Design of highly stabilized nanocomposite inks based on biodegradable polymer-matrix and gold nanoparticles for Inkjet Printing

Nowadays there is a worldwide growing interest in the Inkjet Printing technology owing to its potentially high levels of geometrical complexity, personalization and resolution. There is also social concern about usage, disposal and accumulation of plastic materials. In this work, it is shown that sugar-based biodegradable polyurethane polymers exhibit outstanding properties as polymer-matrix for gold nanoparticles composites. These materials could reach exceptional stabilization levels, and demonstrated potential as novel robust inks for Inkjet based Printing. Furthermore, a physical comparison among different polymers is discussed based on stability and printability experiments to search for the best ink candidate. The University of Seville logo was printed by employing those inks, and the presence of gold was confirmed by ToF-SIMS. This approach has the potential to open new routes and applications for fabrication of enhanced biomedical nanometallic-sensors using stabilized AuNP.Spanish Ministerio de Economía y Competitividad MINECO, (Grants Nos. CTQ2016- 78703-P and MAT2016-78703-P)Junta de Andalucía (Consolidation Grant for Research Group FQM135 and 2017/FQM-386, P-2018/809)University of Seville (V y VI Plan Propio PP2016-5937

Porous titanium substrates coated with a bilayer of bioactive glasses

Porous titanium substrates coated by dripping-sedimentation technique with a novel bilayer of (45S5 / 1393) bioactive glasses are proposed to overcome some limitations of the use of titanium for implants, such as the stress shielding and the poor osseointegration. Composition, thickness, roughness and micromechanical behavior (P-h curves) of the coating and the influence of the porous titanium substrates have been characterized. Best results were found for the substrate with 30 vol.% of porosity and a range size of 355 ‒ 500 μm, since it enhanced the mechanical and biofunctional behavior, due to the good adhesion of the 1393 bioglass to the substrate and the greater bioactivity of the 45S5 bioglass, which would be in contact with the bone.Junta de Andalucía–FEDER (Spain) US-1259771M.E.C. (Spain) 2004/00001203 (RYC-2004-001497

Biofunctional and Tribo-mechanical Behavior of Porous Titanium Substrates Coated with a Bioactive Glass Bilayer (45S5 ‒ 1393)

Porous substrates of commercially pure titanium have been coated with a novel bilayer of bioactive glasses, 45S5 and 1393, to improve the osseointegration and solve the stress-shielding phenomenon of titanium partial implants. The porosity of the substrates, the scratch resistance and bioactivity of the coating have been evaluated. Results are discussed in terms of stiffness and yield strength of the substrates, as well as the chemical composition, thickness and design of the bioglass coating (monolithic vs. bilayer). The role of the pores was a crucial issue in the anchoring of the coating, both in porosity percentage (30 and 60 vol. %) and pore range size (100 – 200 and 355 ‒ 500 μm). The study was focused on the adhesion and infiltration of a 1393 bioglass layer (in contact with a porous titanium substrate), in combination with the biofunctionality of the 45S5 bioglass layer (surrounded by the host bone tissue), as 1393 bioglass enhances the adherence, while 45S5 bioglass promotes higher bioactivity. This bioactivity of the raw powder was initially estimated by nuclear magnetic resonance, through the evaluation of the chemical environments, and confirmed by the formation of hydroxyapatite, when immersed in simulated body fluid. Results revealed that the substrate with 30 vol. % of porosity and a range of 355 ‒ 500 μm pore size, coated with this novel bioactive glass bilayer, presented the best combination in terms of mechanical and biofunctional properties.Junta de Andalucía–FEDER (Spain) Project Ref. US-1259771Ministerio de Ciencia y Educación (Spain) Project 2004/00001203 (RYC-2004-001497

Latest Trends in Surface Modification for Dental Implantology: Innovative Developments and Analytical Applications

