Nanoscale Surface Modification Research Articles

REVIEW OF LITERATURE ON NANOSCALE TOPOGRAPHIC MODIFICATION, MAGNETIC NANOPARTICLES, AND THEIR ROLES IN OSSEOINTEGRATION AND BONE TISSUE ENGINEERING

Here, we will review together the roles of nanoscale modification of titanium substrates and use of magnetic nanoparticles in osseointegration and bone tissue engineering. The technological advances in nanotechnology that has been achieved create new measures to increase the implants-biological systems for an optimal osseointegration through improving important cell-specific functions. We systematically review nanoscale surface modification techniques of titanium implants, covering their physicochemical properties, influence on cellular behaviors and clinical relevances. The report also lengthy discusses the clinical applicability of magnetic nanoparticles for drug and gene delivery systems, targeted cancer therapy as well bone tissue engineering regulting their intrinsic superparamagnetism properites, biocompatibility with other therapies etc. We present detailed review of these technologies and their potential applications in clinical settings.

Effect of Nanoscale Surface Modification on the Interfacial Mechanics of Carbon Fibers

AbstractEnhancing fiber surfaces through in situ growth of nanomaterials is known to improve fiber composite properties by enhancing the interface between the fiber and matrix. In this study, hydrothermal processes are used to achieve two types of interfacial modification for carbon fiber: zinc oxide nanowires (ZnO NWs) and nickel‐based metal–organic frameworks (MOF). The interfacial strengths are evaluated using single fiber push‐in tests via nanoindentation and the interfaces are analyzed through dynamic modulus‐mapping. It is found that ZnO modification increases the interface strength by 9.40%, while MOF modification yields an even higher improvement of 16.34%. The load‐displacement plots exhibit distinctive inflection points, elucidated through microstructural observations. Examining the modulus map of the interface region, a transition in the storage modulus from the fiber to the matrix is identified. A capillary flow‐based model is developed to explain the resin penetration through nanoscale features. The findings reported here indicate that the timescale for resin absorption is significantly shorter than the curing timescales for the surface modifications explored in this study.

Hydrophobic and oleophilic lauric acid-grafted carbon nanotubes for recyclable efficient oil/water separation

This work demonstrates a novel nanoscale surface modification procedure to enhance the selectivity of multi-walled carbon nanotubes (MWCNTs) in recovering oil from water. Herein, we developed a novel, cost-effective, and facile method to produce highly hydrophobic and superoleophilic lauric acid (LA)-grafted multi-walled carbon nanotubes (MWCNTs-LA) as an absorbent for effective oil spill remediation. The MWCNTs were first oxidized with sodium hydroxide to anchor hydroxyl groups on their surface (MWCNTs-OH) followed by LA grafting via an esterification reaction. Spectroscopic analyses confirmed the grafting of LA onto the MWCNTs' surface, and this treatment made the water contact angle (WCA) of MWCNTs-LA reach 145.26 ± 1.57°, thus showing excellent hydrophobicity and superoleophilicity. The as-prepared absorbent demonstrates good absorption selectivity and absorption capacity of 20.5–33.5 times weight gain for numerous organic solvents and oils. After 5 cycles of absorption-desorption tests, such highly hydrophobic MWCNTs-LA absorbent maintained high oil absorption performance, therefore displaying good reusability and desirable regeneration for practical uses. The MWCNTs-LA absorbent with superb hydrophobicity, superoleophilicity, proper selectivity, and acceptable reusability appears to be promising for the efficient separation and retrieval of spilled oils and organic solvents from water.

