Structurally Controlled Porphyrin‐Aggregation Process in Phospholipid Membranes

Borovkov, Victor; Anikin, Michael; Wasa, Kiyotaka; Sakata, Yoshiteru

doi:10.1111/j.1751-1097.1996.tb03072.x

Cited by 16 publications

(22 citation statements)

References 32 publications

(31 reference statements)

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“…19 Consistent with studies that have investigated the liposomal incorporation of hydrophobic porphyrin-based photosensitizers [23][24][25] or other fluorescent membrane probes, 6 larger liposomal loading levels (.1 mol%) generally result in significant intermembranous molecular aggregation. That no observable quantity of longer-wavelength emitting PZn 3 -PZn 5 can be incorporated within SOPC-based liposomes likely stems from the fact that the molecular lengths of these species (3.2-5.4 nm) approach or exceed the thickness of conventional lipid membranes (3-5 nm).…”

Section: Resultsmentioning

confidence: 72%

Quantitative membrane loading of polymer vesicles

et al. 2006

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We utilize a series of structurally homologous, multi-porphyrin-based, fluorophores (PBFs) in order to explore the capacity of polymer vesicles (polymersomes) to stably incorporate large hydrophobic molecules, non-covalently within their thick lamellar membranes. Through aqueous hydration of dry, uniform thin-films of amphiphilic polymer and PBF species deposited on Teflon, self-assembled polymersomes are readily generated incorporating the hydrophobic fluorophores in prescribed molar ratios within their membranes. The size-dependent spectral properties of the PBFs allow for ready optical verification (via steady-state absorption and emission spectroscopy) of the extent of vesicle membrane loading and enable delineation of intermembranous molecular interactions. The resultant effects of PBF membrane-loading on polymersome thermodynamic and mechanical stability are further assessed by cryogenic transmission electron microscopy (cryo-TEM) and micropipet aspiration, respectively. We demonstrate that polymersomes can be loaded at up to 10 mol/wt% concentrations, with hydrophobic molecules that possess sizes comparable to those of large pharmaceutical conjugates (e.g. ranging 1.4-5.4 nm in length and Mw = 0.7-5.4 kg mol 21 ), without significantly compromising the robust thermodynamic and mechanical stabilities of these synthetic vesicle assemblies. Due to membrane incorporation, hydrophobic encapsulants are effectively prevented from self-aggregation, able to be highly concentrated in aqueous solution, and successfully shielded from deleterious environmental interactions. Together, these studies present a generalized paradigm for the generation of complex multi-functional materials that combine both hydrophilic and hydrophobic agents, in mesoscopic dimensions, through cooperative self-assembly.

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Section: Resultsmentioning

confidence: 72%

Quantitative membrane loading of polymer vesicles

et al. 2006

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“…These shifts are due to strong interporphyrin interactions in the face-to-face conformation of 13. Similar bathochromic shifts of porphyrin fluorescence bands have been observed for covalently linked cofacial porphyrin dimers [18c,d] and stacked porphyrin aggregates [21a] [24].…”

Section: Methodsmentioning

confidence: 63%

“…The products were recrystallized from CH 2 Cl 2 / MeOH and dried in vacuo: 55 mg (46%) of 2 and 30 mg (25%) of 14. 23 ,kN 24 }i-ron(1 ) Chloride (4). As described for 3, 2 (12.3 mg, 0.01 mmol) in CHCl 3 (30 ml) was treated with 2m HCl (50 ml).…”

Section: Experimental Partmentioning

confidence: 99%

Synthesis of Zn-, Mn-, and Fe-Containing Mono- and Heterometallated Ethanediyl-Bridged Porphyrin Dimers

Borovkov¹,

Lintuluoto²,

Inoue³

1999

HCA

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“…24 In the P-(Lys) n conjugate, however, the strong electrostatic repulsion between the heavily positively charged polylysine side chains appears large enough to potentially weaken interactions which lead to stacking of the solvated porphyrin rings. Both sharper spectral resolution and increased τ F are observed ( Figure 2B and Table 1).…”

Section: Photosensitized Histidine Degradationmentioning

confidence: 99%

Tricationic Porphyrin Conjugates: Evidence for Chain-Structure-Dependent Relaxation of Excited Singlet and Triplet States

et al. 2009

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Conjugates of 5-(4-carboxyphenyl)-10,15,20-tris(4-methylpyridinium-4-yl)porphyrin (P-H) are promising photoactive agents for medical applications. As their ultimate efficacy will depend on the behavior of initial excited states, photophysical parameters have been determined with conventional steady-state absorption and fluorescence as well as time-resolved femto- and nanosecond spectroscopies. The fluorescence quantum yield of P-H and P-H conjugated to uncharged groups increases from approximately 0.03 in pH 7 buffer to approximately 0.05 in Triton X100 micelles (TX100) and in ethanol and to 0.12 in sodium dodecyl sulfate (SDS) micelles. Corresponding (1)S(1) lifetimes are approximately 5-10 ns. In buffer, an equilibrium between P-H monomers and small-size aggregates is observed. Conjugation with poly-S-lysine (P-(Lys)(n)) results in fluorescence quenching in all solvents. Structural reorganization of conjugates bearing a Di-O-isopropylidene-alpha-d-galactopyranosyl or a alpha/beta-d-galactopyranosyl group occurs in ethanol (k approximately 0.15 ps(-1)) after (1)S(1) state solvation (approximately 700 fs). Relaxation of bulky P-(Lys)(n) polypeptide chains takes place on a longer time scale in all solvents (k

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Structurally Controlled Porphyrin‐Aggregation Process in Phospholipid Membranes

Cited by 16 publications

References 32 publications

Quantitative membrane loading of polymer vesicles

Quantitative membrane loading of polymer vesicles

Synthesis of Zn-, Mn-, and Fe-Containing Mono- and Heterometallated Ethanediyl-Bridged Porphyrin Dimers

Tricationic Porphyrin Conjugates: Evidence for Chain-Structure-Dependent Relaxation of Excited Singlet and Triplet States

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