Plasma-Enhanced Chemical Vapor Deposition (PE-CVD) yields better Hydrolytical Stability of Biocompatible SiOx Thin Films on Implant Alumina Ceramics compared to Rapid Thermal Evaporation Physical Vapor Deposition (PVD)

AFM-IR investigation of thin PECVD SiO x films on a polypropylene substrate in the surface-sensitive mode

Thin silicon oxide films deposited on a polypropylene substrate by plasma-enhanced chemical vapor deposition were investigated using atomic force microscopy-based infrared (AFM-IR) nanospectroscopy in contact and surface-sensitive mode. The focus of this work is the comparison of the different measurement methods (i.e., contact mode and surface-sensitive mode) with respect to the chemical surface sensitivity. The use of the surface-sensitive mode in AFM-IR shows an enormous improvement for the analysis of thin films on the IR-active substrate. As a result, in this mode, the signal of the substrate material could be significantly reduced. Even layers that are so thin that they could hardly be measured in the contact mode can be analyzed with the surface-sensitive mode.

Silica coated high performance oxide ceramics promote greater ossification than titanium implants: an in vivo study

BACKGROUND

This in vitro study investigated the osseointegration and implant integration of high performance oxide ceramics (HPOC) compared to titanium implants in rabbits.

METHODS

Histomorphometry was conducted around the distal, proximal, medial, and lateral aspects of the HPOC to quantify the amount of mature and immature ossification within the bone interface. Histomorphometry was conducted by a trained musculoskeletal pathologist. The region of interest (ROI) represented the percentage of surrounding area of the implant. The percentage of ROI covered by osteoid implant contact (OIC) and mature bone implant contact (BIC) were assessed. The surrounding presence of bone resorption, necrosis, and/or inflammation were quantitatively investigated.

RESULTS

All 34 rabbits survived the 6- and 12-week experimental period. All HPOC implants remained in situ. The mean weight difference from baseline was + 647.7 mg (P < 0.0001). The overall OIC of the ceramic group was greater at 6 weeks compared to the titanium implants (P = 0.003). The other endpoints of interest were similar between the two implants at all follow-up points. No difference was found in BIC at 6- and 12-weeks follow-up. No bone necrosis, resorption, or inflammation were observed.

CONCLUSION

HPOC implants demonstrated a greater osteoid implant contact at 6 weeks compared to the titanium implants, with no difference found at 12 weeks. The percentage of bone implant contact of HPOC implants was similar to that promoted by titanium implants.

Enhanced corrosion resistance of epoxy-films on ultra-thin SiOx PECVD film coated laser surface melted Al-alloys

The influence of ultra-thin SiOx plasma deposited films on the corrosion resistance of adhesive films on a laser surface melted 7075 aluminium alloy was investigated by means of complementary techniques in comparison to the just laser surface melted state. Laser surface melting (LSM) was performed using a continuous wave mode at a wavelength of 1064 nm. Ultra-thin plasma polymer films were deposited from a mixture of hexamethyldisilane (HMDSO), oxygen, and argon by means of an audio-frequency glow discharge. The surface morphology and surface chemistry compositions were investigated by employing field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy (EDX), diffuse reflection infrared Fourier transform spectroscopy, and X-ray photoelectron spectroscopy. The corrosion resistance of plasma polymer coated LSM Al-7075 alloy was studied using linear sweep voltammetry and electrochemical impedance spectroscopy in a chloride-containing electrolyte. The electrochemical studies showed an improved corrosion resistance for plasma film-coated alloys compared to the just laser surface melted state. To study the corresponding surface adhesive properties, the samples were coated with an epoxy amine adhesive. 90°-peel test under humid conditions confirmed the improvement of interfacial wet-adhesion corrosion tests showed a strong improvement of the delamination resistance of adhesives caused by the ultra-thin interfacial SiOx-films.

