Silmar Baptista Nunes

Prof. Silmar Baptista Nunes

Centro Universitário SENAI-CIMATEC, Salvador, Bahia, Brazil

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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26 January 2020 in Polymers
Verified
Journal Article
Open access
PDF file
KHKatharine Valéria Saraiva Hodel
Katharine Valéria Saraiva Hodel
LFLarissa Fonseca
Larissa Fonseca
ISIsa Moreira da Silva Santos
Isa Moreira da Silva Santos
JCJamile Costa Cerqueira
Jamile Costa Cerqueira
RSRaimundo Evangelista dos Santos-Júnior
Raimundo Evangelista dos Santos-Júnior
Bruna MachadoBruna Machado
Bruna Machado
Bacterial cellulose (BC) has received considerable attention due to its unique properties, including an ultrafine network structure with high purity, mechanical strength, inherent biodegradability, biocompatibility, high water-holding capacity and high crystallinity. These properties allow BC to be used in biomedical and industrial applications, such as medical product. This research investigated the production of BC by Gluconacetobacter hansenii ATCC 23769 using different carbon sources (glucose, mannitol, sucrose and xylose) at two different concentrations (25 and 50 g∙L−1). The BC produced was used to develop a biocomposite with montmorillonite (MMT), a clay mineral that possesses interesting characteristics for enhancing BC physical-chemical properties, at 0.5, 1, 2 and 3% concentrations. The resulting biocomposites were characterized in terms of their physical and barrier properties, morphologies, water-uptake capacities, and thermal stabilities. Our results show that bacteria presented higher BC yields in media with higher glucose concentrations (50 g∙L−1) after a 14-day incubation period. Additionally, the incorporation of MMT significantly improved the mechanical and thermal properties of the BC membranes. The degradation temperature of the composites was extended, and a decrease in the water holding capacity (WHC) and an improvement in the water release rate (WRR) were noted. Determining a cost-effective medium for the production of BC and the characterization of the produced composites are extremely important for the biomedical applications of BC, such as in wound dressing materials.

19 January 2021 in Materials
Verified
Journal Article
Open access
PDF file
SNSilmar Baptista Nunes
Silmar Baptista Nunes
KHKatharine Valéria Saraiva Hodel
Katharine Valéria Saraiva Hodel
GSGiulia da Costa Sacramento
Giulia da Costa Sacramento
PMPollyana da Silva Melo
Pollyana da Silva Melo
FPFERNANDO PESSOA
FERNANDO PESSOA
Bruna MachadoBruna Machado
Bruna Machado
One of the major benefits of biomedicine is the use of biocomposites as wound dressings to help improve the treatment of injuries. Therefore, the main objective of this study was to develop and characterize biocomposites based on bacterial cellulose (BC) with different concentrations of collagen and starch and characterize their thermal, morphological, mechanical, physical, and barrier properties. In total, nine samples were produced with fixed amounts of glycerol and BC and variations in the amount of collagen and starch. The water activity (0.400–0.480), water solubility (12.94–69.7%), moisture (10.75–20.60%), thickness (0.04–0.11 mm), water vapor permeability (5.59–14.06 × 10−8 g·mm/m2·h·Pa), grammage (8.91–39.58 g·cm−2), opacity (8.37–36.67 Abs 600 nm·mm−1), elongation (4.81–169.54%), and tensile strength (0.99–16.32 MPa) were evaluated and defined. In addition, scanning electron microscopy showed that adding biopolymers in the cellulose matrix made the surface compact, which also influenced the visual appearance. Thus, the performance of the biocomposites was directly influenced by their composition. The performance of the different samples obtained resulted in them having different potentials for application considering the injury type. This provides a solution for the ineffectiveness of traditional dressings, which is one of the great problems of the biomedical sector.

8 June 2022 in Pharmaceutics
Verified
Journal Article
Open access
PDF file
KHKatharine Valéria Saraiva Hodel
Katharine Valéria Saraiva Hodel
Bruna MachadoBruna Machado
Bruna Machado
GSGiulia da Costa Sacramento
Giulia da Costa Sacramento
CMCarine carinerinee Maciel
Carine carinerinee Maciel
GOGessualdo Seixas Oliveira-Junior
Gessualdo Seixas Oliveira-Junior
AGAna Leonor Pardo Campos Godoy
Ana Leonor Pardo Campos Godoy
The use of innate products for the fast and efficient promotion of healing process has been one of the biomedical sector’s main bets for lesion treatment modernization process. The aim of this study was to develop and characterize bacterial cellulose-based (BC) wound dressings incorporated with green and red propolis extract (2 to 4%) and the active compounds p-coumaric acid and biochanin A (8 to 16 mg). The characterization of the nine developed samples (one control and eight active wound dressings) evidenced that the mechanics, physics, morphological, and barrier properties depended not only on the type of active principle incorporated onto the cellulosic matrix, but also on its concentration. Of note were the results found for transparency (28.59–110.62T600 mm−1), thickness (0.023–0.046 mm), swelling index (48.93–405.55%), water vapor permeability rate (7.86–38.11 g m2 day−1), elongation (99.13–262.39%), and antioxidant capacity (21.23–86.76 μg mL−1). The wound dressing based on BC and red propolis was the only one that presented antimicrobial activity. The permeation and retention test revealed that the wound dressing containing propolis extract presented the most corneal stratum when compared with viable skin. Overall, the developed wound dressing showed potential to be used for treatment against different types of dermal lesions, according to its determined proprieties.