Chemical and physical properties of nanocrystalline chitosan by the method: Modified nanochitosan complex and process of obtaining modified nanochitosan.

Nanocrystalline chitosan (NCC) is a modified form of chitosan, prepared from the method for obtaining chitosan acetate (CA). Due to the greater crystallinity of chitosan nanoparticles in relation to CA, NCC is more thermally stable and thus has great potential in the development of a new generation of biomaterials potentially useful in regenerative medicine and tissue engineering. NCC is also characterized by having similar properties to its precursor chitosan, such as its biocompatibility, bioactivity, ability to be bioabsorbed and lack of toxicity. One of the major problems associated with obtaining NCC is the low productivity of the methods. While known methods of obtaining nanostructures produce small amounts (milligrams), the method of synthesis for creating NCC from its salt is often more productive and less costly, and is patented by the authors of this work (registration number: BR10201702272). Thus, the objective of this study was to characterize NCC obtained through this innovative method, and analyze its chemical and physical properties using Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and mechanical property analysis with the mean values for the elasticity module, the resistance to tensile strength and the tensile strength. The results indicate that this new process of obtaining the NCC did not modify the chemical structure of the chitosan. The structure of the film surface created was homogeneous and the mechanical properties emphasized the plastifying effect of glycerol under NCC. The thermogravimetric analysis of NCC indicated greater stability in the polysaccharide structure of the nanocrystalline, due to an increased crystalline region compared to the CA which was confirmed by DSC.

Molecular and genetic analysis of iron uptake proteins in the brazilian purpuric fever clone of Haemophilus influenzae biogroup aegyptius.

Haemophilus influenzae biogroup aegyptius (H. aegyptius) is the etiological agent of Brazilian purpuric fever (BPF), a recently described pediatric disease that is often fatal. The vascular destruction that occurs in this disease is a distinctive trait, and little is known about the mechanism(s) of the overwhelming purpura fulminans that causes the high mortality associated with this pediatric infection. Iron is an essential micronutrient for nearly all living cells, and the mechanisms used by bacteria to acquire and internalize iron are often associated with virulence. Therefore, the focus of our studies is the molecular characterization of the iron uptake system used by H. aegyptius. Specifically, we are investigating the high-affinity transferrin binding proteins in the bacterial outer membrane, components of ABC transporter systems, and a possible regulatory mechanism for the genes encoding these proteins. A detailed understanding of the molecular nature of the regulatory genetic components and proteins involved in the acquisition of iron will broaden the knowledge of the pathogenesis of the disease caused by H. aegyptius and will also lead to a better understanding of the nature of other infections that affect the vascular system.