The antimicrobial peptide Microcin C7 inhibits the growth of Porphyromonas gingivalis and improves the perodontal status in a rat model.

AIMS: This study aimed to investigate the antibacterial and anti-inflammatory effects of the antimicrobial peptide Microcin C7 for Porphyromonas gingivalis-associated diseases. METHODS AND RESULTS: Reverse-phase high-performance liquid chromatography revealed that Microcin C7 could remain 25.5% at 12 hours in saliva. At a concentration of <10 mg mL-1, Microcin C7 showed better cytocompatibility, as revealed by hemolysis test and subchronic systemic toxicity test. Moreover, the minimum inhibitory concentration and minimum bactericidal concentration of Microcin C7 were analyzed using a broth microdilution method, bacterial growth curve, scanning electron microscopy, and confocal laser microscopy and determined to be 0.16 mg mL-1 and 5 mg mL-1, respectively. Finally, in a rat model, 5 mg mL-1 Microcin C7 showed better performance in decreasing the expression of inflammatory factors (IL-1ß, IL-6, IL-8, and TNF-α) and alveolar bone resorption than other concentrations. CONCLUSIONS: Microcin C7 demonstrated favorable biocompatibility, antibacterial activity, anti-inflammatory effect, and could decrease the alveolar bone resorption in a rat model, indicating the promising potential for clincal translation and application on P. gingivalis-associated diseases.

Factors influencing traumatic brain injuries in maxillofacial fractures: A 12-year retrospective analysis of 2841 patients.

BACKGROUND/AIM: Results of studies investigating the association between traumatic brain injury (TBI) and maxillofacial fractures (MFs) have varied considerably. The present study aimed to evaluate the correlation between TBIs and MFs, as well as the impact of age, sex, trauma mechanism, and season on TBIs. MATERIALS AND METHODS: This 12-year retrospective study of 2841 patients used univariate and multivariate logistic regression to assess the association between MFs and other factors impacting TBIs. RESULTS: Among 2841 patients, 1978 TBIs occurred in 829 (29.2%), with intracranial injuries (n = 828) is the most common. Of 829 patients with TBIs, 688 were male and 141 were female, corresponding to a male-to-female ratio of 4.9:1.0. The most common age group was 40-49 years (24.6%). Vehicles (including motor vehicles and electric vehicles) accidents were the primary causes of injuries. Multivariate regression analyses revealed an increased risk for TBIs among males (odds ratio [OR] 0.632, p < 0.001). Patients >40 years of age were at higher risk for TBIs, especially those ≥70 years (OR 3.966, p = 0.001). Vehicle accidents were a high-risk factor for TBIs (OR 6.894, p < 0.001), and winter was the most prevalent season for such injuries (OR 1.559, p = 0.002). Risk for TBI increased by 136.4% in combined midfacial and mandibular fractures (p = 0.016) and by 101.6% in multiple midfacial fractures (p = 0.045). TBIs were less common in single mandibular fractures, notably in single-angle fractures, with a risk of only 0.204-fold. CONCLUSION: TBIs in MFs were significantly correlated with sex, age, aetiology, season and fracture location. Maxillofacial surgeons and emergency physicians must be aware of the possible association between TBIs and MFs to assess and manage this complicated relationship in a timely manner.

Stimuli-Responsive Pickering Emulsions Regulated via Polymerization-Induced Self-Assembly Nanoparticles.

With the development of reversible deactivated radical polymerization techniques, polymerization-induced self-assembly (PISA) is emerging as a facile method to prepare block copolymer nanoparticles in situ with high concentrations, providing wide potential applications in different fields, including nanomedicine, coatings, nanomanufacture, and Pickering emulsions. Polymeric emulsifiers synthesized by PISA have many advantages comparing with conventional nanoparticle emulsifiers. The morphologies, size, and amphiphilicity can be readily regulated via the synthetic process, post-modification, and external stimuli. By introducing stimulus responsiveness into PISA nanoparticles, Pickering emulsions stabilized with these nanoparticles can be endowed with "smart" behaviors. The emulsions can be regulated in reversible emulsification and demulsification. In this review, the authors focus on recent progress on Pickering emulsions stabilized by PISA nanoparticles with stimuli-responsiveness. The factors affecting the stability of emulsions during emulsification and demulsification are discussed in details. Furthermore, some viewpoints for preparing stimuli-responsive emulsions and their applications in antibacterial agents, diphase reaction platforms, and multi-emulsions are discussed as well. Finally, the future developments and applications of stimuli-responsive Pickering emulsions stabilized by PISA nanoparticles are highlighted.

