Light-triggered liposomal cargo delivery platform incorporating photosensitizers and gold nanoparticles for enhanced singlet oxygen generation and increased cytotoxicity

Abstract

We developed light-triggered liposomes incorporating 3–5 nm hydrophobic gold nanoparticles and Rose Bengal (RB), a well-known photosensitizer used for photodynamic therapy. Singlet oxygen generated by these liposomes with 532 nm light illumination was characterized for varying the molar ratio of lipids and gold nanoparticles while keeping the amount of RB constant. Gold nanoparticles were found to enhance the singlet oxygen generation rate, with a maximum enhancement factor of 1.75 obtained for the molar ratio of hydrogenated soy l -α-phosphatidylcholine:1,2-dioleoyl- sn -glycero-3-phosphoethanolamine- N -(hexanoylamine):gold of 57:5:17 compared with liposomes loaded with RB alone. The experimental results could be explained by the local electric field enhancement caused by gold nanoparticles. We further assessed cellular cytotoxicity of gold-loaded liposomes by encapsulating an antitumor drug, doxorubicin (Dox); such Dox-loaded liposomes were applied to human colorectal cancer cells (HCT116) and exposed to light. Gold-loaded liposomes containing RB and Dox where Dox release was triggered by light were found to exhibit higher cytotoxicity compared with the liposomes loaded with RB and Dox alone. Our results indicate that gold-loaded liposomes incorporating photosensitizers may serve as improved agents in photodynamic therapy and chemotherapy.

Photosensitiser-gold nanoparticle conjugates for photodynamic therapy of cancer

“…The development of other conjugation methods and platforms based on gold by which efficient PDT can be achieved have also been reported in the literature. [44][45][46][47][48][49] Hu et al used a LayerbyLayer (LbL) method to assemble the photosensitiser Al(III) phthalocyanine chloride tetrasulfonic acid (AlPcS4) onto gold nanorings. 44 In this case, LbL assembly consists of successive deposition of layers of the photosensitiser around the gold.…”

“…However, its application is limited to superficial tumour lesions due to the nature of the plaster application. 46 Other nanoparticle systems all supported by gold include liposomes loaded with AuNPs, 47 carboxymethyl dextran nanoparticles stabilised with gold, 48 and the use of a thin shell of gold comprised of a gold sulfide (Au2S) dielectric core. 49 Liposomes loaded with 3-5 nm AuNPs and the photosensitiser Rose Bengal were particularly efficient for PDT combined with chemotherapy, when the chemotherapeutic drug doxorubicin was included within the system.…”

“…49 Liposomes loaded with 3-5 nm AuNPs and the photosensitiser Rose Bengal were particularly efficient for PDT combined with chemotherapy, when the chemotherapeutic drug doxorubicin was included within the system. 47 The use of gold to stabilise carboxymethyl dextran nanoparticles loaded with the photosensitiser chlorin e6 was advantageous since it increased the tumour selectivity and thus the PDT effect in vivo. 48 Finally, the physical adsorption of gold-sulfide gold (Au-Au2S) with the photosensitiser ICG was found to be a promising alternative for NIR-PDT/PTT given the non-toxic nature of Au-Au2S and their easy internalisation by tumorigenic cells.…”

Biomedical Applications of Photo- and Sono-Activated Rose Bengal: A Review

“…To improve RB uptake by cancer cells, RB was loaded into multivesicular and in light-triggered liposomes containing gold nanoparticles, and it was tested in vitro. 46,47 Results showed good intracellular RB uptake and a consequent increase in cell death rate in the first case, and good cell-killing efficacy of RB combined with gold in the second case. Gold has also been used in the form of nanorods and combined with photo-activated RB to generate ROS for killing oral cancer cells through the integrated effect of PDT and photo-thermal therapy offers advantages such as high effectiveness and specificity to oral cells both in vitro and in vivo in a hamster tumor model.…”

Technobiology Paradigm in Nanomedicine: Treating Cancer with MagnetoElectric Nanoparticles

“…Gold nanoparticles (AuNPs) are one of the most widely used nanomaterial in the field of nanomedicine. The drug release mechanisms of AuNPs conjugated with mAb to adequately deliver the drug to a cell have been shown to rely highly on a physiological stimulus; i.e., internal stimuli such as the cells' pH level and intracellular enzymes; and external stimuli such as light and temperature (11)(12)(13). AuNPs have also been used in photothermal therapy to eradicate cancer cells; Due to the strong electric field at the surface of the noble metal, when the nanoparticles accumulate near the cancer site and irradiated with an external laser source (14,15), the absorption and scattering of the electromagnetic radiation producing enough heat to eradicate the surrounding tumor cells.…”