Vanusca Dalosto Jahno

Optically transparent membrane based on bacterial cellulose/polycaprolactone

Optically transparent membranes from bacterial cellulose (BC)/polycaprolactone (PCL) have been prepared by impregnation of PCL acetone solution into dried BC membranes. UV-Vis measurements showed an increase on transparency in BC/PCL membrane when compared with pristine BC. The good transparency of the BC/PCL can be related to the presence of BC nanofibers associated with deposit of PCL nano-sized spherulites which are smaller than the wavelength of visible light and practically free of light scattering. XRD results show that cellulose type I structure is preserved inside the BC/PCL membrane, while the mechanical properties suggested indicated that PCL acts as a plasticizer for the BC membrane. The novel BC/PCL membrane could be used for preparation of fully biocompatible flexible display and biodegradable food packaging.

Biodegradation evaluation of bacterial cellulose, vegetable cellulose and poly (3-hydroxybutyrate) in soil

In recent years, the inappropriate disposal of polymeric materials has increased due to industrial development and increase of population consumption. This problem may be minimized by using biodegradable polymers, such as bacterial cellulose and poly(hydroxybutyrate), from renewable resources. This work was aimed at monitoring and evaluating degradation of bacterial cellulose, vegetable cellulose and poly(3-hydroxybutyrate) using Thermogravimetric Analysis and Scanning Electron Microscopy. Controlled mass polymer samples were buried in pots containing soil. Samples were removed in 30 day intervals up to 180 days. The results show that the mass of the polymer increased in the first month when in contact with the soil but then it was degraded as evidenced by mass loss and changes on the sample surface.

Dispositivos poliméricos cardiovasculares: comportamento termomecânico e viabilidade celular

In recent decades new synthetic materials have been developed with adequate biofunctionality and biocompatibility to become a biomaterial. Biostable polymers have widespread use in the biomedical field, and many advances in polymeric biomaterials have been made in the search for improvements to cardiovascular implants. Currently, the most commonly used synthetic materials for the production of vascular grafts are PTFE and PET, due to their chemical stability after implant. In this work, a study of the thermal and mechanical properties of the commercial devices based on PET and PTFE is reported, as well as their cytotoxicity in mouse fibroblast cells, 3T3- NIH, through tests for the evaluation of cell viability (MTT test and VN). These materials showed high thermal stability (over 300 ° C), even after 270 days in vitro degradation and elastic behavior (maximal strain value of 186±22% by PET and 65±19% by PTFE). Cell viability by VN and MTT of PTFE device was more than 80%, thus, classified as non-cytotoxic. For PET device, VN test showed no cytotoxic effect, however the results obtained by MTT indicated that it causes alteration of mitochondrial function, independent of dose and time measured.

Characterization of environmental aspects and impacts of five university restaurants at a public higher education institution in Brazil

Endereço para correspondência: Virgílio José Strasburg – Faculdade de Medicina da Universidade Federal do Rio Grande do Sul –Rua Ramiro Barcelos, 2.400 – Santa Cecília – 90035-003 – Porto Alegre (RS), Brasil – E-mail: virgilio_nut@ufrgs.br ABSTRACT University Restaurants (URs) of Universidade Federal do Rio Grande do Sul (UFRGS) are distributed across four campi at Porto Alegre, the capital of the state of Rio Grande do Sul. More than 1.5 million meals were served in 2012. This paper describes a characterization study of the environmental aspects and impacts of the activities involved in producing meals at the five URs. Two checklists were developed to conduct the survey of the environmental aspects and impacts, and they were applied at the URs. A typology of the waste produced at the URs was compiled, identifying organic waste originating from the employed foodstuffs and recyclable waste from the packaging of a wide range of items. It was observed that the URs’ waste separation practices were inadequate. As to the use of natural resources, we identified: the water supply outlets, and the equipment that use electricity and liquefied petroleum gas. The identification and understanding of the environmental aspects and impacts of providing meals is the first step in the direction of improving sustainability.

Wettability and Morphological Characterization of a Polymeric Bacterial Cellulose / corn Starch Membrane

The uses of polymer blends have stimulated research to promote a better performance of existing raw materials. The implementation of blends in the production of polymeric membranes has shown great results in regenerative medicine and consequently it has improved the application of biomaterials in this area. This study aimed to evaluate the morphology and wettability of a bacterial cellulose/corn starch polymeric membrane. In relation to biomaterials, wettability is an important property to be evaluated because it is possible to observe if the degradation is accelerated even when in contact with biological fluids. The membrane was morphologically evaluated by SEM. Results showed that there was interaction between the polymers. Additionally, by the technique of contact angle it was also possible to observe the ability to absorb water, being highly satisfactory, showing a complete wetting with a contact angle of 10.7° in the initial assessment and 6.6° in the evaluation after 5 seconds.