Nanophytosome formulation of β-1,3-glucan and Euglena gracilis extract for drug delivery applications

Euglena gracilis (EG) is a unicellular freshwater alga known for its high β-1,3-glucan (BG) content with well-known biological properties and immune response. The high molecular weight structure of BG traditionally poses a challenge in terms of its size and absorption. Therefore, the aim of this study was to develop a novel drug delivery mechanism of BG and EG to nanophytosomes (NPs) by converting the heavy molecular weight of BG and EG into lipid phosphatidylcholine (PC), which plays an important role in improving their bioavailability and entrapment in captivity. The BG and EG NPs were developed by the solvent evaporation method while varying time and temperature to optimize their drug delivery ability. The size of BG-PC and EG-PC obtained by the Dynamic Light Scattering (DLS) method was 134.62 and 158.38 nm, respectively. Chemical (Fourier Transform Infra-Red) and structural (X-Ray Diffraction) characterization of NPs improved the binding capacity and the amorphous nature of both NPs. The shape of the NPs by Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM) revealed their spherical, vesicular nature. The encapsulation efficiency of BG-PC and EG-PC was 82 ± 1.62 % and 87 ± 3.22 %, respectively, which improves the bioavailability. The developed methodology has thus proven effective in synthesizing BG-PC and EG-PC, which may be useful as NP drug delivery carriers. Future research could demonstrate the safety and effectiveness of long-term storage conditions for medical and pharmaceutical applications.•Nanophytosomes are tailored in size, shape and composition to optimize the delivery of phytochemicals/phytocompounds through nanoscale size and surface modification for better physiological absorption.•Nanophytosomes increase the stability of phytochemicals/phytocompounds and protect them from degradation due to heat or chemical reactions, leading to longer shelf life and improved therapeutic efficacy.•In this method, optimal conditions were created for the formation of β-1,3-glucan and Euglena gracilis extract nanophytosomes for successful development of drug delivery system that can effectively deliver bioactive compounds.

A facile fabrication method of wettability modification of TiAl6V4 based on alkali solution treatment: Superhydrophilic, superhydrophobic and slippery surface

The rapid development of nanoscale surface modification technology has led to the development of superhydrophilic, superhydrophobic, and slippery liquid-infused porous surfaces (SLIPS) in recent decades. These surfaces have excellent self-cleaning and anti-contamination performance, and many studies have reported their industrial applications. Industrial and modern medical applications of titanium are rapidly expanding owing to its advantages of chemical stability, high mechanical strength, stable corrosion resistance, and biocompatibility; however, performing surface modification of titanium remains challenging. In this study, superhydrophilic, superhydrophobic, and SLIPS were fabricated on titanium using a simple surface fabrication method, and their wettabilities were analyzed and compared. Furthermore, we succeeded in applying the method used in this study to bulky and complex objects. Chemical and physical analyses were performed to confirm the fabrication, wettability properties, and nanostructures of the modified surfaces. The simple fabrication method presented a significant advancement as there are no limitations in its application to large areas, complex shapes, or mass production, unlike existing titanium wettability modification methods.

Zinc (Zn) Doping by Hydrothermal and Alkaline Heat-Treatment Methods on Titania Nanotube Arrays for Enhanced Antibacterial Activity.

Titanium (Ti) is a popular biomaterial for orthopedic implant applications due to its superior mechanical properties such as corrosion resistance and low modulus of elasticity. However, around 10% of these implants fail annually due to bacterial infection and poor osseointegration, resulting in severe pain and suffering for the patients. To improve their performance, nanoscale surface modification approaches and doping of trace elements on the surfaces can be utilized which may help in improving cell adhesion for better osseointegration while reducing bacterial infection. In this work, at first, titania (TiO2) nanotube arrays (NT) were fabricated on commercially available pure Ti surfaces via anodization. Then zinc (Zn) doping was conducted following two distinct methods: hydrothermal and alkaline heat treatment. Scanning electron microscopic (SEM) images of the prepared surfaces revealed unique surface morphologies, while energy dispersive X-ray spectroscopy (EDS) revealed Zn distribution on the surfaces. Contact angle measurements indicated that NT surfaces were superhydrophilic. X-ray photoelectron spectroscopy (XPS) provided the relative amount of Zn on the surfaces and indicated that hydrothermally treated surfaces had more Zn compared to the alkaline heat-treated surfaces. X-ray crystallography (XRD) and nanoindentation techniques provided the crystal structure and mechanical properties of the surfaces. While testing with adipose-derived stem cells (ADSC), the surfaces showed no apparent cytotoxicity to the cells. Finally, bacteria adhesion and morphology were evaluated on the surfaces after 6 h and 24 h of incubation. From the results, it was confirmed that NT surfaces doped with Zn drastically reduced bacteria adhesion compared to the Ti control. Zn-doped NT surfaces thus offer a potential platform for orthopedic implant application.

