Non-thermal plasma reduces periodontitis-induced alveolar bone loss in rats.

Periodontitis, a chronic infectious disease induced by microbial biofilm, is one of the most common diseases worldwide. Scaling and root planning (SRP) has always been recognized as the typical treatment. However, the therapeutic efficiency is often limited due to the intraoperative bleeding and the limitations of instruments. Non-thermal atmospheric plasma (NTP) appears to be a potential tool for periodontitis due to its promising biofilm degradation and decontamination effects. In this study, we investigated the role of NTP, as an adjuvant approach for the treatment of ligature-induced periodontitis in rats. Herein we showed that SRP or SRP-NTP application attenuated the periodontitis-induced alveolar bone loss, reflected by the increased BV/TV value and the decreased CEJ-AB distance, which might be related to the lower detection rate of periodontal pathogen in SRP and SRP-NTP groups. Besides, SRP-NTP rats showed less bone loss and lower CEJ-AB distance than that of SRP group at 30d post treatment, indicating a more comprehensive and long-lasting effect of SRP-NTP. A remarkable decrease of osteoclast number and lower expression of RANKL was also detected in SRP-NTP rats. In addition, expression of inflammatory-related cytokines such as TNF-α and IL-1ß decreased significantly in SRP-NTP group, while IL-10 level increased substantially. These results together illustrated that a combination of SRP and NTP treatment was an effective way to prevent periodontitis progress, which reduced alveolar bone loss and promoted periodontium restoration in ligature-induced periodontitis rats. In conclusion, non-thermal plasma treatment may be considered as a feasible and effective supplementary approach to control periodontitis.

Evaluation of plasma treatment effects on improving adhesive-dentin bonding by using the same tooth controls and varying cross-sectional surface areas.

The objective of this study was to evaluate and verify the effectiveness of plasma treatment for improving adhesive-dentin interfacial bonding by performing microtensile bond-strength (µTBS) testing using the same-tooth controls and varying cross-sectional surface areas. Extracted unerupted human third molars were used after removal of the crowns to expose the dentin surface. One half of each dentin surface was treated with a non-thermal argon plasma brush, whilst the other was shielded with glass slide and used as an untreated control. Adper Single Bond Plus adhesive and Filtek Z250 dental composite were then applied as directed. The teeth thus prepared were further cut into micro-bar specimens, with cross-sectional sizes of 1 × 1 mm², 1 × 2 mm², and 1 × 3 mm², for µTBS testing. The test results showed that plasma-treated specimens gave substantially stronger adhesive-dentin bonding than their corresponding same-tooth controls. Compared with their untreated controls, plasma treatment gave statistically significant higher bonding strength for specimens with a cross-sectional area of 1 × 1 mm² and 1 × 2 mm², with mean increases of 30.8% and 45.1%, respectively. Interface examination using optical and electron microscopy verified that plasma treatment improved the quality of the adhesive-dentin interface by reducing defects/voids and increasing the resin tag length in dentin tubules.

Plasma SiOx:H Nanocoatings to Enhance the Antibacterial and Anti-Inflammatory Properties of Biomaterials.