Biomimetic superhydrophobic metal/nonmetal surface manufactured by etching methods: A mini review

As an emerging fringe science, bionics integrates the understanding of nature, imitation of nature, and surpassing nature in one aspect, and it organically combines the synergistic complementarity of function and structure–function integrated materials which is of great scientific interest. By imitating the microstructure of a natural biological surface, the bionic superhydrophobic surface prepared by human beings has the properties of self-cleaning, anti-icing, water collection, anti-corrosion and oil–water separation, and the preparation research methods are increasing. The preparation methods of superhydrophobic surface include vapor deposition, etching modification, sol–gel, template, electrostatic spinning, and electrostatic spraying, which can be applied to fields such as medical care, military industry, ship industry, and textile. The etching modification method can directly modify the substrate, so there is no need to worry about the adhesion between the coating and the substrate. The most obvious advantage of this method is that the obtained superhydrophobic surface is integrated with the substrate and has good stability and corrosion resistance. In this article, the different preparation methods of bionic superhydrophobic materials were summarized, especially the etching modification methods, we discussed the detailed classification, advantages, and disadvantages of these methods, and the future development direction of the field was prospected.

Functionalised High-Performance Oxide Ceramics with Bone Morphogenic Protein 2 (BMP-2) Induced Ossification: An In Vivo Study

This study investigated the in vivo osseointegration potential of high-performance oxide ceramics (HPOCs) with peptide bone morphogenic protein 2 (BMP-2), comparing them with titanium implants. Histomorphometry was conducted around the distal, proximal, medial, and lateral sides of the implants to quantify the amount of mature and immature ossification within the bone interface. We hypothesised that HPOCs functionalised with BMP-2 promote ossification. HPOCs functionalised with BMP-2 were manufactured at the Department of Dental Materials Science and Biomaterial Research of the RWTH University Aachen, Germany. Histomorphometry was conducted by a professional pathologist in all samples. The region of interest (ROI) represented the percentage of the surrounding area of the implant. The percentages of ROI covered by osteoid implant contact (OIC) and mature bone−implant contact (BIC) were assessed. The surrounding presence of bone resorption, necrosis, and/or inflammation was quantitatively investigated. A total of 36 rabbits were used for the experiments. No bone resorption, necrosis, or inflammation was found in any sample. At the 12-week follow-up, the overall BIC was significantly increased (p < 0.0001). No improvement was evidenced in OIC (p = 0.6). At the 6-week follow-up, the overall OIC was greater in the BMP-2 compared to the titanium group (p = 0.002). The other endpoints of interest evidenced similarity between the two implants at various follow-up time points (p > 0.05). In conclusion, alumina HPOCs functionalised with peptide BMP-2 promote in vivo ossification in a similar fashion to titanium implants.

Histomorphometry of Ossification in Functionalised Ceramics with Tripeptide Arg-Gly-Asp (RGD): An In Vivo Study

The present study investigated the osseointegration promoted by functionalised ceramics with peptide Arg-Gly-Asp (RGD) in a rabbit model in vivo. Histomorphometry of the RGD functionalised ceramic implants was conducted by a trained pathologist to quantify the amount of mature and immature ossification at the bone interface, and then compared to titanium alloy implants. The region of interest was the area surrounding the implant. The percentage of ROI covered by osteoid implant contact and mature bone implant contact were assessed. The presence of bone resorption, necrosis, and/or inflammation in the areas around the implant were quantitatively investigated. All 36 rabbits survived the experimental period of 6 and 12 weeks. All implants remained in situ. No necrosis, bone resorption, or inflammation were identified. At 12 weeks follow-up, the overall mean bone implant contact (p = 0.003) and immature osteoid contact (p = 0.03) were improved compared to the mean values evidenced at 6 weeks. At 6 weeks follow-up, the overall osteoid implant contact was greater in the RGD enhanced group compared to the titanium implant (p = 0.01). The other endpoints of interest were similar between the two implants at all follow-up points (p ≥ 0.05). Functionalised ceramics with peptide RGD promoted ossification in vivo. The overall osteoid and bone implant contact improved significantly from 6 to 12 weeks. Finally, RGD enhanced ceramic promoted faster osteoid implant contact in vivo than titanium implants. Overall, the amount of ossification at 12 weeks is comparable with the titanium implants. No necrosis, bone resorption, or inflammation were observed in any sample.

