Silk fibroin nanoparticles for locoregional cancer therapy: Preliminary biodistribution in a murine model and microfluidic GMP-like production

Silk fibroin nanoparticles (SFNs) have been widely investigated for drug delivery, but their clinical application still faces technical (large-scale and GMP-compliant manufacturing), economic (cost-effectiveness in comparison to other polymer-based nanoparticles), and biological (biodistribution assessments) challenges. To address biodistribution challenge, we provide a straightforward desolvation method (in acetone) to produce homogeneous SFNs incorporating increasing amounts of Fe 2 O 3 (SFNs-Fe), detectable by Magnetic Resonance Imaging (MRI), and loaded with curcumin as a model lipophilic drug. SFNs-Fe were characterized by a homogeneous distribution of the combined materials and showed an actual Fe 2 O 3 loading close to the theoretical one. The amount of Fe 2 O 3 incorporated affected the physical-chemical properties of SFNs-Fe, such as polymer matrix compactness, mean diameter and drug release mechanism. All formulations were cytocompatible; curcumin encapsulation mitigated its cytotoxicity, and iron oxide incorporation did not impact cell metabolic activity but affected cellular uptake in vitro. SFNs-Fe proved optimal for biodistribution studies, as MRI showed significant nanoparticle retention at the administration site, supporting their potential for locoregional cancer therapy. Finally, technical and economic challenges in SFN production were overcome using a GMP-compliant microfluidic scalable technology, which optimized preparation to produce smaller particle sizes compared to manual methods and reduced acetone usage, thus offering environmental and economic benefits. Moreover, enabling large-scale production of GMP-like SFNs, this represents a considerable step forward for their application in the clinic. • Silk fibroin nanoparticles face significant challenges in large-scale manufacturing, cost-effectiveness compared to other polymer-based nanoparticles, and biodistribution assessments. • A straightforward desolvation method was developed to produce homogeneous SFNs incorporating increasing amounts of Fe 2 O 3 (iron oxide), detectable by Magnetic Resonance Imaging and loaded with curcumin as a model drug. • The physical-chemical properties of the obtained SFNs-Fe changed due to the amount of Fe 2 O 3 incorporated that affected the polymer matrix compactness: the mean diameter increased with a lower Fe 2 O 3 amount, while the curcumin released through diffusion increased when adding Fe 2 O 3 . • SFNs-Fe proved optimal for the biodistribution studies, as MRI showed significant nanoparticle retention at the administration site, supporting their potential for locoregional cancer therapy. • Technical and economic challenges in SFN production were addressed using a GMP-compliant microfluidic scalable technology, optimizing preparation to produce smaller particle sizes and offering environmental and economic benefits by reducing acetone usage.