Detection of Phase Transition in Photosensitive Liposomes by Advanced QCM

Viitala, Lauri; Lajunen, Tatu; Urtti, Arto; Murtomäki, Lasse

doi:10.1021/acs.jpcc.5b04042

Cited by 14 publications

(6 citation statements)

References 49 publications

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“…Several studies have reported similar observations, describing lipid bilayers that underwent phase transition by CW laser in the presence of gold nanorods and released drug. − This study differs from the previous study in two-fold: (1) we demonstrated the lipid bilayer phase transition by pulsed laser and (2) further verified reversibility of individual liposomes via collision frequency measurement.…”

Section: Resultssupporting

confidence: 55%

Effect of Laser Irradiation on Reversibility and Drug Release of Light-Activatable Drug-Encapsulated Liposomes

et al. 2020

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Although several studies have demonstrated repetitive drug release using light-activatable liposomes, inconsistent drug release at each activation limits widespread usage. Here, we report reversible plasmonic material-coated encapsulated liposomes for proportional controlled delivery of methotrexate (MTX), which is a common drug for cancer and autoimmune diseases, using repetitive laser irradiation. Our results suggest a proportional increase in total drug release after repetitive laser irradiation. We hypothesize that the drug is released via "melted" lipid bilayers when the plasmonic materials on the liposome surface are heated by laser irradiation followed by reversible formation of the liposome. To evaluate our hypothesis, the number density of liposomes after laser irradiation was measured using single-particle (liposome) collision experiments at an ultramicroelectrode. Collisional frequency data suggest that the number density of liposomes remains unaltered even after 60 s of laser irradiation at 1.1 and 1.8 W, indicating that the liposome structure is reversible. The results were further compared with gold nanorod-coated nanodroplets where drug is released via irreversible phase transition. In contrast to what was observed with the liposome particles, the number density of the nanodroplets decreased with increasing laser irradiation duration. The structure reversibility of our liposome particles may be responsible for repetitive drug release with laser heating. We also studied the temperature rise in the lipid bilayer by incorporating polymerized 10,12pentacosadiynoic acid (PCDA) in the lipid composition. The red shift in the UV−vis spectrum due to the structural change in PCDA lipids after laser irradiation indicates a rise in temperature above 75 °C, which is also above the chain-melting temperature of the main lipid used in the liposomes. All these results indicate that drug is released from the light-activatable liposomes due to reversible nanostructural alteration in the lipid bilayer by plasmonic resonance heating. The liposomes have potential to be a drug carrier for dose-controlled repetitive drug delivery.

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Section: Resultssupporting

confidence: 55%

Effect of Laser Irradiation on Reversibility and Drug Release of Light-Activatable Drug-Encapsulated Liposomes

et al. 2020

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“…4,5,8,14 Gold nanoparticles convert absorbed light energy to heat, permeabilizing the liposomal membrane and enabling drug release to the surrounding tissue. 4,5,15,16 The maximum absorption wavelength of the gold nanoparticles depends on the size and shape of the particles. 17−19 Small gold nanoparticles absorb light in the ultraviolet range (<400 nm), but such short wavelengths penetrate tissues poorly and may cause DNA damage to the cells.…”

Section: Introductionmentioning

confidence: 99%

“…Liposomes are nanocarriers that are already in clinical use; they are biocompatible, and their surface and lipid wall properties can be modified in a versatile manner . Previously, light-activated release from liposomes has been achieved using gold nanoparticles as a light-triggering component. ,,, Gold nanoparticles convert absorbed light energy to heat, permeabilizing the liposomal membrane and enabling drug release to the surrounding tissue. ,,, The maximum absorption wavelength of the gold nanoparticles depends on the size and shape of the particles. − Small gold nanoparticles absorb light in the ultraviolet range (<400 nm), but such short wavelengths penetrate tissues poorly and may cause DNA damage to the cells. − Larger gold nanoparticles absorb light in the near IR range (700–900 nm), , the “phototherapeutic window”. These wavelengths are safer to the tissues and show maximal tissue penetration. , Therefore, the use of near IR light is a promising approach for light-triggered drug delivery and phototherapy. ,− …”

