Search Results (8)

Bacterial cellulose (BC) is a versatile biopolymer with significant potential across biomedical, food, and industrial applications. To remove bacterial contaminants, such as protein and DNA, BC pellicles undergo purification, which traditionally relies on harsh alkali treatments, such as sodium hydroxide or strong surfactants, which present environmental concerns. In response, this study evaluates the efficacy of various non-conventional surfactants—both non-biodegradable and biodegradable—as alternatives for BC purification. Among the surfactants tested, sodium cocoyl isethionate (SCI), a mild anionic and biodegradable surfactant, emerged as particularly effective, achieving an 80.7% reduction in protein content and a 65.19% reduction in double-stranded DNA (dsDNA) content relative to untreated samples. However, these advantages were not without additional challenges, such as the appearance of residual surfactants. Given SCI’s promising performance and biodegradability, it was further examined in two-step treatment protocols; additionally, sodium dodecyl sulfate (SDS) was also examined as a more traditional anionic surfactant as well as NaOH. For the two-step treatment protocol, BC pellicles were treated with one reagent for 3 h, followed by a second reagent for an additional 3 h. Notably, by using NaOH as the final step in the two-step treatment protocol, residual surfactant was not detected in the FTIR analysis. Overall, this work demonstrates that SCI, in addition to subsequent NaOH treatment, can be used as a surfactant-based approach for BC purification, representing a potential environmentally friendly alternative to traditional surfactant-based approaches for BC purification. Full article

Soft tissue adhesion and sealing around dental and maxillofacial implants, related prosthetic components, and crowns are a clinical imperative to prevent adverse outcomes of periodontitis and periimplantitis. Zirconia is often used to fabricate implant components and crowns. Here, we hypothesized that UV treatment of zirconia would induce unique behaviors in fibroblasts that favor the establishment of a soft tissue seal. Human oral fibroblasts were cultured on zirconia specimens to confluency before placing a second zirconia specimen (either untreated or treated with one minute of 172 nm vacuum UV (VUV) light) next to the first specimen separated by a gap of 150 µm. After seven days of culture, fibroblasts only transmigrated onto VUV-treated zirconia, forming a 2.36 mm volume zone and 5.30 mm leading edge. Cells migrating on VUV-treated zirconia were enlarged, with robust formation of multidirectional cytoplastic projections, even on day seven. Fibroblasts were also cultured on horizontally placed and 45° and 60° tilted zirconia specimens, with the latter configurations compromising initial attachment and proliferation. However, VUV treatment of zirconia mitigated the negative impact of tilting, with higher tilt angles increasing the difference in cellular behavior between control and VUV-treated specimens. Fibroblast size, perimeter, and diameter on day seven were greater than on day one exclusively on VUV-treated zirconia. VUV treatment reduced surface elemental carbon and induced superhydrophilicity, confirming the removal of the hydrocarbon pellicle. Similar effects of VUV treatment were observed on glazed zirconia specimens with silica surfaces. One-minute VUV photofunctionalization of zirconia and silica therefore promotes human oral fibroblast attachment and proliferation, especially under challenging culture conditions, and induces specimen-to-specimen transmigration and sustainable photofunctionalization for at least seven days. Full article

Denture plaque control for the prevention of aspiration pneumonia is very important. The pellicle is the major cause of denture plaque adhesion. Few basic studies have evaluated the effectiveness of denture cleansers for pellicles composed of salivary proteins. The adhesion of salivary proteins formed on denture base metal and the removal rate were quantitatively analyzed using the QCM method after denture cleanser injection. This is the first study to compare the cleaning effects of denture cleanser on denture base metal using the QCM method. Au and Ti sensors were employed as the denture base metals. Albumin was used for the adsorption of salivary proteins. The results showed that no significant difference was found between Au and Ti in the amounts of albumin adsorbed, and the rate of albumin removal from Ti was significantly higher than that of Au. In this study, the cleaning effectiveness of denture cleanser was confirmed based on the adsorbed amount and the removal rate of salivary proteins adsorbed onto denture base metals. Thus, the QCM method was suggested to be a useful tool for removing the effects of salivary proteins from denture cleaning agents on denture base metal. Full article

The world production of chestnuts has significantly grown in recent decades. Consumer attitudes, increasingly turned towards healthy foods, show a greater interest in chestnuts due to their health benefits. Consequently, it is important to develop reliable methods for the selection of high-quality products, both from a qualitative and sensory point of view. In this study, Castanea spp. fruits from Italy, namely Sweet chestnut cultivar and the Marrone cultivar, were evaluated by an official panel, and the responses for sensory attributes were used to verify the correlation to the near-infrared spectra. Data fusion strategies have been applied to take advantage of the synergistic effect of the information obtained from NIR and sensory analysis. Large nuts, easy pellicle removal, chestnut aroma, and aromatic intensity render Marrone cv fruits suitable for both the fresh market and candying, i.e., marron glacé. Whereas, sweet chestnut samples, due to their characteristics, have the potential to be used for secondary food products, such as jam, mash chestnut, and flour. The research lays the foundations for a superior data fusion approach for chestnut identification in terms of classification sensitivity and specificity, in which sensory and spectral approaches compensate each other’s drawbacks, synergistically contributing to an excellent result. Full article

