Polydopamine Nanoparticles Enhance Drug Release for Combined Photodynamic and Photothermal Therapy

Abstract

Our study shows a facile two-step method which does not require the use of core templates to load a hydrophobic photosensitizer drug chlorin e6 (Ce6) within polydopamine (PDA) nanoparticles (NPs) while maintaining the intrinsic surface properties of PDA NPs. This structure is significantly different from hollow nanocapsules which are less stiff as they do not possess a core. To our knowledge, there exist no similar studies in the literature on drug loading within the polymer matrix of PDA NPs. We characterized the drug loading and release behavior of the photosensitizer Ce6 and demonstrated the therapeutic efficacy of the combined photodynamic (PDT) and photothermal therapy (PTT) from Ce6 and PDA, respectively, under a single wavelength of 665 nm irradiation on bladder cancer cells. We obtained a saturated loading amount of 14.2 ± 0.85 μM Ce6 in 1 nM PDA NPs by incubating 1 mg/mL dopamine solution with 140 μM of Ce6 for 20 h. The PDA NPs maintained colloidal stability in biological media, whereas the pi-pi (π-π) interaction between PDA and Ce6 enabled a release profile of the photosensitizer until day 5. Interestingly, loading of Ce6 in the polymer matrix of PDA NPs significantly enhanced the cell uptake because of endocytosis. An increased cell kill was observed with the combined PDT + PTT from 1 nM PDA-Ce6 compared to that with PTT alone with 1 nM PDA and PDT alone with 15 μM equivalent concentration of free Ce6. PDA-Ce6 NPs could be a promising PDT/PTT therapeutic agent for cancer therapy.

The employment of a conformal polydopamine thin layer reduces the cytotoxicity of silver nanoparticles

“…Cytotoxicity tests of PDOP NPs depicted that this NP system is highly biocompatible with Caco2 cells and the low cytotoxicity is a valuable indicator to explore them as a promising candidate for the conformal coating of toxic NPs. Similar results were detected in some reports in the literature (Zhang et al, 2012;Chen et al, 2014;Zhong et al, 2015;Tang et al, 2016;Li et al, 2017;Yu et al, 2017;Zhu and Su, 2017;Dong et al, 2018;Gu et al, 2018;Poinard et al, 2018). For example, Tang et al tested the cytotoxicity of PDOP NPs on the HepG2 cell line and analyzed this through the MTT assay (Tang et al, 2016).…”

From Bioinspired Glue to Medicine: Polydopamine as a Biomedical Material

“…The NPs were reported to deliver their cargo into the cancer cells and, upon near-infrared irradiation, released their payload and efficiently killed the cells [123]. Similarly, Poinard et al incorporated the hydrophobic photosensitiser drug chlorin e6 into PDA NPs [124]. When irradiated with 665 nm light, the drug was released and, thus, photodynamic and thermal therapy were successfully combined with drug delivery [124].…”

“…Similarly, Poinard et al incorporated the hydrophobic photosensitiser drug chlorin e6 into PDA NPs [124]. When irradiated with 665 nm light, the drug was released and, thus, photodynamic and thermal therapy were successfully combined with drug delivery [124]. Zhou et al were also able to incorporate a dye into PDA NPs and subsequently functionalise them with a targeting moiety [125].…”

In situ measurement of intracellular thermal conductivity using heater-thermometer hybrid diamond nanosensor

“…Therefore, PDA-coated nanoparticles (e.g. gold, magnetic, and silica nanoparticles) have been utilized for multifunctional hyperthermia applications, especially for cancer therapy [38][39][40][41][42] . Several papers have already reported PDA-coated FNDs (PDA-FNDs) as a platform for chemical functionalization 43,44 .…”