TiO2 nanoparticle coatings on glass surfaces for the selective trapping of leukemia cells from peripheral blood

Photodynamic therapy (PDT) using TiO₂ nanoparticles has become an important alternative treatment for different types of cancer due to their high photocatalytic activity and high absorption of UV-A light. To potentiate this treatment, we have coated commercial glass plates with TiO₂ nanoparticles prepared by the sol-gel method (TiO₂ -m), which exhibit a remarkable selectivity for the irreversible trapping of cancer cells. The physicochemical properties of the deposited TiO₂ -m nanoparticle coatings have been characterized by a number of complementary surface-analytical techniques and their interaction with leukemia and healthy blood cells were investigated. Scanning electron and atomic force microscopy verify the formation of a compact layer of TiO₂ -m nanoparticles. The particles are predominantly in the anatase phase and have hydroxyl-terminated surfaces as revealed by Raman, X-ray photoelectron, and infrared spectroscopy, as well as X-ray diffraction. We find that lymphoblastic leukemia cells adhere to the TiO₂ -m coating and undergo amoeboid-like migration, whereas lymphocytic cells show distinctly weaker interactions with the coating. This evidences the potential of this nanomaterial coating to selectively trap cancer cells and renders it a promising candidate for the development of future prototypes of PDT devices for the treatment of leukemia and other types of cancers with non-adherent cells.

Human osteoblast-like SAOS-2 cells on submicron-scale fibers coated with nanocrystalline diamond films

A unique composite nanodiamond-based porous material with a hierarchically-organized submicron-nano-structure was constructed for potential bone tissue engineering. This material consisted of submicron fibers prepared by electrospinning of silicon oxide (SiO_x), which were oxygen-terminated (O-SiO_x) and were hermetically coated with nanocrystalline diamond (NCD) films. The NCD films were then terminated with hydrogen (H-NCD) or oxygen (O-NCD). The materials were tested as substrates for the adhesion, growth and osteogenic differentiation of human osteoblast-like Saos-2 cells. The number and the spreading area of the initially adhered cells, their growth rate during 7 days after seeding and the activity of alkaline phosphatase (ALP) were significantly higher on the NCD-coated samples than on the uncoated O-SiO_x samples. In addition, the concentration of type I collagen was significantly higher in the cells on the O-NCD-coated samples than on the bare O-SiO_x samples. The observed differences could be attributed to the tunable wettability of NCD and to the more appropriate surface morphology of the NCD-coated samples in contrast to the less stable, rapidly eroding bare SiO_x surface. The H-NCD coatings and the O-NCD coatings both promoted similar initial adhesion of Saos-2 cells, but the subsequent cell proliferation activity was higher on the O-NCD-coated samples. The concentration of beta-actin, vinculin, type I collagen and alkaline phosphatase (ALP), the ALP activity, and also the calcium deposition tended to be higher in the cells on the O-NCD-coated samples than on the H-NCD-coated samples, although these differences did not reach statistical significance. The improved cell performance on the O-NCD-coated samples could be attributed to higher wettability of these samples (water drop contact angle less than 10°), while the H-NCD-coated samples were hydrophobic (contact angle >70°). NCD-coated porous SiO_x meshes can therefore be considered as appropriate scaffolds for bone tissue engineering, particularly those with an O-terminated NCD coating.