Tailoring the flow properties of inhaled micronized drug powders by atomic and molecular layer deposition

For dry powder inhaled formulations, good flow behaviour is vital in re-dispersing the powder. However, inhaled drug powders with a particle size below 10 µm are classified as highly cohesive materials with poor flow characteristics. Here we demonstrate how to alter the flow properties of micronized budesonide powders by depositing different materials (organic, inorganic, and hybrid organic–inorganic) in the forms of nanoscale films onto the drug particles using atomic/molecular layer deposition (ALD/MLD) coatings. The angle of repose (static) and pneumatic delivery measurements were performed to access the flow characteristics. The flowability can be effectively improved with the growth of inorganic nanofilm (SiO2, TiO2, or Al2O3) via ALD and hybrid nanofilm (titanicone) via combined ALD-MLD coating. This improvement is reflected by the decrease in the angle of repose and minimum pick-up velocity (Upu), as well as promoting the pneumatic delivery of a much larger amount of drug powders after ALD or hybrid coating. In contrast, the organic PET coated budesonide via MLD exhibits comparable poor flow characteristics as the uncoated budesonide. Rather than being transported in individual particles, the uncoated or PET-coated budesonide powders are pneumatically delivered in form of complex clusters with a size of over 500 μm, whereas the ALD budesonide is dispersed in form of small agglomerates (<100 μm). Despite the difference in agglomerate size, entraining behaviors of all samples agree well with the prediction of Kalman’s pick-up Zone I correlation. The inorganic nanofilm deposited via ALD alters the surface chemistry to reduce the inter-particle forces measured by atomic force microscopy, giving rise to an improved drug delivery performance. Nanoscale surface modification of dry powder particles has good potential for inhaled drug delivery enhancement.

Uniform lithium deposition enabled by a carbon nanotubes framework modified with nanosized ZIF-8 particles for dendrite-free lithium metal anode

Lithium (Li) metal is considered as an exciting anode candidate for next-generation high-performance Li metal batteries because of its high theoretical capacity and lowest redox potential. Unfortunately, unavoidable challenges consisting of dendritic behavior and volume change obstruct its widely commercial application. Here, a three-dimensional (3D) oxidized carbon nanotubes framework modified with lithiophilic nano-ZIF-8 particles (CNTs@ZIF-8) has been fabricated by a simple solution method as the collector for uniform Li deposition. The polar groups from oxidized CNTs and ZIF-8 nanoparticles provide adhesion sites for Li nucleation. Meanwhile, the nano-ZIF-8 particles with large specific surface area enhance electrolyte absorption, attracting electrolyte to the CNTs surface. The composite structure with nanoscale surface modification can guide homogeneous Li plating and restrain Li dendrites growth. As a consequence, the symmetrical cell of CNTs@ZIF-8/Cu–Li reveals a stable cycle time (over 1500 h) with a hysteresis voltage (9 mV) at 1 mA cm−2. The full cell assembled by LiFePO4 (LFP) cathode and CNTs@ZIF-8/Cu–Li anode achieves outstanding rate and cycle performance which is superior to the CNTs/Cu–Li‖LFP, demonstrating that the CNTs@ZIF-8 is prospective for practical applications.