PURPOSE: To evaluate the antibacterial and anti-inflammatory properties of SiOx:H nanocoatings using a plasma-deposition technique. MATERIALS AND METHODS: Four groups of SiOx:H nanocoatings were prepared by plasma nanocoating technique using different deposition gases and durations, specifically trimethylsilane (TMS) for groups A1 and A2 and a mixture of TMS and oxygen for groups B1 and B2. Changes in surface chemistry and physical properties were measured. Staphylococcus aureus and Streptococcus mutans were cultured on plasma SiOx:H nanocoatings to evaluate antibacterial and antibiofilm formation activities. Human gingival fibroblasts (HGFs) and HaCaT human keratinocytes were cultured and stimulated with tumor necrosis factor-α (TNF-α). Cell viability was measured using a Cell Counting Kit-8 (CCK-8) assay. Quantitative real-time polymerase chain reaction (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA) were used to evaluate anti-inflammatory properties, including the mRNA and protein levels of inflammatory mediators and proinflammatory cytokines. RESULTS: The carbon content was dominant in group A nanocoatings and the oxygen and silicon elements were dominant in group B nanocoatings. Groups A2 and B2 were approximately threefold thicker than groups A1 and B1. The plasma SiOx:H nanocoatings decreased bacterial growth and biofilm formation by 30-70% (p < 0.05). Scanning electron microscopy (SEM) revealed damaged biofilm structures. Moreover, the antibacterial properties of group B were greater than group A, and the antibacterial properties of groups A2 and B2 were more effective than A1 and B1, respectively. CCK-8 assays revealed the plasma SiOx:H nanocoatings had good biocompatibility. Furthermore, under TNF-α-induced inflammation, the mRNA and protein levels of interleukin-6, interleukin-8, cyclooxygenase-2, and monocyte chemoattractant protein-1 were downregulated in the plasma SiOx:H nanocoating groups (p < 0.05). CONCLUSION: Plasma SiOx:H nanocoatings exerted antibacterial and anti-inflammatory effects with excellent biocompatibility. Therefore, the plasma SiOx:H nanocoating technique has potential for implant materials and other medical devices.

Synthesis and characterization of multifunctional poly(glycidyl methacrylate) microspheres and their use in cell separation.

Multifunctional poly(glycidyl methacrylate) (PGMA) microspheres containing magnetic, fluorescent, and cancer cell-specific moieties were prepared in four steps: (i) preparation of parent PGMA microspheres by dispersion polymerization and their reaction with ethylenediamine to obtain amino groups, (ii) precipitation of iron ions (Fe(2+) and Fe(3+)) to form Fe(3)O(4) nanoparticles within the microspheres, (iii) consecutive reactions of folic acid with the amino groups on PGMA, and (iv) incorporation of fluorescein isothiocyanate into the microspheres. The microspheres were superparamagnetic, highly monodispersive, intensively fluorescent, and capable of recognizing and binding cancer cells that overexpress folic acid receptors. It was demonstrated that with these microspheres, HeLa cells could be captured from their suspension and easily moved in the direction of the externally applied magnetic field.

An in vitro and in vivo study of plasma treatment effects on oral biofilms.

Management of dental plaque/biofilms is critical to maintain oral health. The objective of this study is to investigate the treatment effects of non-thermal atmospheric gas plasmas on oral biofilm formation and recovery under in vitro and in vivo conditions. Streptococcus mutans biofilms, a significant contributor to tooth decay, were cultured and treated by plasma. It was found that plasma treatment not only significantly reduced the in vitro biofilms, but also increased the metabolic activity of the bacteria in the biofilms. As compared with untreated control group, the cell metabolic activity, as measured by MTT assay, increased by 273%, and the aconitase activity increased by 446% for the plasma-treated group. The increased metabolic activity of the plasma-treated biofilm bacteria enhanced their susceptibility to antibiotic and host defense. An in vivo animal model using a total of 60 female rats (19 days old) were used to evaluate the anti-caries effects on the molars by 2 min of plasma treatment. It was found that, 6 months after the plasma treatment, the decayed surfaces were reduced by 62.5% on the upper molars and by 31.6% on the lower molars as compared with the untreated upper and lower molars, respectively. These in vitro and in vivo data demonstrate that the physiological state change of the biofilm due to plasma treatment provided benefit to caries control and prevention.

Repair effect of diabetic ulcers with recombinant human epidermal growth factor loaded by sustained-release microspheres.

