In this study, we investigate the potential of texture control for preferred {001} orientation to reduce the Young's modulus in the new biomedical body-centered cubic (BCC) Nb30Ti30Zr30Cr5Mo5 MEA. The fabrication of {001} oriented grains on a compression plane is controlled by so-called preferential dynamic grain growth under high temperature uniaxial compression. The uniaxial compression is carried out at temperature between 1073 and 1473 K by a true strain rate between 1 x 10(-4) - 1 x 10(-2) s(-1) until -1.0 in true strain. The microstructures after the compression at 1473 K are significantly developed by dynamic recrystallization. A decrease in true strain rate promotes a formation of {001} oriented grains due to enhanced preferential dynamic grain growth. The highest volume fraction of {001} texture (similar to 64 %) is observed after the compression at 1473 K under the strain rate of 5.0 x 10(-4) s(-1). An increase in volume fraction of {001} texture decrease the Young's modulus. The Young's modulus in this study can reduce as low as 68 GPa, compared with similar to 93 GPa in the initial sample prior to high-temperature deformation.

This study reports the successful development of bioactive coatings on in-situ alloyed Ti-40Nb substrates fabricated via selective laser melting (SLM) using plasma electrolytic oxidation (PEO). Two electrolytes were employed for PEO processing: phosphate–silicate (PS) and phosphate–silicate–hydroxyapatite (PSHA). A comparative evaluation was performed to investigate the influence of electrolyte composition on surface morphology, corrosion resistance, and biological performance. The incorporation of hydroxyapatite (HAp) in the PSHA electrolyte significantly modified the coating structure, resulting in reduced porosity, increased surface roughness, and enhanced wettability. X-ray diffraction analysis confirmed the formation of TiO₂ (anatase and rutile) and Nb₂O₅ phases, with a higher rutile fraction observed in the HAp-incorporated coatings due to intensified plasma discharges. Electrochemical testing in simulated body fluid (SBF) demonstrated improved corrosion resistance for the HAp-containing samples, as evidenced by lower corrosion current density and passivation current values. In vitro assays with MC3T3 pre-osteoblast cells further revealed superior cell viability and proliferation on the HAp-incorporated coatings, attributed to the synergistic effects of roughened topography and the sustained release of bioactive ions. Overall, the PEO-modified Ti40Nb samples exhibited enhanced corrosion protection and cytocompatibility, underscoring their strong potential as next-generation Ti-based orthopedic implant materials.

Implant associated infections represent a major global threat to be addressed owing to the rise of antimicrobial resistant bacterial strains. This paper reports gallium oxyhydroxide (GaOOH) nanostructures grown on Ti surface via a facile hydrothermal route to obtain a multifunctional surface capable of attaining synergistic improvement of bone cell interactions and bactericidal activity. Herein, uniform nanorice shaped morphologies are developed along with a surface profile of reduced skewness (-0.4068) and kurtosis (2.54) values. Detailed X-ray photoelectron spectroscopy analysis reveals GaOOH species on a reduced Ti surface. Ga release kinetics assessed in phosphate buffer saline solution with bovine serum albumin protein indicates steady release of Ga3 + ions within safe limits (22.8 ppb after 28 days). Improved antibacterial activity (139 % increase in bacterial inhibition after 48 h) against Escherichia coli is observed due to the Ga releasing bactericidal surface. Cell studies reveal significant improvement in osteoblast viability, with cell morphologies depicting elongated and well-spread cells. This improved cytocompatibility can be attributed to the nanorice morphology, topography, and the role of Ga in improving cell signaling. Overall, the developed GaOOH nanostructures on Ti surface offers a prospective strategy to effectively support bone cell growth, combat implant bacterial activity and complement systemic antibiotic therapy.

