In fact, sulfated polysaccharides are commonly investigated for their biological properties, and the ones obtained from green algae are no exception. A summary of reported activities demonstrated in these polysaccharides is presented in Table 3. Table 3. Biological effects associated with sulfated polysaccharides from green kinase assay algae For instance, these polysaccharides exhibit antioxidant effects, as was recently reported in several research works, describing sulfated polysaccharides with superoxide and hydroxyl radicals scavenging activity, reducing power and able to chelate metals.129-135 Antitumoral activity and antiproliferative effects have also been described and associated with these polysaccharides.

129,131,136 Another important features of these polysaccharides are their immunostimulating ability, similar to other algal polysaccharides,137-141 as well as their heparin-like character.105 Besides, these polysaccharides are largely studied for their antihyperlipidemic activities,130,142-145 or antiviral effects.111,131,146-148 Although common to the several sulfated polysaccharides extracted from green algae, the expression of those biological activities is dependent on different sugar composition, molecular weight and sulfate content,149 and thus, as abovementioned, on genus, species and ecological and environmental factors. Several studies stress this variability regarding heparin-like behavior according to the genus and species of the studied algae,115-117,129,131,150-152 but similar variability can be found on anticoagulant150-152 and antioxidant activities,133-135 as well as on antiproliferative effect, which was shown to be strongly related with the polysaccharide sulfate content.

129 Within this scenario, an attractive use and exploitation of green algae would take advantage of these biological properties and translate them into applications with pharmacological and medical relevance. However, among the three main divisions of macroalgae, green algae remain a rather underexploited biomass, particularly in areas where other algal origin polysaccharides have already proven their value. A striking example of commercial success is carrageenan (as discussed in the previous section). Alongside its biological activity and potential pharmaceutical use, green algae sulfated polysaccharides may also be used for biomedical applications, in areas as demanding as regenerative medicine.

In this particular arena, both their biological activities and their resemblance with glycosaminoglycans might position these polysaccharides in an advantageous point. In this regard, some important research work has already been performed related with polysaccharide modification, Cilengitide processing and biomaterial development, particularly using ulvan as a starting material. Described ulvan structures include nanofibers,153 membranes,154 particles,155 hydrogels156 and 3D porous structures.

The experiments were conducted in triplicate. Surface contact angle measurements The wettability of breath figure films was measured using the sessile drop method with a standard goniometer (Rame-Hart model 250) and analyzed using the DROPimage Advanced software for contact angle determination. selleck catalog A 3 ��L distilled water droplet was placed on the polymer film surface and the contact angle ���ȡ� measured. The measurement was done for a minimum of five samples of a specific polymer film, and the average value reported. Typical standard deviations are of the order of 0.3. In vitro release characteristics Ibuprofen and Salicylic acid were used as model drugs to characterize the release profiles of breath figure polymer films. The equivalent non-porous smooth films were used as controls.

In vitro release studies were performed by incubating 1.5 cm side square drug incorporated films in 15 ml of PBS medium at 37��C and stirred gently using a magnetic stirrer. At specific time intervals, 0.650 ml aliquots of the solution was withdrawn and centrifuged to remove any possible debris from the degrading polymer. Then, the aliquot was returned to the vial after measuring the absorbance to quantify drug release. The pH of the medium was monitored during the course of the experiment to verify that the solution is buffered adequately during polymer degradation. Ibuprofen and salicylic acid release were quantified through the absorbance at 221 and 296 nm, respectively. Standard calibration plots of ibuprofen and salicylic acid absorbance were constructed to correlate absorbance with drug release levels.

All experiments were conducted in triplicate. Conclusions Morphological characteristics of breath figure films of degradable PLGA and PEG/PLGA materials were analyzed through scanning electron microscopy as they were allowed to degrade in vitro. The degradation pattern shows a flattening of surface structure where the walls of the surface breath figure pores are first degraded away, followed by the gradual degradation of the underlying layers. Pinprick pores extending to the base of the film are subsequently formed which evolve into larger pore structures that eventually break up the film. The morphology of the film has a significant effect on release characteristics with breath figure morphologies in general exhibiting faster release than their nonporous analogs.

Additionally the incorporation of poly (ethylene glycol) into the films enhances release rates, which we attribute to improvement of water ingress into the film. Drug release from such thin films Cilengitide appears to follow diffusion pathways rather than a constant release rate based on degradation of the material through dissolution of surface layers. The use of breath figure morphologies in biodegradable polymer films adds an additional level of control to drug release. Coating medical devices (stents, surgical meshes, etc.

Table 1. Values of ultimate tensile strength and maximum Bicalutamide structure strain for films with 0 to 23 wt% of bioactive glass. Statistical analysis of the results show that there is no significant difference between maximum stress values for films with 0�C17% glass, but there is difference between these compositions and the films with 23% glass. For the maximum strain, although differences were observed in the average values for different compositions, there were no statistically significant differences. Therefore, we can say that values of maximum stress proved to be lower for the film containing 23% of glass, as compared with those with 0�C17% of glass, suggesting better mechanical properties for films with 0�C17% glass.

