Bacterial nanocellulose in dentistry: Perspectives and challenges

Bacterial cellulose (BC) is a natural polymer that has fascinating attributes, such as biocompatibility, low cost, and ease of processing, being considered a very interesting biomaterial due to its options for moldability and combination. Thus, BC-based compounds (for example, BC/collagen, BC/gelatin, BC/fibroin, BC/chitosan, etc.) have improved properties and/or functionality, allowing for various biomedical applications, such as artificial blood vessels and microvessels, artificial skin, and wounds dressing among others. Despite the wide applicability in biomedicine and tissue engineering, there is a lack of updated scientific reports on applications related to dentistry, since BC has great potential for this. It has been used mainly in the regeneration of periodontal tissue, surgical dressings, intraoral wounds, and also in the regeneration of pulp tissue. This review describes the properties and advantages of some BC studies focused on dental and oral applications, including the design of implants, scaffolds, and wound-dressing materials, as well as carriers for drug delivery in dentistry. Aligned to the current trends and biotechnology evolutions, BC-based nanocomposites offer a great field to be explored and other novel features can be expected in relation to oral and bone tissue repair in the near future.Fil: de Oliveira Barud, Hélida Gomes. BioSmart Nanotechnology, LTDA; BrasilFil: da Silva, Robson Rosa. Chalmers University of Technology; SueciaFil: Costa Borges, Marco Antonio. University of Araraquara; BrasilFil: Castro, Guillermo Raul. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Química; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: José Lima Ribeiro, Sidney. São Paulo State University; BrasilFil: da Silva Barud, Hernane. University of Araraquara; Brasi

Bacterial cellulose hydrogel and calcium alginate in the cicatricial wound process from diabetic foot implementation

Objectives: Due to the excellent properties of alginate-containing bacterial cellulose hydrogel, the objective was to treat a wound that is difficult to heal in a diabetic patient. Method: The treatment was carried out at the Santa Casa de Misericordia de São Carlos Ambulatory for 30 days, with the application of bacterial cellulose hydrogel containing alginate twice a week Results: After 30 days of treatment, the wound showed an 84% reduction in its initial size Conclusion: Bacterial cellulose hydrogel containing alginate has high potential for the treatment of wounds

Bacterial cellulose-based hydrogel for wound healing: characterization and in vitro evaluation

Bacterial cellulose (BC) has been considered a promising biopolymer with applications in several areas of knowledge, including medicine, mainly due to its ability to assist in the treatment of dermal lesions. Many groups and companies have been making efforts to develop new BC-based materials in order to add new characteristics and therapeutic possibilities. Recently, Seven Indústria de Produtos Biotecnológicos Ltda company developed a BC-based hydrogel aiming to verify the interaction among the formulation components, its potential for wound healing and biocompatibility studies. BC-based hydrogel was characterized and compared with pristine BC film. Physicochemical characterization includes rheological measurements, thermal analyses, field emission gun - scanning electron microscopy (FE-SEM) and in vitro cell migration. BC-based hydrogel showed adequate interaction among the components of the formulation, which may positively influence its stability. In addition, the BC-based hydrogel accelerated the healing processes demonstrating its potential in dermal lesion treatment

Microbial Cellulose — Biosynthesis Mechanisms and Medical Applications

Currently some principles of sustainability, eco-efficiency and green chemistry are guiding the development of a new generation of materials as an alternative to conventional polymers based on petroleum. Then, in the field of biodegradable polymers one of the most promising investigations is focused on the use of microbial cellulose (MC), biocellulose or bacterial cellulose. MC has received substantial interest since it is synthesized from the bacterium Gluconacetobacter genus from a variety of carbon sources such as glucose, fructose, galactose, etc. MC is an interesting emerging biomaterial, with no toxicity, and since its discovery has shown tremendous potential in various fields, because the structural aspect of MC is far superior to those of plant cellulose. Thus, the main focus of the chapter review involves detailed aspects about the biosynthesis and recent advances on microbial production, including mechanism for the biochemistry of the cellulose synthesis, new sources for culture medium, main aspects about static and air-reactor productions and genetic modifications. We also revised microbial cellulose devices for biomedical applications: artificial skin, artificial blood vessels and microvessels, wound dressing of second- or third-degree burn ulcers, scaffolds for tissue engineering, drug delivery systems, dental implants, among others

Polylactic acid scaffolds obtained by 3D printing and modified by oxygen plasma

The purpose of tissue engineering is to repair, replace, and regenerate tissues and organs. For this aim, materials supports, as polylactic acid (PLA) are used. PLA is a thermoplastic polymer that presents biodegradability, biocompatibility and good processability. PLA scaffolds can accurately constructed by 3D printing. Then, the objectives of this work were to modify the hydrophobic surface of PLA scaffolds using oxygen plasma and to study the cell viability and proliferation. The characterization was done by AFM, contact angle, FTIR and studies of proliferation and cell viability. Results showed that the material acquired hydrophilic properties by the presence of oxygen reactive species and by contact angle decrease. It was also observed an increase in the surface roughness. We can conclude that although the surface modifications were effective and the PLA scaffolds were not cytotoxic, there were no improvements in the proliferation process with the studied osteo-1 lineage cells.

