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.

Exploring Schwann Cell Behavior on Electrospun Polyhydroxybutyrate Scaffolds with Varied Pore Sizes and Fiber Thicknesses: Implications for Neural Tissue Engineering.

The placement of a polymeric electrospun scaffold is among the most promising strategies to improve nerve regeneration after critical neurotmesis. It is of great interest to investigate the effect of these structures on Schwann cells (SCs), as these cells lead nerve regeneration and functional recovery. The aim of this study was to assess SC viability and morphology when cultured on polyhydroxybutyrate (PHB) electrospun scaffolds with varied microfiber thicknesses and pore sizes. Six electrospun scaffolds were obtained using different PHB solutions and electrospinning parameters. All the scaffolds were morphologically characterized in terms of fiber thickness, pore size, and overall appearance by analyzing their SEM images. SCs seeded onto the scaffolds were analyzed in terms of viability and morphology throughout the culture period through MTT assay and SEM imaging. The SCs were cultured on three scaffolds with homogeneous smooth fibers (fiber thicknesses: 2.4 µm, 3.1 µm, and 4.3 µm; pore sizes: 16.7 µm, 22.4 µm, and 27.8 µm). SC infiltration and adhesion resulted in the formation of a three-dimensional network composed of intertwined fibers and cells. The SCs attached to the scaffolds maintained their characteristic shape and size throughout the culture period. Bigger pores and thicker fibers resulted in higher SC viability.

Osteoinductive Electrospun Scaffold Based on PCL-Col as a Regenerative Therapy for Peri-Implantitis.

Peri-implantitis is a serious condition affecting dental implants that can lead to implant failure and loss of osteointegration if is not diagnosed and treated promptly. Therefore, the development of new materials and approaches to treat this condition is of great interest. In this study, we aimed to develop an electrospun scaffold composed of polycaprolactone (PCL) microfibers loaded with cholecalciferol (Col), which has been shown to promote bone tissue regeneration. The physical and chemical properties of the scaffold were characterized, and its ability to support the attachment and proliferation of MG-63 osteoblast-like cells was evaluated. Our results showed that the electrospun PCL-Col scaffold had a highly porous structure and good mechanical properties. The resulting scaffolds had an average fiber diameter of 2-9 µm and high elongation at break (near six-fold under dry conditions) and elasticity (Young modulus between 0.9 and 9 MPa under dry conditions). Furthermore, the Col-loaded scaffold was found to decrease cell proliferation when the Col content in the scaffolds increased. However, cytotoxicity analysis proved that the PCL scaffold on its own releases more lactate dehydrogenase into the medium than the scaffold containing Col at lower concentrations (PCL-Col A, PCL-Col B, and PCL-Col C). Additionally, the Col-loaded scaffold was shown to effectively promote the expression of alkaline phosphatase and additionally increase the calcium fixation in MG-63 cells. Our findings suggest that the electrospun membrane loaded with Col can potentially treat peri-implantitis by promoting bone formation. However, further studies are needed to assess the efficacy and safety of this membrane in vivo.

Electrospun Fibers Loaded with Natural Bioactive Compounds as a Biomedical System for Skin Burn Treatment. A Review.

Burns are a major threat to public health and the economy due to their costly and laborious treatment and high susceptibility to infection. Efforts have been made recently to investigate natural bioactive compounds with potential use in wound healing. The importance lies in the capacities that these compounds could possess both in infection control by common and resistant microorganisms, as well as in the regeneration of the affected tissues, having in both cases low adverse effects. However, some bioactive molecules are chemically unstable, poorly soluble, and susceptible to oxidative degradation or have low bioavailability. Therefore, developing new technologies for an efficient treatment of wound healing poses a real challenge. In this context, electrospun nanofibers have gained increasing research interest because bioactive molecules can be easily loaded within the nanofiber, resulting in optimal burst control and enhanced drug stability. Additionally, the nanofibers can mimic the extracellular collagen matrix, providing a suitable highly porous structural support for growing cells that facilitate and accelerate skin burns healing. This review gives an overview of the current state of electrospun fibers loaded with natural bioactive compounds as a biomedical system for skin burn treatment.

One-step electrospun scaffold of dual-sized gelatin/poly-3-hydroxybutyrate nano/microfibers for skin regeneration in diabetic wound.

