Approaches in biotechnological applications of natural polymers

Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them are reviewed in this article.. }To the Conselho Nacional de Desenvolvimento Cientfíico e Tecnológico (CNPq) for fellowships (LCBBC and MGCC) and the Coordenação de Aperfeiçoamento de Pessoal de Nvíel Superior (CAPES) (PBSA). This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462) and COMPETE 2020 (POCI-01-0145-FEDER-006684) (JAT)

Cry features reflect pain intensity in term newborns: an alarm threshold

The purpose of this study was to assess differences in sound spectra of crying of term newborns in relation to different pain levels. Fifty-seven consecutively born neonates were evaluated during heel-prick performed with different analgesic techniques. Crying was recorded and frequency spectrograms analyzed. A pain score on the DAN (Douleur Aiguë du Nouveau-né) scale was assigned to each baby after the sampling. Three features were considered and correlated with the corresponding DAN scores: 1) whole spectral form; 2) the fundamental frequency of the first cry emitted (F0); and 3) root mean square sound pressure normalized to its maximum. After emission of the first cry, babies with DAN scores >8, but not with DAN scores 8 had a significantly higher F0 than those with lower DAN scores (p = 0.016). An alarm threshold exists between high (>8) and low (< or =8) DAN scores: crying has different features in these two groups. When pain exceeds a DAN score of 8, usually a first cry at a high pitch is emitted, followed by the siren cry, with a sound level maintained near its maximum

Functionalized Graphene Oxide with Chitosan for Protein Nanocarriers to Protect against Enzymatic Cleavage and Retain Collagenase Activity

Proteins have short half-life because of enzymatic cleavage. Here, a new protein nanocarrier made of graphene oxide (GO) + Chitosan (CS) is proposed to successfully prevent proteolysis in protein and simultaneously retain its activity. Bovine serum albumin (BSA) and collagenase were loaded on GO and GO-CS to explore the stability and activity of proteins. SEM, AFM, TEM, DSC, UV-Vis, FT-IR, RBS, Raman, SDS-PAGE and zymography were utilized as characterization techniques. The protecting role of GO and GO-CS against enzymatic cleavage was probed by protease digestion analysis on BSA, where the protease solution was introduced to GO-BSA and GO-CS-BSA at 37 °C for 0.5-1-3-6 hours. Characterizations showed the successful synthesis of few layers of GO and the coverage by CS. According to gelatin zymographic analysis, the loaded collagenase on GO and GO-CS lysed the gelatin and created non-staining bands which confirmed the activity of loaded collagenase. SDS-PAGE analysis revealed no significant change in the intact protein in the GO-BSA and GO-CS-BSA solution after 30-minute and 1-hour exposure to protease; however, free BSA was completely digested after 1 hour. After 6 hours, intact proteins were detected in GO-BSA and GO-CS-BSA solutions, while no intact protein was detected in the free BSA solution