Conjugated Polymer Nanoparticles: Photothermal and Photodynamic Capabilities According to Molecular Ordering in Their Assembly Structures

Abstract

We report that conjugated polymer nanoparticles (CPNs) coated with polyethylene glycols (PEGs) exhibit photothermal and photodynamic capabilities according to molecular ordering in their assembly structures. CPN-PEGs were made using three different methods: a dispersion process of phase-separated film assemblies of a conjugated polymer and a phospholipid-conjugated PEG (CPN-I), a dispersion process of a conjugated polymer and a phospholipid followed by surface conjugation with PEGs (CPN-II), and a miniemulsification of the conjugated polymer and the phospholipid-conjugated PEG. Our findings revealed that the ordered molecular assembly structures in CPN-I and CPN-II increased intermolecular interactions and decreased the optical band gap, promoting nonradiative exciton relaxation via the energy-gap law’s internal conversion mechanism and rationalizing CPN-I’s shorter singlet exciton lifetime (13 ps). Meanwhile, CPN-III with a disordered structure generated more singlet oxygen than CPN-I and CPN-II, indicating increased triplet exciton generation upon the polaron recombination. Our findings present that the photothermal and photodynamic properties of CPNs are obviously dependent on the assembly structure order and that CPNs with an ordered assembly of conjugated backbones have a stronger photothermal effect, whereas those with a disordered structure have a better photodynamic effect.

Enhanced Photocatalytic Oxygen Evolution Using Copper‐Coordinated Perylene Diimide Nanorod Assemblies

“…The femtosecond transition absorption (fs‐TA) spectroscopy was performed to investigate the recombination of the photo‐induced charges. The details of the fs‐TA spectrometry system can be found in the previous report [45] . Briefly, 6 kHz repetition rate femtosecond Yb:KGW amplifier laser (PHAROS, Light Conversion, Lithuania) and an optical parametric amplifier system (ORPHEUS, Light Conversion) in the National Research Facilities and Equipment Center (NanoBio‐Energy Materials Center) at Ewha Womans University was used as an excitation source, and a small portion of femtosecond Yb:KGW amplifier output was used to generate broadband white‐light‐continuum probe beam.…”

“…The details of the fs-TA spectrometry system can be found in the previous report. [45] Briefly, 6 kHz repetition rate femtosecond Yb:KGW amplifier laser (PHAROS, Light Conversion, Lithuania) and an optical parametric amplifier system (ORPHEUS, Light Conversion) in the National Research Facilities and Equipment Center (NanoBio-Energy Materials Center) at Ewha Womans University was used as an excitation source, and a small portion of femtosecond Yb:KGW amplifier output was used to generate broadband white-lightcontinuum probe beam. The fs-TA spectra of CuPDI-Hm NRs and PDI-Hm NFs upon the photoexcitation at 454 nm were recorded using a transient absorption spectrometer (Harpia-TA, Light Conversion).…”

Metronomic Photodynamic Therapy with Conjugated Polymer Nanoparticles in Glioblastoma Tumor Microenvironment

“…However, to date, there have been no studies investigating mPDT with third-generation PSs such as conjugated polymer nanoparticles (CPNs). This type of nanoparticulated PS has been studied for the PDT of several cancer types and was shown to efficiently generate 1 O 2 [1,16,31,32]. CPNs have several advantages compared to molecular PSs, such as superb extinction coefficients (several orders of magnitude higher than molecular PSs), excellent photostability and easy surface functionalization with bioactive molecules for cell targeting [33][34][35].…”