Photodegradable polyesters for triggered release

Abstract

Photodegradable polyesters were synthesized with a photolabile monomer 2-nitrophenylethylene glycol and dioyl chlorides with different lengths. These polymers can be assembled to form polymeric particles with encapsulation of target substances. Light activation can degrade these particles and release payloads in both aqueous solutions and RAW 264.7 cells.

Figure 1

UV-Vis absorbance spectra of polymer P3 upon photolysis at 365 nm (50 μg/mL).

Figure 2

SEM images of Np1, left without UV irradiation, right with UV irradiation.

Figure 3

Relative stability of nanoparticles (a) at different temperatures and (b) in the buffers with different pH values. The Nile red fluorescence intensity of nanoparticle solutions at 30 °C, and pH 7.0 was used as the standard.

Figure 4

(a) Fluorescence spectra of Nile red-loaded Np1 solution upon light irradiation (365 nm, 11 mW/cm²) with excitation wavelength at 550 nm; (b) Plots of normalized fluorescence intensity of Nile red at 630 nm vs. irradiation time for aqueous solutions of Np1–3.

Figure 5

Plots of normalized fluorescence vs. irradiation time and curve fitting for Nile red loaded particle Np1–3 aqueous solutions exposed to UV light (365 nm, 11 mW/cm²).

Figure 6

Fluorescence microscopy images of RAW 264.7 cells incubated with (a, b) free FDA; (c, d) free FDA followed by 15 min light irradiation; (e, f) FDA-loaded Np1 for 4 h and (g, h) FDA-loaded Np1 for 4 h followed by 15 min light irradiation. The concentration of FDA-loaded Np1 was 25 μg/mL. (scale bar = 100 μm)

Scheme 1

Synthesis of photodegradable polymers P1–3.