Cellulose esters: Synthesis for further formation of films with magnetite nanoparticles incorporated.

This study investigated the homogeneous synthesis of cellulose acetate (CA) and propionate (CP) with varying degrees of substitution (DS) from sisal cellulose in a N, N-dimethylacetamide/lithium chloride (DMAc/LiCl) solvent system. These esters were used to prepare neat (CADSF/CPDSF) and nanocomposite films (CADSFFe/CPDSFFe) from prior synthesized magnetite nanoparticles (NPs, Fe3O4, 5.1 ± 0.5 nm). Among the CA and CP series, the composite CA0.7FFe and the neat CP0.7F films exhibited the highest modulus of elasticity, 2105 MPa and 2768 MPa, respectively, probably a consequence of the continuous fibrous structures present on the surface of these films. Microsphere formation on the film's surface was observed in scanning electron microscopy micrographs. This points to applications in the controlled release of targeted substances. The VSM analysis showed that the cellulosic matrices preserved the superparamagnetic characteristics of the NPs. This study suggested a reduced coupling effect between nanoparticles inside polymeric films due to magnetic saturation at low fields. CA0.7FFe and CA1.3FFe composite films reached a saturation magnetization (MSAT) of 46 emu/g around 7 kOe field. Hosting magnetite nanoparticles in cellulose ester matrices may be an interesting way to develop new functional cellulose-based materials, which have the potential for diverse applications, including microelectromechanical systems and microsensors.

Uso de plasma rico em plaquetas para reparação tecidual: revisão da literatura / Use of platelet-rich plasma for tissue repair: literature review

Elucidar o potencial terapêutico do uso de plasma rico em plaquetas (PRP). Foi realizado um levantamento de dados sobre o assunto em estudo nas bases de dados: PubMed, SciELO e Google Acadêmico, em língua portuguesa e inglesa, sendo considerado apenas trabalhos científicos publicados no período de 2011 a 2022. Foram consultados no total dezessete artigos para compor a presente revisão. Os estudos evidenciam que o plasma rico em plaquetas possui capacidade de atuar na síntese e liberação de fatores de crescimento e citocinas, que auxiliam na ação anti-inflamatória e antibacteriana promovendo a regeneração tecidual. Os fatores de crescimento derivados de plaquetas atuam como agentes reguladoras e estimuladoras dos processos celulares de mitogênese, quimiotaxia, diferenciação e metabolismo. Essas propriedades das plaquetas conferem ao plasma rico em plaquetas uma potencialidade em melhorar a integração de enxertos cutâneos, ósseos, cartilaginosos ou de gordura, proporcionando uma proteção natural contra processos infecciosos. Os resultados em conjunto sugerem que a aplicação do PRP é considerada uma técnica segura, eficaz e confiável por ser um procedimento autólogo, trazendo avanços promissores quanto ao tempo deregeneração tecidual. O uso dessa técnica pode trazer enormes benefícios aos pacientes, mas ainda há necessidade de maiores estudos científicos, objetivando sempre o aprimoramento da técnica.

Review of Bacterial Nanocellulose-Based Electrochemical Biosensors: Functionalization, Challenges, and Future Perspectives.

Electrochemical biosensing devices are known for their simple operational procedures, low fabrication cost, and suitable real-time detection. Despite these advantages, they have shown some limitations in the immobilization of biochemicals. The development of alternative materials to overcome these drawbacks has attracted significant attention. Nanocellulose-based materials have revealed valuable features due to their capacity for the immobilization of biomolecules, structural flexibility, and biocompatibility. Bacterial nanocellulose (BNC) has gained a promising role as an alternative to antifouling surfaces. To widen its applicability as a biosensing device, BNC may form part of the supports for the immobilization of specific materials. The possibilities of modification methods and in situ and ex situ functionalization enable new BNC properties. With the new insights into nanoscale studies, we expect that many biosensors currently based on plastic, glass, or paper platforms will rely on renewable platforms, especially BNC ones. Moreover, substrates based on BNC seem to have paved the way for the development of sensing platforms with minimally invasive approaches, such as wearable devices, due to their mechanical flexibility and biocompatibility.