Intravenous injectable metformin-Cu(ii)-EGCG coordination polymer nanoparticles for electrothermally enhanced dual-drug synergistic tumor therapy

Intravenous injectable metformin-Cu(II)-EGCG infinite coordination polymer nanoparticles (metformin-Cu(II)-EGCG ICP NPs) have been synthesized, and an efficient strategy for synergistic tumor therapy by utilizing these nanoparticles in conjunction with micro-electrothermal needles (MENs) was proposed. These nanoparticles display exceptional uniformity with a diameter of 117.5 ± 53.3 nm, exhibit an extraordinary drug loading capacity of 90% and allow for precise control over the drug ratio within the range of 1 : 1 to 1 : 20 while maintaining excellent thermal stability. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction were employed to determine their chemical structure and coordination state. The combination index (CI) value of the metformin-Cu(II)-EGCG ICP NPs was calculated to be 0.19, surpassing that of the two individual drugs and metformin mixed with EGCG (0.98). Importantly, upon intravenous injection, metformin in nanoparticles demonstrated exceptional stability in the bloodstream, while both drugs were rapidly released within the acidic tumor microenvironment. Animal experiments showcased an impressive tumor inhibition rate of 100% within a mere 20-day time frame after the synergistic therapy with a lower dosage (5.0 mg kg^-1 of nanoparticles), coupled with a minimal tumor recurrence rate of only 18.75% over a 60-day observation period. These findings indicate the promising prospects of these nanoparticles in tumor treatment.