Gold nanoparticles (AuNPs) were synthesized in one-step by reducing gold salt using nontoxic and biodegradable chitosan as dual roles of reducing agent and stabilizer. The obtained AuNPs were characterized with UV–vis spectroscopy and transmission electron microscopy. The results indicated that control over the size and shape of AuNPs is achieved through the careful selection of experimental conditions, such as reaction temperature, reaction time, concentration of gold salt and chitosan, and chitosan molecular parameters, i.e., degree of deacetylation (DD) and molecular weight (MW). At low chitosan concentration (0.005% and 0.01% (w/v)), individual spherical AuNPs with average particle size around 10 nm were obtained regardless of chitosan DD and MW, while anisotropic AuNPs were obtained at concentration above 0.05% (w/v) for all investigated chitosan at the optimum condition (1 mL of 1 mmol/L HAuCl₄ added to 3 mL of chitosan solution reacted for 120 min at 70 °C). The growth of larger polygonal AuNPs was promoted as the higher concentration and lower DD chitosan was used as reducing agent and stabilizer. Au nanoplate was synthesized by water-soluble chitosan (M_v 566 kDa, DD 53%) at concentration above 0.15% (w/v). Chitooligomers (M_v 2.4 kDa, DD 94%) showed the highest reduction ability for Au³⁺ and the synthesized AuNPs exhibited aggregation on morphology. It was considered that chitosan DD and concentration played a more important role than MW in the size and shape of AuNPs.

中文翻译：

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使用脱乙酰度和分子量不同的壳聚糖一锅法合成金纳米颗粒

通过使用无毒且可生物降解的壳聚糖作为还原剂和稳定剂的双重作用，通过还原金盐来一步合成金纳米颗粒（AuNPs）。通过紫外可见光谱和透射电子显微镜对获得的AuNPs进行表征。结果表明，通过精心选择实验条件，如反应温度，反应时间，金盐和壳聚糖的浓度以及壳聚糖分子参数（即脱乙酰度（DD）），可以控制AuNPs的大小和形状。和分子量（MW）。在低的壳聚糖浓度（0.005％和0.01％（w / v））下，无论壳聚糖DD和MW如何，均获得平均粒径为10 nm左右的球形AuNP，而在高于0的浓度下获得各向异性AuNPs。_将4添加到3mL的壳聚糖溶液中，在70℃下反应120分钟。随着较高的浓度和较低的DD壳聚糖用作还原剂和稳定剂，促进了较大的多边形AuNPs的生长。通过水溶性壳聚糖（M _v 566 kDa，DD 53％）以高于0.15％（w / v）的浓度合成Au纳米板。壳寡聚体（M _v 2.4 kDa，DD 94％）显示出对Au ³⁺的最高还原能力，并且合成的AuNPs在形态上表现出聚集。据认为，壳聚糖的DD和浓度在AuNPs的大小和形状方面比MW更为重要。