Encapsulation of biogenic and synthetic polyamines by nanoparticles PEG and mPEG-anthracene

• Polyamines bind PEG and PEG-anthracene via hydrophilic and hydrophobic contacts.
• Polymer binding affinity decreases as polyamine positive charge increases.
• Biogenic polyamines form stronger complexes than synthetic polyamines.
• PEG and its derivatives can act as carriers for antitumor polyamine analogues.

Synthetic polymers play a major role in drug delivery in vitro and in vivo. We report the bindings of biogenic polyamines, spermine (spm), and spermidine (spmd), and their synthetic analogues, 3,7,11,15-tetrazaheptadecane⋅4HCl (BE-333) and 3,7,11,15,19-pentazahenicosane⋅5HCl (BE-3333) with poly(ethylene glycol) PEG-3000, PEG-8000 and methoxy poly(ethylene glycol) anthracene (PEG-anthracene). Fourier transform infrared (FTIR), UV–visible and fluorescence spectroscopic were used to analyze polyamine binding mode, the binding constant and the effect of PEG compositions on polyamine–polymer interaction. Structural analysis showed that polyamines bind PEG through hydrophobic and hydrophilic contacts with overall binding constants of Kspm-PEG-3000 = 3.1 × 104 M−1, Kspmd-PEG-3000 = 5.5 × 104 M−1, KBE-333-PEG-3000 = 2.5 × 104 M−1, KBE-3333-PEG-3000 = 1.5 × 105 M−1, Kspm-PEG-8000 = 4.1 × 105 M−1, Kspmd-PEG-8000 = 7.5 × 105 M−1, KBE-333-PEG-8000 = 4.5 × 104 M−1, KBE-3333-PEG-8000 = 2.2 × 105 M−1, Kspm-mPEG-ant = 6.5 × 105 M−1, Kspmd-mPEG-ant = 1.1 × 106 M−1, KBE-333-mPEG-ant = 2.2 × 105 M−1 and KBE-3333-mPEG-ant = 6.9 × 104 M−1. The number of binding sites (n) occupied by polyamines were from 0.2 to 0.5. Biogenic polyamines showed stronger affinity toward polymer complexation than synthetic polyamines, while weaker interaction was observed as polyamine cationic charges increased. Our results suggest that PEG and its derivative can act as carriers for delivering antitumor polyamine analogues to target tissues.

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