Gallium-doped dual micro-nano titanium dental implants towards soft-tissue integration and bactericidal functions

Alongside osseointegration, effective soft-tissue integration (STI) is crucial to the long-term success of dental implants by preventing the ingress of oral pathogens. Nanoscale surface modification of titanium dental implants has shown promise in achieving enhanced bioactivity and antibacterial efficacy. We propose the fabrication of dual micro-nano anisotropic titania nanopores (TNPs) via electrochemical anodization of Ti, followed by incorporating gallium (Ga) towards enhanced antibacterial efficacy. Optimization of Ga chemical functionalization on TNPs was followed by in-depth surface topographical/chemical characterizations and in vitro Ga release. This study revealed that the surface chemistry, hydrophilicity, and topography of the TNPs were altered upon Ga-doping, resulting in the formation of Ga-containing nanoscale particulates firmly bound to TNPs. Further, gingival fibroblast bioactivity was favorably maintained on TNPs and Ga-releasing TNPs. Finally, a human oral salivary biofilm model confirmed the significant antibacterial efficacy of Ga-doped TNPs. Ga-doped dual micro-nano Ti dental implants are suitable as the next generation of bioactive and bactericidal dental implants.

Nanoscale surface modification to suppress capacity fade of Ni-Rich layered oxide material at high cut-off voltage

Ni-rich layered oxide is a promising cathode material for future advanced lithium-ion batteries (LIBs). However, the nickel-rich layered cathode material exhibits insufficient high-voltage cycling stability ascribing to the phase transformation, surface side reactions, and lattice oxygen evolution. This work developed an effective inorganic coating strategy to construct LiNiO2/Na1-xNi1-yPO4 surface hybrid coating layer and Na bulk doping simultaneously by a simple wet-chemical method, improving the high-voltage performance of LiNi0.8Co0.1Mn0.1O2 (NCM) effectively. It is found that the surface oxygen vacancy and surface residual lithium on NCM reacts with NaNiPO4 precursors at 500 °C to form LiNiO2 inner layer in addition to the Na1-xNi1-yPO4 outer layer, which is structurally coherent to the layered lattice of NCM. In the constructed hybrid layer, layered phase LiNiO2 firmly fixes on the NCM surface. At the same time, highly chemical stable Na1-xNi1-yPO4 with lattice tunnels can enable lithium-ion transport and act as a protecting layer to inhibit surface side reactions. In addition, Na bulk doping could enlarge lithium-ion diffusion channels and stabilize lattice structure. All these advantages contribute to improving the electrochemical performance of NCM. The results show that the surface treatment NCM cathode exhibit excellent cycling stability with a higher capacity retention of 88 % after 200 cycles under 25 °C and 86 % after 100 cycles under 55 °C, both at 1C. This method provides a feasible strategy to promote the high-voltage cycling performance of electrode material, thus improving the service life, energy density, and safety performance of Li-ion batteries.

Nanoscale surface modification via scanning electrochemical probe microscopy

Micro- and nanoscale surface modification using scanning probe microscopy techniques in combination with electrochemically induced surface structuring provides a maskless in situ fabrication strategy enabling deposition or etching of three-dimensional nanostructures. This current opinion article focuses on scanning electrochemical probe microscopy techniques highlighting recent progress in nanoscale 3D surface modification along with a spotlight on approaches of practical relevance.

Wrinkle-Shaped Nickel Sulfide Grown on Three-Dimensional Nickel Foam: A Binder-Free Electrode Designed for High-Performance Electrochemical Supercapacitor Applications

