Search

Nosocomial infections or healthcare-associated infections, normally develops after the healthcare treatment in the hospital. Most of them are caused by infected medical devices. Plastics are the most common materials for manufacturing these devices because of their good processability, sterilization efficacy, ease of handling and harmlessness, however, it usually do not display antimicrobial properties. Here, in order to infer antimicrobial activity to poly(lactic acid), it was modified by maleation, followed by l-lysine grafting to its structure. The chemical modifications were confirmed by FTIR and 1 H NMR analysis, indicating the success of the reactions. The antimicrobial activity was tested using Escherichia coli and Staphylococcus aureus and the results showed that the sample was capable of inhibiting about 99 % of the S. aureus growth by contact. The samples cytotoxicity was also tested using the L929 mouse cells and the results indicated no cytotoxic effect. These results indicated the sample antimicrobial potential, without affect the normal eukaryotic cells. In addition, the processability of the modified PLA (PLA-g-Lys) was improved without compromising its mechanical properties, as shown by thermal analysis and tensile tests. Thus, this novel PLA derivative can be seen as a promising material for future applications in the manufacturing of biomedical devices., Competing Interests: Declaration of competing interest Eliane Trovatti reports financial support was provided by State of Sao Paulo Research Foundation - FAPESP. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

A significant mechanical properties mismatch between natural bone and the material forming the orthopedic implant device can lead to its failure due to the inhomogeneous loads distribution, resulting in less dense and more fragile bone tissue (known as the stress shielding effect). The addition of nanofibrillated cellulose (NFC) to biocompatible and bioresorbable poly(3-hydroxybutyrate) (PHB) is proposed in order to tailor the PHB mechanical properties to different bone types. Specifically, the proposed approach offers an effective strategy to develop a supporting material, suitable for bone tissue regeneration, where stiffness, mechanical strength, hardness, and impact resistance can be tuned. The desired homogeneous blend formation and fine-tuning of PHB mechanical properties have been achieved thanks to the specific design and synthesis of a PHB/PEG diblock copolymer that is able to compatibilize the two compounds. Moreover, the typical high hydrophobicity of PHB is significantly reduced when NFC is added in presence of the developed diblock copolymer, thus creating a potential cue for supporting bone tissue growth. Hence, the presented outcomes contribute to the medical community development by translating the research results into clinical practice for designing bio-based materials for prosthetic devices.

Several synthetic and natural materials have been studied for the confection of temporary grafts for application in regenerative medicine, however, the development of a material with adequate properties remains a challenge, mainly because its degradation kinetics in biological systems. Nature provides materials with noble properties that can be used as such for many applications, thus, taking advantage of the available morphology and assembled structures of plants, we propose to study the vegetable stems for use as temporary graft. Since the in vivo degradation is maybe one of the most important features of the temporary grafts, here we have implanted the plant stems from pumpkin, papaya, and castor into the subepithelial tissue of animals and followed their biodegradation process and the local inflammatory response. Mechanical tests, FTIR and contact angle with water were also analysed. The results indicated the mechanical properties and the contact angle were adequate for use in regenerative medicine. The results of the in vivo studies indicated a beneficial inflammatory process and a gradual disintegration of the materials within 60 days, suggesting the plants stems as new and potential materials for development of grafts for use in the field of regenerative medicine., (© 2022 IOP Publishing Ltd.)

Cellulose nanofibers (CNF) are renewable and biodegradable nanomaterials with attractive barrier, mechanical and surface properties. In this work, three different recombinant enzymes: an endoglucanase, a xylanase and a lytic polysaccharide monooxygenase, were combined to enhance cellulose fibrillation and to produce CNF from sugarcane bagasse (SCB). Prior to the enzymatic catalysis, SCB was chemically pretreated by sodium chlorite and KOH, while defibrillation was accomplished via sonication. We obtained much longer (μm scale length) and more thermostable (resisting up to 260 °C) CNFs as compared to the CNFs prepared by TEMPO-mediated oxidation. Our results showed that a cooperative action of the set of hydrolytic and oxidative enzymes can be used as a "green" treatment prior to the sonication step to produce nanofibrillated cellulose with advanced properties., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

The study deals with the synthesis of thermally reversible hydrogels from modified cellulose nanofibers via the Diels-Alder "click" reaction in an aqueous medium. "Never-dried" cellulose fibres derived from hardwood were submitted to shearing and surface TEMPO-oxidation before being modified with furfurylamine. The ensuing pendant furan moieties were reacted with a water-soluble bismaleimide via Diels-Alder coupling at 65 °C to produce a hydrogel, whose deconstruction was induced by the corresponding retro-Diels-Alder reaction carried out at 95 °C. Differential scanning calorimetry and rheological measurement were used to characterize the hydrogels. These aqueous cellulosic materials should provide original applications in such areas as strong paper-based artefacts and biocompatible gels., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Chitosan is high potential material for new applications due to its properties, especially its antimicrobial activity, and because it is one of the most abundant natural polymers. However, chitosan can be processed only from solution limiting its applications. Methods for processing chitosan in molten have been a subject of recent interest. One method, involves thermoplastic its blends with poly(vinyl alcohol), however these blends undergo degradation due to acid residues from previous processing steps. Here we described a process to produce thermoplastic blends of poly(vinyl alcohol)-chitosan in a poly(lactic acid) matrix by avoiding degradation even at higher chitosan contents. The process involves the use of spray- and freeze-drying techniques to produce acid free blends of PVA/chitosan, then incorporated in PLA matrix by extrusion. These findings are expected to contribute to increasing and extending the applications of polysaccharides, such as chitosan, in new applications such as textiles, medical and food packing., (Copyright © 2018 Elsevier Ltd. All rights reserved.)