Synthesis and Antitumor Application of Antiangiogenetic Gold Nanoclusters

Synergistic interactions between physical exercise intervention, innovative materials, and neurovascular coupling in bone repair and injury recovery: a comprehensive review

Bone injury presents a prevalent challenge in clinical settings, with traditional treatment modalities exhibiting inherent limitations. Recent advancements have highlighted the potential of combining physical exercise intervention and innovative materials to enhance bone repair and recovery. This review explores the synergistic effects of physical exercise and novel materials in promoting bone regeneration, with a particular focus on the role of neurovascular coupling (NVC) mechanisms. Physical exercise not only stimulates bone cell function and blood circulation but also enhances the bioactivity of novel materials, such as nanofiber membranes and smart materials, which provide supportive scaffolds for bone cell attachment, proliferation, and differentiation. NVC, involving the interaction between neural activity and blood flow, is integral to the bone repair process, ensuring the supply of nutrients and oxygen to the injured site. Studies demonstrate that the combination of physical exercise and novel materials can accelerate bone tissue regeneration, with exercise potentially enhancing the bioactivity of materials and materials improving the effectiveness of exercise. However, challenges remain in clinical applications, including patient variability, material biocompatibility, and long-term stability. Optimizing the integration of physical exercise and novel materials for optimal therapeutic outcomes is a key focus for future research. This review examines the collaborative mechanisms between physical exercise, novel materials, and NVC, emphasizing their potential and the ongoing challenges in clinical settings. Further exploration is needed to refine their application and improve bone repair strategies.

Selenium-Chondroitin Sulfate Nanoparticles Inhibit Angiogenesis by Regulating the VEGFR2-Mediated PI3K/Akt Pathway

Chondroitin sulfate (CS), a class of glycosaminoglycans covalently attached to proteins to form proteoglycans, is widely distributed in the extracellular matrix and cell surface of animal tissues. In our previous study, CS was used as a template for the synthesis of seleno-chondroitin sulfate (SeCS) through the redox reaction of ascorbic acid (Vc) and sodium selenite (Na2SeO3) and we found that SeCS could inhibit tumor cell proliferation and invasion. However, its effect on angiogenesis and its underlying mechanism are unknown. In this study, we analyzed the effect of SeCS on tube formation in vitro, based on the inhibition of tube formation and migration of human umbilical vein endothelial cells (HUVECs), and evaluated the in vivo angiogenic effect of SeCS using the chick embryo chorioallantoic membrane (CAM) assay. The results showed that SeCS significantly inhibited the angiogenesis of chicken embryo urothelium. Further mechanism analysis showed that SeCS had a strong inhibitory effect on VEGFR2 expression and its downstream PI3K/Akt signaling pathway, which contributed to its anti-angiogenic effects. In summary, SeCS showed good anti-angiogenic effects in an HUVEC cell model and a CAM model, suggesting that it may be a potential angiogenesis inhibitor.

Applications of Au25 Nanoclusters in Photon-Based Cancer Therapies

Atomically precise gold nanoclusters (AuNCs) exhibit unique physical and optical properties, making them highly promising for targeted cancer therapy. Their small size enhances cellular uptake, facilitates rapid distribution to tumor tissues, and minimizes accumulation in non-target organs compared to larger gold nanoparticles. AuNCs, particularly Au25, show significant potential in phototherapy, including photothermal (PTT), photodynamic (PDT), and radiation therapies. These therapies benefit with minimal damage to surrounding healthy tissue. AuNCs also demonstrate excellent stability and biocompatibility, crucial for their effective use in clinical applications. Recent advances in the synthesis and functionalization of AuNCs have further improved their therapeutic efficacy, making them versatile agents for enhancing cancer treatment outcomes. Ongoing research aims to better understand their pharmacokinetics, biodistribution, and long-term safety, paving the way for their broader application in advanced cancer therapies.

