Development and thermochemical characterization of an antioxidant material based on polyhydroxybutyrate electrospun microfibers

Poly-3-hydroxybutyrate-silver nanoparticles membranes as advanced antibiofilm strategies for combatting peri-implantitis

Dental implant success is threatened by peri-implantitis, an inflammation leading to implant failure. Conventional treatments struggle with the intricate microbial and host factors involved. Antibacterial membranes, acting as barriers and delivering antimicrobials, may offer a promising solution. Thus, this study highlights the potential of developing antibacterial membranes of poly-3-hydroxybutyrate and silver nanoparticles (Ag Nps) to address peri-implantitis challenges, discussing design and efficacy against potential pathogens. Electrospun membranes composed of PHB microfibers and Ag Nps were synthesized in a blend of DMF/chloroform at three different concentrations. Various studies were conducted on the characterization and antimicrobial activity of the membranes. The synthesized Ag Nps ranged from 4 to 8 nm in size. Furthermore, Young's modulus decreased, reducing from 13.308 MPa in PHB membranes without Ag Nps to 0.983 MPa in PHB membranes containing higher concentrations of Ag Nps. This demonstrates that adding Ag Nps results in a less stiff membrane. An increase in elongation at break was noted with the rise in Ag Nps concentration, from 23.597 % in PHB membranes to 60.136 % in PHB membranes loaded with Ag Nps. The antibiotic and antibiofilm activity of the membranes were evaluated against Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus mutans, and Candida albicans. The results indicated that all PHB membranes containing Ag Nps exhibited potent antibacterial activity by inhibiting the growth of biofilms and planktonic bacteria. However, inhibition of C. albicans occurred only with the PHB-Ag Nps C membrane. These findings emphasize the versatility and potential of Ag Nps-incorporated membranes as a multifunctional approach for preventing and addressing microbial infections associated with peri-implantitis. The combination of antibacterial and antibiofilm properties in these membranes holds promise for improving the management and treatment of peri-implantitis-related complications.

Preparation and Preliminary Analysis of Several Nanoformulations Based on Plant Extracts and Biodegradable Polymers as a Possible Application for Chronic Venous Disease Therapy

Nanotechnology is one of the newest directions for plant-based therapies. Chronic venous disease often predisposes to long-term and invasive treatment. This research focused on the inclusion of vegetal extracts from Sophorae flos (SE), Calendulae flos (CE), and Ginkgo bilobae folium (GE) in formulations with PHB and PLGA polymers and their physicochemical characterization as a preliminary stage for possible use in the development of a complex therapeutic product. The samples were prepared by an oil-water emulsification and solvent evaporation technique, resulting in suspensions with high spreadability and a pH of 5.5. ATR-FTIR analysis revealed bands for stretching vibrations (O-H, C=O, and C-H in symmetric and asymmetric methyl and methylene) in the same regions as the base components, but switched to high or low wavenumbers and absorbance, highlighting the formation of adducts/complexes between the extracts and polymers. The obtained formulations were in the amorphous phase, as confirmed by XRD analysis. AFM analysis emphasized the morphological peculiarities of the extract-polymer nanoformulations. It could be noticed that, in the case of SE-based formulations, the dominant characteristics for SE-PHB and SE-PLGA composition were the formation of random large (SE-PHB) and smaller uniform (SE-PLGA) particles; further on, these particles tended to aggregate in the case of SE-PHB-PLGA. For the CE- and GE-based formulations, the dominant surface morphology was their porosity, generally with small pores, but larger cavities were observed in some cases (CE- and GE-PHB). The highest roughness values at the (8 µm × 8 μm) scale were found for the following samples and succession: CE-PHB < SE-PLGA < SE-PHB-PLGA. In addition, by thermogravimetric analysis, impregnation in the matrix of compression stockings was evaluated, which varied in the following order: CE-polymer > SE-polymer > GE-polymer. In conclusion, nine vegetal extract-polymer nanoformulations were prepared and preliminarily characterized (by advanced physicochemical methods) as a starting point for further optimization, stability studies, and possible use in complex pharmaceutical products.

