A novel biopolymer derived from diallyl sucrose (A2S) and dithiotreitol (DTT) was prepared by means of Thiol-Ene Photopolymerization. A2S was prepared by alkylating the sucrose with allyl bromide, using water as solvent. After purification by column chromatography, a fraction (F2A2S) with 94% diallyl sucrose (A2S), 4 % of triallyl sucrose (A3S) and 2 % of monoallyl sucrose (A1S) was obtained. This fraction was subsequently photopolymerized with Dithiothreitol (DTT) which is a difunctional thiol. Kinetics of photopolymerization were determined by means of Real-Time Infrared spectroscopy. It was found that the photocurable formulation with DTT and F2A2S, polymerized rapidly in the presence and absence of a photoinitiator, at low intensities of UV light. After bulk polymerization, a flexible material with high elastic modulus and a Tg of 30 °C was obtained. Besides, the polymer displayed moderate water absorbance properties as a result of the presence of multiple hydroxyl groups. This property was pH dependent with maximum absorbance at pH=14. The polymer degraded rapidly under acidic conditions

The fraction of soluble and insoluble fiber was determinate by AOAC International official method for dietary fiber in four varieties of Bamboo called Guadua Angustifolia Kunth. The elastic modulus of the four bamboo varieties was determined using an universal machine INSTROM 4401 based on the ASTM standard method D-143. Finally, the fiber content and the mechanical behavior were correlated using the Pearson coefficient calculated by statistical package STATGRAPHICS 5.1 The fiber content is the main factor responsible for the bamboo mechanical properties. The results show that the all fiber content into the bamboo culms is related with the mechanical behavior. These results confirm that the Guadua Bamboo is a natural composite material with aligned fibers embedded in a matrix formed by soluble fiber.

Micron-scale and submicron-scale surface roughness enhance osteoblast differentiation on titanium (Ti) substrates and increases bone-to-implant contact in vivo. However, bacterial adhesion is also strongly influenced by roughness and surface chemistry. The aim of this study was to investigate if chemical surface modifications alter initial bacterial attachment. To achieve this, two polyelectrolyte layers [chitosan (Ch) and poly(L-lysine) (PLL)] were used to coat Ti surfaces with different roughness (PT [Ra<0.3μm], SLA [Ra≥3.0μm]). Bacterial attachment was evaluated using Aggregatibacter actinomycetemcomitans, Actinomyces israelii, Campylobacter rectus, Eikenella corrodens, Fusobacterium nucleatum, Parvimonas micra, Porphyromonas gingivalis, Prevotella intermedia and Streptococcus sanguinis. After 24h incubation, bacteria were detached from the samples with sonication and the counting plate technique was performed to determine the number of colony forming units (CFU's). Additionally, surfaces were observed by scanning electron microscopy to determine bacteria surface coverage. Statistical significance was determined using ANOVA followed by Bonferroni's modification of Student's t-test. The results showed that polyelectrolyte coatings did not affect surface roughness. Modified surfaces were more hydrophilic than the controls. PT surfaces covered by Chi exhibited lower CFUs than the same surface covered by PLL or the control PT (140 × 105/mL, 343 × 105/mL and 283 × 105/mL, respectively). The opposite effect was observed on the SLA surfaces, PLL coated samples shown lower CFUʼs than Chi or uncoated SLA (199 × 105/mL, 229 × 105/mL and 227 × 105/mL, respectively). The Chi layer appeared to reduce bacterial adhesion only on the smooth surfaces. In contrast, PLL coatings reduced bacterial attachment on rougher surfaces. These results suggest that chemical modification of Ti without alteration of surface roughness affects oral bacterial attachment, and could be useful to prevent peri-implantitis related diseases.

Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans are considered key pathogens in periodontitis that is the principal cause of tooth loss in adults. The treatment of periodontal disease consists on the use of chemicals which can alter oral microbiota and have undesirable side-effects such as vomiting, diarrhea and tooth staining

At recent years, the use of natural sources like biomaterials such as biopolymers and plant extracts are enjoying great popularity. Chitosan and pullulan are polymers that have been proposed due to their favorable properties such as biocompatibility, biodegradability, adhesion ability and nontoxicity

The aim of this study was to develop films from chitosan and pullulan containing plant extracts as delivery system and determine the in vitro antibacterial activity against periodontopathogen microorganisms and their stability under different conditions of storage

Linear rheological behavior and Microrheology measurements of sodium salt calf-thymus DNA aqueous solutions as a function of concentration are reported here. The microrheological behavior was obtained by a combination of experimental techniques: mechanical Rheometry and Dynamic light scattering (DLS). The viscoelastic properties of DNA in water as a function of concentration were performed at 20 °C and rheological and microrhelogical curves were performed. The result indicated that for concentrations lower than the entanglement concentration (Ce) the system exhibits a predominantly viscous behavior, whereas for higher concentrations exhibits a predominantly elastic behavior. The plateau modulus (G0) and the zero complex viscosity () follow a power law concentration dependence of the form: and , respectively The microrheology results overlap perfectly in a single line with the mechanical rheology results, extending the time resolution to faster breathing modes

The adsorption of bovine serum albumin (BSA) and fibrinogen proteins dissolved on Phosphate buffer solution onto Ta, Nb and Ti oxide thin films was studied. The metal oxide thin films were deposited by magnetron sputtering on Si(100) wafers and characterized by contact angle measurements and profilometry. Spectroscopic ellipsometry was employed to characterize the kinetics of the protein adsorption process in-situ at the solid-liquid interface and the optical properties of the adsorbed protein layer formed after 45 minutes of immersion of the thin film in the protein solution. Infrared spectroscopy was used to study the proteins within the adsorbed layer. A trend indicating that the surface mass density of the adsorbed protein layer increases as the Rt (peak-to-valley height) surface roughness parameter increases was observed for fibrinogen and BSA. An increment in the surface mass density of the adsorbed protein layer was also observed onto surfaces with higher polar components of the surface energy. BSA and fibrinogen seemed to more readily adsorbed onto tantalum oxide than onto titanium oxide.