Recently, three-dimensional nickel foam (3D-Nf) has been increasingly studied; however, further modifications in nanoscale surface modification are necessary for particular applications. In this work, three-dimensional hierarchically porous nanogranular NiS (NiS-3D-Nf) and wrinkle-shaped NiS (w-NiS-3D-Nf) structures were fabricated directly on nickel foam by a simple one-step solvothermal process using two different solvents. Several characterization techniques, including X-ray diffraction pattern, X-ray photoelectron spectroscopy, and scanning electron microscopy, were used to characterize the samples’ properties. To prove their applicability, supercapacitor electrodes were tested directly in a three-electrode assembly cell. The resulting w-NiS-3D-Nf electrodes exhibited greater capacitive activity than the NiS-3D-Nf electrodes. The optimized w-NiS-3D-Nf electrodes delivered an excellent specific capacitance of 770 Fg−1, at a current density of 1 Ag−1, compared with the NiS-3D-Nf electrodes (162.0 Fg−1 @ 1 Ag−1), with a cyclic stability of over 92.67% capacitance retention after 2200 cycles. The resultant unique structure with integrated hierarchical three-dimensional configuration can not only enhance abundant accessible surface areas but also produce strong adhesion to the 3D-Nf, facilitating the fast transportation of ions and electrons for the electrochemical reaction via the conductive 3D-Nf. This set of results suggests that the modification of 3D-Nf surfaces with a suitable solvent has highly significant effects on morphology, and ultimately, electrochemical performance. Additionally, the current preparation approach is simple and worthwhile, and thus offers great potential for supercapacitor applications.

Nanoscale surface modification of polymer nanofibers enables uniform lithium nucleation and deposition for stable lithium metal anodes

The growth of lithium dendrites and the huge volume change are the critical issues for the practical application of lithium metal anodes. In this work, a novel strategy is proposed to address the above challenges using oxidized polyacrylonitrile (PAN) nanofibers anchored with well-distributed metal–organic frameworks (MOFs) as the lithium metal anode host. The obtained hybrid structure possesses integrated multiple lithium ion affinities to regulate the lithium ion flux inside the three-dimensional scaffold. On the one hand, the strong chemical lithophilicity is achieved with the abundant surface polar groups from oxidized PAN nanofibers and MOFs. On the other hand, the high capillary force from the microporous structure of MOFs serves them as electrolyte nanoreservoirs enabling improved lithium adsorption. Site-selective lithium nucleation and deposition via nanoscale surface modification of oxidized PAN nanofibers regulates the Li plating/stripping behavior and effectively suppresses dendrite growth. As a result, the symmetrical cell based on the composite anode delivers a prolonged cycling life of 5 times longer than that of bare Cu at a high current density of 3 mA cm−2. Moreover, when paired with the LiNi0.5Co0.2Mn0.3O2 (NCM) cathode, the assembled full cell also exhibits outstanding rate capability and improved cycling performance.

A Brief Review on the Evolution of Metallic Dental Implants: History, Design, and Application

In recent years, significant advances in the field of medical materials have begun to emerge, especially in nanotechnology. The modern area of nanostructured implants possesses wide applications in various medical implants including their dental use. Nano-surface functions present substantial resolutions to medical obstacles through improved biomaterial proficiency, innovative dental-implant designs, and surface design procedures, such as nanoscale adhesive surfaces, bio-chemical anodization, and surface modification technique. This work covers dental implant history, nanotechnological advances, and its development that includes a description, basic properties, and the related results of composites and surface morphology, and the different types of nanomaterials used in dental implants. Significant attempts have been made over the last few decades to strengthen osteointegration and prevent bacterial attachment to the implant surfaces. The micro and nano-topography of the hierarchical surface orchestrate the biological reactions of implants and may solve the problems associated with implant-tissue issues. This research investigates the implant articles from 1964 to 2021, which offers a brief description of the nanostructured biomaterials to enhance dental implants’ performance and may open new frontiers in the advancement of implant technology.

Bulk Energy Transferability Linked to Critical N–H Modes of an Interfacial Nanoscale Surface Modification via Unique Isophorone Diisocyanate Amine Exchange Reaction