An increase in the world population and its life expectancy, as well as the ongoing concern about our physical appearance, have elevated the relevance of dental implantology in recent decades. Engineering strategies to improve the survival rate of dental implants have been widely investigated, focusing on implant material composition, geometry (usually guided to reduce stiffness), and interface surrounding tissues. Although efforts to develop different implant surface modifications are being applied in commercial dental prostheses today, the inclusion of surface coatings has gained special interest, as they can be tailored to efficiently enhance osseointegration, as well as to reduce bacterial-related infection, minimizing peri-implantitis appearance and its associated risks. The use of biomaterials to replace teeth has highlighted the need for the development of reliable analytical methods to assess the therapeutic benefits of implants. This literature review considers the state-of-the-art strategies for surface modification or coating and analytical methodologies for increasing the survival rate for teeth restoration.Ministerio de Ciencia e Innovación PID2019-109371GB-I00Junta de Andalucía PAIDI 2020, P20_00671Universidad de Sevilla US-1380878, PPI505/2020, PPI532/202

Ink-jet 3D printing as a strategy for developing bespoke non-eluting biofilm resistant medical devices

Chronic infection as a result of bacterial biofilm formation on implanted medical devices is a major global healthcare problem requiring new biocompatible, biofilm-resistant materials. Here we demonstrate how bespoke devices can be manufactured through ink-jet-based 3D printing using bacterial biofilm inhibiting formulations without the need for eluting antibiotics or coatings. Candidate monomers were formulated and their processability and reliability demonstrated. Formulations for in vivo evaluation of the 3D printed structures were selected on the basis of their in vitro bacterial biofilm inhibitory properties and lack of mammalian cell cytotoxicity. In vivo in a mouse implant infection model, Pseudomonas aeruginosa biofilm formation on poly-TCDMDA was reduced by ∼99% when compared with medical grade silicone. Whole mouse bioluminescence imaging and tissue immunohistochemistry revealed the ability of the printed device to modulate host immune responses as well as preventing biofilm formation on the device and infection of the surrounding tissues. Since 3D printing can be used to manufacture devices for both prototyping and clinical use, the versatility of ink-jet based 3D-printing to create personalised functional medical devices is demonstrated by the biofilm resistance of both a finger joint prosthetic and a prostatic stent printed in poly-TCDMDA towards P. aeruginosa and Staphylococcus aureus.Engineering and Physical Sciences Research Council del Reino Unido-EP/I033335/2, EP/N024818/1, EP/P031684/1 y EP/L015072/1Wellcome Trust Senior Investigator Joint Awards del Reino Unido-103882/Z/14/Z y 103884/Z/14/

Fabrication and Characterization of Bioactive Gelatin–Alginate–Bioactive Glass Composite Coatings on Porous Titanium Substrates

In this research work, the fabrication of biphasic composite implants has been investigated. Porous, commercially available pure Ti (50 vol % porosity and pore distributions of 100–200, 250–355, and 355–500 μm) has been used as a cortical bone replacement, while different composites based on a polymer blend (gelatin and alginate) and bioactive glass (BG) 45S5 have been applied as a soft layer for cartilage tissues. The microstructure, degradation rates, biofunctionality, and wear behavior of the different composites were analyzed to find the best possible coating. Experiments demonstrated the best micromechanical balance for the substrate containing 200–355 μm size range distribution. In addition, although the coating prepared from alginate presented a lower mass loss, the composite containing 50% alginate and 50% gelatin showed a higher elastic recovery, which entails that this type of coating could replicate the functions of the soft tissue in areas of the joints. Therefore, results revealed that the combinations of porous commercially pure Ti and composites prepared from alginate/gelatin/45S5 BG are candidates for the fabrication of biphasic implants not only for the treatment of osteochondral defects but also potentially for any other diseases affecting simultaneously hard and soft tissues

Development of porous silver nanoparticle/polycaprolactone/polyvinyl alcohol coatings for prophylaxis in titanium interconnected samples for dental implants

