Effect of radiofrequency glow discharge on proliferation and osteogenic behavior of normal human osteoblasts

BACKGROUND: Implants have been widely used in the medical field. It was adopted in dentistry, offering patients replacement of missing teeth. Researchers have been investigating techniques to improve implants’ survival. Among these techniques is plasma glow discharge. Radio-frequency Glow discharge (RGD) is a surface treatment and sterilization technique with the aim to improve the titanium oxide layer for better osseointegration. Previous studies have evaluated its effect on non-human cell lines with promising results. Up to date, there is no report on how RGD surface treatment of titanium affects normal human osteoblasts. MATERIAL AND METHODS: Human bone fragments were obtained from dental extraction sites and were processed to culture normal human osteoblasts. Cells were seeded on three different surfaces at a concentration of 1x105 cells per plate; Titanium discs with and without Argon RGD (ARGD), and tissue culture plates (TCP). Dishes were allocated to 3 timelines: 16 hours, 7 days and 14 days. The outcome measures were cell attachment, cell number, alkaline phosphatase and osteocalcin levels. RESULTS: Data was analyzed using a one-way ANOVA test. Mean cell proliferation percentage for the ARGD group at 7 days was the highest (167.966%). The difference in means among the three groups at 7 days was statistically significant (p=0.0022). At 14 days, the highest mean of cell proliferation percentage was highest for the ARGD group. When testing all pairs, at 7 days the differences in means were statistically significant between (ARGD vs. no ARGD, and ARGD vs. TCP) (p=0.0018, and p=0.0286), respectively. At 14 days, the differences in means were statistically significant between (ARGD vs. TCP, p= 0.0003) and (no ARGD vs. TCP, p=0.0007). There was a significant difference in means for alkaline phosphatase and osteocalcin at 7 and 14 days between TCP and ARGD, and TCP and no ARGD groups (p < 0.05). CONCLUSIONS: The results of this study on normal human osteoblasts indicated that ARGD significantly enhanced cell proliferation. There was no significant difference in osteogenic behavior between with and without ARGD treatment on titanium surfaces within the time studied. A prolonged phase of cell proliferation was observed in ARGD treated groups

Modulation of release kinetics by plasma polymerization of ampicillin-loaded ß-TCP ceramics

Beta-tricalcium phosphate (ß-TCP) bioceramics are employed in bone repair surgery. Their local implantation in bone defects puts them in the limelight as potential materials for local drug delivery. However, obtaining suitable release patterns fitting the required therapeutics is a challenge. Here, plasma polymerization of ampicillin-loaded ß-TCP is studied for the design of a novel antibiotic delivery system. Polyethylene glycol-like (PEG-like) coating of ß-TCP by low pressure plasma polymerization was performed using diglyme as precursor, and nanometric PEG-like layers were obtained by simple and double plasma polymerization processes. A significant increase in hydrophobicity, and the presence of plasma polymer was visible on the surface by SEM and quantified by XPS. As a main consequence of the plasma polymerisation, the release kinetics were successfully modified, avoiding burst release, and slowing down the initial rate of release leading to a 4.5¿h delay in reaching the same antibiotic release percentage, whilst conservation of the activity of the antibiotic was simultaneously maintained. Thus, plasma polymerisation on the surface of bioceramics may be a good strategy to design controlled drug delivery matrices for local bone therapiesPeer ReviewedPostprint (author's final draft

Nonthermal Plasma Technology as a Versatile Strategy for Polymeric Biomaterials Surface Modification: A Review

In modern technology, there is a constant need to solve very complex problems and to fine-tune existing solutions. This is definitely the case in modern medicine with emerging fields such as regenerative medicine and tissue engineering. The problems, which are studied in these fields, set very high demands on the applied materials. In most cases, it is impossible to find a single material that meets all demands such as biocompatibility, mechanical strength, biodegradability (if required), and promotion of cell-adhesion, proliferation, and differentiation. A common strategy to circumvent this problem is the application of composite materials, which combine the properties of the different constituents. Another possible strategy is to selectively modify the surface of a material using different modification techniques. In the past decade, the use of nonthermal plasmas for selective surface modification has been a rapidly growing research field. This will be the highlight of this review. In a first part of this paper, a general introduction in the field of surface engineering will be given. Thereafter, we will focus on plasma-based strategies for surface modification. The purpose of the present review is twofold. First, we wish to provide a tutorial-type review that allows a fast introduction for researchers into the field. Second, we aim to give a comprehensive overview of recent work on surface modification of polymeric biomaterials, with a focus on plasma-based strategies. Some recent trends will be exemplified. On the basis of this literature study, we will conclude with some future trends for research

