# Research Progress of Polysaccharide-Gold Nanocomplexes in Drug Delivery
## 1 Introduction  
Water solubility and stability are indeed significant factors that impede the clinical application of various drugs. In order to overcome these challenges, carrier-based drug delivery systems (DDSs) have been developed. Such systems have shown promise as an effective strategy to enhance therapeutic efficiency due to their ability to achieve high drug-loading capacities and facilitate sustained drug release [1]. Drug delivery systems refer to the use of carriers to transport drugs and control their release and distribution within the human body. These systems are designed to enhance the specificity and utilization of drugs while minimizing harm to normal tissues. By loading drugs onto carriers, DDSs can effectively deliver drugs to specific locations in the body and regulate their release rate, optimizing the therapeutic effect and reducing potential side effects. DDSs employs a variety of carriers, such as nanoparticles, liposomes, and micelles, to encapsulate drugs and protect them from degradation. These carriers can be designed to target specific cells or tissues through surface modifications or active targeting strategies, allowing for precisedrug delivery. Once the carriers reach the desired location, the drug can be released in a controlled manner, either through diffusion, degradation, or external triggers. This controlled release ensures that the drug reaches its intended target and maintains a therapeutic concentration for a prolonged period. Moreover, DDSs allow for the customization of drug release profiles, enabling tailored therapy for individual patients. For instance, some drugs may require sustained release over an extended period, while others may require a burst release for immediate action. DDSs can accommodate these diverse requirements through the design of carrier properties, such as particle size, surface charge, and composition. In the first 40 years of drug delivery technology's existence (1950-1990), significant advancements were made. However, it was not until the introduction of the first polyethylene glycolized protein in 1990 that the era of polyethylene glycol began. This breakthrough had a profound impact on the development of liposomes and lipid nanoparticle formulations, and it drew considerable attention to nanodelivery systems [2]. This review primarily focuses on the research progress of polysaccharide gold nanoparticles as drug delivery systems and discusses their potential future applications (Scheme 1). The rest of the manuscript will delve into the synthesis methods, characterization techniques, and various applications of these nanoparticles in drug delivery. Additionally, the review will discuss the challenges and opportunities associated with using polysaccharide gold nanoparticles in the medical field. By examining the current research and discussing potential future developments, this review aims to provide a comprehensive understanding of the role of polysaccharide gold nanoparticles in drug delivery systems. Nanocarriers are a novel drug delivery system with the ability to efficiently transport drugs to the intended target site. They possess a larger specific surface area, allowing for a higher drug load, thereby increasing the concentration of released drugs at the designated site. This enhanced drug release rate makes nanocarriers the optimal choice for drug delivery in current times (Figure 1). Nano-drug delivery systems (Nano-DDSs) have shown promise in improving drug effectiveness by targeting diseased cells. Multifunctional DDSs are tailored to deliver drug molecules selectively to the desired tissue or organ using passive and active targeting mechanisms, enhancing accumulation, retention, and overall efficacy [3]. Nano-drug delivery systems include targeted nanocarriers and stimulus responsive nanocarriers. Targeted nanocarriers include passive and active nanoparticle delivery systems.