# Research Progress of Polysaccharide-Gold Nanocomplexes in Drug Delivery
## 6 Drug Release from Polysaccharide-AuNPs
In their study, they modified the carrier with gold nanoparticles using chitosan. CH was added to improve the dispersibility of curcumin in an aqueous solution, while AuNPs were used to enhance the electrostatic binding ability of the carrier to the bacterial cell membrane. They developed a polysaccharide-AuNPs antibacterial platform with electrostatic-targeting photodynamic and photothermal antibacterial properties [155]. [PERSON] et al. [156] developed a pH-responsive nanocomposite hydrogel by synthesizing chitosan-grafted acrylamide monomers and incorporating gold nanoparticles. This nanocomposite hydrogel demonstrated a high sensitivity to changes in pH and exhibited rapid and efficient drug release, specifically at pH 7.4. Furthermore, it exhibited cytotoxic solid effects against hepatocellular carcinoma cells [156]. High concentrations of glutathione (GSH) can cause a shift in the cellular environment, altering the pH from its physiological condition of 7.4 to pH 5.6. To address this issue, HA-modified dendrimers encapsulating AuNPs have been developed as active targeted drug delivery nanocarriers. These nanocarriers can efficiently load DOX by thioulation of the drug onto their surface, providing an effective treatment option for ovarian cancer. Furthermore, the loaded DOX can be explicitly released in the acidic tumor microenvironment with high GSH concentrations (pH 5.6) [157]. CAO was a biocompatible reductant to facilitate the green synthesis of CAO-AuNPs. Subsequently, the resultant CAO-AuNPs were employed as a delivery system for pH-triggered release of eprinticin (EPI). The EPI-CAO-AuNPs demonstrated a significant release of EPI under acidic conditions, which mimic the tumor microenvironment, while the release was negligible under physiological pH conditions in vitro. This study presents a novel approach to achieving pH-triggered freedom of anticancer drugs using the EPI-CAO-AuNPs system, marking the first instance of such findings. The developed EPI-CAO-AuNPs nanosystem exhibits excellent potential for pH-responsive delivery of antitumor agents [158]. The potential for toxicity remains the main obstacle to the current in vivo use of stimuli-responsive gold nanocomplexes. In innovative targeted drug release systems, polysaccharides in gold nanocarriers can specifically bind to receptors overexpressed on tumor cell membranes. [PERSON] et al. prepared a galactose and alignose ligand-modified gold nanorod, a nanocomposite that effectively inhibited and killed Pseudomonas aeruginosa infections through lectin-targeting functionality and the near-infrared photothermal effect of AuNPs, a strategy that could be used to further generate antimicrobial agents, and its therapeutic effect on other infectionsshould be verified [159]. Trastuzumab (Tmab) exhibits specificity in binding to the HER2 receptor. When combined with DOX and the monoclonal antibody trastuzumab, AuNPs can be used as a targeted drug delivery system for treating HER2+ cancers. This approach enables the delivery of the drug directly to the tumor site [160]. Polic acid (FA) binds explicitly to folate-targeting receptors, which are highly expressed on the surface of tumor cells. Therefore, by binding polysaccharide-AuNPs to FA, drug release at the tumor site can be enhanced. To achieve this, [PERSON] et al. prepared FA-coupled and DOX-loaded chitosan oligosaccharidescharide-encapsulated AuNRs (FA-COS-TGA-GNRs-DOX). They found that under NIR light irradiation, these nanoparticles could accurately locate and destroy tumor tissues [161]. 2-[(Aminocarbonyl)amino]-5-(4-fluorophenyl)-3-thiophene carboxamide (TPCA-1) inhibits the NF-xB signaling pathway, thereby suppressing the transcription of TNF-\(\alpha\), LL-6, and other pro-inflammatory cytokines. AuNCs can be loaded with TPCA-1, and the binding of TPCA-1 to the HA-modified peptide allows HA to function as a targeting factor. This targeted delivery system facilitates the release of TPCA-1 and enzyme-responsive releases.