Surface oxide net charge of a titanium alloy Comparison between effects of treatment with heat or radiofrequency plasma glow discharge

In the current study we have compared the effects of heat and radiofrequency plasma glow discharge (RFGD) treatment of a Ti6Al4V alloy on the physico chemical properties of the alloys surface oxide Titanium alloy (Ti6Al4V) disks were passivated alone heated to 600 C or RFGD plasma treated in pure oxygen RFGD treatment did not alter the roughness topography elemental composition or thickness of the alloys surface oxide layer In contrast heat treatment altered oxide topography by creating a pattern of oxide elevations approximately 50-100 nm in diameter These nanostructures exhibited a three fold increase in roughness compared to untreated surfaces when RMS roughness was calculated after applying a spatial high-pass filter with a 200 nm cutoff wavelength Heat treatment also produced a surface enrichment in aluminum and vanadium oxides Both RFGD and heat treatment produced similar increases in oxide wettability Atomic force microscopy (AFM) measurements of metal surface oxide net charge signified by a long-range force of attraction to or repulsion from a (negatively charged) silicon nitride AFM probe were also obtained for all three experimental groups Force measurements showed that the RFGD treated Ti6Al4V samples demonstrated a higher net positive surface charge at pH values below 6 and a higher net negative surface charge at physiological pH (pH values between 7 and 8) compared to control and heat treated samples These findings suggest that RFGD treatment of metallic implant materials can be used to study the role of negatively charged surface oxide functional groups in protein bioactivity osteogenic cell behavior and osseointegration independently of oxide topography Published by Elsevier B

Production of biofunctional titanium surface using plasma electrolytic oxidation and glow discharge plasma for biomedical applications

Orientador: Valentim Adelino Ricardo BarãoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Este estudo avaliou o papel dos tratamentos com plasma de oxidação eletrolítica (PEO) e plasma por descarga incandescente (PDI) quanto (i) ao comportamento eletroquímico, (ii) propriedades físicas, químicas e mecânicas e (iii) adsorção de proteínas pelo titânio comercialmente puro (Ticp). Discos de Ticp (15 mm × 2 mm) foram separados em 4 grupos (n=5) em função do tipo de tratamento de superfície. Superfícies polida e jateada com óxido de alumínio (Al2O3) foram consideradas controles. Para o ensaio eletroquímico, testes padrões foram conduzidos em saliva artificial (pHs 3,0; 6,5 e 9,0) para simular o ambiente bucal e solução de fluido corpóreo (pH 7,4) para simular o plasma sanguíneo. Testes de caracterização foram realizados, antes e após o ensaio eletroquímico, através da Microscopia Eletrônica de Varredura (MEV), Espectroscopia de Energia Dispersiva (EDS), Microscopia de Força Atômica (AFM), Espectroscopia Fotoeletrônica de Raios-X (XPS), Difratografia de Raios-X (XRD), Perfilometria, Microdureza Vickers e Energia de Superfície. A adsorção de albumina, fibronectina e fibrinogênio foi mensurada através do método do ácido bicinconínico. Os dados foram avaliados por meio da análise de variância e pelo teste Bonferroni (?=0,05). Os tratamentos com plasma mostraram melhor comportamento eletroquímico quando comparados aos controles por exibirem maiores valores de resistência à polarização (Rp) e menores valores de capacitância (Q) (p 0,05). Após o processo corrosivo, a energia de superfície do PDI reduziu-se significativamente (p .05). After the corrosion process, GDP energy surface significantly reduced (p <.05). Greater albumin adsorption was observed for PEO and sandblasting surfaces (p <.05). PEO, sandblasting and GDP groups showed greater fibronectin adsorption (p <.05). PEO group showed the highest values for fibrinogen adsorption (p <.05). Based on the results, plasma treated samples were able to improve the electrochemical behavior of cpTi when compared to machined and sandblasting surfaces. Acidic saliva reduced the corrosion resistance of cpTi. The presence of Ca, P and Si ions positively affected the protein adsorption results. Plasma is a promising technique to treat biomedical implantsMestradoProtese DentalMestra em Clínica Odontológica653/13Funcam

Plasma-Enhanced Vapor Deposition Process for the Modification of Textile Materials

Nowadays many techniques are used for the surface modification of fabrics and textiles. Two fundamental techniques based on vacuum deposition are known as chemical vapor deposition (CVD) and physical vapor deposition (PVD). In this chapter, the effect of plasma-enhanced physical and chemical vapor deposition on textile surfaces is investigated and explained