Microcin C7-laden modified gelatin based biocomposite hydrogel for the treatment of periodontitis.

Periodontitis is an oral disease with the highest incidence globally, and plaque control is the key to its treatment. In this study, Microcin C7 was used to treat periodontitis, and a novel injectable temperature-sensitive sustained-release hydrogel was synthesized as an environmentally sensitive carrier for drug delivery. First, modified gelatin was formed from gelatin and glycidyl methacrylate. Then, Microcin C7-laden hydrogel was formed from cross-linking with double bonds between modified gelatin, N-isopropyl acrylamide, and 2-Methacryloyloxyethyl phosphorylcholine through radical polymerization, and the model drug Microcin C7 was loaded by electrostatic adsorption. The hydrogel has good temperature sensitivity, self-healing, and injectable properties. In vitro results showed that the hydrogel could slowly and continuously release Microcin C7 with good biocompatibility and biodegradability, with a remarkable antibacterial effect on Porphyromonas gingivalis. It also confirmed the antibacterial and anti-inflammatory effects of Microcin C7-laden hydrogel in a periodontitis rat model. The results showed that Microcin C7-laden hydrogel is a promising candidate for local drug delivery systems in periodontitis.

Status of research on the resource utilization of stainless steel pickling sludge in China: a review.

The pickling sludge produced in the stainless steel pickling process is a hazardous waste and disposal in landfill poses a potential environmental risk. Stainless steel pickling sludge contains metal elements such as Fe, Cr, and Ni and substances such as SiO2 and CaO, which have good value for resource recycling. This paper briefly introduces the generation, nature, and hazards of stainless steel pickling sludge; and clustering analysis of relevant literature keywords in recent years; and detailed analysis and comparison of sludge obtained from different steel mills and resource utilization process. The current situation of pickling sludge resource utilization and the development of relevant policies in China in recent years are summarized, and new thoughts on the direction of its resource utilization are put forward.

Influence of sterilization conditions on sulfate-functionalized polyGGE.

Sulfated biomolecules are known to influence numerous biological processes in all living organisms. Particularly, they contribute to prevent and inhibit the hypercoagulation condition. The failure of polymeric implants and blood contacting devices is often related to hypercoagulation and microbial contamination. Here, bioactive sulfated biomacromolecules are mimicked by sulfation of poly(glycerol glycidyl ether) (polyGGE) films. Autoclaving, gamma-ray irradiation and ethylene oxide (EtO) gas sterilization techniques were applied to functionalized materials. The sulfate group density and hydrophilicity of sulfated polymers were decreased while chain mobility and thermal degradation were enhanced post autoclaving when compared to those after EtO sterilization. These results suggest that a quality control after sterilization is mandatory to ensure the amount and functionality of functionalized groups are retained.

Defeating antibiotic-resistant bacteria with protein-resistant polyGGE film.

Biofouling on medical device surfaces, which is initiated by protein adsorption and adhesion of microbes especially the antibiotic-resistant bacteria, attracts global attention for centuries due to its enduring challenges in healthcare. Here, the antifouling effect of hydrophilic poly(glycerol glycidyl ether) (polyGGE) film is explored in comparison to hemocompatible and protein-resistant control polymers. The chemical and thermomechanical stability of polyGGE in hydrated conditions at body temperature was achieved via adjusting UV curing and KOH quenching time. The polyGGE surface is inert to the plasma protein adsorption and interfered the metabolism conditions, biofilm formation and growth of both Gram negative (Gram-) and antibiotic-resistant Gram positive (Gram+) bacteria. These results indicate the potential application of polyGGE for combating the risk of hospital-acquired infections and preventing drug-resistant superbug spreading.

A simple one-step modification of various materials for introducing effective multi-functional groups.

Covalent immobilization of various biomolecules is a desired strategy for bio-multifunctional surface modification. Multi-functionalization of a material surface is considered to be the premise of immobilizing a variety of biomolecules. However, currently adopted methods, used to introduce proper reactive functional groups on material surfaces, mostly are hard to be carried out and frequently can only introduce insufficient functional groups. In this work, we successfully develop the films (GAHD films) prepared via the simple copolymerization of gallic acid (GA) and hexamethylenediamine (HD), which can be deposited on different kinds of material surfaces including metals, ceramics and polymers by a one-step dip-coating method. Moreover, these copolymerized GAHD films possess high concentration of multi-functional groups like carboxyl (COOH), primary amine (-NH2) and quinone groups on the surfaces. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) results prove either the occurrence of Michael addition reaction, Schiff base reaction in the film-forming process, or the existence of COOH, NH2 and quinone groups on the surfaces. The maximum contents of carboxyl and amine on the GAHD film are 24.9 nmol/cm(2) and 31.7 nmol/cm(2) respectively. After dynamical immersion for 30 days, slight swellings can be observed, which reveals that the GAHD films possess good stability. Moreover, Heparin (Hep), fibronectin (Fn) and laminin (Ln) are successfully immobilized on the GAHD film surfaces. The results of cell counting kit-8 (CCK-8) and rhodamine fluorescence photograph indicate that the 1:1.62 GAHD film has good cytocompatibility.

