To fully accomplish all promises and hopes on clinical applications of carbon nanotubes, it is crucial to understand their interactions with physiological environment. One of these applications is polymer fillers, and it is important to review the toxicology of carbon nanotubes themselves because some polymer matrices may be biodegradable. Therefore, the interactions with organic molecules such as water, electrolytes, and proteins are reviewed and results of multiple studies on cellular interaction, cytotoxicity, immune response, biodistribution, and biopersistence are further presented. Finally, a section describing the interaction of polymer matrices with carbon nanotube reinforcements and the physiological environment is presented.

The β titanium alloys are highly attractive metallic materials for biomedical applications due to their high specific strength, high corrosion resistance and excellent biocompatibility, including low elastic modulus. The aim of this work is the evaluation of hardening mechanism through phase separation in β Ti-35Nb-7Zr-5Ta (TNZT) and Ti-35Nb-7Ta (TNT) alloys. Ingots (50 g) of TNZT and TNT alloys were arc-furnace melted in Ar(g)atmosphere. XRD using synchrotron radiation together with TEM and HRTEM analysis showed the coexistence of two separated phases (β and β’) with similar crystalline structures and slightly different lattice parameters in TNZT and TNT alloys. It was detected a heterogeneous microstructure alternating nanosized dark and bright regions (∼10 nm) with different compositions (Nb-rich β and Ta-Zr-rich β’).In aged condition (400ºC/4h), TNZT and TNT alloys undergoes coherent spinodal decomposition of β phase into two solid solution phases with coherent interface, different compositions and elastic strain associated with nanometric domains of Nb-rich β and Ta-(Zr)-rich β’ phases.

Bismuth has been used as an antimicrobial agent for treating gastrointestinal disorders, and has been used in the eradication of Helicobacter pylori. The aim of the present study was to analyze the antimicrobial activity of different Bi compounds against opportunistic pathogens. Ten bismuth compounds were tested with three different concentrations (60, 30 and 10%), against pure cultures of the following bacterial strains: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis. The results show that Bismuth subsalicylate, Bismuth trioxide and Bismuth subgallate had a good antibacterial activity however, Bismuth subsalicylate was the most effective in the inhibition of the four bacterial strains tested. In this study we confirm the antibacterial properties of Bi-based compounds for other bacteria than H. pylori.

The scaffold is obtained from acellular bovine bone: Nukbone® (produced by Biocriss SAPI de CV). This acellular bone was subjected to a demineralization process after which the composition was found to be 10% water, 65% of collagen and 25% of hydroxyapatite. The techniques used to characterize these natural scaffolds were: optical microscopy, scanning electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, thermo gravimetric analysis, differential scanning calorimetry and determination of pore size using nitrogen adsorption, and physical adsorption of N2. The pore size is between 100 and 500 microns. These scaffolds have been tested in several biological tissues as urethra, trachea, blood vessels, bone and heart successfully.

Arabinoxylans are polysaccharides constituted of a linear backbone of xylose in which arabinose substituents are attached, some ferulic acid esterifies arabinose. Arabinoxylan can form covalent gels by oxidative coupling of ferulic acid. Arabinoxylan gels could have potential applications for colon-specific biomolecules delivery due to their macroporous structure, and their aqueous environment and their dietary fiber nature. Lycopene has received increasing attention for its possible role in the prevention of colon cancer. It has been previously reported that arabinoxylan gels could be formed in presence of lycopene with no detriment on the lycopene antioxidant activity. The objective of this research was to investigate the in vitro degradation of arabinoxylan gels (AX gels) by two human colon bacterial species (Bacteroides ovatus and Bifidobacterium longum). Bacterial counts (CFU ml-1) and metabolic heat production (p) followed a similar pattern with a high response during the first 24 h at 37 °C. A regression model related CFU ml-1 and p (r2= 0.98). These results show that AX gels could be carriers for lycopene delivery in colon due structure degradation by gut microbiota.

Organic nanoparticles were deposited on LTA, ZSM5, FAU, clinoptilolite zeolites and montmorillonite clay forming a group of hybrid materials. The nanoparticles were analyzed by GC-Mass and proceed from the active phase of a plant constituted by 1.2 benzenedicarboxylic acid (66.1%), mono (2 ethilester) (66.1%), hexadecanoic acid (74.9%), and Y-isosterol (81.4%). Each of the hybrid materials was characterized by XRD, SEM and EDS. Additionally; the materials obtained were analyzed by high resolution adsorption (HRAD). The N2adsorption isotherms at 76 K obtained in the presence or absence of nanoparticles showed an Ia character for (LTA, FAU and ZSM5) synthetic zeolites, whilst (clinoptilolite) natural zeolite and clay (montmorillonite) showed a type II-IV character. The adsorption capacity of these substrates was analyzed by means of the Lagnmuir, de Boer, and Gursvitch rule approachs. The supermicropores present were measured by the NLDFT approach. The results indicated that the growth of nanoparticles in zeolites resulted in the emergence and opening of emerging pores of different geometry. However, in the case of ZSM5 and LTA zeolites their porosities were blocked by the nanoparticles.

Arabinoxylan gels are receiving increasing attention as oral delivery systems of biomolecules for therapeutic purposes. The aim of this research was to evaluate arabinoxylan gels as an oral delivery system for insulin, representing a painless therapy for diabetics. Gels at two concentrations of arabinoxylan were prepared (2.5 and 3.5 % w/v). One concentration of insulin (0.05 % w/v) entrapped in the arabinoxylan gels was investigated. At the end of gelation elasticity (G’) values were 11 and 20 for gels at 2.5 and 3.5% (w/v) in arabinoxylan, respectively. The presence of insulin in the gels did not affect the values of G’. The apparent diffusion coefficient for insulin decreased from 1.30 x 10-7 to 1.09 x 10-7 cm2/s when the concentration of arabinoxylan in the gel increased from 2.5 to 3.5% (w/v). The percentage of proteolysis for insulin entrapped in the gels at 2.5 and 3.5% in arabinoxylan (w/v) were 35 and 17%, respectively, in relation to 100% hydrolysis of insulin in solution. Results indicate that arabinoxylan gels could be potential candidates as oral delivery systems for insulin.