Characterization of cellular uptake, anti-colorectal cancer effects and pharmacokinetics of curcumin-loaded polypropylene/rice husk composites filled with nano-SiO2

Curcumin-loaded polypropylene/rice husk/SiO2 composites were fabricated with tunable nano-SiO2 filler loadings (0–10 wt%) via melt-blending and injection molding. XRD analysis revealed effective intercalation of nanoparticles and interaction with the polymer chains up to 6 wt% loading. Incorporation of SiO2 fillers significantly enhanced mechanical strength with 6 % nano-SiO2 formulation demonstrating 27 % higher tensile strength, 52 % increased flexural modulus and 51 % greater impact resistance. The silica nanoparticles also reduced heat release rate through protective charring and decreased moisture absorption by over 8 % due to hydrophilic surface groups. In vitro studies showed that curcumin nano-composites with 6 % nano-SiO2 exhibited maximal cytotoxicity against HT-29 and HCT-116 colon cancer cells with CC50 values of 12.4±1.1 μg/ml and 10.3±0.9 μg/ml respectively, attributed to optimal drug release profile. The formulation arrested 22.1% cells in sub-G1 phase inducing apoptosis. Oral administration in tumor-bearing mice led to 3-fold increase in plasma exposure (Cmax 186±14 ng/ml) and relative bioavailability versus free curcumin, indicating capacity to evade presystemic clearance. The composites also enabled 3 times higher tumor accumulation highlighting potential for targeted colorectal cancer therapy via improved pharmacokinetics and site-specific action. Overall, precise tuning of nanostructured fillers augments mechanical and transport properties while potentiating anticancer performance.