In the present study, first, saffron petal anthocyanin (SPA) and copper oxide nanoparticles (CuO-NPs) were extracted and synthesized, respectively. Then, multifunctional bio-based films based on carboxymethyl chitosan (CMCS), SPA, and CuO-NPs were fabricated using solvent casting method. The mechanical, thermal, physical, optical, antibacterial, toxicity, and pH sensitivity properties of the prepared films were evaluated. The obtained results demonstrated that simultaneous incorporation of CuO-NPs and SPA improved the mechanical, UV absorption, barrier properties as well as the thermal stability of the films. Moreover, the nanocomposite films exhibited a great antimicrobial activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Fabricated nanocomposite films obviously exhibited color change from pink to green in acidic and alkaline media, respectively. The multifunctional films could effectively sense the freshness of lamb meat during storage time, and thus they can be introduced as pH-indicators for monitoring the freshness/spoilage of meat in real-time.

Graphical Abstract

中文翻译：

---

氧化铜纳米颗粒增强羧甲基壳聚糖和番红花花青素多功能生物安全薄膜的制备与表征

在本研究中，首先，分别提取和合成了藏红花花瓣花青素（SPA）和氧化铜纳米颗粒（CuO-NPs）。然后，使用溶剂浇铸法制备了基于羧甲基壳聚糖 (CMCS)、SPA 和 CuO-NPs 的多功能生物基薄膜。评估了制备的薄膜的机械、热、物理、光学、抗菌、毒性和 pH 敏感性性能。获得的结果表明，同时掺入 CuO-NPs 和 SPA 改善了薄膜的机械、紫外线吸收、阻隔性能以及热稳定性。此外，纳米复合膜对革兰氏阳性（金黄色葡萄球菌）和革兰氏阴性（大肠杆菌）都表现出很强的抗菌活性。） 细菌。制备的纳米复合薄膜在酸性和碱性介质中分别明显表现出从粉红色到绿色的颜色变化。多功能薄膜可以有效地感知羊肉在储存期间的新鲜度，因此它们可以作为pH指示剂用于实时监测羊肉的新鲜度/变质。

图形概要