Gold nanostructure-mediated delivery of anticancer agents: Biomedical applications, reversing drug resistance, and stimuli-responsive nanocarriers.

The application of nanoarchitectures in cancer therapy seems to be beneficial for the delivery of antitumor drugs. In recent years, attempts have been made to reverse drug resistance, one of the factors threatening the lives of cancer patients worldwide. Gold nanoparticles (GNPs) are metal nanostructures with a variety of advantageous properties, such as tunable size and shape, continuous release of chemicals, and simple surface modification. This review focuses on the application of GNPs for the delivery of chemotherapy agents in cancer therapy. Utilizing GNPs results in targeted delivery and increased intracellular accumulation. Besides, GNPs can provide a platform for the co-delivery of anticancer agents and genetic tools with chemotherapeutic compounds to exert a synergistic impact. Furthermore, GNPs can promote oxidative damage and apoptosis by triggering chemosensitivity. Due to their capacity for providing photothermal therapy, GNPs can enhance the cytotoxicity of chemotherapeutic agents against tumor cells. The pH-, redox-, and light-responsive GNPs are beneficial for drug release at the tumor site. For the selective targeting of cancer cells, surface modification of GNPs with ligands has been performed. In addition to improving cytotoxicity, GNPs can prevent the development of drug resistance in tumor cells by facilitating prolonged release and loading low concentrations of chemotherapeutics while maintaining their high antitumor activity. As described in this study, the clinical use of chemotherapeutic drug-loaded GNPs is contingent on enhancing their biocompatibility.

Current transfer torque and Hall conductance at the ferromagnetic topological insulators junction.

In-plane magnetization on the surface of three-dimensional topological insulators (3D TIs) tunes the Dirac cone's location in thek-space. We theoretically show that a normal/ferromagnetic junction on the surface of 3D TIs bends the propagation direction of Dirac fermions when the magnetization has a component perpendicular to the junction. This effect leads to a Hall conductance, which flows parallel to the interface. Also, it creates an indirect gap that manifests itself in the longitudinal conductance of the junction. The sign of Hall conductance is related to the in-plane magnetization direction. Based on this effect, we propose a set up to detect it experimentally. Moreover, this bending effect imposes a torque on the junction calledcurrent transfer torque(CTT). We show thez-component of CTT is non-zero in the presence of bending effect. Also, its value and direction that can be used in fabricating new devices are related to the Hall conductance.

Switchable crossed spin conductance in a graphene-based junction: The role of spin-orbit coupling.

We theoretically investigate the crossed spin conductance (CSC) of a graphene-based heterostructure consists of ferromagnet, Rashba spin-orbit and superconductor regions. Using Dirac Bogoliubov-de Gennes formalism in the ballistic regime, we show that in the presence of Rashba spin-orbit coupling there are an anomalous crossed Andreev reection and spin-ipped co-tunneling in the process of quantum transport. We demonstrate that the CSC can be reversed with respect to charge conductance by tuning the Rashba spin-orbit coupling which experimentally can be adjusted by the applied perpendicular electric field on the graphene sheet. This feature in addition to a long spin relaxation time of Dirac fermions in graphene proposes designing a device with a non-local spin switch which is crucial for spintronics circuits.