Major adsorbent materials used in heavy metal ion removal from polluted aqueous streams are expensive and difficult to regenerate. In this study, the possibility of using pectin, as an alternative biosorbent material to remediate heavy metal pollution was investigated. The effects of different parameters such as pH, concentration and temperature of metal solution, and contact time on the biosorption process were studied. The maximum removal efficiency was obtained at pH 2.0 for lead and zinc and pH 4.0 for cadmium. For most of the metals tested, a contact time of 15 minutes was sufficient for achieving the maximum removal. There was no significant influence on the removal capacity of pectin by the concentration and temperature of the metal solution. Under these experimental conditions the biosorption was favorable (65% lead, 42% zinc and 55% cadmium). The ability to use pectin for the removal or recovery of metals from aqueous solutions is evident.

The pollution caused by heavy metals is one of the major environmental problems that is imperative to be solved. New technologies, easy to implement and to adapt to any system, deserve special attention and are a focus of this work the ability of Chlorella sp. and E. coli genetically engineered with mice metallothionein I, both immobilized in alginate of calcium to remove Cd(II) and Pb(II) from aqueous solutions was investigated in batch assays for the treatment of diluted aqueous solutions. The kinetics, sorption capacities and sorption percentage were determined. The influence of metal concentration in solution is discussed in the terms of Langmuir isotherm and constants. Sorption capacities increased with increasing metal concentration in solution. For solution containing 300 mg/L of metal, the observed uptake capacities were 94.941±1.094 mgCd/gChlorella., 24.076±2.292 mgCd/gE.coli and 239.17±2.478 mgPb/gChlorella, 37.952±4.245 mgPb/gE.coli. The Langmuir constants to Chlorella sp. were qmax=285.72(mgPb/g), b=0.0276(l/mgPb), qmax=103.65(mgCd/g) and b=0.0005(l/mgCd) while to E. coli were qmax=28.141(mgPb/g), b=0.113(l/mgPb), qmax=24.272(mgCd/g) and b =0.019(l/mgCd). The biomass of the algae showed to have better capacity of metallic sorption that the biomass of the bacteria genetically engineering. The study proved that microorganisms biomass is a suitable material for the removal of the studied heavy metals ions from aqueous solutions, achieving removal efficiencies higher than 90%, and could be considered as a potential material for treating effluent polluted with Cd(II) and Pb(II) ions.

Magnesium (Mg) alloys can be use as biodegradable medical devices, eliminating the need for a second operation for implant removal. An important feature on biomedical devices is to avoid the bacterial adhesion and subsequent biofilm formation that cause most of the implant-failures. The aim of this study was to analyze the differences on bacterial adhesion and biofilm development on Magnesium alloys (Mg-Al-Zn) modified by different transition metals; Tantalum, Niobium and Titanium. Nine oral bacterial strains (Aggregatibacter actinomycetemcomitans serotipe b, Actinomyces israelii, Campylobacter rectus, Eikenella corrodens, Fusobacterium nucleatum, Parvimonas micra, Porphyromonas gingivalis, Prevotella intermedia and Streptococcus sanguinis) were incubated on the different alloys and commercial medical grade stainless steel (AISI 316L) was used as a control. The initial bacterial adhesion was determined after 24 hours using a counting plate technique and the subsequent biofilm development at 1, 3, 7 days was studied using the Scanning Electron Microscopy. Significant differences were determined using t-test. The results showed that on the magnesium-alloys, the number of bacteria attached after 24 hours was two orders of magnitude lower than the stainless steel. On the other hand, bacterial colonies were not observed by electron microscopy in any of the days of incubation, even though in the control surface clear colonies and biofilm development were observed. This study showed that magnesium alloys inhibits the bacterial adhesion and the subsequent biofilm development.

In the last fifteen years, there have been significant changes in the production of medicines, mainly in the addition of new components to the formulation of solid dosage forms. The current trend of “back to nature” to lead to a healthier life has led those who are engaged in the pharmaceutical field to develop new formulations that allow the use of natural products of plant origin

For example, excipient ingredients, used as carriers for a drug's active ingredients, are now being used. These are incorporated into a drug in order to facilitate the drug's preparation, maintenance, or administration. The excipient is beneficial to the patient because it allows the drug to be easily administered and absorbed by the human body [3]

There is evidence that the clays have great potential for both absorption and adsorption due to its tiny particles. In addition, it has been reported that some clays have an effective antiseptic and healing ability [5–8]

In the present work, a clay called bentonite was tested as a support vehicle of an inflammatory agent derived from a Mexican native plant called Distictis buccinatoria, commonly named “Tonacaxóchitl”. Studies carried out by Rojas et al. have shown that the organic extract of this plant has important antibacterial, antifungal, cytotoxic and anti-inflammatory properties [9]