This work aimed to implement an electrospinning protocol that allows simultaneous production of micro- and nanofibers in a single scaffold to mimic the extracellular matrix (ECM) combining biodegradable polymers and proteins, and to evaluate its capability to manage diabetic wounds. Poly-3-hydroxybutyrate (PHB) and gelatin (Ge) were chosen to prepare micro- and nanofibers, respectively. Electrospinning conditions were optimized testing various polymer concentrations, voltages, and flow rates. One-step dual-size fibers were obtained from 8%w/v PHB in chloroform (microfibers, 1.25 ± 0.17 µm) and 30%w/v gelatin in acetic acid (75%w/v) (nanofibers, 0.20 ± 0.04 µm), at 0.5 mL/h and 25 kV. A chemical characterization, swelling, hydrophilicity of scaffolds made of PHB-microfibers, Ge-nanofibers and their combination (Ge-PHB) were evaluated before and after crosslinking with genipin. All scaffolds showed excellent fibroblasts viability and attachment after incubation for 1, 3, and 7 days, and low levels of hemolysis. In vivo wound healing was evaluated in diabetic rats for 21 days. Ge-containing scaffolds promoted faster healing. The wounds treated with the Ge-PHB scaffolds proved to be in a late proliferative stage showing higher content of hair follicles and sweat glands and lower content in fibroblast compared with the control wounds.

Degree of crosslinking in ß-cyclodextrin-based nanosponges and their effect on piperine encapsulation.

Piperine (PIP) is an alkaloid which is potent as a therapeutic agent. However, its applications are restricted by its poor water solubility. Nanosponges (NS) derived from polymers are versatile carriers for poor water-soluble substances. The aim of this work was to synthesize ß-cyclodextrin NS, by microwave-assisted fusion, for the encapsulation of PIP. Different formulations of NS were synthesized by varying the molar ratio of ß-cyclodextrin:diphenyl carbonate (ß-CD:DPC; 1:2, 1:6 and 1:10). NS specimens derived from 1:2, 1:6 and 1:10 ß-CD:DPC molar ratios exhibited degree of substitution values of 0.345, 0.629 and 0.878, respectively. The crystallinity of NS was enhanced by increasing diphenyl carbonate concentration. A high degree of crosslinking in the NS increased the loading efficiency due to increased surface area available for bioactive inclusion. This study demonstrated the feasibility of synthesizing NS derived from ß-cyclodextrin of high crystallinity for the encapsulation of PIP at high loading capacity.

Gallic acid loaded PEO-core/zein-shell nanofibers for chemopreventive action on gallbladder cancer cells.

Coaxial electrospinning was used to develop gallic acid (GA) loaded poly(ethylene oxide)/zein nanofibers in order to improve its chemopreventive action on human gallbladder cancer cells. Using a Plackett-Burman design, the effects of poly(ethylene oxide) and zein concentration and applied voltage on the diameter and morphology index of nanofibers were investigated. Coaxial nanofibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). GA loading efficiency as high as 77% was obtained under optimal process conditions. The coaxial nanofibers controlled GA release in acid and neutral pH medium. Cytotoxicity and reactive oxygen species (ROS) production on gallbladder cancer cell lines GB-d1 and NOZ in the presence of GA-nanofibers were assessed. GA-nanofibers triggered an increase in the cellular cytotoxicity compared with free GA on GB-d1 and NOZ cells. Statistically significant differences were found in ROS levels of GA-nanofibers compared with free GA on NOZ cells. Differently, ROS production on GB-d1 cell line was similar. Based on these results, the coaxial nanofibers obtained in this study under optimized operational conditions offer an alternative for the development of a GA release system with improved chemopreventive action on gallbladder cancer cells.

Bacterial polyhydroxybutyrate for electrospun fiber production.

Nano- and microfibers obtained by electrospinning have attracted great attention due to its versatility and potential for applications in diverse technological fields. Polyhydroxyalkanoates (PHAs) are biopolymers synthesized by microorganisms such as the bacterium Burkholderia xenovorans LB400. In particular, LB400 cells are capable to synthesize poly(3-hydroxybutyrate) (PHB) from glucose. The aim of this study was to produce and characterize electrospun fibers obtained from bacterial PHBs. Bacterial strain LB400 was grown in M9 minimal medium using xylose and mannitol (10gL-1) as the sole carbon sources and NH4Cl (1gL-1) as the sole nitrogen source. Biopolymer-based films obtained were used to produce fibers by electrospinning. Diameter and morphology of the microfibers were analyzed by scanning electron microscopy (SEM) and their thermogravimetric properties were investigated. Bead-free fibers using both PHBs were obtained with diameters of less than 3µm. The surface morphology of the microfibers based on PHBs obtained from both carbon sources was different, even though their thermogravimetric properties are similar. The results indicate that the carbon source may determine the fiber structure and properties. Further studies should be performed to analyze the physicochemical and mechanical properties of these PHB-based microfibers, which may open up novel applications.