金纳米颗粒（AuNPs）已成为癌症治疗方面具有潜力和多功能的纳米颗粒，广泛应用于药物和基因输送、生物医学成像、诊断和生物传感器。本研究描述了一种基于生物的策略，利用金黄色链霉菌细胞游离上清液来合成AuNPs。生物合成的AuNPs在530-535 nm处具有吸收峰。透射电镜图像显示，AuNPs呈球形，大小范围为4至20 nm。AuNPs的表面覆盖分子带负电荷，Zeta电位为-10.9 mV。FTIR分析表明，AuNPs表面组分含有多种功能基团，如-OH、C-H、N-、C=O、NH3+、氯化胺、蛋白质酰胺基团、C-C和C-N。采用中心复合设计（CCD）对影响AuNPs生物合成的生物过程变量进行了优化，以最大程度地增大AuNPs的生物合成。在温度（35℃）、孵育时间（4天）、HAuCl4浓度（1000 µg/mL）和初始pH值（6）下，得到了AuNPs的最大产量（866.29 µg AuNPs/mL）。通过比较CCD和基于人工神经网络（ANN）方法的预测和相应的实验结果，评估了AuNPs生物合成值。ANN预测的AuNPs生物合成值与实验结果更加合理地吻合。在体外和体内条件下评估了AuNPs的抗癌活性。结果表明，用AuNPs处理的MCF-7和Hela癌细胞株的增殖受到显著抑制，IC50值分别为13.4±0.44 μg/mL和13.8±0.45 μg/mL。此外，AuNPs对肿瘤承载小鼠模型的肿瘤生长具有潜在的抑制作用。AuNPs显著降低了肿瘤体积、肿瘤重量，并减少了EAC承载小鼠中存活的肿瘤细胞数量。© 2023年 Springer Nature Limited.

Gold nanoparticles (AuNPs) have emerged as promising and versatile nanoparticles for cancer therapy and are widely used in drug and gene delivery, biomedical imaging, diagnosis, and biosensors. The current study describes a biological-based strategy for AuNPs biosynthesis using the cell-free supernatant of Streptomyces flavolimosus. The biosynthesized AuNPs have an absorption peak at 530-535 nm. The TEM images indicate that AuNPs were spherical and ranged in size from 4 to 20 nm. The surface capping molecules of AuNPs are negatively charged, having a Zeta potential of - 10.9 mV. FTIR analysis revealed that the AuNPs surface composition contains a variety of functional groups as -OH, C-H, N-, C=O, NH3+, amine hydrochloride, amide group of proteins, C-C and C-N. The bioprocess variables affecting AuNPs biosynthesis were optimized by using the central composite design (CCD) in order to maximize the AuNPs biosynthesis. The maximum yield of AuNPs (866.29 µg AuNPs/mL) was obtained using temperature (35 °C), incubation period (4 days), HAuCl4 concentration (1000 µg/mL) and initial pH level 6. Comparison was made between the fitness of CCD versus Artificial neural network (ANN) approach based on their prediction and the corresponding experimental results. AuNPs biosynthesis values predicted by ANN exhibit a more reasonable agreement with the experimental result. The anticancer activities of AuNPs were assessed under both in vitro and in vivo conditions. The results revealed a significant inhibitory effect on the proliferation of the MCF-7 and Hela carcinoma cell lines treated with AuNPs with IC50 value of 13.4 ± 0.44 μg/mL and 13.8 ± 0.45 μg/mL for MCF-7 and Hela cells; respectively. Further, AuNPs showed potential inhibitory effect against tumor growth in tumor-bearing mice models. AuNPs significantly reduced the tumor volume, tumor weight, and decreased number of viable tumor cells in EAC bearing mice.© 2023. Springer Nature Limited.