Size uniformity and defined surface coating are important parameters for the biological properties of silver nanoparticles (AgNPs). Green synthesis uses biomolecules either in pure form or plant extracts as both reductants and stabilizers yielding a wide size range and capping composed of oxidation products and biomolecules present in the reaction mixture. Herein, we used an established methodology, silver nitrate as the metal precursor, and sodium citrate and tannic acid for reduction and stabilization to produce weakly passivated citrate capped AgNPs (CtAgNPs). Inductively coupled plasma mass spectrometry was used to determine the total concentration of silver in the purified nanoparticles colloidal dispersion and results correlated with absorbance at localized surface plasmon resonance (LSPR) peak for quick estimation of silver concentration. The CtAgNPs were functionalized with chitosan oligosaccharide (mean M_n 5000) and betanin to yield chitosan and betanin capped AgNPs. Their biocidal properties were tested against Staphylococcus aureus American Type Culture Collection (ATCC) 12,600. Citrate-stabilized AgNPs had a LSPR peak at 432 nm, mean core diameter of 37.9 ± 8.6 nm, and a monomodal distribution, and were roughly spherical. A slight red shift in LSPR peak was observed upon capping change. The minimum inhibitory concentration against S. aureus was 12.5 ppm Ag for all the nanoparticles. Our study advances the path of exploiting size reproducible techniques in AgNP synthesis, post-synthesis biomolecule functionalization for defined surface, and a clear procedure for estimating the concentration of Ag in assays. This is envisaged to encourage investigations with distinct sizes and capping for cross-comparison.

尺寸均匀性和确定的表面涂层是银纳米颗粒（AgNPs）生物学特性的重要参数。绿色合成使用纯净形式或植物提取物形式的生物分子作为还原剂和稳定剂，产生较大的粒径范围，并由反应混合物中存在的氧化产物和生物分子组成的封端。在这里，我们使用一种既定的方法，硝酸银作为金属前体，柠檬酸钠和单宁酸进行还原和稳定化，以产生弱钝化的柠檬酸盐封端的AgNP（CtAgNP）。电感耦合等离子体质谱法用于确定纯化的纳米粒子胶体分散液中银的总浓度，其结果与局部表面等离子体共振（LSPR）峰处的吸光度相关，可快速估算银浓度。M _n 5000）和甜菜碱生成壳聚糖和甜菜碱封端的AgNPs。针对金黄色葡萄球菌美国典型培养物保藏中心（ATCC）12,600测试了它们的杀生物特性。柠檬酸盐稳定的AgNPs在432 nm处具有LSPR峰，平均核心直径为37.9±8.6 nm，并且具有单峰分布，并且大致呈球形。封顶更改后，观察到LSPR峰略有红移。对金黄色葡萄球菌的最低抑制浓度所有纳米颗粒的Ag为12.5 ppm。我们的研究为在AgNP合成中利用尺寸可复制技术，为限定的表面合成后生物分子功能化以及在测定中估算Ag浓度的清晰程序提供了可能。设想这样做是为了鼓励进行具有不同规模和上限的交叉比较研究。