In this study the w/o/w extraction-evaporation technique was adopted to prepare poly(lactic-co-glycolic acid) (PLGA) microspheres loading recombinant human epidermal growth factor (rhEGF). The microspheres were characterized for morphology by transmission electron microscopy (TEM) and particle size distribution. The release performances, the proliferation effects and therapeutic effects of rhEGF-loaded PLGA microspheres were all studied. The results showed that these spherical microspheres had a narrow size distribution and a high drug encapsulation efficiency (85.6%). RhEGF-loaded microspheres enhanced the growth rate of fibroblasts and wound healing more efficiently than pure rhEGF. The number of the proliferating cell nuclear antigen (PCNA) in the epidermis layer with the microsphere treatment was significantly larger than those of the control groups. Overall locally sustained delivery of rhEGF from biodegradable PLGA microspheres may serve as a novel therapeutic strategy for diabetic ulcer repair.

Incorporation of antibacterial agent derived deep eutectic solvent into an active dental composite.

OBJECTIVE: To incorporate an antibacterial agent derived deep eutectic solvent (DES) into a dental resin composite, and investigate the resulting mechanical properties and antibacterial effects. METHOD: The DES was derived from benzalkonium chloride (BC) and acrylic acid (AA) and was incorporated into the dental resin composite through rapid mixing. A three-point bending test was employed to measure the flexural strength of the composite. An agar diffusion test was used to investigate antibacterial activity. Artificial (accelerated) aging was undertaken by immersing the composites in buffer solutions at an elevated temperature for up to 4 weeks. UV-vis spectrophotometry and NMR analysis were conducted to study BC release from the composite. Finally, the biocompatibility of the composite materials was evaluated using osteoblast cell culture for 7 days. Results were compared to those of a control composite which contained no BC. RESULT: The DES-incorporated composite (DES-C) displayed higher flexural strength than a similar BC-incorporated composite BC (BC-C) for the same level of BC. The inclusion of BC conferred antibacterial activity to both BC-containing composites, although BC-C produced larger inhibition halos than DES-C at the same loading of BC. Control composites which contained no BC showed negligible antibacterial activity. After artificial aging, the DES-C composite showed better maintenance of the mechanical properties of the control compared with BC-C, although a decrease was observed during the three-point bending test, particularly upon storage at elevated temperatures. No BC release was detected in the aged solutions of DES-C, whereas the BC-C showed a linear increase in BC release with storage time. Significantly, cell viability results indicated that DES-C has better biocompatibility than BC-C. SIGNIFICANCE: The incorporation of a BC-based DES into a dental resin composite provides a new strategy to develop antibacterial dental materials with better biocompatibility and longer effective lifetimes without sacrificing the intrinsic mechanical properties of the composite structure.

Plasma treatment of dentin surfaces for improving self-etching adhesive/dentin interface bonding.

This study is to evaluate plasma treatment effects on dentin surfaces for improving self-etching adhesive and dentin interface bonding. Extracted unerupted human third molars were used after crown removal to expose dentin. One half of each dentin surface was treated with atmospheric non-thermal argon plasmas, while another half was untreated and used as the same tooth control. Self-etching adhesive and universal resin composite was applied to the dentin surfaces as directed. After restoration, the adhesive-dentin bonding strength was evaluated by micro-tensile bonding strength (µTBS) test. Bonding strength data was analyzed using histograms and Welch's t-test based on unequal variances. µTBS test results showed that, with plasma treatment, the average µTBS value increased to 69.7±11.5 MPa as compared with the 57.1±17.5 MPa obtained from the untreated controls. After 2 months immersion of the restored teeth in 37 °C phosphate buffered saline (PBS), the adhesive-dentin bonding strengths of the plasma-treated specimens slightly decreased from 69.7±11.5 MPa to 63.9±14.4 MPa, while the strengths of the untreated specimens reduced from 57.1±17.5 MPa to 48.9±14.6 MPa. Water contact angle measurement and scanning electron microscopy (SEM) examination verified that plasma treatment followed by water rewetting could partially open dentin tubules, which could enhance adhesive penetration to form thicker hybrid layer and longer resin tags and consequently improve the adhesive/dentin interface quality.

