Obesity has emerged as one of the most complex and urgent public health challenges of the twenty-first century, driven by genetic, environmental, metabolic, and psychosocial determinants that collectively disturb energy homeostasis and systemic health. It is characterized by adipose tissue dysfunction, insulin resistance, chronic low-grade inflammation, and gut microbiota dysbiosis, all of which interact to perpetuate metabolic and cardiovascular diseases. Beyond the biological dimension, obesity profoundly affects mental health, being closely linked to depression, anxiety, body-image dissatisfaction, and stigma, which further reduce adherence to treatment. Current therapeutic strategies rely on a stepped-care approach, beginning with lifestyle interventions encompassing dietary modification, physical activity, and behavioral therapy. Pharmacologic treatments, particularly incretin-based agents such as semaglutide, liraglutide, and tirzepatide have transformed medical management through substantial and sustained weight loss, while bariatric surgery remains the most effective long-term option for severe obesity. Emerging approaches, including gene therapy, microbiome modulation, and nanomedicine, offer mechanistically targeted and potentially safer alternatives, though they remain largely experimental. Pharmacoeconomic analyses support the cost-effectiveness of combining behavioral, pharmacological, and surgical modalities, highlighting the economic advantage of integrated care models. Meanwhile, artificial intelligence and machine learning are redefining obesity research and management, enhancing cancer risk prediction, personalizing pharmacotherapy, optimizing resource allocation, and enabling precision medicine through multi-omics and imaging integration. Collectively, these insights support a shift toward a learning health-system paradigm that unites mechanistically anchored therapies with digital and AI-driven personalization to achieve sustainable weight reduction, reduce cardiometabolic and cancer burden, and improve global health outcomes.

Nanoparticles have gained considerable attention as important platforms in pharmaceutical and biomedical research due to their size, morphology, surface chemistry, and colloidal behavior, which can affect drug delivery, antimicrobial activity, diagnostics, imaging, and therapeutic performance. However, conventional chemical and physical synthesis routes may require hazardous reagents, high energy demands, and procedures that raise environmental, safety, and scalability concerns. In this context, biologically mediated synthesis has emerged as an approach in which plants, microorganisms, including fungi and algae, and isolated biomolecules contribute to nanoparticle formation by acting as reducing, capping, and stabilizing agents. This narrative review evaluates these routes as potential green strategies, covering formation principles, biological sources, nanoparticle classes, characterization challenges, pharmaceutical applications, comparison with conventional synthesis, and limitations. The reviewed evidence indicates that the composition of biological sources and reaction conditions can shape nanoparticle size, morphology, surface chemistry, stability, and biological activity, highlighting green synthesis as a design-dependent process rather than a simple substitute for chemical reducing agents. Integrated characterization using optical, spectroscopic, diffraction, microscopic, and colloidal techniques is essential for interpreting nanoparticle identity and reproducibility. Biologically mediated nanoparticles show experimental and preclinical potential in drug delivery, antimicrobial therapy, anticancer research, biosensing, imaging, and diagnostics; however, most evidence remains preclinical and model-dependent. Translation remains limited by source variability, batch inconsistency, scale-up and purification challenges, stability, incomplete safety evidence, and regulatory uncertainty. Progress will require standardized process control, comparative life cycle and techno-economic assessment, scalable manufacturing, and rigorous pharmacokinetic, biodistribution, toxicological, and regulatory validation.