Construction and hemocompatibility study of highly bioactive heparin-functionalized surface.

A simple method is developed to construct anticoagulant surfaces via passive adsorption of heparin onto the protonated plasma-polymerized allylamine (PPAam) films from phosphate-buffered saline (PBS). These protonated PPAam surfaces are found to have high affinity to heparin. Importantly, the heparin-functionalized PPAam (Hep-PPAam) surfaces show good retention of heparin after long-term immersion in PBS. The Hep-PPAam surface prolongs the activated partial thromboplastin time for about 20 s as compared to 316L stainless steel even though the adsorption amount of heparin is only about 300 ng/cm(2). This indicates that the heparin bound to the protonated PPAam surfaces in this way maintains a high bioactivity. Blood platelet adhesion and activation on this surface is remarkably reduced and adsorption and activation of fibrinogen is inhibited. Thus, Hep-PPAam surface modification leads to a significant improve of the hemocompatibility.

Direct thrombin inhibitor-bivalirudin functionalized plasma polymerized allylamine coating for improved biocompatibility of vascular devices.

The direct thrombin inhibitor of bivalirudin (BVLD), a short peptide derived from hirudin, has drawn an increasing attention in clinical application because it is safer and more effective than heparin for diabetic patients with moderate- or high-risk for acute coronary syndromes (ACS). In this study, BVLD was covalently conjugated on plasma polymerized allylamine (PPAam) coated 316L stainless steel (SS) to develop an anticoagulant surface. QCM-D real time monitoring result shows that 565±20 ng/cm2 of BVLD was bound to the PPAam surface. Infrared spectroscopy (IR) and X-ray photoelectron spectroscopy (XPS) confirmed the immobilization of BVLD. The conjugation of BVLD onto the PPAam coating led to enhanced binding of thrombin, and the activity of the thrombin adsorbed on its surface was effectively inhibited. As a result, the BVLD immobilized PPAam (BVLD-PPAam) substrate prolonged the clotting times, and exhibited inhibition in adhesion and activation of platelets and fibrinogen. We also found that the BVLD-PPAam coating significantly enhanced endothelial cell adhesion, proliferation, migration and release of nitric oxide (NO) and secretion of prostaglandin I2 (PGI2). In vivo results indicate that the BVLD-PPAam surface restrained thrombus formation by rapidly growing a homogeneous and intact endothelium on its surface. These data suggest the potential of this multifunctional BVLD-PPAam coating for the application not only in general vascular devices such as catheters, tubes, oxygenator, hemodialysis membranes but also vascular grafts and stents.

The effect of coimmobilizing heparin and fibronectin on titanium on hemocompatibility and endothelialization.

Currently available cardiovascular implants, such as heart valves and stents, exhibit suboptimal biocompatibility because of the incomplete endothelialization and sequential thrombosis formation especially after a long-term implantation. To improve the blood compatibility and endothelialization simultaneously and ensure the long-term effect of the cardiovascular implants, a technique of combining electrostatic interaction and coimmobilization was developed to form heparin and fibronectin (Hep/Fn) films on aminosilanized titanium (Ti) surfaces. The Hep/Fn coimmobilized films were stable after immersion in PBS for five days, probed by wettability studies and by the release kinetics of heparin and fibronectin. Blood compatibility tests showed that the coimmobilized Hep/Fn films displayed lower hemolysis rate, prolonged blood coagulation time, higher AT III binding density, less platelets activation and aggregation, and less fibrinogen conformational change compared with Ti surface. Endothelial cells (ECs) seeding and fibronectin bioactivity results showed more attached and proliferated ECs and exposed cell-binding sites on the Hep/Fn immobilized samples than that on Ti surfaces. Thus, the Hep/Fn coimmobilized films kept excellent bioactivity even after immersion in PBS for five days. Systemic evaluation suggests that the coimmobilization of Hep/Fn complex improves the blood compatibility and promotes the endothelialization simultaneously. We envisage that this method will provide a potential and effective selection for biomaterials surface modification of cardiovascular implants.