AbstractA surface‐modified carbon‐fiber reinforced epoxy (CF/E) via a unique isophorone diisocyanate amine (IDA) reaction produces a new interfacial epoxy‐polyurea “matrix” (IEPM) that elicits excellent mechanical energy transferability in brittle CF/E. The chemical bonding property in the IEPM molecule is produced via moieties of an epoxy mixture and N‐H‐concentrated urea molecules, where IDA thermodynamics are controlled via a curing parameter, tc (in hours). Nano‐scale properties of the IDA reaction, confirmed via fourier‐transform infrared spectroscopy and chemical mapping of molecules comprising the IEPM structure, are linked to bulk mechanical energy transferability, specifically loss modulus, E″(ω), and post‐elastic energy absorption. Using dynamic mechanical analysis (DMA) of six test specimens and a Generalized Maxwell Model – verified via Prony Series calibration of the storage modulus to DMA data to compute relaxation parameters – the ultrathin IEPM is isolated, and E″(ω) is computed as a function of tc. IEPM that is produced via tc = 0 exhibited two, six, and ten times greater loss modulus than IEPM produced via 0.5 ≤ tc ≤ 2; tc = 3.5; and tc = 24 (baseline design utilizes cured CF/E). Finally, IDA surface‐modification of CF/E improved energy absorption capacity (post‐elasticity) between 250% (tc = 0.5) and 300% (tc = 0).

Histomorphometric assessment of implant coated with mixture of nano-alumina and fluorapatite in rabbits

BackgroundThe application of nanoscale surface modification was found to be useful in the improvement of osseointegration of endosseous dental implants. The fluorapatite (FA)/alumina (Al2O3) mixture is recognized for its outstanding bioinertia and can significantly increase the biocompatibility and bioactivity of biomaterials. ObjectiveThe aim of the present work was to evaluate the bone response to nano-alumina- and fluorapatite-coated dental implants using rabbit tibiae. Material and MethodsThe coating was performed using the dip-coating method. Commercially pure titanium screw-type implants were used as a control group. The coated implants were the experimental group. Each group consisted of 12 screws that were surgically implanted in 6 healthy New Zealand rabbits. Histological and histomorphometric evaluations were performed at the bone to implant contact (BIC) interface, bone fraction area occupancy (BAFO) and fibrous tissue at 2 and 6 weeks of healing. ResultsThis analysis showed that the coated implants had more rapid osseointegration than the control group, with a significant difference after 2 and 6 weeks of healing for both groups. The histomorphometric evaluation demonstrated higher values for BIC% and BAFO% and lower values of fibrous tissue in the mixture-coated Ti implants than in the control group. ConclusionThe current study suggested that the nano-alumina and fluorapatite mixture coating is a favourable candidate for rapid osseointegration over uncoated implants.

3D Printing in alloy design to improve biocompatibility in metallic implants

3D Printing (3DP) or additive manufacturing (AM) enables parts with complex shapes, design flexibility, and customization opportunities for defect specific patient-matched implants. 3DP or AM also offers a design platform that can be used to innovate novel alloys for application-specific compositional modifications. In medical applications, the biological response from a host tissue depends on a biomaterial's structural and compositional properties in the physiological environment. Application of 3DP can pave the way towards manufacturing innovative metallic implants, combining structural variations at different length scales and tailored compositions designed for specific biological responses. This study shows how 3DP can be used to design metallic alloys for orthopedic and dental applications with improved biocompatibility using in vitro and in vivo studies. Titanium (Ti) and its alloys are used extensively in biomedical devices due to excellent fatigue and corrosion resistance and good strength to weight ratio. However, Ti alloys' in vivo biological response is poor due to its bioinert surface. Different coatings and surface modification techniques are currently being used to improve the biocompatibility of Ti implants. We focused our efforts on improving Ti's biocompatibility via a combination of tantalum (Ta) chemistry in Ti, the addition of designed micro-porosity, and nanoscale surface modification to enhance both in vitro cytocompatibility and early stage in vivo osseointegration, which was studied in rat and rabbit distal femur models.

