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)

Facile Method for Obtaining Gold-Coated Polyester Surfaces with Antimicrobial Properties

The antimicrobial and antifungal activity of polymers used in medical devices has been extensively studied due to the growing impact of hospital-related infections in patients. The ideal biocidal polymeric materials should be very effective in the microorganism’s inhibition, not toxic to the human body, and environmentally friendly. In this context, this work is aimed at obtaining antimicrobial and antifungal properties at the polyester film surfaces without introducing toxic effects. Poly (ethylene terephthalate) (PET) films were functionalized with Ar plasma and then immersed in a solution containing gold nanoparticles (AuNps). The results demonstrated the appearance of the hydrophilic groups on the film surface after modification of PET film by plasma Ar treatment and the formation of the polar groups such as C=O, COO-, and OH, which then reacted with AuNps. The changes induced in the treated polymer samples were investigated in terms of AuNp adsorption efficiency on polyester film by contact angle, profilometry, Scanning Electron Microscopy (SEM), Attenuated Total Reflectance Spectroscopy-Fourier Transform Infrared (ATR-FTIR), and X-ray Photoelectron Spectroscopy (XPS) measurements. The morphological and structural analyses have shown a good adhesion of AuNps at treated film surfaces. The results of biocompatibility antimicrobial and antifungal tests proved the nontoxic behavior of the sample and its good antimicrobial and antifungal activity

“Washed away”—assessing community perceptions of flooding and prevention strategies: a North Queensland example

This article explored the perceptions of residents of a regional city in North Queensland of how to remain safe during flood events. It also explored reasons for and how to prevent risk-taking behaviour in floodwater using the protection motivation theory (PMT). PMT is a psychological theory which has recently been applied to assess behaviour during floods and was used as a framework to analyse the themes of responses to the online survey. The online survey was conducted prior to the wet season of 2011/2012 with 130 Townsville residents participating. The results indicate that about half of respondents (55 %) had some experience with floods of which driving through floodwater (38 %) was the most common type of flood experience listed and was more common amongst male respondents. Respondents' advice to keep friends and family safe during floods was consistent with "coping appraisal", which would improve their ability to cope with the flood. Prior experiences with floodwater influenced the reasons given for why people drive through floodwater and were taken to be indicative of an actor/observer bias. Respondents who had experience driving through floodwater (the actors) indicate how the context of the situation can influence decision-making, whereas those respondents who had no personal experience of driving through floodwater (the observers) were more likely to cite low perceived vulnerability of harm as a motivator. Prevention strategies focused on structural mechanisms to block access, information provision and punishment of offenders. It is suggested that in communities which regularly experience flooding, timely and context specific reminders of the dangers inherent in floodwater along with the type, effectiveness and cost of protective action could minimise the public's contact with floodwater and prove useful regardless of past experiences