Optically Controlled Pore Formation in Self‐Sealing Giant Porphyrin Vesicles

Abstract

Efforts to develop self-contained microreactors and artificial cells have been limited by difficulty in generating membranes that can be robustly and repeatedly manipulated to load and release cargo from phospholipid compartments. Here we describe a purely optical method to form pores in a membrane generated from porphyrin-phospholipid conjugates electro-assembled into microscale giant porphyrin vesicles and manipulated using confocal microscopy. The pores in the membrane resealed within a minute allowing for repeated pore formation with precise spatial and temporal control and optical gating to allow selective diffusion of biomolecules across the membrane. Temporal control of pore formation was illustrated by performing sequential DNA hybridization reactions. A biotin-avidin based strategy was developed to selectively attach enzymes to the interior of the vesicle, demonstrating spatial control and the potential of giant porphyrin vesicles as versatile microreactors.

Porphyrin–phospholipid liposomes permeabilized by near-infrared light

“…The nature of the NIR-induced permeabilization is not well understood and further work must seek to better characterize both its chemical and physical mechanism. Optical microscopy has recently been shown to be useful for observing light-induced permeabilization in porphyrin–lipid microvesicles48, although mechanistic aspects between nanoscale and microscale vesicle permeabilization are likely different. Although the in vivo results of the systemically administered Dox–PoP-liposomes clearly demonstrated the synergistic effects of light treatment, further investigation is required to characterize the mechanism of action in the tumour.…”

Near‐Infrared‐Light‐Activatable Nanomaterial‐Mediated Phototheranostic Nanomedicines: An Emerging Paradigm for Cancer Treatment

“…To generate local hyperthermia to induce transient membrane rupture, it is not necessary to limit to the use of NIR light absorbing metal nanostructures. In another study, it was demonstrated that red light (658 nm, 200 mW cm −2 , 10 min) irradiation of porphyrin‐conjugated phospholipid‐based liposome (PoP‐liposome) can successfully lead to release of encapsulated doxorubicin from the liposomes . When the porphyrin lipid is beyond 10 mol% in the liposome membrane, self‐quenching of photoexcited porphyrin moieties can effectively convert photon energy to heat, leading to drastic increase in the transient membrane permeability, rapid release of encapsulated DOX anticancer drug, decrease in the in vitro cell viabilities, and prolonged average lifespan of KB tumor‐bearing nude mice .…”

“…However, near‐infrared phosphorescence emission at 1270 nm is the most widely used detection method. Alternatively, singlet oxygen can also be detected using the spin‐trapping ESR technique with the help of spin‐trapping agents such as 2,2,6,6‐tetramethyl‐4‐piperidone (TEMP) to form a TEMPO (TEMP‐ 1 O 2 ) spin adduct . The reaction of chemiluminescence probe reagents with 1 O 2 generates an electronically excited fluorescent product .…”

Advanced Functional Nanomaterials for Theranostics

“…Light-triggered reversible opening and sealing can also be achieved at the micro-scale. [380] Recently, Luo et al found that the light-triggered drug release speed can be controlled by adjusting the concentrations of porphyrin-phospholipid (PoP) and unsaturated lipid in the liposome, and the stability can be tuned by varying the drug-to-lipid ratio. [381, 382] With only 2% PoP in a conventional long-circulating liposome formulation, blood circulation of entrapped doxorubicin was 21.9 h, and was effective for tumor photoablation relative to photodynamic therapy or chemotherapy alone.…”