Woo Kyoung Lee

Photodynamic therapy (PDT) is an innovative cancer treatment that utilizes light. When light irradiates, purpurin-18-N-propylimide methyl ester (P18 N PI ME) generates reactive oxygen species that destroy cancer cells. The hydrophobic nature of P18 N PI ME presents challenges regarding its aggregation in the body, which can affect its effectiveness. This study aimed to enhance the bioavailability and effectiveness of cancer treatment by synthesizing P18 N PI ME and formulating P18 N PI ME-loaded solid lipid nanoparticles (SLNs). The efficacy of PDT was estimated using the 1,3-diphenylisobenzofuran (DPBF) assay and photocytotoxicity tests on the HeLa (human cervical carcinoma) and A549 (human lung carcinoma) cell lines. The P18 N PI ME-loaded SLNs demonstrated particle sizes in the range of 158.59 nm to 248.43 nm and zeta potentials in the range of –15.97 mV to –28.73 mV. These SLNs exhibited sustained release of P18 N PI ME. DPBF analysis revealed enhanced PDT effects with SLNs containing P18 N PI ME compared with standalone P18 N PI MEs. Photocytotoxicity assays indicated toxicity under light irradiation but no toxicity in the dark. Furthermore, the smallest-sized formulation exhibited the most effective photodynamic activity. These findings indicate the potential of P18 N PI ME-loaded SLNs as promising strategies for PDT in cancer therapy.

In this study, we condensed methyl pyropheophorbide-a (2) with 1,2-phenylenediamine to synthesize benzimidazolo-chlorin (3a) as an effective near-infrared photosensitizer (PS) with an absorption maximum of 730 nm. The ability of 3a to generate singlet oxygen, as well as its photodynamic effect on A549 and HeLa cells, was investigated. PS exhibited strong phototoxicity and negligible dark toxicity. Its structure was examined by UV-visible spectroscopy, nuclear magnetic resonance, and high-resolution fast atom bombardment mass spectrometry.

Photodynamic therapy (PDT) is a promising anticancer treatment because it is patient-friendly and non-invasive. Methyl pyropheophorbide-a (MPPa), one of the chlorin class photosensitizers, is a drug with poor aqueous solubility. The purpose of this study was to synthesize MPPa and develop MPPa-loaded solid lipid nanoparticles (SLNs) with improved solubility and PDT efficacy. The synthesized MPPa was confirmed ¹H nuclear magnetic resonance (¹H-NMR) spectroscopy and UV–Vis spectroscopy. MPPa was encapsulated in SLN via a hot homogenization with sonication. Particle characterization was performed using particle size and zeta potential measurements. The pharmacological effect of MPPa was evaluated using the 1,3-diphenylisobenzofuran (DPBF) assay and anti-cancer effect against HeLa and A549 cell lines. The particle size and zeta potential ranged from 231.37 to 424.07 nm and − 17.37 to − 24.20 mV, respectively. MPPa showed sustained release from MPPa-loaded SLNs. All formulations improved the photostability of MPPa. The DPBF assay showed that SLNs enhanced the ¹O₂ generation from MPPa. In the photocytotoxicity analysis, MPPa-loaded SLNs demonstrated cytotoxicity upon photoirradiation but not in the dark. The PDT efficacy of MPPa improved following its entrapment in SLNs. This observation suggests that MPPa-loaded SLNs are suitable for the enhanced permeability and retention effect. Together, these results demonstrate that the developed MPPa-loaded SLNs are promising candidates for cancer treatment using PDT.

Purpurin-18 (P18) is one of the essential photosensitizers used in photodynamic therapy (PDT), but its hydrophobicity causes easy coalescence and poor bioavailability. This study aimed to synthesize P18 and design P18-loaded solid lipid nanoparticles (SLNs) to improve its bioavailability. The characteristics of the synthesized P18 and SLNs were evaluated by particle characteristics and release studies. The effects of P18 were evaluated using the 1,3-diphenylisobenzofuran (DPBF) assay as a nonbiological assay and a phototoxicity assay against HeLa and A549 cell lines as a biological assay. The mean particle size and zeta potential of the SLNs were 164.70–762.53 nm and −16.77–25.54 mV, respectively. These results indicate that P18-loaded SLNs are suitable for an enhanced permeability and retention effect as a passive targeting anti-cancer strategy. The formulations exhibited a burst and sustained release based on their stability. The DPBF assay indicated that the PDT effect of P18 improved when it was entrapped in the SLNs. The photocytotoxicity assay indicated that P18-loaded SLNs possessed light cytotoxicity but no dark cytotoxicity. In addition, the PDT activity of the formulations was cell type- and size-dependent. These results suggest that the designed P18-loaded SLNs are a promising tool for anticancer treatment using PDT.

Photodynamic therapy (PDT) is a non-invasive and tumour-specific therapy. Photosensitizers (PSs) (essential ingredients in PDT) aggregate easily owing to their lipophilic properties. The aim of this study was to synthesise a PS (methyl pheophorbide a, MPa) and design a biocompatible lipid-based nanocarrier to improve its bioavailability and pharmacological effects. MPa-loaded nano-transfersomes were fabricated by sonication. The characteristics of synthesised PS and nano-transfersomes were assessed. The effects of PDT were evaluated by 1,3-diphenylisobenzofuran assay and by measuring photo-cytotoxicity against HeLa and A549 cell lines. The mean particle size and zeta potential for nano-transfersomes ranged from 95.84 to 267.53 nm and −19.53 to −45.08 mV, respectively. Nano-transfersomes exhibited sustained drug release for 48 h in a physiological environment (as against burst release in an acidic environment), which enables its use as a pH-responsive drug release system in PDT with enhanced photodynamic activity and reduced side effects. The formulations showed light cytotoxicity, but no dark toxicity, which meant that light irradiation resulted in anti-cancer effects. Additionally, formulations with the smallest size exhibited photodynamic activity to a larger extent than those with the highest loading capacity or free MPa. These results suggest that our MPa-loaded nano-transfersome system is a promising anti-cancer strategy for PDT.