A Mechanistic study of Plasma Treatment Effects on Demineralized Dentin Surfaces for Improved Adhesive/Dentin Interface Bonding.

Our previous work has shown that non-thermal plasma treatment of demineralized dentin significantly (p<0.05) improved adhesive/dentin bonding strength for dental composite restoration as compared with the untreated controls. This study is to achieve mechanistic understanding of the plasma treatment effects on dentin surface through investigating the plasma treated dentin surfaces and their interaction with adhesive monomer, 2-Hydroxyethyl methacrylate (HEMA). The plasma treated dentin surfaces from human third molars were evaluated by water contact angle measurements and scanning electron microscopy (SEM). It was found that plasma-treated dentin surface with subsequent HEMA immersion (Plasma/HEMA Treated) had much lower water contact angle compared with only plasma-treated (Plasma Treated) or only HEMA immersed (HEMA Treated) dentin surfaces. With prolong water droplet deposition time, water droplets spread out completely on the Plasma/HEMA Treated dentin surfaces. SEM images of Plasma/HEMA Treated dentin surfaces verified that dentin tubules were opened-up and filled with HEMA monomers. Extracted type I collagen fibrils, which was used as simulation of the exposed dentinal collagen fibrils after acid etching step, were plasma treated and analyzed with Fourier transform infrared spectroscopy (FT-IR) and circular dichroism (CD) spectra. FT-IR spectra of the Plasma/HEMA Treated collage fibrils showed broadened amide I peak at 1660 cm-1 and amide II at 1550 cm-1, which indicate secondary structure changes of the collagen fibrils. CD spectra indicated that 67.4% collagen helix structures were denatured after plasma treatment. These experimental results demonstrate that non-thermal argon plasma treatment was very effective in loosing collagen structure and enhancing adhesive monomer penetration, which are beneficial to thicker hybrid layer and longer resin tag formation, and consequently enhance adhesive/dentin interface bonding.

Separation of oil from oily wastewater by sorption and coalescence technique using ethanol grafted polyacrylonitrile.

Polyacrylonitrile fiber (PANF) was modified by alcoholysis reaction and the efficiencies of the PANF and the modified polyacrylonitrile fiber (MPANF) for oil removal were investigated. Fourier transform infrared (FTIR) spectroscopy revealed that new organophilic functional groups were grafted on the fiber surface. Scanning electron microscopy (SEM) showed that the alcoholysis process made the surface of the MPANF rougher than that of the PANF. Oil sorption tests of the PANF and the MPANF for motor oil SAE 30, motor oil SAE 50, and multigrade engine oil (MEO) were carried out in batch tank (in water and in oil without water), and the MPANF showed higher oil sorption capacity compared to the PANF. Dynamic sorption of diesel oil-in-water emulsion (initial oil concentration of 630 mg/dm(3)) was investigated in coalescing bed. The experiments in the coalescing bed indicated that the MPANF could resist higher interstitial velocity, as compared to the PANF. More than 97% of oil content in the influent stream could be removed by the MPANF bed under the optimum condition. The results indicated that reuse of the PANF as oil sorbent was quite feasible.

A new lead-free radiation shielding material for radiotherapy.

Lead has recently been recognised as a source of environmental pollution, including the lead used for radiation shielding in radiotherapy. The bremsstrahlung radiation caused by the interaction between the electron beam and lead may reduce the accuracy of radiotherapy. To avoid the use of lead, a new material composed of tungsten and hydrogenated styrene-butadiene-styrene copolymer is studied with the Monte Carlo (MC) method and experiment in this paper. The component of the material is chosen after simulation with the MC method and the practical measurement is taken to validate the shielding ability of the material. The result shows that the shielding ability of the new material is good enough to fulfill the requirement for application in radiotherapy. Compared with lead alloy, the present new material is so flexible that can be easily customized into arbitrary shapes. Moreover, the material is environmentally friendly and can be recycled conveniently. Therefore, the material can be used as an effective lead substitute for shielding against electron beams in radiotherapy.