Plant-synthesized gold nanotheranostics for photothermal treatment and imaging of breast cancer: Harnessing flavonoids for dual-functionality

Breast cancer remains a major global health challenge, driving the need for more precise and less toxic therapeutic strategies. Gold nanoparticles (AuNPs) have emerged as powerful agents for cancer theranostics, offering unique optical properties for photothermal therapy (PTT) and multimodal imaging. In parallel, plant-mediated green synthesis of AuNPs presents an eco-friendly and biocompatible alternative to conventional chemical routes, leveraging phytochemicals, especially flavonoids, as natural reducing and capping agents. Flavonoids, such as quercetin, kaempferol, luteolin, apigenin, and epigallocatechin gallate, not only facilitate nanoparticle formation but also confer intrinsic anticancer bioactivity, thereby enhancing therapeutic efficacy in breast cancer models. This review provides a comprehensive synthesis of advances in plant-synthesized AuNPs and flavonoid-functionalized systems for PTT and imaging in breast cancer. We examine the mechanisms of photothermal conversion, the role of AuNP morphology in optimizing therapeutic outcomes, and the synergistic effects of flavonoid bioactivity. Comparative analyses highlight the superior biocompatibility and dual-functionality of green AuNPs over chemically synthesized counterparts. Moreover, emerging technologies, such as AI-assisted nanoparticle design, stimuli-responsive delivery systems, and hybrid nanocarriers, are poised to address current challenges in reproducibility, scalability, and clinical translation. Plant-synthesized AuNP-flavonoid platforms represent a promising frontier in breast cancer nanotheranostics, with the potential to enhance treatment precision, safety, and patient outcomes. However, systematic toxicological studies, regulatory harmonization, and standardized manufacturing protocols are essential for advancing these innovative systems toward clinical application. • Main Findings: The gold nanoparticles synthesized by plants combine photothermal efficacy, multimodal imaging capabilities, and intrinsic anti-cancer activity, addressing the key limitations of traditional therapies. • Future Prospects: Although these systems show potential in targeted breast cancer ablation and real-time tumor visualization, they still face challenges such as the reproducibility of large-scale synthesis, pharmacokinetics, and long-term biological safety. Optimizing functionalization strategies to enhance tumor specificity and exploring AI-driven nanoparticle design can further improve clinical outcomes. • Research Significance: The AuNP-flavonoid platform synthesized by plants has great potential in advancing personalized, safe, and effective breast cancer treatment methods.