Stress shielding phenomenon, poor osseointegration, or bacterial infections of titanium dental implants are widely recognized as key problems that deeply affect their survival rate. In this work, a joint solution to solve these three limitations is proposed. The first two issues were minimized applying porous Ti samples. This substrate exhibits an appropriated biomechanical equilibrium (stiffness and mechanical resistance) and good biofunctionality (ability to promote bone ingrowth). On the other hand, the porous Ti disc was coated with biocompatible and non-toxic polymeric composites matrices using poly-ε-caprolactone and partially acetylated polyvinyl alcohol, combined with silver nanoparticles as a therapeutic antimicrobial agent. The optimization of the best blend composition and optimal nanoparticles concentration were investigated. Finally, the two composites with the best antimicrobial activity were infiltrated into porous Ti discs. The deposited coatings presented good adhesion and a honeycomb-like surface structure that could promote vascularization of the implant and enhance osseointegration.Ministerio de Ciencia e Innovación PID2019-109371GB-I00Junta de Andalucía PAIDI 2020, P20_00671Universidad de Sevilla US-138087, PPI505/2020, PPI532/202

Bioactive Bilayer Glass Coating on Porous Titanium Substrates with Enhanced Biofunctional and Tribomechanical Behavior

The use of porous titanium samples fabricated by space-holder powder metallurgy with bioactive coatings has already been reported to prevent resorption of the bone surrounding the implant and improve osseointegration, respectively. However, the presence of pores as well as the poor adherence and the brittle behavior inherent to glassy coatings affect the service behavior of implants fabricated from these samples. Therefore, they need to be optimized. In this work, 50 vol.% of porosity titanium substrates were manufactured with different pore range size (100–200 and 355–500 µm) spacer particles and coated with a bilayer of bioactive glasses (45S5/1393). The effect of the pores on the tribomechanical properties and infiltration of the bioactive glass 1393 along with the bioactivity of the bioactive glass 45S5 were evaluated by instrumented micro-indentation and scratch tests and the formation of hydroxyapatite in simulated body fluid. The results obtained were very promising as potential implants for the replacement of small tumors in cortical bone tissues, mainly due to the smaller pores that present an improved biomechanical and biofunctional balance.Ministry of Science and Innovation of Spain grant PID2019-109371GB-I00Junta de Andalucía-FEDER (Spain) Project US-1259771Junta de Andalucía-FEDER (Spain) Project US-1380878Junta de Andalucía (Spain) Project PAIDI 2020 P20_0067

Development of porous silver nanoparticle/polycaprolactone/polyvinyl alcohol coatings for prophylaxis in titanium interconnected samples for dental implants

Stress shielding phenomenon, poor osseointegration, or bacterial infections of titanium dental implants are widely recognized as key problems that deeply affect their survival rate. In this work, a joint solution to solve these three limitations is proposed. The first two issues were minimized applying porous Ti samples. This substrate exhibits an appropriated biomechanical equilibrium (stiffness and mechanical resistance) and good biofunctionality (ability to promote bone ingrowth). On the other hand, the porous Ti disc was coated with biocompatible and non-toxic polymeric composites matrices using poly-ε-caprolactone and partially acetylated polyvinyl alcohol, combined with silver nanoparticles as a therapeutic antimicrobial agent. The optimization of the best blend composition and optimal nanoparticles concentration were investigated. Finally, the two composites with the best antimicrobial activity were infiltrated into porous Ti discs. The deposited coatings presented good adhesion and a honeycomb-like surface structure that could promote vascularization of the implant and enhance osseointegration.Ministry of Science and Innovation of Spain grant PID2019-109371GB-I00Junta de Andalucía (Spain) PAIDI P20_00671FEDER Andalucía US-1380878Universidad de Sevilla, Spain PPI505/2020Universidad de Sevilla, Spain PPI532/202