Vapor-deposited functional polymer thin films in biological applications

Functional polymer coatings have become ubiquitous in biological applications, ranging from biomaterials and drug delivery to manufacturing-scale separation of biomolecules using functional membranes. Recent advances in the technology of chemical vapor deposition (CVD) have enabled precise control of the polymer chemistry, coating thickness, and conformality. That comprehensive control of surface properties has been used to elicit desirable interactions at the interface between synthetic materials and living organisms, making vapor-deposited functional polymers uniquely suitable for biological applications. This review captures the recent technological development in vapor-deposited functional polymer coatings, highlighting their biological applications, including membrane-based bio-separations, biosensing and bio-MEMS, drug delivery, and tissue engineering. The conformal nature of vapor-deposited coatings ensures uniform coverage over micro- and nano-structured surfaces, allowing the independent optimization of surface and bulk properties. The substrate-independence of CVD techniques enables facile transfer of surface characteristics among different applications. The vapor-deposited functional polymer thin films tend to be biocompatible because they are free of remnant toxic solvents and precursor molecules, potentially lowering the barrier to clinical success.

A Review of In-Situ Grown Nanocomposite Coatings for Titanium Alloy Implants

Composite coatings are commonly applied to medical metal implants in order to improve biocompatibility and/or bioactivity. In this context, two types of titanium-based composite coatings have been reviewed as biocompatible and anti-bacterial coatings. The different composites can be synthesised on the surface of titanium using various methods, which have their own advantages and disadvantages. Moving with the smart and nanotechnology, multifunctional nanocomposite coatings have been introduced on implants and scaffolds for tissue engineering with the aim of providing more than one properties when required. In this context, titanium dioxide (TiO2) nanotubes have been shown to enhance the properties of titanium-based implants as part of nanocomposite coatings.

Biological Activation of Bioinert Medical High-Performance Oxide Ceramics by Hydrolytically Stable Immobilization of c(RGDyK) and BMP-2

High-performance oxide ceramics (HPOC), such as alumina, zirconia, and dispersion ceramics thereof are successfully used as articulating components in joint arthroplasty. HPOC exhibit excellent wear resistance, high strength, and cytocompatible behavior; however, they lack sufficient tissue bonding capability. Thus, they are primarily deployed as low-wear-bearing articulating components in arthroplasty without direct tissue contact, although proper cellular stimulation would hold significant advantages. Here, we describe a surface modification approach for HPOC, enabling hydrolytically stable interfacial binding of c(RGDyK) peptides and BMP-2 proteins to significantly improve the adhesion and osteogenic differentiation of human mesenchymal stem cells (hMSCs) without altering the mechanical properties of the underlying ceramic substrates. Analyses of cellular attachment of murine fibroblasts (L929), human alveolar basal epithelial cells (A549), hMSCs on c(RGDyK), and osteogenic differentiation of hMSCs on BMP-2-coated interfaces demonstrate significant improvements of cell adhesion and an enhanced osteogenic differentiation potential in vitro. The presented approach provides a strategy for the development of a novel class of bioactive HPOC with osseointegration potential that could lead to novel therapeutic solutions for biomedical applications. Furthermore, the developed surface modification is designed in a way to be readily translated to other medically employed bioinert materials in the future.

Solutions for the problems of silicon-carbon anode materials for lithium-ion batteries

Lithium-ion batteries are widely used in various industries, such as portable electronic devices, mobile phones, new energy car batteries, etc., and show great potential for more demanding applications like electric vehicles. Among advanced anode materials applied to lithium-ion batteries, silicon-carbon anodes have been explored extensively due to their high capacity, good operation potential, environmental friendliness and high abundance. Silicon-carbon anodes have demonstrated great potential as an anode material for lithium-ion batteries because they have perfectly improved the problems that existed in silicon anodes, such as the particle pulverization, shedding and failures of electrochemical performance during lithiation and delithiation. However, there are still some problems, such as low first discharge efficiency, poor conductivity and poor cycling performance, which need to be improved. This paper mainly presents some methods for solving the existing problems of silicon-carbon anode materials through different perspectives.