Smart biomaterials have significantly impacted human healthcare by advancing the development of medical devices designed to function within human tissue, mimicking the behavior of natural tissues. While the intelligence of biomaterials has evolved from inert to active over the past few decades, smart biomaterials take this a step further by making their surfaces or bulk respond based on interactions with surrounding tissues, imparting outcomes similar to natural tissue functions. This interaction with the surrounding tissue helps in creating stimuli-responsive biomaterials, which can be useful in tissue engineering, regenerative medicine, autonomous drug delivery, orthopedics, and much more. Traditionally, material engineering focused on refining the static properties of biomaterials to accommodate them within the body without evoking an immune response, which was a major obstacle to their unrestricted operation. This review highlights and explains various engineering approaches currently under research for developing stimuli-responsive biomaterials that tune their outcomes based on responses to bodily factors like temperature, pH, and ion concentration or external factors like magnetism, light, and conductivity. Applications in soft and hard tissue engineering, 4D printing, and scaffold design are also discussed. The advanced application of microfluidics, like organ-on-a-chip models, extensively benefits from the intrinsic smart properties of biomaterials, which are also discussed below. The review further elaborates on how smart biomaterial engineering could revolutionize biosensor applications, thereby improving patient care quality. We delineate the limitations and key challenges associated with biomaterials, providing insights into the path forward and outlining future directions for developing next-generation biomaterials that will facilitate clinical translation.

Musculoskeletal disorders are on the rise, and despite advances in alternative materials, treatment for orthopedic conditions still heavily relies on biometal-based implants and scaffolds due to their strength, durability, and biocompatibility in load-bearing applications. Bare metallic implants have been under scrutiny since their introduction, primarily due to their bioinert nature, which results in poor cell-material interaction. This challenge is further intensified by mechanical mismatches that accelerate failure, tribocorrosion-induced material degradation, and bacterial colonization, all contributing to long-term implant failure and posing a significant burden on patient populations. Recent efforts to improve orthopedic medical devices focus on surface engineering strategies that enhance the interaction between cells and materials, creating a biomimetic microenvironment and extending the service life of these implants. This review compiles various physical, chemical, and biological surface engineering approaches currently under research, providing insights into their potential and the challenges associated with their adoption from bench to bedside. Significant emphasis is placed on exploring the future of bioactive coatings, particularly the development of smart coatings like self-healing and drug-eluting coatings, the immunomodulatory effects of functional coatings and biomimetic surfaces to tackle secondary infections, representing the forefront of biomedical surface engineering. The article provides the reader with an overview of the engineering approaches to surface modification of metallic implants, covering both clinical and research perspectives and discussing limitations and future scope.

Biomimetic approaches to implant construction are a rising frontier in implantology. Triple Periodic Minimal Surface (TPMS)-based additively manufactured gyroid structures offer a mean curvature of zero, rendering this structure an ideal porous architecture. Previous studies have demonstrated the ability of these structures to effectively mimic the mechanical cues required for optimal implant construction. The porous nature of gyroid materials enhances bone ingrowth, thereby improving implant stability within the body. This enhancement is attributed to the increased surface area of the gyroid structure, which is approximately 185% higher than that of a dense material of the same form factor. This larger surface area allows for enhanced cellular attachment and nutrient circulation facilitated by the porous channels. This study aims to evaluate the biological performance of a gyroid-based Ti6Al-4V implant material compared to a dense alloy counterpart. Cellular viability was assessed using the lactate dehydrogenase (LDH) assay, which demonstrated that the gyroid surface allowed marginally higher viability than dense material. The in vivo integration was studied over 6 weeks using a rabbit tibia model and characterized using X-ray, micro-CT, and histopathological examination. With a metal volume of 8.1%, the gyroid exhibited a bone volume/total volume (BV/TV) ratio of 9.6%, which is 11-fold higher than that of dense metal (0.8%). Histological assessments revealed neovascularization, in-bone growth, and the presence of a Haversian system in the gyroid structure, hinting at superior osteointegration.

