carrier to be used as blood substitute.
Bioerodible polymers such as copolymers of maleic anhydride and butyl vinyl ether (VAM 40) hemiesterified with 2-methoxy ethanol and polyethylene glycol (VAM 41) were used, in association with Human Haemoglobin and a steric stabilizer (modified β- cyclodextrin) in the preparation of stealth nanoparticles. These systems were prepared according to an original procedure (co-precipitation technique), formerly developed in our laboratory.
The morphological-dimensional characterization of the prepared nanoparticles was performed by Scanning Electron Microscopy (SEM) and granulometry in suspension (laser diffraction analysis).
Investigation of nanoparticles surface charge was carried out by means of Zeta Potential
measurements, while quantitative evaluation of haemoglobin encapsulation into nanoparticles was performed using Drabkin’s assay.
Moreover, haemoglobin loaded nanoparticles in-vitro cytocompatibility was investigated using the mouse embryo fibroblast balb/ 3T3 clone A31 cell line, by means of above- mentioned biological assays.
