Synthesis of Metallo-Chromone Porphyrin Nano-Starch Sensitizers as Photodynamic Therapeutics for the Eradication of Enterococci Dental Pathogens

Photodynamic therapy (PDT), as an advanced, alternative,
and promising
treatment, can inhibit dental pathogens. PDT employs the activation
of photosensitizers via the light of a particular wavelength and molecular
oxygen to inhibit dental pathogens. Herein, we present a comprehensive
study on the synthesis and characterization of three chromone-porphyrins
[Zn(II)-5-[4-chromone]-15-(4-phenyl)porphyrin (ZnCP), 5-[4-chromone]-15-(4-12
phenyl)porphyrin (DMCP), and Pd(II)-5-[4-chromone]-15-(4-phenyl)porphyrin
(PdCP)]. Next, the computational study was also performed to establish
the correlation between photophysical properties and theoretical calculations
for those chromone-porphyrins using density functional theory and
time-dependent density functional theory. Furthermore, chromone-porphyrins
were encapsulated in starch nanoparticles to develop soluble nano-starch
sensitizers (ZnCP-SNPs, DMCP-SNPs, and PdCP-SNPs) via the nanoprecipitation
technique. Upon green light exposure, these nano-starch sensitizers
exhibited excellent singlet oxygen generation ability. Moreover, final
nanoformulations have been explored for pH responsiveness. Based on
our intriguing findings, the chromone-porphyrin-loaded nano-starch
sensitizers displayed great potential as prospective PDT to treat
enterococci dental pathogens.