Orange Pectin Mediated Growth and Stability of Aqueous Gold and Silver Nanocolloids

International audienceThe role of orange based pectin in the nucleation and growth of silver and gold nanoparticles is addressed. Pectin is a complex polysaccharide found in fruits such as oranges, lemons, passion fruits or apples. It displays smooth and hairy chain regions contg. hydroxyl-​, ester-​, carboxylate- and eventually amine groups that can act as surface ligands interacting under various pH conditions more or less efficiently with growing nanometals. Here, a high methoxy pectin (>50​% esterified) was used as a stabilizer​/reducing agent in the prepn. of gold, silver and silver-​gold nanoparticles. Com. pectin (CP) and pectin extd. from orange bagasse (OP) were used. Optionally, trisodium citrate or oxalic acid we used to reduce AgNO3 and HAuCl4 in aq. environment. Characterization methods included UV-​vis absorption spectroscopy, transmission electron microscopy, electron diffraction and energy-​dispersive X-​ray spectroscopy. The results show that under different pH conditions, pectin and reducing agents allow producing various nanostructures shapes (triangles, spheres, rods, octahedrons and decahedrons) often with high polydispersity and sizes ranging between 5 nm and 30 nm. In addn., depending on Ag​/Au-​ratio and pH, the surface plasmon bands can be continuously shifted between 410 nm and 600 nm. Finally, pectin seems to be a highly efficient stabilizer of the colloidal systems that show a remarkable stability and unchanged optical spectral response even after five years

Functional Properties of Brazilian Propolis: From Chemical Composition Until the Market

Propolis is a product obtained from resins and exudates of different plants from different regions in order to protect the comb, with peculiar organoleptic, chemicals and biological properties. Considering this, this chapter presents the types of Brazilian propolis as the types available nowadays, their chemical compositions, as well as, some of their important biological properties enabling employing them as important health food, such as antimicrobial, antioxidant, and immunomodulation action. Various “in vivo” and clinical trial studies, conducted in different regions, on the safety and dosage of propolis, technologies used to obtain propolis extract, and several innovative presentations of this promising bee product are also presented in this chapter. Finally, this chapter aims to present the regulatory affairs, potential market for propolis around the world, and perspectives for a near future

Development and characterization of high-absorption microencapsulated organic propolis EPP-AF® extract (i-CAPs)

The demand for organic and functional food continues to increase yearly. Among the available functional foods, propolis is a bee product that has various beneficial properties, including antimicrobial, antioxidant, and anti-inflammatory activities. However, it generally is only available in ethanol solution, which has poor bioavailability, as it is relatively insoluble in water. The use of such ethanol extracts is often objectionable because of the alcohol content and because they have a strong and striking taste. Development of alternatives that can efficiently and safely increase solubility in water, and that meet organic production specifications, has been a challenge. To address these concerns, microcapsules were developed using spray-dryer technology from an emulsion based on EPP-AF® propolis and gum arabic (i-CAPS). These propolis-loaded microcapsules were characterized using FT-IR, SEM, TGA, HPLC, and spectrophotometric techniques, along with determination of antimicrobial, antioxidant, antitumor, anti-inflammatory, and antihypercholesterolemic activities, as well as permeability in in vitro models. The production system resulted in microcapsules with a spherical shape and an encapsulation efficiency of 93.7 0.7%. They had IC50s of 2.654 0.062 and 7.342 0.058 g/mL by FRAP and DPPH antioxidant methods, respectively. The EPP-AF® i-CAPS also had superior antimicrobial activity against Gram-positive bacteria. Antitumor activity was calculated based on the concentration that inhibited 50% of growth of AGS, Caco-2, and MCF-7 cell strains, giving results of 154.0 1.0, 117 1.0, and 271.0 25 g/mL, respectively. The microcapsule presentation reduced the permeation of cholesterol by 53.7%, demonstrating antihypercholesterolemic activity, and it improved the permeability of p-coumaric acid and artepillin C. The IC50 for NO production in RAW264.7 cells was 59.0 0.1 g/mL. These findings demonstrate the potential of this new propolis product as a food and pharmaceutical ingredient, though additional studies are recommended to validate the safety of proposed dosages.CNPq financially supported this research through the CNPQ/MCTI/SEMPI No. 021/2021 process on RHAE modality, contract number 424727/2021-8. It was also supported by São Paulo Research Foundation (FAPESP) grant #2017/04138-8, CNPq (grant 309614/2021-0; INCT-INFO), CNPq grants 350088/2022-5 and 350089/2022-1, São Paulo Research Foundation (FAPESP) (grant no. 2013/07276-1). The authors are grateful to the Foundation for Science and Technology (FCT, Portugal) for financial support by national funds FCT/MCTES to CIMO (UIDB/00690/2020 and UIDP/00690/2020) and SusTEC (LA/P/0007/2021). Thanks to the project GreenHealth, Norte-01- 0145-FEDER-000042.info:eu-repo/semantics/publishedVersio