Extended cultivation with multiple removal of BC pellicles is proposed herein as a new biosynthetic process for bacterial cellulose (BC). This method enhances the BC surface area by 5–11 times per unit volume of the growth medium, improving the economic efficiency of biosynthesis. The resultant BC gel-films were thin, transparent, and congruent. The degree of polymerization (DP) and elastic modulus (EM) depended on the number of BC pellicle removals, vessel shape, and volume. The quality of BC from removals II–III to VII was better than from removal I. The process scale-up of 1:40 by volume increased DP by 1.5 times and EM by 5 times. A fact was established that the symbiotic Medusomyces gisevii Sa-12 was adaptable to exhausted growth medium: the medium was able to biosynthesize BC for 60 days, while glucose ran low at 24 days. On extended cultivation, DP and EM were found to decline by 39–64% and 57–65%, respectively. The BC gel-films obtained upon removals I–VI were successfully trialed in experimental tension-free hernioplasty. Full article

Bacterial nanocellulose (BNC) is a unique product of microbiological synthesis, having a lot of applications among which the most important is biomedicine. Objective complexities in scaling up the biosynthesis of BNC are associated with the nature of microbial producers for which BNC is not the target metabolite, therefore biosynthesis lasts long, with the BNC yield being small. Thus, the BNC scale-up problem has not yet been overcome. Here we performed biosynthesis of three scaled sheets of BNC (each having a surface area of 29,400 cm², a container volume of 441 L, and a nutrient medium volume of 260 L and characterized them. The static biosynthesis of BNC in a semisynthetic nutrient medium was scaled up using the Medusomyces gisevii Sa-12 symbiotic culture. The experiment was run in duplicate. The BNC pellicle was removed once from the nutrient medium in the first experiment and twice in the second experiment, in which case the inoculum and glucose were not additionally added to the medium. The resultant BNC sheets were characterized by scanning electron microscopy, capillary viscosimetry, infrared spectroscopy, thermomechanical and thermogravimetric analyses. When the nutrient medium was scaled up from 0.1 to 260 L, the elastic modulus of BNC samples increased tenfold and the degree of polymerization 2.5-fold. Besides, we demonstrated that scaled BNC sheets could be removed at least twice from one volume of the nutrient medium, with the yield and quality of BNC remaining the same. Consequently, the world’s largest BNC sheets 210 cm long and 140 cm wide, having a surface area of 29,400 cm² each (weighing 16.24 to 17.04 kg), have been obtained in which an adult with burns or vast wounds can easily be wrapped. The resultant sheets exhibit a typical architecture of cellulosic fibers that form a spatial 3D structure which refers to individual and extremely important characteristics of BNC. Here we thus demonstrated the scale-up of biosynthesis of BNC with improved properties, and this result was achieved by using the symbiotic culture. Full article

This in vitro study evaluated the effectiveness of a novel dentifrice containing stabilized chlorine dioxide, sodium lauroyl sarcosinate (sarkosyl), and sodium fluoride in enhancing enamel fluoride uptake, remineralization, pellicle cleaning and inhibiting biofilm regrowth. Remineralization was measured by fluoride uptake and surface microhardness assessment tests. Artificial stains were removed and scored based on pellicle cleaning ratio. Biofilm regrowth was measured by counting colonies on the agar plates. All studies were conducted using bovine teeth specimens. The efficacy of Toothpaste C (CloSYS anticavity toothpaste) was compared with United States Pharmacopoeia Reference Dentifrice, Toothpaste B (discontinued CloSYS anticavity toothpaste formulation) and leading commercial toothpastes. The enamel fluoride uptake and remineralization by Toothpaste C was 96.1% to 303.3% and 38.0% to 102.4% higher than the tested toothpastes, respectively. The mean pellicle cleaning ratio of Toothpaste C was similar to American Dental Association Reference Material. Toothpaste C had a significant reduction in regrowth of the oral polymicrobial biofilm compared to the control. All tested toothpastes contained 0.24% sodium fluoride. Toothpaste C exhibited significantly superior performance towards fluoride uptake and remineralization compared to the tested toothpastes. Therefore, toothpaste ingredients other than sodium fluoride accounted for the enhanced fluoride uptake and remineralization. Full article

As concerns are increasing about drinking water contamination with heavy metals, we investigated the possible use of a pellicle (floating biofilm)-like biofilm-producing microorganism as a biosorbent for the treatment of Pb(II) in aqueous solutions. The bacterial pellicle-producing Methylobacterium hispanicum EM2 strain (EM2) was newly isolated from mine tailing soil, and we investigated its use as a biosorbent for treating a Pb(II)-contaminated aqueous solution. The EM2 strain was strongly resistant to Pb(II) up to a concentration of 800 mg/L, and achieved remarkable adsorption performance (adsorption rate and maximum adsorption capacity of 96% ± 3.2% and 79.84 mg/g, respectively) under optimal conditions (pH, biomass content, contact time, and initial Pb(II) concentration of 7.1 g/L, 60 min, and 10 mg/L, respectively). The adsorption of Pb(II) was characterized by scanning electron microscopy-energy dispersive x-ray spectroscopy and Fourier-transform infrared analysis. The equilibrium data matched the Freundlich isotherm model well, indicating the occurrence of multilayer adsorption of Pb(II) onto the heterogeneous surface of the EM2 strain, which was also consistent with the pseudo-second-order kinetic model (R² = 0.98). The high Pb(II) removal efficiency was also confirmed by conducting an adsorption experiment using Pb(II)-contaminated industrial wastewater. Full article