# Research Progress of Polysaccharide-Gold Nanocomplexes in Drug Delivery
## 4 Application of polysaccharide-AuNPs
To further improve the stability and antibacterial efficacy against multidrug-resistant pathogenic bacteria and reduce toxicity in humans, the conjugation of the biopolymer CH with silver or gold nanoparticles offers a promising approach [98]. Cs-AuNPs have been demonstrated as efficacious bactericidal materials that circumvent damage to human cells. Including a positively charged CH amplifies its interactions with bacteria, thus allowing the positively charged AuNPs to disrupt the anionic bacterial cell membrane efficiently. As a result, CH enhances the biocompatibility and antibacterial activity of AuNPs, and charge density is an essential parameter for antimicrobial activity, and only chitosan that meets specific conditions can demonstrate good antimicrobial activity in the region [99]. The study conducted by [PERSON] et al. focused on synthesizing gold nanoparticles (AuNPs) using CH, glycol chitosan (GC), and poly(\(\gamma\)-glutamic acid) and investigating their antimicrobial properties. Their findings provided compelling evidence to demonstrate the remarkable antimicrobial properties of these CH-coated AuNPs, but further elucidation of their antimicrobial mechanism is still needed [100]. Tumorigenesis refers to the process by which normal cells transform into cancer cells. It is a multistage and progressive process involving genetic and epigenetic changes in cells. During tumorigenesis, these altered genes can confer new capabilities to the affected cells, such as uncontrolled proliferation, evasion of cell death, evasion of the immune system, and the ability to invade nearby tissues and spread to distant sites (metastasis). Each of these capabilities evolves over time, leading to a tumor's subsequent formation and progression [101]. Biofouling refers to the undesired adsorption of cells, proteins, or intracellular and extracellular biomolecules on the surface of metal nanocomplexes. In this context, HA is a bioactive, naturally occurring mucopolysaccharide. HA is hydrophilic and polyanionic in physiological environments, exhibiting excellent antifouling properties. A noteworthy finding is that HA-thiol (HA-SH) (MW 10 kDa) of AuNPs displayed higher peritumor distribution in lung cancer compared to gold nanoparticles alone and lower distribution in normal organs. This observation offers promising possibilities for utilizing nanomaterials in tumor diagnosis and therapy [102]. [PERSON] et al. have designed and developed a new multifunctional nanocarrier known as anti-epidermal growth factor receptor antibody-conjugated and paclitaxel loaded-thiol chitosan-layered gold nanoshells (anti-EGFR-PTX-TCS-GNSs). This new nanocarrier has been shown to kill tumor cells almost wholly under laser irradiation. Moreover, it possesses a solid ability to visualize tumors. Consequently, this nanocarrier presents a novel strategy for future tumor diagnosis and treatment, offering a new approach in the field [103]. Pholiota adipose (PA) is a widely used edible and medicinal mushroom in traditional Chinese medicine. This mushroom is known for containing a polysaccharide (PAP-1a), considered its primary physiologically active component. In a study conducted by [PERSON] et al., it was found that by synthesizing AuNPs using PAP-1a, there was a significant improvement in immune regulation and antitumor effect in vitro and in vivo compared to using PAP-1a alone. This discovery demonstrates the potential of PAP-AuNPs as a novel nanomedicine for hepatic carcinoma [104]. Central nervous system malignancies are characterized by the lowest survival and highest morbidity rates. This is mainly attributed to the presence of the blood-brain barrier, which restricts the accessibility of drugs to the tumor microenvironment. To overcome this limitation, a potential solution is the use of ultrasmall spherical AuNPs that are capped by galactoyl dextran PST001.