Laser shock peening without coating (LSPwC), a prospective surface modification technique for improving the mechanical aspects of Ti-6Al-4V alloy for automotive/aerospace sector, is also expected to dictate the efficiency of this material class for implant application. Here we unravel the impact of LSPwC on Ti-6Al-4V material surface characteristics, in-vitro tribocorrosion and biocompatibility. Micrography shows the presence of nano and submicron sized pores after LSPwC process. The role of nano and sub-micron sized pores along with topography modification induced by LSPwC to serve as cues for controlling gene expressions, cell adhesion and activities offer novel insights in this research direction. A detailed X-ray photoelectron spectroscopy analysis detected local chemical non-stoichiometry with reduced number of oxygen diffusion channels. A crucial outcome of this oxide layer modification is the negative skewness (-0.55 +/- 0.11) and reduced kurtosis (3.49 +/- 0.14) of the surface, along with localized plastic deformation. These factors are correlated with the shift in potential during fretting tribo-corrosion from -800 to -250 mV after LSPwC, accompanied by a lower coefficient of friction of 0.4. Furthermore, the presence of well-spread cells and the up-regulation of beneficial genetic markers (Ki67) on LSPwC surfaces have the potential to form a better bone-material interface. The findings open new frontiers of the LSPwC-treated Ti-6Al-4V surface to synergistically modulate the tribocorrosion and biocompatibility aspects, with exciting possibilities for biomedical implants.

A newly developed single BCC phase 30Nb5Ta30Ti15V20Zr refractory high entropy alloy (RHEA) has been designed for low density, high mechanical properties, and superior fretting wear resistance. In this study, we focus on the study of the fretting wear resistance in a comparison with Ti6Al4V alloy. The 30Nb5Ta30Ti15V20Zr demonstrated the better fretting wear resistance with low friction coefficient and wear loss. The phase constituent, crystal structure and mutual interaction of complex composition in 30Nb5Ta30Ti15V20Zr contribute to improving the fretting wear resistance. The superior fretting wear resistance increases candidacy potential of the 30Nb5Ta30Ti15V20Zr RHEA for structural applications, especially under fretting conditions.

This paper reports the effect of varying laser-peening fluences (3, 6 and 9 GW/cm2) on surface topography, oxide composition and wettability of low modulus Ti-22Nb at.% (Ti-35.4Nb wt.%) alloy with specific focus on the ensuing fretting wear and biocompatibility. Microtopography with nano-sized pores were generated during the laser interaction. LP-6 and LP-9 GW/cm2 surfaces displayed nano-porous distribution, with topographies characterized by negative skewness and platykurtosis. X-ray photoelectron studies revealed the development of mixed oxide layers rich in Ti4+ and Nb5+ when laser fluence was increased. Improved hydrophilic behavior was observed with increment in laser fluence displaying contact angles of 47.1° and 43.2° for LP-6 and LP-9 GW/cm2. Based on the preliminary surface characterizations, LP-6 and LP-9 GW/cm2 which displayed a platykurtic surface with negative skewness, Ti-Nb based mixed oxides and stable hydrophilic nature were selected for further analysis. Presence of Nb5+ ions rendered the oxide surfaces less defective, thereby improving fretting wear resistance. In particular, well-spread cells and up-regulation of beneficial genetic-markers (Ki67) on laser-peened surfaces demonstrated the role of nano-sized cues and oxide-layer in improving osseointegration aspects. Results demonstrate that LP-6 and LP-9 GW/cm2 surfaces on low modulus Ti-22Nb alloy can beneficially contribute towards the fretting wear and biocompatibility.

Biomimetics is an emerging field of science that adapts the working principles from nature to fine-tune the engineering design aspects to mimic biological structure and functions. The application mainly focuses on the development of medical implants for hard and soft tissue replacements. Additive manufacturing or 3D printing is an established processing norm with a superior resolution and control over process parameters than conventional methods and has allowed the incessant amalgamation of biomimetics into material manufacturing, thereby improving the adaptation of biomaterials and implants into the human body. The conventional manufacturing practices had design restrictions that prevented mimicking the natural architecture of human tissues into material manufacturing. However, with additive manufacturing, the material construction happens layer-by-layer over multiple axes simultaneously, thus enabling finer control over material placement, thereby overcoming the design challenge that prevented developing complex human architectures. This review substantiates the dexterity of additive manufacturing in utilizing biomimetics to 3D print ceramic, polymer, and metal implants with excellent resemblance to natural tissue. It also cites some clinical references of experimental and commercial approaches employing biomimetic 3D printing of implants.