Analysis of bioactivity The hybrid synthesis conditions result in acid byproducts; however, the polymer content is sensitive to high temperatures, which restrains the elimination of toxic products by heat treatment. When in contact with the culture medium, hybrid dissolution products can modify the pH of the medium and cell growth, promoting lower cell viability. If this should occur, it will require a neutralization step to reduce the acidity of the samples and make them more biocompatible. Therefore, the pH of the SBF solution was measured at 37��C. It could be noted that, before the samples were immersed in SBF, the solution initially prepared at pH = 7.40 showed pH = 7.48. As such, no significant change in the pH of the SBF after different immersion times could be observed. Figure 5 shows the FTIR spectra for films with 0�C23% glass content after 1 d of immersion in SBF.

A peak displacement could be observed between 1,024 cm-1 and 1,002 cm-1. This effect occurs in direct proportion to the increase in the glass percentage within the film, which corresponds to the appearance of the P-O stretching vibration. The peak at 875 cm-1 corresponds to the C-O bending-vibration of CO3-2 incorporated into the films and can be observed only in the film with 23% glass, along with peaks at 560 and 600 cm-1 associated with the P-O bending-vibration. These peaks were not identified after 3 d of immersion in films with 9% and 17% of glass contents. However, the spectra for films after 7 d of immersion (Fig. 6) indicate that films with 9 and 17% exhibit the same peaks at 1,002 cm-1, 875 cm-1, 560 and 600 cm-1. Figure 5.

FTIR spectra of films with: (A) 23%, (B) 17%, (C) 9%, (D) 0% of bioactive glass after 1 d of immersion in SBF. Figure 6. FTIR spectra of films with: (A) 23%; (B) 17%; (C) 9%; (D) 0% of bioactive glass after 7 d of immersion in SBF. Figure 7 shows the Anacetrapib FTIR spectra for the film with 23% bioactive glass before and after different periods of immersion. A peak displacement could be observed between 1,063 cm-1 and 1,002 cm-1, throughout the immersion time, as could the appearance of bands at 560 cm-1 and 600 cm-1 and the peak at 875 cm-1 after 1 d of immersion.

Considering each swimmer individually, a positive correlation was observed between the hip and CM values regarding velocity (ranging from 0.50 to 0.83), which is in accordance with Maglischo et al. (1987) in front crawl technique protocol (values between 0.86 and 0.96, with a mean coefficient of 0.87). These data, associated with the obtained high digitize-redigitize reliability values, evidence that, although there is an associated error that should be taken into account, the hip reflects satisfactorily the CM motion in front crawl when swimming at moderate intensity. The velocity to time curve obtained for one swimmer for both CM and hip showed similar patterns of positive and negative accelerations as described in the literature (Maglischo et al., 1987; Craig et al.

, 2006): both CM and hip decelerated during the downsweep phases (that are coincident with the recovery of the opposite arm) and in the transition from one propulsive phase to another, and both body points accelerated during the catch, insweep and upsweep phases. Thus, coaches should incorporate specific training drills aiming to perform faster transitions between propulsive phases, as well as to finish the stroke at maximal arm velocity. It was also evident that swimmers choose a catch-up inter-arm coordination mode that is typical of moderate paces due to a long gliding phase (Schnitzler et al., 2008; Seifert and Chollet, 2009; Seifert et al., 2010). In fact, the existence of a discontinuity between the end of the propulsion of one arm and the beginning of propulsion of the other arm is typical of front crawl swimming at moderate intensities (Seifert and Chollet, 2009; Seifert et al.

, 2010). Thus, coaches should not advise swimmers to adopt superposition arm synchronization when implementing aerobic pace training series. Furthermore, it was also evidenced that the hip presents higher and lower forward velocity peaks magnitude compared to CM, as shown by Maglischo et al. (1987) for higher swimming intensities. Notwithstanding that the forward velocity and displacement of the hip and CM are similar, and the evidence that the IVV determination using the hip is reliable, allows multiple cycles to be evaluated and enables the assessment of fatigue (Holm��r, 1979; Maglischo et al., 1987), differences between hip and CM were found for the IVV. Such differences corroborates the literature (Figueiredo et al.

, 2009), and might be explained by the inter-segmental actions during the front crawl swimming cycle that frequently changes the CM position (Barbosa et al., 2003). In addition, the CM vmax and vmin values seem to be over and underestimated (respectively) by the hip values, as previously proposed by Psycharakis and Sanders (2009). In fact, when the arms in front crawl accelerate the body Brefeldin_A mass, they simultaneously move backwards with respect to a body fix landmark refraining the acceleration of the CM.