Strong Electronic Identification: Survey & Scenario Planning

The deployment of more high-risk services such as online banking and government services on the Internet has meant that the need and demand for strong electronic identity is bigger today more than ever. Different stakeholders have different reasons for moving their services to the Internet, including cost savings, being closer to the customer or citizen, increasing volume and value of services among others. This means that traditional online identification schemes based on self-asserted identities are no longer sufficient to cope with the required level of assurance demanded by these services. Therefore, strong electronic identification methods that utilize identifiers rooted in real world identities must be provided to be used by customers and citizens alike on the Internet. This thesis focuses on studying state-of-the-art methods for providing reliable and mass market strong electronic identity in the world today. It looks at concrete real-world examples that enable real world identities to be transferred and used in the virtual world of the Internet. The thesis identifies crucial factors that determine what constitutes a strong electronic identity solution and through these factors evaluates and compares the example solutions surveyed in the thesis. As the Internet become more pervasive in our lives; mobile devices are becoming the primary devices for communication and accessing Internet services. This has thus, raised the question of what sort of strong electronic identity solutions could be implemented and how such solutions could adapt to the future. To help to understand the possible alternate futures, a scenario planning and analysis method was used to develop a series of scenarios from underlying key economic, political, technological and social trends and uncertainties. The resulting three future scenarios indicate how the future of strong electronic identity will shape up with the aim of helping stakeholders contemplate the future and develop policies and strategies to better position themselves for the future

Preparo e caracterização de novos compósitos de celulose bacteriana

A celulose bacteriana obtida pela cultura de Acetobacter xylinum apresenta alta massa molecular e alta cristalinidade quando comparada à celulose vegetal. Devido à auto-organização, microcristalinidade e estrutura tridimensional tem gerado um grande número de produtos comerciais. Eles incluem membranas para autofalantes e fones de ouvido, Biofill® (usado como pele artificial), fibras dietéticas (nata-de-coco), membranas para celas de combustível, e outros . Nesse trabalho, novos compósitos celulose/fosfato de sódio e celulose bacteriana/sílica foram preparados a partir de celulose bacteriana. Para os compósitos celulose/polifosfato de sódio, a difratometria de raios X apresentou contribuição das fases Ia e Iß da celulose e de fosfato recobrindo as fibras da estrutura da celulose. Alterações nas propriedades mecânicas e térmicas foram evidenciadas através das análises térmicas e mecânicas. Compósitos de celulose bacteriana e sílica foram preparados pela hidrólise de tetraetoxisilano (TEOS) na presença da celulose. Observou-se o depósito de nanopartículas de sílica sobre as microfibrilas de celulose. A presença de fase inorgânica contribui para a melhora das estabilidades térmicas e mecânicas da celulose bacteriana.Bacterial cellulose obtained from cultures of Acetobacter xylinum presents higher molecular weight and higher crystallinity than plant cellulose. The selfassembled, microcrystalline and three dimensional network structures have lead to a number of commercial products. These include headphone membranes, paper, Biofill® (to be used as a temporary skin substitute), dietary fiber (nata-de-coco), fuel cells, and others 2. In this work, new composites based on bacterial cellulose/sodium phosphate and bacterial cellulose/silica were prepared. In the bacterial cellulose/polyphosphate composite DRX analyses presents Ia and Iß cellulose phases and adsorbed phosphate covering the cellulose microfibrils. Important changes in mechanical and thermal properties were evidenced for thermal and mechanics analyses. Composites on bacterial cellulose and silica were prepared from the hydrolysis/condensation of tetraethoxysilane (TEOS) on the cellulose microfibrils. The inorganic phase improves cellulose thermal stability and mechanical properties.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES