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Future biomedical applications of nanomachines require elimination of fuel requirements since most of the fuels have potential toxic effects. Herein, we report fuel-free magnetically powered gold–nickel (Au–Ni) nanowires as nanomotors for multipurpose biomedical applications. Fabrication of the nanowire-based nanomotors developed in this study is unique, and this protocol was dependent on the electrochemical preparation of Au nanowires followed by the direct current (DC) magnetron sputtering of Ni part. DC magnetron sputtering-based preparation used for the first time in the literature not only ensured homogeneous distribution and rapid deposition of the metal directly but also provided reproducible thin layers of magnetic Ni resulting in a significant improvement at nanomotor speeds. Besides magnetic propulsion, acoustic propulsion was also successfully applied. The effects of both propusion mechanisms were tested on the speed and direction of Au–Ni nanomotors. Biomedical applications of the motors accomplished in this study are rapid and sensitive detection of an important cancer biomarker microRNA-21 (miRNA-21) and pH-dependent and near-infrared (NIR) triggered release of a commonly used chemotherapeutic drug doxorubicin (DOX). Sensitive and selective miRNA-21 detection was achieved by using dye-labeled single-stranded DNA (ssDNA probe) modified Au–Ni nanomotors with a wide linear concentration range of 0.01 nM to 25 nM. Low detection limits of 2.9 pM and 1.6 pM were obtained for fluorescence and speed-based detection, respectively (n = 3). In addition, magnetically powered DOX-loaded Au–Ni nanomotors were guided on cancer cells (human breast cancer cell lines, MCF-7) in a controllable way for the efficient and controlled delivery of DOX. Cytotoxicity studies of the nanomotors presented negligible influence on the cell viability.

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Polyoxazolines are a new promising class of polymers for biomedical applications. Antibiofouling polyoxazoline coatings can suppress bacterial colonization of medical devices, which can cause infections to patients. However, the creation of oxazoline-based films using conventional methods is difficult. This study presents a new way to produce plasma polymerized oxazoline-based films with antibiofouling properties and good biocompatibility. The films were created via plasma deposition from 2-methyl-2-oxazoline vapors in nitrogen atmospheric pressure dielectric barrier discharge. Diverse film properties were achieved by increasing the substrate temperature at the deposition. The physical and chemical properties of plasma polymerized polyoxazoline films were studied by SEM, EDX, FTIR, AFM, depth-sensing indentation technique, and surface energy measurement. After tuning of the deposition parameters, films with a capacity to resist bacterial biofilm formation were achieved. Deposited films also promote cell viability.

b-Type titanium alloys are promising materials for orthopaedic implants due to their relatively low Young's modulus and excellent biocompatibility. However, their strength is lower than those of a-or a ? b-type titanium alloys. Grain refinement by severe plastic deformation (SPD) techniques provides a unique opportunity to enhance mechanical properties to prolong the lifetime of orthopaedic implants without changing their chemical composition. In this study, b-type Ti-45Nb (wt%) biomedical alloy in the form of 30 mm rod was subjected to hydrostatic extrusion (HE) to refine the microstructure and improve its mechanical properties. HE processing was carried out at room temperature without intermediate annealing in a multi-step process, up to an accumulative true strain of 3.5. Significant microstructure refinement from a coarse-grained region to an ultrafine-grained one was observed by optical and transmission electron microscopy. Vickers hardness measurements (HV 0.2 ) demonstrated that the strength of the alloy increased from about 150 to 210 HV 0.2 . Nevertheless, the measurements of Young's modulus by nanoindentation showed no significant changes. This finding is substantiated by X-ray diffraction analyses which did not exhibit any phase transformation out of the bcc phase being present still before processing by HE. These results thus indicate that HE is a promising SPD method to obtain significant grain refinement and enhance strength of b-type Ti-45Nb alloy without changing its low Young's modulus, being one prerequisite for biomedical application.

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Beside biomaterials’ bulk properties, their surface properties are equally important to control interfacial biocompatibility. However, due to the inadequate interaction with tissue, they may cause foreign body reaction. Moreover, surface induced thrombosis can occur when biomaterials are used for blood containing applications. Surface modification of the biomaterials can bring enhanced surface properties in biomedical applications. Sulfated polysaccharide coatings can be used to avoid surface induced thrombosis which may cause vascular occlusion (blocking the blood flow by blood clot), which results in serious health problems. Naturally occurring heparin is one of the sulfated polysaccharides most commonly used as an anticoagulant, but its long term usage causes hemorrhage. Marine sourced sulfated polysaccharide fucoidan is an alternative anticoagulant without the hemorrhage drawback. Heparin and fucoidan immobilization onto a low density polyethylene surface after functionalization by plasma has been studied. Surface energy was demonstrated by water contact angle test and chemical characterizations were carried out by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Surface morphology was monitored by scanning electron microscope and atomic force microscope. Finally, their anticoagulation activity was examined for prothrombin time (PT), activated partial thromboplastin time (aPTT), and thrombin time (TT).