Emerging indocyanine green-integrated nanocarriers for multimodal cancer therapy: a review

Abstract

Nanotechnology is a branch of science dealing with the developing processes of a new type of nanomaterials by several methods. In the biomedical field, nanotechnology is widely used in the...

Spontaneous Transfer of Indocyanine Green from Liposomes to Albumin Is Inhibited by the Antioxidant α-Tocopherol

“…10,11 With regard to phototherapeutics, ICG nanoparticles have been investigated for photothermal therapy, 26,27 photodynamic therapy, 12,81 and light-triggered drug release. 10,11 There is literature evidence that the geometric location of a photosensitizer relative to a liposome membrane (i.e., photosensitizer embedded in the membrane or protruding into the aqueous solution) can affect the rate and extent of light-triggered liposome leakage, 82 and we were curious to learn if ICG transfer to albumin would diminish the extent of NIR light-activated membrane disruption and subsequent content leakage. Therefore, we conducted experiments that measured the NIR light-triggered leakage of aqueous contents from 1,2-dipalmitoyl-sn-glycero-3phosphocholine (DPPC) liposomes that also contained ICG as the light-absorbing trigger.…”

“…Although this study focused on ICG liposomes, we note that ICG transfer to albumin has been observed for a related solid nanoparticle formulation and is thus likely to occur with many types of nanoscale ICG formulations. , With regard to phototherapeutics, ICG nanoparticles have been investigated for photothermal therapy, , photodynamic therapy, , and light-triggered drug release. , There is literature evidence that the geometric location of a photosensitizer relative to a liposome membrane (i.e., photosensitizer embedded in the membrane or protruding into the aqueous solution) can affect the rate and extent of light-triggered liposome leakage, and we were curious to learn if ICG transfer to albumin would diminish the extent of NIR light-activated membrane disruption and subsequent content leakage. Therefore, we conducted experiments that measured the NIR light-triggered leakage of aqueous contents from 1,2-dipalmitoyl- sn -glycero-3-phosphocholine (DPPC) liposomes that also contained ICG as the light-absorbing trigger. − ,,,,, DPPC liposomes are thermally responsive, and they leak when heated close to their transition temperature of ∼41 °C.…”

“…The half-life for ICG transfer from gel-phase DPPC liposomes is ∼3 min at 22 °C. This ICG transfer process has been observed with lipid core nanoparticles, , but it seems to have not been considered by most published studies (perhaps all of them) that use ICG liposomes. ,− …”

“…The half-life for ICG transfer from gel-phase DPPC liposomes is ∼3 min at 22 °C. This ICG transfer process has been observed with lipid core nanoparticles, , but it seems to have not been considered by most published studies (perhaps all of them) that use ICG liposomes. ,− Unlike ICG, the classic lipophilic cyanine dyes such as DiI 20(5) with two long hydrocarbon chains do not transfer from liposomes or related lipid core nanoparticles to external BSA, − thus, it is not accurate to assume that ICG exhibits the same phase transfer behavior as the classic lipophilic cyanine dyes The presence of 20% α-tocopherol in ICG liposomes helps retain the ICG in the membrane (presumably by forming favorable aromatic stacking interactions) and inhibits ICG photobleaching.…”

“…ICG is an amphiphilic molecule with a propensity to self-aggregate at low micromolar concentrations in water, and its log P has been measured to be 1.81 when the aqueous phase is phosphate buffer (100 mM, pH 7.4) . Over the years, efforts to improve the photophysical and pharmaceutical properties of ICG have investigated numerous nanoparticle formulations. − A significant fraction of these nanoparticle formulations are ICG-containing liposomes, and they have been evaluated for various applications in fluorescence imaging and phototherapeutics. ,− Quite a few published studies have assessed the stability of ICG-containing liposomes by monitoring the change in sample absorbance or fluorescence intensity over time. However, this type of bulk sample measurement does not unambiguously eliminate the possibility of ICG transfer from the liposomes to albumin and related serum proteins within the same sample.…”