The roles of templates consisting of amino acids in the synthesis and application of gold nanoclusters

Gold nanoclusters (AuNCs) with low toxicity, high photostability, and facile synthesis have attracted great attention. The ligand is of great significance in stabilizing AuNCs and regulating their properties. Ligands consisting of amino acids (proteins and peptides) are an ideal template for synthesizing applicative AuNCs due to their inherent bioactivity, biocompatibility, and accessibility. In this review, we summarize the correlation of the template consisting of amino acids with the properties of AuNCs by analyzing different peptide sequences. The selection of amino acids can regulate the fluorescence excitation/emission and intensity, size, cell uptake, and light absorption. By analyzing the role played by AuNCs stabilized by proteins and peptides in the application, universal rules and detailed performances of sensors, antibacterial agents, therapeutic reagents, and light absorbers are reviewed. This review can guide the template design and application of AuNCs when selecting proteins and peptides as ligands.

Mercaptopyrimidine-templated gold nanoclusters for antithrombotic therapy

Here we report for the first time that mercaptopyrimidine-templated gold nanoclusters (DAMP-AuNCs) can be used as a novel anticoagulant candidate for the design of antithrombotic drugs. Anticoagulant mechanisms revealed that DAMP-AuNCs significantly inhibited thrombus formation by interacting with fibrinogen. Carrageenan-induced mice tail thrombosis model experiments showed that DAMP-AuNCs had antithrombotic efficacy comparable to heparin in vivo. More importantly, these ultrasmall AuNCs possess excellent blood compatibility and only induce negligible bleeding side effects. Our study is a successful attempt at developing novel antithrombotic agents with high biosafety.

Vascular Endothelial Growth Factor Receptor 1 Targeting Fusion Polypeptides with Stimuli-Responsiveness for Anti-angiogenesis

Genetically engineered fusion polypeptides have been investigated to introduce unique bio-functionality and improve some therapeutic activity for anti-angiogenesis. We report herein that stimuli-responsive, vascular endothelial growth factor receptor 1 (VEGFR1) targeting fusion polypeptides composed of a VEGFR1 (fms-like tyrosine kinase-1 (Flt1)) antagonist, an anti-Flt1 peptide, and a thermally responsive elastin-based polypeptide (EBP) were rationally designed at the genetic level, biosynthesized, and purified by inverse transition cycling to develop potential anti-angiogenic fusion polypeptides to treat neovascular diseases. A series of hydrophilic EBPs with different block lengths were fused with an anti-Flt1 peptide, forming anti-Flt1-EBPs, and the effect of EBP block length on their physicochemical properties was examined. While the anti-Flt1 peptide decreased phase-transition temperatures of anti-Flt1-EBPs, compared with EBP blocks, anti-Flt1-EBPs were soluble under physiological conditions. The anti-Flt1-EBPs dose dependently inhibited the binding of VEGFR1 against vascular endothelial growth factor (VEGF) as well as tube-like network formation of human umbilical vein endothelial cells under VEGF-triggered angiogenesis in vitro because of the specific binding between anti-Flt1-EBPs and VEGFR1. Furthermore, the anti-Flt1-EBPs suppressed laser-induced choroidal neovascularization in a wet age-related macular degeneration mouse model in vivo. Our results indicate that anti-Flt1-EBPs as VEGFR1-targeting fusion polypeptides have great potential for efficacious anti-angiogenesis to treat retinal-, corneal-, and choroidal neovascularization.

A Simple Schiff Base as Fluorescent Probe for Detection of Al3+ in Aqueous Media and its Application in Cells Imaging

A novel fluorescence probe for the detection of Al³⁺ was developed based on methionine protected gold nanoclusters (Met-AuNCs). A fluorescent Schiff base (an aldimine) is formed between the aldehyde group of salicylaldehyde (SA) and the amino groups of Met on the AuNCs, and developed for selective detection of Al³⁺ in aqueous solution. Al³⁺ can strongly bind with the Schiff base ligands, accompanied by the blue-shift and an obvious fluorescence emission enhancement at 455 nm. The limits of detection (LODs) of the probe are 2 pmol L^-1 for Al³⁺. Moreover, the probe can successfully be used in fluorescence imaging of Al³⁺ in living cells (SHSY5Y cells), suggesting that the simple fluorescent probe has great potential use in biological imaging.

