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Nitinol is a versatile alloy known for its shape memory effect and thus finds multiple applications in biomedical devices and implants. The biomedical applications of nitinol-based devices are, however, limited because of concerns related to leaching and its associated cytotoxicity. In particular, nitinol nanoparticles (NPs), despite being highly promising for biomedical applications such as nano-actuators and biomolecular delivery agents are not explored, owing to the same concerns. Moreover, nitinol nanoparticles and their biological interactions are not fully characterized, and the available literature on their toxicity portrays a divided picture. Surface passivation of nitinol using multiple methods has been explored in the past to reduce the leaching of nickel in implants while also improving the thrombogenic properties. In this work, we reported the preparation of passivized nitinol NPs by laser ablation of nitinol targets, followed by different surface treatments. The effect of different treatments in reducing nickel leaching and its influence on biocompatibility were studied. The biocompatibility and multi-faceted interaction of nitinol NPs with osteoblast cells and associated toxicity were explored. Homogenous nitinol NPs were found to be generated at 25 W of laser power. Also, surface modification using hydrogen peroxide, anodization, and acid etching was found to be effective in waning the nickel leaching and improving biocompatibility. In view of the observed results of cellular interactions, we discussed the possible routes of cellular toxicity of these NPs. The prospective applications of such passivized NPs in the biomedical field are also discussed in this work.

Site-specific drug delivery has the potential to reduce drug dosage by 3 to 5-folds. Given the propensity of drugs used in the treatment of tuberculosis and cancers, the increased drug dosages via oral ingestion for several months to a few years of medication is often detrimental to the health of patients. In this study, the sustained delivery of drugs with multiscale structured novel Neovius lattices was achieved. 3D Neovius Open Cell Lattices (NOCL) with porosities of 40, 45, and 50 % were fabricated layer-by-layer on the laser bed fusion process. Micron-sized Ti6Al4V Eli powder was used for 3D printing. The Young’s modulus achieved from the novel Neovius lattices were in the range of 1.2 to 1.6 GPa, which is comparable to human cortical bone and helps to improve implant failure due to the stress shielding effect. To provide sustained drug delivery, nanotubes (NTs) were fabricated on NOCLs via high-voltage anodisation. The osteogenic agent icariin was loaded onto the NOCL-NT samples and their release profiles were studied for 7 days. A significantly steady and slow release rate of 0.05% per hour of the drug was achieved using NOCL-NT. In addition, the initial burst release of NOCL-NT was 4 fold lower than that of the open-cell lattices without nanotubes. Cellular studies using MG63 human osteoblast-like cells were performed to determine their biocompatibility and osteogenesis which were analysed using Calcein AM staining and Alamar Blue after 1, 5, and 7 days. 3D printed NOCL samples with NTs and with Icariin loaded NTs demonstrated a significant increase in cell proliferation as compared to as printed NOCL samples.

The avascular nature of cartilage tissue limits the self-regeneration ability of the tissue to counter any damage and this has become a substantial burden to health of individuals. As a result, there is a high demand to repair and regenerate cartilage; several methods have been developed, primarily based on tissue-engineering techniques. So far, emphasis has been given to modifying the scaffold’s surface chemistry, crosslinking, and porosity to induce stem cell differentiation into chondrocytes to deposit thick cartilage extracellular matrix (ECM). However, most of these studies produced either microporous or nano-fibrous scaffolds to regenerate cartilage, but they lack biomimetic dual architecture of microporous construct with nano-fibrous interconnected structure like the native cartilage. Over the years, researchers have designed scaffolds to mimic tissue microenvironment with key metabolic components to promote efficient regeneration of tissue. Thus, scaffolds with dual architecture of microporous construct comprising of a nano-fibrous interconnected networks like native cartilage embedded with metabolite sources are necessary for a successful engineering of cartilage regeneration. Hence, in the present work, we have developed a biomimetic elastic, micro porous construct with nano-fibrous interconnection network of cellulose aerogel reinforced with arginine amino acid-functionalized graphene oxide for cartilage regeneration. The designed dual architectured aerogel loaded with bioenergetics provided multifunctionality via biomimetic morphology, enhanced mechanical stability, and cellular energetics to address the need for regeneration of cartilage tissues.