Section: Introductionmentioning

confidence: 99%

Indocyanine Green-Loaded Liposomes for Light-Triggered Drug Release

et al. 2016

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Light-triggered drug delivery systems enable site-specific and time-controlled drug release. In previous work, we have achieved this with liposomes containing gold nanoparticles in the aqueous core. Gold nanoparticles absorb near-infrared light and release the energy as heat that increases the permeability of the liposomal bilayer, thus releasing the contents of the liposome. In this work, we replaced the gold nanoparticles with the clinically approved imaging agent indocyanine green (ICG). The ICG liposomes were stable at storage conditions (4-22 °C) and at body temperature, and fast near-infrared (IR) light-triggered drug release was achieved with optimized phospholipid composition and a 1:50 ICG-to-lipid molar ratio. Encapsulated small molecular calcein and FITC-dextran (up to 20 kDa) were completely released from the liposomes after light exposure for 15 s. Location of ICG in the PEG layer of the liposomes was simulated with molecular dynamics. ICG has important benefits as a light-triggering agent in liposomes: fast content release, improved stability, improved possibility of liposomal size control, regulatory approval to use in humans, and the possibility of imaging the in vivo location of the liposomes based on the fluorescence of ICG. Near-infrared light used as a triggering mechanism has good tissue penetration and safety. Thus, ICG liposomes are an attractive option for light-controlled and efficient delivery of small and large drug molecules.

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“…6,11 As the GNP turns absorbed light energy into heat, heat is transported to the surrounding lipid bilayer (MD simulation; see e.g. ref 12) and the lipids undergo a phase transition 8,13 followed by drug release. 6,9 The underlying mechanism of action is no different than in thermotherapy, where GNPs are heated by light in order to kill cancer cells.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Light-to-heat conversion has been done by encapsulating hydrophilic gold nanoparticles (GNPs) inside the liposomes or hydrophobic GNPs into the bilayer of the liposomes. , As the GNP turns absorbed light energy into heat, heat is transported to the surrounding lipid bilayer (MD simulation; see e.g. ref ) and the lipids undergo a phase transition , followed by drug release. , The underlying mechanism of action is no different than in thermotherapy, where GNPs are heated by light in order to kill cancer cells . In addition to gold colloids, some organic dyes such as indocyanine green (ICG) and IR820 act as a photothermal agent and can also be used in thermal therapy. , Remarkably, these dyes have so far not been used in drug release from liposomes.…”

Section: Introductionmentioning

confidence: 99%

Photothermally Triggered Lipid Bilayer Phase Transition and Drug Release from Gold Nanorod and Indocyanine Green Encapsulated Liposomes

et al. 2016

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In light-activated liposomal drug delivery systems (DDSs), the light sensitivity can be obtained by a photothermal agent that converts light energy into heat. Excess heat increases the drug permeability of the lipid bilayer, and drug is released as a result. In this work, two near-IR responsive photothermal agents in a model drug delivery system are studied: either gold nanorods (GNRs) encapsulated inside the liposomes or indocyanine green (ICG) embedded into the lipid bilayer. The liposome system is exposed to light, and the heating effect is studied with fluorescent thermometers: laurdan and CdSe quantum dots (QDs). Both photothermal agents are shown to convert light into heat in an extent to cause a phase transition in the surrounding lipid bilayer. This phase transition is also proven with laurdan generalized polarization (GP). In addition to the heating results, we show that the model drug (calcein) is released from the liposomal cavity with both photothermal agents when the light power is sufficient to cause a phase transition in the lipid bilayer.

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Detection of Phase Transition in Photosensitive Liposomes by Advanced QCM

Cited by 14 publications

References 49 publications

Effect of Laser Irradiation on Reversibility and Drug Release of Light-Activatable Drug-Encapsulated Liposomes

Effect of Laser Irradiation on Reversibility and Drug Release of Light-Activatable Drug-Encapsulated Liposomes

Indocyanine Green-Loaded Liposomes for Light-Triggered Drug Release

Photothermally Triggered Lipid Bilayer Phase Transition and Drug Release from Gold Nanorod and Indocyanine Green Encapsulated Liposomes

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