Bioactive Coatings on Titanium: A Review on Hydroxylation, Self-Assembled Monolayers (SAMs) and Surface Modification Strategies

Titanium (Ti) and its alloys have been demonstrated over the last decades to play an important role as inert materials in the field of orthopedic and dental implants. Nevertheless, with the widespread use of Ti, implant-associated rejection issues have arisen. To overcome these problems, antibacterial properties, fast and adequate osseointegration and long-term stability are essential features. Indeed, surface modification is currently presented as a versatile strategy for developing Ti coatings with all these challenging requirements and achieve a successful performance of the implant. Numerous approaches have been investigated to obtain stable and well-organized Ti coatings that promote the tailoring of surface chemical functionalization regardless of the geometry and shape of the implant. However, among all the approaches available in the literature to functionalize the Ti surface, a promising strategy is the combination of surface pre-activation treatments typically followed by the development of intermediate anchoring layers (self-assembled monolayers, SAMs) that serve as the supporting linkage of a final active layer. Therefore, this paper aims to review the latest approaches in the biomedical area to obtain bioactive coatings onto Ti surfaces with a special focus on (i) the most employed methods for Ti surface hydroxylation, (ii) SAMs-mediated active coatings development, and (iii) the latest advances in active agent immobilization and polymeric coatings for controlled release on Ti surfaces.This research was funding by Basque Government (ELKARTEK program, HAZITEK program–IMABI exp number ZE-2019/00012), Department of Development and Infrastructures of the Basque Country, University of the Basque Country UPV/EHU (GIU 207075), Ministry of Economy, Industry and Competitiveness (grant MAT2017-89553-P) and i+Med S. Coop

Ultrasound and Eco-Detergents for Sustainable Cleaning

Green chemistry faces a major challenge imposed by the Sustainable Development Goals (6, 14 and 15) defined in the 2030 Agenda. In the case of cleaning products (detergents), the challenges often become a paradox: even if it is biodegradable, no surfactant is harmless to aquatic life. Compared to other studies in the field, this paper covers ultrasound–detergent interactions beyond the cavitation removal process. It also considers synergistic effects with regard to the initial wetting phase and final rinsing. It concludes that the best detergent–ultrasound combination is that which minimises receding and critical sliding angles. At the same time, detergent concentration should be reduced so as to just to capture grease in micelles and avoid reattachment during rinsing. In combination with ultrasound, the concentration of eco-detergents can thus be reduced by up to 10% of their nominal value while attaining the same results.The projects leading to this research have received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreements No. 654479 WASCOP and No. 792103 SOLWARIS

Hydrogel-Core Microstructured Polymer Optical Fibers for Selective Fiber Enhanced Raman Spectroscopy

A new approach of Fiber Enhanced Raman Spectroscopy (FERS) is described within this article based on the use of Hydrogel-Core microstructured Polymer Optical Fibers (HyC-mPOF). The incorporation of the hydrogel only on the core of the Hollow-Core microstructured Polymer Optical Fiber (HC-mPOF) enables to perform FERS measurements in a functionalized matrix, enabling high selectivity Raman measurements. The hydrogel formation was continuously monitored and quantified using a Principal Component Analysis verifying the coherence between the components and the Raman spectrum of the hydrogel. The performed measurements with high and low affinity target molecules prove the feasibility of the presented HyC-mPOF platform

Hydrogel-Core Microstructured Polymer Optical Fibers for Selective Fiber Enhanced Raman Spectroscopy

A new approach of Fiber Enhanced Raman Spectroscopy (FERS) is described within this article based on the use of Hydrogel-Core microstructured Polymer Optical Fibers (HyC-mPOF). The incorporation of the hydrogel only on the core of the Hollow-Core microstructured Polymer Optical Fiber (HC-mPOF) enables to perform FERS measurements in a functionalized matrix, enabling high selectivity Raman measurements. The hydrogel formation was continuously monitored and quantified using a Principal Component Analysis verifying the coherence between the components and the Raman spectrum of the hydrogel. The performed measurements with high and low affinity target molecules prove the feasibility of the presented HyC-mPOF platform

Bioactive Coatings on Titanium: A Review on Hydroxylation, Self-Assembled Monolayers (SAMs) and Surface Modification Strategies

Titanium (Ti) and its alloys have been demonstrated over the last decades to play an important role as inert materials in the field of orthopedic and dental implants. Nevertheless, with the widespread use of Ti, implant-associated rejection issues have arisen. To overcome these problems, antibacterial properties, fast and adequate osseointegration and long-term stability are essential features. Indeed, surface modification is currently presented as a versatile strategy for developing Ti coatings with all these challenging requirements and achieve a successful performance of the implant. Numerous approaches have been investigated to obtain stable and well-organized Ti coatings that promote the tailoring of surface chemical functionalization regardless of the geometry and shape of the implant. However, among all the approaches available in the literature to functionalize the Ti surface, a promising strategy is the combination of surface pre-activation treatments typically followed by the development of intermediate anchoring layers (self-assembled monolayers, SAMs) that serve as the supporting linkage of a final active layer. Therefore, this paper aims to review the latest approaches in the biomedical area to obtain bioactive coatings onto Ti surfaces with a special focus on (i) the most employed methods for Ti surface hydroxylation, (ii) SAMs-mediated active coatings development, and (iii) the latest advances in active agent immobilization and polymeric coatings for controlled release on Ti surfaces

Multifunctional ternary composites with silver nanowires and titanium dioxide nanoparticles for capacitive sensing and photocatalytic self-cleaning applications

Multifunctional polymer composites are of increasing interest as they allow tuning of physical–chemical properties for specific applications. A ternary composite material is presented based on the incorporation of titanium dioxide (TiO2) nanoparticles and conductive silver nanowires (AgNWs) into a poly(vinylidene fluoride) (PVDF) polymer matrix. The films were prepared by solvent casting, varying the contents of the filler up to 10 wt %, and showed improved mechanical and dielectric responses and tailorable optical properties. In contrast, the morphology, polymer phase, and thermal stability are nearly independent of the filler type and content within the composite. A dielectric constant of up to 14 at 1 kHz was obtained for the 7.5%AgNWs/2.5%TiO2/PVDF sample. The (multi)functionality of the developed materials is demonstrated for photocatalytic self-cleaning and capacitive sensing applications, indicating the suitability of the approach for next-generation hybrid multifunctional materials.The authors thank the Fundação para a Ciência e Tecnologia (FCT) and COMPETE 2020 for financial support under the framework of Strategic Funding grants UID/FIS/04650/2021, UID/EEA/04436/2021, and UIDB/04650/2020 and under projects POCI-01-0145-FEDER-028157 and PTDC/FIS-MAC/28157/2017. The authors also thank the FCT for financial support under grant SFRH/BD/131729/2017 (N.P.) and the investigator contracts 2020.02802.CEECIND (P.M.M.) and 2020.04028.CEECIND (C.M.C.). Financial support from the Basque Government Industry Department under the ELKARTEK program is acknowledged. L. Campos thanks the University of Basque Country (UPV/EHU) for the doctoral grant PIFI20/04. Technical and human support provided by SGIker (UPV/EHU, MICINN, GV/EJ, EGEF, and ESF) is gratefully acknowledged. The authors would like to thank Asma Mooti for technical assistance