All-in-one trifunctional strategy: A cell adhesive, bacteriostatic and bactericidal coating for titanium implants

Strategies to inhibit initial bacterial adhesion are extremely important to prevent infection on biomaterial surfaces. However, the simultaneous attraction of desired eukaryotic cells remains a challenge for successful biomaterial-host tissue integration. Here we describe a method for the development of a trifunctional coating that repels contaminating bacteria, kills those that adhere, and promotes osteoblast adhesion. To this end, titanium surfaces were functionalized by electrodeposition of an antifouling polyethylene glycol (PEG) layer and subsequent binding of a peptidic platform with cell-adhesive and bactericidal properties. The physicochemical characterization of the samples via SEM, contact angle, FTIR and XPS analysis verified the successful binding of the PEG layer and the biomolecules, without altering the morphology and topography of the samples. PEG coatings inhibited protein adsorption and osteoblast-like (SaOS-2) attachment; however, the presence of cell adhesive domains rescued osteoblast adhesion, yielding higher values of cell attachment and spreading compared to controls (p < 0.05). Finally, the antibacterial potential of the coating was measured by live/dead assays and SEM using S. sanguinis as a model of early colonizer in oral biofilms. The presence of PEG layers significantly reduced bacterial attachment on the surfaces (p < 0.05). This antibacterial potential was further increased by the bactericidal peptide, yielding values of bacterial adhesion below 0.2% (p < 0.05). The balance between the risk of infection and the optimal osteointegration of a biomaterial is often described as “the race for the surface”, in which contaminating bacteria and host tissue cells compete to colonize the implant. In the present work, we have developed a multifunctional coating for a titanium surface that promotes the attachment and spreading of osteoblasts, while very efficiently inhibits bacterial colonization, thus holding promise for application in bone replacing applications.Peer ReviewedPostprint (author's final draft

Funcionalización de superficies anti-fouling sobre titanio para mejora de sus propiedades

Currently, implant and prosthetic infections are a serious problem, due to the increased use of these prostheses and the presence of bacteria multiresistant to antibiotics. These infections originate, in most cases, from planktonic bacteria. A possible strategy to avoid infections is to develop anti-fouling surfaces that prevent bacterial adhesion. Another strategy focuses on conferring bactericidal properties to the surfaces of the implants with the use of antimicrobial peptides. In both cases, it is necessary to maintain the excellent union to the tissues that titanium presents. The ideal surface for prostheses would combine antifouling, bactericidal and osseointegration properties, achieving an excellent synergic effect on the surfaces of the implants, improving their stability and functionality. To achieve this goal it is necessary to solve a critical point, which is to functionalize the anti-fouling layer with other biomolecules that can improve its properties. The objective of the present work is to deposit an anti-fouling layer on a metallic biomaterial, which can be further functionalized with other biomolecules. Titanium has been coated with functionalized polyethylene glycol (PEG) to which the Arg-Gly-Asp (RGD) peptide sequence has been attached. The treated titanium surfaces have shown an excellent combination of antifouling properties and good cellular response.Actualmente las infecciones de implantes y prótesis son un problema grave, debido al incremento de uso de dichas prótesis y a la cada vez mayor presencia de bacterias resistentes a los antibióticos. Estas infecciones tienen su origen, en la mayoría de casos, en bacterias planctónicas. Una posible estrategia para evitar las infecciones es desarrollar superficies anti-fouling que eviten la adhesión bacteriana. Otra estrategia se centra en conferir propiedades bactericidas a las superficies de los implantes en el uso de péptidos antimicrobianos. En ambos casos, es necesario mantener la excelente unión a los tejidos que presenta el titanio.La superficie ideal para prótesis combinaría los efectos anti-fouling, bactericida y osteointegrativo, logrando un excelente efecto sinérgico en las superficies de los implantes, mejorando su estabilidad y funcionalidad. Para conseguir este objetivo es necesario solventar un punto crítico, que es funcionalizar la capa anti-fouling con otras biomoléculas que permitan dotarla de las propiedades mencionadas.El objetivo del presente trabajo es depositar una capa anti-fouling sobre un biomaterial metálico con un grupo funcional que permita enlazar a la superficie tratada otras biomoléculas. Se ha conseguido depositar una capa de (poli)etilenglicol (PEG) funcionalizado sobre titanio, al cual se ha unido la secuencia tripeptídica Arg-Gly-Asp (RGD). Las superficies tratadas han mostrado una excelente combinación de propiedades anti-fouling y de buena respuesta celular

On the plasma deposition of vancomycin-containing nano-capsulesfor drug-delivery applications

Aerosol-assisted atmospheric pressure plasma allows for a one-step synthesis of vancomycin-containing nano-capsules. Morphological and chemical analyses are carried out to estimate how different discharge parameters affect the plasma deposition process. Nano-capsules size and abundance largely depend on the shell precursor content in the gas feed and on the drug concentration in the aerosol solution. Based on these results a deposition mechanism is proposed, where, interestingly, the key step is the formation of the nano-capsules in the plasma phase. Furthermore, the related antibacterial activity is proved against Staphylococcus aureus. Preliminary release tests indicate the possible exploitation of the plasma-deposited vancomycin-containing nano-capsules in the drug delivery field, and systems based on other bioactive molecules can be expected

All-in-one trifunctional strategy: A cell adhesive, bacteriostatic and bactericidal coating for titanium implants

Strategies to inhibit initial bacterial adhesion are extremely important to prevent infection on biomaterial surfaces. However, the simultaneous attraction of desired eukaryotic cells remains a challenge for successful biomaterial-host tissue integration. Here we describe a method for the development of a trifunctional coating that repels contaminating bacteria, kills those that adhere, and promotes osteoblast adhesion. To this end, titanium surfaces were functionalized by electrodeposition of an antifouling polyethylene glycol (PEG) layer and subsequent binding of a peptidic platform with cell-adhesive and bactericidal properties. The physicochemical characterization of the samples via SEM, contact angle, FTIR and XPS analysis verified the successful binding of the PEG layer and the biomolecules, without altering the morphology and topography of the samples. PEG coatings inhibited protein adsorption and osteoblast-like (SaOS-2) attachment; however, the presence of cell adhesive domains rescued osteoblast adhesion, yielding higher values of cell attachment and spreading compared to controls (p < 0.05). Finally, the antibacterial potential of the coating was measured by live/dead assays and SEM using S. sanguinis as a model of early colonizer in oral biofilms. The presence of PEG layers significantly reduced bacterial attachment on the surfaces (p < 0.05). This antibacterial potential was further increased by the bactericidal peptide, yielding values of bacterial adhesion below 0.2% (p < 0.05). The balance between the risk of infection and the optimal osteointegration of a biomaterial is often described as “the race for the surface”, in which contaminating bacteria and host tissue cells compete to colonize the implant. In the present work, we have developed a multifunctional coating for a titanium surface that promotes the attachment and spreading of osteoblasts, while very efficiently inhibits bacterial colonization, thus holding promise for application in bone replacing applications.Peer Reviewe