Fabrication and characterization of shellac nanofibers with colon-targeted delivery of quercetin and its anticancer activity

In this study, the feasibility of shellac nanofibers as carrier system for colonic delivery of quercetin was evaluated. Firstly, the nanofibers without and with different amounts (2.5 %, 5.0 %, and 7.5 %) of quercetin were fabricated using pure shellac as a carrier by electrospinning. The morphology of nanofibers was bead-shape confirmed by SEM. FTIR, XRD, and DSC analysis showed that quercetin was encapsulated into shellac nanofibers, forming an amorphous complex. The molecular docking simulation indicated quercetin bound well to shellac through hydrogen bonding and van der Waals forces. These nanofibers had higher thermal stability than pure quercetin, and their surface wettability exhibited a pH-responsive behavior. The loading capacity of quercetin varied from 2.25 % to 6.84 % with the increased amount of quercetin, and it affected the stability of nanofibers in food simulants by measuring the release profiles of quercetin. The shellac nanofibers had high gastrointestinal stability, with a minimum quercetin release of 16.87 % in simulated digestive fluids, while the remaining quercetin was delivered to the colon and was released gradually. Moreover, the nanofibers exerted enhanced anticancer activity against HCT-116 cells by arresting cell cycle in G0/G1 phase and inducing cell apoptosis. Overall, shellac nanofibers are promising materials for colon-targeted delivery of active compounds.

Fabrication of colon-targeted ethyl cellulose/gelatin hybrid nanofibers: Regulation of quercetin release and its anticancer activity

A colon-targeted delivery system that can efficiently deliver and release quercetin is essential to improve its bioavailability. We previously found that hydrophobic ethyl cellulose (EC) nanofibers could efficiently deliver quercetin to colon, but the release of quercetin was limited. To address this problem, hydrophilic gelatin (GN) was used as a regulator, and quercetin-loaded nanofibers with different mass ratios of EC to GN (3:1, 1:1, 1:2, 1:3) were fabricated by electrospinning. All nanofibers had a cylindrical morphology and high encapsulation efficiency (over 94 %), and there existed molecular interactions among quercetin, EC, and GN. The high GN content reduced the thermal stability of nanofibers but increased their surface wettability. Besides, these nanofibers had good stability in acidic and aqueous foods. Importantly, the release of quercetin in the simulated gastrointestinal fluid was <3 %. The addition of GN was beneficial to the release of quercetin in colon, and nanofibers with EC to GN being 1:3 had a more preferable release performance. The anticancer activity of nanofibers against HCT-116 cells was proved by inhibiting cell viability through the induction of apoptosis. Therefore, these nanofibers are potential carriers for efficient colon-targeted delivery of bioactive compounds in the food industry.

New perspectives on electrospun nanofiber applications in smart and active food packaging materials

Packaging plays a critical role in determining the quality, safety, and shelf-life of many food products. There have been several innovations in the development of more effective food packaging materials recently. Polymer nanofibers are finding increasing attention as additives in packaging materials because of their ability to control their pore size, surface energy, barrier properties, antimicrobial activity, and mechanical strength. Electrospinning is a widely used processing method for fabricating nanofibers from food grade polymers. This review describes recent advances in the development of electrospun nanofibers for application in active and smart packaging materials. Moreover, it highlights the impact of these nanofibers on the physicochemical properties of packaging materials, as well as the application of nanofiber-loaded packaging materials to foods, such as dairy, meat, fruit, and vegetable products.

Biopackaging Potential Alternatives: Bioplastic Composites of Polyhydroxyalkanoates and Vegetal Fibers

Initiatives to reduce plastic waste are currently under development worldwide. As a part of it, the European Union and private and public organizations in several countries are designing and implementing regulations for single-use plastics. For example, by 2030, plastic packaging and food containers must be reusable or recyclable. In another approach, researchers are developing biopolymers using biodegradable thermoplastics, such as polyhydroxyalkanoates (PHAs), to replace fossil derivatives. However, their production capacity, high production costs, and poor mechanical properties hinder the usability of these biopolymers. To overcome these limitations, biomaterials reinforced with natural fibers are acquiring more relevance as the world of bioplastics production is increasing. This review presents an overview of PHA–vegetal fiber composites, the effects of the fiber type, and the production method’s impact on the mechanical, thermal, barrier properties, and biodegradability, all relevant for biopackaging. To acknowledge the behaviors and trends of the biomaterials reinforcement field, we searched for granted patents focusing on bio-packaging applications and gained insight into current industry developments and contributions.