Photophysics of an octasubstituted zinc(II) phthalocyanine incorporated into solid polymeric magnetic and non-magnetic PLGA–PVA nanoparticles

• Photosensitizer S1 was encapsulated into a biodegradable PLGA–PVA nanoparticles.
• The nanoparticles were stabilized by PVA.
• Incorporation of magnetite nanoparticles maintained singlet oxygen generation of S1.
• An increase of singlet oxygen generation was obtained due to the heavy-atom effect.

2,3,9,10,16,17,23,24-octakis[(N,N-dimethylaminoethylsulfanyl)]phthalocyaninatozinc (II) (S1) was used as a lipophilic photosensitizer to be encapsulated into biodegradable poly(d,l lactide-co-glycolide)-polyvinyl alcohol nanoparticles. The synthesis, size, and spectroscopic, photophysical, and magnetic properties of nanoparticles, were analyzed. A greater number of sonication cycles afforded smaller nanoparticles. The stabilization by means of polyvinyl alcohol of all the nanoparticles synthesized provided a negative charge to the systems in a wide pH range. The thermograms obtained by differential scanning calorimetry showed that the nanoparticles were stabilized by polyvinyl alcohol. The incorporation of magnetite nanoparticles was verified by FT-IR, magnetization measurements by means of hysteresis curves and potential Z. S1 retained its efficiency in generating singlet oxygen. The incorporation of magnetite into the nanoparticles showed an increase in singlet oxygen quantum yields due to the heavy atom effect.

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