A novel gold nanorods coated by stimuli-responsive ABC triblock copolymer for chemotherapy of solid tumors

Gold Nanorods for Drug and Gene Delivery: An Overview of Recent Advancements

Over the past few decades, gold nanomaterials have shown great promise in the field of nanotechnology, especially in medical and biological applications. They have become the most used nanomaterials in those fields due to their several advantageous. However, rod-shaped gold nanoparticles, or gold nanorods (GNRs), have some more unique physical, optical, and chemical properties, making them proper candidates for biomedical applications including drug/gene delivery, photothermal/photodynamic therapy, and theranostics. Most of their therapeutic applications are based on their ability for tunable heat generation upon exposure to near-infrared (NIR) radiation, which is helpful in both NIR-responsive cargo delivery and photothermal/photodynamic therapies. In this review, a comprehensive insight into the properties, synthesis methods and toxicity of gold nanorods are overviewed first. For the main body of the review, the therapeutic applications of GNRs are provided in four main sections: (i) drug delivery, (ii) gene delivery, (iii) photothermal/photodynamic therapy, and (iv) theranostics applications. Finally, the challenges and future perspectives of their therapeutic application are discussed.

Development of gold nanorods for cancer treatment

There has been growing interest in the application of gold nanorods (GNRs) to tumor therapy due to the unique properties they possess. In the past, GNRs were not used in clinical treatments as they lacked stability in vivo and were characterized by potential toxicity. Despite these issues, the significant potential for utilizing GNRs to conduct safe and effective treatments for tumors cannot be ignored. Therefore, it remains crucial to thoroughly investigate the mechanisms behind the toxicity of GNRs in order to provide the means of overcoming obstacles to its full application in the future. This review presents the toxic effects of GNRs, the factors affecting toxicity and the methods to improve biocompatibility, all of which are presently being studied. Finally, we conclude by briefly discussing the current research status of GNRs and provide additional perspective on the challenges involved along with the course of development for GNRs in the future.

Recent Advancements in Stimuli Responsive Drug Delivery Platforms for Active and Passive Cancer Targeting

The tumor-specific targeting of chemotherapeutic agents for specific necrosis of cancer cells without affecting the normal cells poses a great challenge for researchers and scientists. Though extensive research has been carried out to investigate chemotherapy-based targeted drug delivery, the identification of the most promising strategy capable of bypassing non-specific cytotoxicity is still a major concern. Recent advancements in the arena of onco-targeted therapies have enabled safe and effective tumor-specific localization through stimuli-responsive drug delivery systems. Owing to their promising characteristic features, stimuli-responsive drug delivery platforms have revolutionized the chemotherapy-based treatments with added benefits of enhanced bioavailability and selective cytotoxicity of cancer cells compared to the conventional modalities. The insensitivity of stimuli-responsive drug delivery platforms when exposed to normal cells prevents the release of cytotoxic drugs into the normal cells and therefore alleviates the off-target events associated with chemotherapy. Contrastingly, they showed amplified sensitivity and triggered release of chemotherapeutic payload when internalized into the tumor microenvironment causing maximum cytotoxic responses and the induction of cancer cell necrosis. This review focuses on the physical stimuli-responsive drug delivery systems and chemical stimuli-responsive drug delivery systems for triggered cancer chemotherapy through active and/or passive targeting. Moreover, the review also provided a brief insight into the molecular dynamic simulations associated with stimuli-based tumor targeting.

Development of a graphene oxide-poly lactide nanocomposite as a Smart Drug Delivery System

In this study, a nanoscale graphene oxide polymer composite drug delivery system was synthesized and investigated for possible oral delivery of doxorubicin. A doxorubicin-loaded nanocomposite composed of graphene oxide/poly(2-hydroxyethylmethacrylate)-g-poly(lactide)-b-polyethyleneglycol-b-poly(2-hydroxyethylmethacrylate)-g-poly(lactide) GO/(PHEMA-g-PLA)-b-PEG-b-(PHEMA-g-PLA) was synthesized via reversible addition fragmentation chain (RAFT) and ring open polymerization (ROP). The GO/(PHEMA-g-PLA)-b-PEG-b- (PHEMA-g-PLA) nanocomposites was characterized by scanning electron microscopy (FE-SEM), thermogravimetry (TG), ultraviolet-visible (UV-Vis) spectroscopy, and dynamic light scattering (DLS). Doxorubicin was successfully loaded into the nanocomposite with a small particle size of 51 nm and an encapsulation efficiency (EE) of 82% ±1.12%. The results showed that DOX was attached to the graphene surface via hydrophobic interactions and π-π stacking. DOX release took place under neutral and acidic conditions, reaching 24.7% and 41.2% respectively after 72 h. Cytotoxicity experiments on 4T1 murine breast cancer cells demonstrated the antitumor activity of the DOX@GO nanocomposite. Biocompatibility, cell uptake, DAPI staining, Annexin V/PI double staining, intracellular reactive oxygen species (ROS) assay, and scratch healing assay were measured. The DOX@graphene nanocomposite system could be promising for breast cancer therapy.

Porous Graphene Oxide Films Prepared via the Breath-Figure Method: A Simple Strategy for Switching Access of Redox Species to an Electrode Surface

Porous materials can be modified with physical barriers to control the transport of ions and molecules through channels via an external stimulus. Such capability has brought attention toward drug delivery, separation methods, nanofluidics, and point-of-care devices. In this context, gated platforms on which access to an electrode surface of species in solution can be reversibly hindered/unhindered on demand are appearing as promising materials for sensing and microfluidic switches. The preparation of a reversible gated device usually requires mesoporous materials, nanopores, or molecularly imprinted polymers. Here, we show how the breath-figure method assembly of graphene oxide can be used as a simple strategy to produce gated electrochemical materials. This was achieved by forming an organized porous thin film of graphene oxide onto an ITO surface. Localized brushes of thermoresponsive poly(N-isopropylacrylamide) were then grown to specific sites of the porous film by in situ reversible addition-fragmentation chain-transfer polymerization. The gating mechanism relies on the polymeric chains to expand and contract depending on the thermal stimulus, thus modulating the accessibility of redox species inside the pores. The resulting platform was shown to reversibly hinder or facilitate the electron transfer of solution redox species by modulating temperature from the room value to 45 °C or vice versa.

Multi-stimuli-responsive nanomicelles fabricated using synthetic polymer polylysine conjugates for tumor microenvironment dependent drug delivery

A poly(lysine)-synthetic polymer hybrid nanomicelles were fabricated as promising platform for efficient tumor targeting and glutathione/pH/temperature-responsive anticancer drug delivery.