Field electron emission enhanced streamer cold plasma interaction on seed surface wettability

Hybrid streamer cold plasma (HSCP) can be used in nanoscale surface modification, especially for curved biological surfaces. Here, the HSCP was applied to a rice (Oryza sativa L.) seed under different gas ambient and electric field distributions. Seed wettability enhancement (water imbibition (WI) and apparent contact angle (ACA)) is the primary method used to understand the dynamic of plasma interaction on biological surfaces. The extremely non-uniform electric field is directly responsible for plasma generation, via fringe field enhanced electron emission, which consequently impacts the ionization process. Further, this process is indirectly related to the plasma-enhanced electrochemical and physical reactions on biological nanoscale surface etching and functionalization. Despite being generated by means of different plasma mechanisms, the water imbibition time (WItime) on the top and bottom (shadow) of treated seed surfaces show similar characteristics, namely exponentially fast decay right after treatment, and a consequent linear decrease until reaching the saturation level. The stronger the corona discharge plasma, the less the difference in surface functionalization between the top and bottom surfaces. We demonstrate the model of WItime enhancement as a function of treatment time based on fringe field enhanced electron emission mediated impact ionization and reactive species (RS) generation for surface transformation.

Nanoscale surface modification of P2-type Na0.65[Mn0.70Ni0.16Co0.14]O2 cathode material for high-performance sodium-ion batteries

P2-type Na0.65[Mn0.70Ni0.16Co0.14]O2 (NMNCO) is a promising cathode material for sodium-ion batteries (SIBs). However, NMNCO faces challenges of inferior rate capability and cycling stability owing to its poor structural stability induced by the P2-O2 phase transition during high voltage charging. In order to improve the performance of NMNCO, surface modification has been identified as one of the most effective approaches. Among various surface modifiers, NASICON-type NaTi2(PO4)3 (NTP) attracts tremendous attention due to its three-dimensional structure with open framework of large interstitial spaces. Nevertheless, the fundamental understanding of the effect of NTP surface modification on the electrochemical performance is still lacking and needs to be further investigated. Here, NMNCO is successfully modified with NTP (NMNCO@NTP) via a wet chemical method. Particularly, the effect of NTP surface modification on the electrochemical performance is unraveled by a combination of in-situ X-ray diffraction (XRD) technique, ex-situ transmission electron microscopy (TEM) analysis and first-principles calculations. When evaluated as a cathode material for SIBs, the NMNCO@NTP composite can deliver a high reversible capacity of 105.1 mA h g−1 with a capacity retention of 84.3% after 500 cycles at 5C, suggesting significantly improved rate capability and cycling stability. The results revealed that the NTP surface coating and doping can effectively suppress the structural change of NMNCO during sodiation/desodiation process, leading to a highly structural reversibility. In addition, NTP coating layer with exceptional ion conductivity can effectively restrain gradual encroachment, and guarantee stable phase interfaces.

Direct comparison of additively manufactured porous titanium and tantalum implants towards in vivo osseointegration

Material properties of implants such as volume porosity and nanoscale surface modification have been shown to enhance cell-material interactions in vitro and osseointegration in vivo. Porous tantalum (Ta) and titanium (Ti) coatings are widely used for non-cemented implants, which are fabricated using different processing routes. In recent years, some of those implants are being manufactured using additive manufacturing. However, limited knowledge is available on direct comparison of additively manufactured porous Ta and Ti structures towards early stage osseointegration. In this study, we have fabricated porous Ta and Ti6Al4V (Ti64) implants using laser engineered net shaping (LENS™) with similar volume fraction porosity to compare the influence of surface characteristics and material chemistry on in vivo response using a rat distal femur model for 5 and 12 weeks. We have also assessed whether surface modification on Ti64 can elicit similar in vivo response as porous Ta in a rat distal femur model for 5 and 12 weeks. The harvested implants were histologically analyzed for osteoid surface per bone surface. Field emission scanning electron microscopy (FESEM) was done to assess the bone-implant interface. The results presented here indicate comparable performance of porous Ta and surface modified porous Ti64 implants towards early stage osseointegration at 5 weeks post implantation through seamless bone-material interlocking. However, a continued and extended efficacy of porous Ta is found in terms of higher osteoid formation at 12 weeks post-surgery.