Synthesis of multifunctional chlorhexidine-doped thin films for titanium-based implant materials

Abstract

Our goal was to create bio-functional chlorhexidine (CHX)-doped thin films on commercially pure titanium (cpTi) discs using the glow discharge plasma approach. Different plasma deposition times (50, 35 and 20 min) were used to create bio-functional surfaces based on silicon films with CHX that were compared to the control groups [no CHX and bulk cpTi surface (machined)]. Physico-chemical and biological characterizations included: 1. Morphology, roughness, elemental chemical composition, film thickness, contact angle and surface free energy; 2. CHX-release rate; 3. Antibacterial effect on Streptococcus sanguinis biofilms at 24, 48 and 72 h; 4. Cytotoxicity and metabolic activity using fibroblasts cell culture (NIH-F3T3 cells) at 1, 2, 3 and 4 days; 5. Protein expression by NIH-F3T3 cells at 1, 2, 3 and 4 days; and 6. Co-culture assay of fibroblasts cells and S. sanguinis to assess live and dead cells on the confocal laser scanning microscopy, mitochondrial activity (XTT), membrane leakage (LDH release), and metabolic activity (WST-1 assay) at 1, 2 and 3 days of co-incubation. Data analysis showed that silicon films, with or without CHX coated cpTi discs, increased surface wettability and free energy (p<0.05) without affecting surface roughness. CHX release was maintained over a 22-day period and resulted in a significant inhibition of biofilm growth (p<0.05) at 48 and 72 h of biofilm formation for 50 min and 20 min of plasma deposition time groups, respectively. In general, CHX treatment did not significantly affect NIH-F3T3 cell viability (p>0.05), whereas cell metabolism (MTT assay) was affected by CHX, with the 35 min of plasma deposition time group displaying the lowest values as compared to bulk cpTi (p<0.05). Moreover, data analysis showed that films, with or without CHX, significantly affected the expression profile of inflammatory cytokines, including IL-4, IL-6, IL-17, IFN-y and TNF-α by NIH-F3T3 cells (p<0.05). Co-culture demonstrated that CHX-doped film did not affect the metabolic activity, cytotoxicity and viability of fibroblasts cells (p>0.05). Altogether, the findings of the current study support the conclusion that silicon films added with CHX can be successfully created on titanium discs and have the potential to affect bacterial growth and inflammatory markers without affecting cell viability/proliferation rates.

Antimicrobial behavior of titanium coating with chlorhexidine-doped thin film exposed to a biofilm supplemented with nicotine

“…Despite being the gold standard oral antibacterial agent in the treatment and prevention of a wide range of bacteria, CHX is unfortunately known to have negative side effects, such as low levels of toxicity to cells in the oral cavity. In contrast to the machined control group, the group with CHX on the titanium surface displayed increased surface free energy and had lower levels of IL-6, according to our previous study 26) . In order to reduce IL-6 expression, the surface wettability is crucial 55) .…”

“…For film deposition, a custom-made steel reactor (Technological Plasma Laboratory, Sao Paulo State University, Brazil) was used, following our previously published protocol 26) . Two different thin films were developed in an atmosphere containing 85% of HMDSO, and 15% of argon; for the HMDSO+CHX group, 0.8 g of chlorhexidine diacetate salt hydrate (Sigma Aldrich, St. Louis, MO, USA) powdered was placed in the reactor.…”

“…Our previous study developed a multifunctional CHX-doped thin film onto cpTi using the GDP. Reduced Streptococcus sanguinis bacterial growth, modulation of inflammatory makers, and biocompatibility were noted 26) . However, whether this surface would overcome the upregulation of nicotine on a pathogenic anaerobicgrown biofilm remains unknown and was the objective of this current study.…”

Análise físico-química da superfície de titânio após tratamento químico de descontaminação com clorexidina: estudo in vitro

“…Analisando os dados da EDS para os teores percentuais de Ti nas amostras tratadas com CLX, observa-se uma redução significativa do nível percentual de Ti na superfície e, ao mesmo passo, existe um aumento dos níveis percentuais de O. Comparando este fato com a análise microbiológica proposta em trabalhos prévios 23 , nos quais CLX gel 2% apresenta ausência de unidades formadoras de colônia, esta superfície com alto grau de O pode ter configurado uma resposta química, que facilitou a descontaminação da superfície. Devido à característica da técnica de EDS, que é apenas de análise de elementos químicos, não é possível afirmar que foi gerada uma fase cristalina de óxido de titânio (TiO 2 ) após a aplicação do agente descontaminante.…”

Biofilms: Formation, Research Models, Potential Targets, and Methods for Prevention and Treatment

“…In their continuous study, Matos et al used the glow discharge plasma method to deposit CHX-doped thin films on pure titanium (cpTi). [221] CHX release was sustained for more than 22 days, leading to a significant suppression of biofilm formation at 48 and 72 h for 50 and 20 min of plasma deposition, respectively.…”