Gold nanoparticles (AuNPs) with interesting optical properties have attracted much attention in recent years. The synthesis and plasmonic properties of AuNPs with a controllable size and shape have been extensively investigated. Among these AuNPs, gold nanotriangles (AuNTs) exhibited unique optical and plasmonic properties due to their special triangular anisotropy. Indeed, AuNTs showed promising applications in optoelectronics, optical sensing, imaging and other fields. However, only few reviews about these applications have been reported. Herein, we comprehensively reviewed the synthesis and self-assembly of AuNTs and their applications in recent years. The preparation protocols of AuNTs are mainly categorized into chemical synthesis, biosynthesis and physical-stimulus-induced synthesis. The comparison between the advantages and disadvantages of various synthetic strategies are discussed. Furthermore, the specific surface modification of AuNTs and their self-assembly into different dimensional nano- or microstructures by various interparticle interactions are introduced. Based on the unique physical properties of AuNTs and their assemblies, the applications towards chemical biology and sensing were developed. Finally, the future development of AuNTs is prospected.

Along with the development of controlled delivery systems for targeted therapy, ‘single-strategy’ therapy often fails to achieve the desired performance in real body internal environments. In such a case, it is necessary to develop synergistic therapy strategies. Herein, for the first time, we designed and synthesized hyaluronic acid (HA) modified Ag@S-nitrosothiol core–shell nanoparticles for synergistic tumor cell targeted therapy based on photothermal therapy (PTT) and nitric oxide (NO) based chemotherapy. Triggered by near-infrared irradiation (NIR), the Ag core nanoparticle would convert the light to cytotoxic heat via a surface plasmon resonance mechanism for cancer cell apoptosis. Meanwhile, responding to NIR as well as the generated heat, the S-nitrosothiol polymeric shells would give off free NO at high concentration, inducing NO based chemotherapy. Tumor cell selective cytotoxicity assay in vitro as well as tumor bearing mouse experiments in vivo demonstrated the effective photothermal and NO based chemical synergistic tumor targeted therapy. This spatiotemporally controllable system could provide a new option and era for tumor targeted therapy in the future.

Magnetite nanoparticles (Fe₃O₄ NPs) have garnered significant attention over the past twenty years, primarily due to their superparamagnetic properties. These properties allow the NPs to respond to external magnetic fields, making them particularly useful in various technological applications. One of the most fascinating aspects of Fe₃O₄ NPs is their ability to self-assemble into complex structures. Research over this period has focused heavily on how these nanoparticles can be organized into a variety of superstructures, classified by their dimensionality—namely one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) configurations. Despite a wealth of studies, the literature lacks a systematic review that synthesizes these findings. This review aims to fill that gap by providing a thorough overview of the recent progress made in the fabrication and organization of Fe₃O₄ NP assemblies via a bottom-up self-assembly approach. This methodology enables the controlled construction of assemblies at the nanoscale, which can lead to distinctive functionalities compared to their individual counterparts. Furthermore, the review explores the diverse applications stemming from these nanoparticle assemblies, particularly emphasizing their contributions to important areas such as imaging, drug delivery, and the diagnosis and treatment of cancer.

Among the strategies for the treatment of bacterial infections, antibiotics are one of the preferred options. With prolonged use, however, antibiotic resistance has become a growing problem, especially the significant antibacterial activity loss against acidity associated bacterial infections. Herein, surface charge switchable nitric oxide (NO)-releasing nanoparticles (PNBNPs) were designed and synthesized. With the protection of the surface charge switchable shell, the PNBNPs maintain weak negative surface charge and “silent” status during transmission under normal physiological pH conditions. In an acidic environment, the surface polymeric shell is protonated, giving it a positively charged surface, and this benefits the binding of the PNBNPs with the negatively charged bacterial surface. In contrast to the significant antibacterial activity loss of antibiotics in acidic environments, the PNBNPs trigger faster NO release to form highly reactive oxynitride species (such as N₂O₃, NO₂ ⁻, OONO⁻, etc.), causing strong membrane disruption and cell apoptosis, leading to intensive antibacterial activity. The PNBNPs demonstrated excellent biocompatibility and acidity-associated bacterial infection targeted treatment, according to the bacteria binding, the antibacterial activity, and normal cell cytotoxicity assays in vitro, as well as investigations into the therapeutic effects in different pH environments in vivo. These responsive NO-releasing nanoparticles will provide a new option for overcoming acidity-associated bacterial infections and antibiotic resistance problems in the future.

Tumor targeted hollow double-layered polymer nanoparticles (HDPNs) with S-nitrosothiols for nitric oxide (NO)-release as chemotherapy were described. Via a two-stage distillation precipitation co-polymerization, simple post-treatment and S-nitrosothiol modification, the S-nitroso HDPNs showed pH and glucose dual responsiveness. This would benefit accurate binding with the sialic acid over-expressed cancer cells, providing prerequisites for the disulfide polymer assisted cell uptake, intracellular GSH induced decomposition and rapid NO release. Confocal microscopy and cytotoxicity assay with normal versus tumor cells demonstrated in vitro recognition, intracellular delivery ability and tumor cell targeting cytotoxicity. Especially worth mentioning, the inevitable small amount of NO leakage in the transmission would take part in normal physiological activities and not cause serious side effects, providing a possible solution to avoid the intolerable side effects of traditional chemotherapy treatments for cancer.