Stimuli-responsive nanoassemblies for targeted delivery against tumor and its microenvironment

Despite the emergence of various cancer treatments, such as surgery, chemotherapy, radiotherapy, and immunotherapy, their use remains restricted owing to their limited tumor elimination efficacy and side effects. The use of nanoassemblies as delivery systems in nanomedicine for tumor diagnosis and therapy is flourishing. These nanoassemblies can be designed to have various shapes, sizes, and surface charges to meet the requirements of different applications. It is crucial for nanoassemblies to have enhanced delivery of payloads while inducing minimal to no toxicity to healthy tissues. In this review, stimuli-responsive nanoassemblies capable of combating the tumor microenvironment (TME) are discussed. First, various TME characteristics, such as hypoxia, oxidoreduction, adenosine triphosphate (ATP) elevation, and acidic TME, are described. Subsequently, the unique characteristics of the vascular and stromal TME are differentiated, and multiple barriers that have to be overcome are discussed. Furthermore, strategies to overcome these barriers for successful drug delivery to the targeted site are reviewed and summarized. In conclusion, the possible challenges and prospects of using these nanoassemblies for tumor-targeted delivery are discussed. This review aims at inspiring researchers to develop stimuli-responsive nanoassemblies for tumor-targeted delivery for clinical applications.

Comparative Toxicity, Biodistribution and Excretion of Ultra-Small Gold Nanoclusters with Different Emission Wavelengths

The exponentially increased use of gold nanoclusters in diagnosis and treatment has raised serious concern about their potential threat to living organisms. However, the mechanisms of toxicity of gold nanoclusters in vitro and in vivo remain poorly understood. In this work, comparative toxicity studies, including biodistribution and excretion, were carried out with mildly and chemically synthesized ultra-small L-histidine-protected and bovine serum albumin (BSA)-protected gold nanoclusters in an all-aqueous process. These nanoclusters did not induce a remarkable impact on cell viability, even at relatively high concentrations (100 μg/mL). The haemolytic assay demonstrated that the gold nanoclusters could not destroy blood cell at 600 μg/mL. After intravenous injection with mice, the biocompatibility, biodistribution, and excretion were determined. Quantitative analysis results showed that accumulation varied in the liver, spleen, kidney, and lung, though primarily in the liver and spleen. They were excreted in urine and faeces, but mainly excreted through urine. In our study, no obvious abnormalities were found in body weight, behavioral changes, blood and serum biochemical indicators, and histopathology. These findings suggested that both gold nanoclusters showed similar effects in vivo and were safe and biocompatible, laying the foundation for safe biomedical application in the future.

The Peptide Functionalized Inorganic Nanoparticles for Cancer-Related Bioanalytical and Biomedical Applications

In order to improve their bioapplications, inorganic nanoparticles (NPs) are usually functionalized with specific biomolecules. Peptides with short amino acid sequences have attracted great attention in the NP functionalization since they are easy to be synthesized on a large scale by the automatic synthesizer and can integrate various functionalities including specific biorecognition and therapeutic function into one sequence. Conjugation of peptides with NPs can generate novel theranostic/drug delivery nanosystems with active tumor targeting ability and efficient nanosensing platforms for sensitive detection of various analytes, such as heavy metallic ions and biomarkers. Massive studies demonstrate that applications of the peptide-NP bioconjugates can help to achieve the precise diagnosis and therapy of diseases. In particular, the peptide-NP bioconjugates show tremendous potential for development of effective anti-tumor nanomedicines. This review provides an overview of the effects of properties of peptide functionalized NPs on precise diagnostics and therapy of cancers through summarizing the recent publications on the applications of peptide-NP bioconjugates for biomarkers (antigens and enzymes) and carcinogens (e.g., heavy metallic ions) detection, drug delivery, and imaging-guided therapy. The current challenges and future prospects of the subject are also discussed.