Poly-(D,L-lactide-co-glycolide) nanoparticles with covalently-bound porphyrins for efficient singlet oxygen photosensitization

Abstract

With the aim of assessing the role of the chemical structure of the photosensitizer on the photophysical and photochemical properties of the final nanoparticle suspension, we have investigated a series of poly-(ethylene glycol)-poly-([Formula: see text]-lactide-co-glycolide) nanoparticles containing a hydrophobic or a hydrophilic porphyrin covalently conjugated to the nanoparticle. Covalent conjugation responded to the objective of trying to improve photosensitizer loading in these nanoparticles, especially for hydrophilic photosensitizers, but also enabled the porphyrins to remain attached to the nanoparticle without necessarily being inside the poly-([Formula: see text]-lactide-co-glycolide) core. This strategy has provided valuable information about the dependence of the photophysical and singlet oxygen photosensitizing properties of the suspensions on the nature of the photosensitizer. It is concluded that poly-([Formula: see text]-lactide-co-glycolide) nanoparticles with covalently-bound hydrophilic porphyrins show superior singlet oxygen photosensitizing ability.

c(RGDfK)‐ and ZnTriMPyP‐Bound Polymeric Nanocarriers for Tumor‐Targeted Photodynamic Therapy

“…Furthermore, they showed a smaller contribution of a very short component of 0.5 ns. These two populations observed are consistent with the values reported before for ZnTriMPyP‐PLGA‐PEG NPs (28). In this previous publication, we attributed the 0.5 ns component to the presence of aggregates due to the dimerization of some neighboring ZnTriMPyP molecules at the surface of the NPs.…”

“…The average size of blank, ZnTriMPyP‐PLGA‐PEG and ZnTriMPyP‐PLGA‐PLA‐PEG‐c(RGDfK) NPs was found to be ~75 nm, ~80 nm and ~94 nm, respectively. These are similar to previously reported PLGA‐PEG NPs prepared with this methodology (28,31,36). Size is an important parameter in the passive targeting ability of NPs since it governs the biodistribution of the nanocarrier system.…”

“…As mentioned in Ref. (28), aqueous suspensions of both ZnTriMPyP‐NPs showed a slight redshift in absorption spectra as compared to the spectra in organic solvent. Similarly, their emission spectra showed a reduced intensity of the Q (0,1) band when compared to the spectra in DMSO.…”

“…However, the NP suspensions need to have an adequate ZnTriMPyP concentration to achieve phototoxicity in vitro . To reach this compromise, we selected a contribution of 10% based on previous studies (28).…”

Modification of Oligo- and Polylactides With Macrocyclic Fragments: Synthesis and Properties

“…In 2016, poly(lactide-co-glycolide) fragment was covalently linked to porphyrin blocks by click reaction (Boix-Garriga et al, 2016; Figure 2A). The resulting copolymers 4 and 5 (Figure 2B) formed in aqueous solutions negatively charged nanoparticles of 114–148 nm in size, in which porphyrin fragments were located at the outer layer.…”