We report a facile method to synthesize magnetite nanoparticles with mesoporous structure by coprecipitation method using different stabilizing agents like salicylic acid, glutamic acid, and trichloroacetic acid. The stabilizing agents were used to prevent the aggregation of the magnetite nanocrystals and to obtain stable nanostructures even in the biological environment. The structure and morphology of magnetic nanocrystals were determined using X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller (BET) analysis, infrared (IR) spectra, scanning and transmission electron microscopy (SEM and TEM), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED). The results reveal important differences between these magnetic nanoparticles (MNPs), which are mainly attributed to the stabilizing agents. The smallest nanoparticles were obtained in the presence of trichloroacetate ions. The mechanism of formation of these suprastructures is strongly correlated with the end functional groups of the stabilizing agent. Thus, the obtained nanoparticles are potential candidates for contrast agents as well as targeted carrier for specific diseases, especially cancer.

No abstract

Synthesis of biomimetic materials for implants and prostheses is a hot topic in nanobiotechnology strategies. Today the major approach of orthopaedic implants in hard tissue engineering is represented by titanium implants. A comparative study of hybrid thin coatings deposition was performed by spin coating and matrix-assisted pulsed laser evaporation (MAPLE) onto titanium substrates. The Collagen-calcium phosphate (Coll-CaPs) combination was selected as the best option to mimic natural bone tissue. To accelerate the mineralization process, Zn2+ ions were inserted by substitution in CaPs. A superior thin film homogeneity was assessed by MAPLE, as shown by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) microscopy. A decrease of P-O and amide absorbance bands was observed as a consequence of different Zn2+ amounts. A variety of structural modifications of the apatite layer are then generated, which influenced the confinement process towards the collagen template. The in-vitro Simulated Body Fluid (SBF) assay demonstrated the ability of Coll/Zn2+-CaPs coatings to stimulate the mineralization process as a result of synergic effects in the collagen-Zn2+ substituted apatite. For both deposition methods, the formation of droplets associated to the growth of CaPs particulates inside the collagen matrix was visualized. This supports the prospective behavior of MAPLE biomimetic coatings to induce mineralization, as an essential step of fast implant integration with vivid tissues.

Cancer is the second disease in the world from the point of view of mortality. The conventional routes of treatment were found to be not sufficient and thus alternative ways are imposed. The use of hybrid, magnetic nanostructures is a promising way for simultaneous targeted diagnosis and treatment of various types of cancer. For this reason, the development of core@shell structures was found to be an efficient way to develop stable, biocompatible, non-toxic carriers with shell-dependent internalization capacity in cancer cells. So, the multicomponent approach can be the most suitable way to assure the multifunctionality of these nanostructures to achieve the desired/necessary properties. The in vivo stability is mostly assured by the coating of the magnetic core with various polymers (including polyethylene glycol, silica etc.), while the targeting capacity is mostly assured by the decoration of these nanostructures with folic acid. Unfortunately, there are also some limitations related to the multilayered approach. For instance, the increasing of the thickness of layers leads to a decrease the magnetic properties, (hyperthermia and guiding ability in the magnetic field, for instance), the outer shell should contain the targeting molecules (as well as the agents helping the internalization into the cancer cells), etc.

An electrospinning method was used to fabricate a bilayer collagen sponge/chitosan (Col/CS) matrix to develop a new wound healing dressing. The aim of the study was to improve the mechanical properties and antimicrobial activity of a collagen sponge matrix used as medical device. Col/CS matrix was subjected to detailed analysis by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Atomic force microscopy (AFM), comparative physico-chemical characteristics (swelling ratio and hydrolysis properties, enzymolytic properties, bilayer Col/CS morphology) between collagen sponge and Col/CS matrix, bioburden determination and antimicrobial activity. The physical characteristics, morphology and antimicrobial properties showed that this biomaterial has a high ratio of surface area and superior mechanical properties, than collagen sponge. After sterilization, the recovery efficiency of S. aureus and E. coli from Col/CS matrix was 36% and 52%, result confirmed through qualitative antimicrobial activity. These results suggest that Col/CS matrix could be a promising solution for chronic wounds management.