18 research outputs found
Trans-membrane Fluorescence Enhancement by Carbon Dots: Ionic Interactions and Energy Transfer
We report on trans-membrane interactions between blueemitting carbon dots (CDs) and fluorescein. Hydrophobic CDs with a positive surface charge are embedded as-synthesized in the lipophilic sheet of the bilayer membrane of large synthetic phospholipid vesicles. The vesicles are prepared by mixing DOPC phospholipids and lipid molecules that contain anionic fluorescein attached to their hydrophilic head. Due to attractive electrostatic interactions, the CDs and fluorescein conjoin within the vesicle membrane, which leads to photoluminescence enhancement of fluorescein and facilitates trans-membrane energy transfer between the CDs and the dye.Fil: Pritzl, Stefanie D.. Ludwig Maximilians Universitat; AlemaniaFil: Pschunder, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Ehrat, Florian. Ludwig Maximilians Universitat; AlemaniaFil: Bhattacharyya, Santanu. Ludwig Maximilians Universitat; AlemaniaFil: Lohmüller, Theobald. Ludwig Maximilians Universitat; AlemaniaFil: Huergo, María Ana Cristina. Ludwig Maximilians Universitat; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; ArgentinaFil: Feldmann, Jochen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas; Argentin
Trans-membrane fluorescence enhancement by carbon dots: ionic interactions and energy transfer
We report on trans-membrane interactions between blue-emitting carbon dots (CDs) and fluorescein. Hydrophobic CDs with a positive surface charge are embedded as-synthesized in the lipophilic sheet of the bilayer membrane of large synthetic phospholipid vesicles. The vesicles are prepared by mixing DOPC phospholipids and lipid molecules that contain anionic fluorescein attached to their hydrophilic head. Due to attractive electrostatic interactions, the CDs and fluorescein conjoin within the vesicle membrane, which leads to photoluminescence enhancement of fluorescein and facilitates trans-membrane energy transfer between the CDs and the dye.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada
Label-Free Time-Resolved Monitoring of Photolipid Bilayer Isomerization by Plasmonic Sensing
The photo-isomerization of the photolipid azo-PC, a derivative of phosphatidylcholine containing an azobenzene group in its sn2 acyl chain, enables optical control over key properties of supported lipid bilayers (SLBs), such as membrane fluidity and bilayer thickness. However, azobenzenes are well-known for their interaction with various dyes through photo-modulation and -sensitization pathways, presenting a challenge in bilayer characterization by fluorescence microscopy. Label-free tools capable of monitoring the switching process of photolipid SLBs at the nanoscale are therefore highly desired. In this study, the use of dark field scattering spectroscopy on gold nanorods as a highly sensitive approach is demonstrated for analyzing the reversible photo-isomerization dynamics of photolipid SLBs in real time at the single particle level
Indefinite and Bidirectional Near Infrared Nanocrystal Photoswitching
Materials whose luminescence can be switched by optical stimulation drive
technologies ranging from superresolution imaging1-4, nanophotonics5, and
optical data storage6-8, to targeted pharmacology, optogenetics, and chemical
reactivity9. These photoswitchable probes, including organic fluorophores and
proteins, are prone to photodegradation, and often require phototoxic doses of
ultraviolet (UV) or visible light. Colloidal inorganic nanoparticles have
significant stability advantages over existing photoswitchable materials, but
the ability to switch emission bidirectionally, particularly with NIR light,
has not been reported with nanoparticles. Here, we present 2-way, near-infrared
(NIR) photoswitching of avalanching nanoparticles (ANPs), showing full optical
control of upconverted emission using phototriggers in the NIR-I and NIR-II
spectral regions useful for subsurface imaging. Employing single-step
photodarkening10-13 and photobrightening12,14-18, we demonstrate indefinite
photoswitching of individual nanoparticles (>1000 cycles over 7 h) in ambient
or aqueous conditions without measurable photodegradation. Critical steps of
the photoswitching mechanism are elucidated by modeling and by measuring the
photon avalanche properties of single ANPs in both bright and dark states.
Unlimited, reversible photoswitching of ANPs enables indefinitely rewritable 2D
and 3D multi-level optical patterning of ANPs, as well as optical nanoscopy
with sub-{\AA} localization superresolution that allows us to distinguish
individual ANPs within tightly packed clusters.Comment: 15 pages, 5 figure
Label‐Free Time‐Resolved Monitoring of Photolipid Bilayer Isomerization by Plasmonic Sensing
The photo-isomerization of the photolipid azo-PC, a derivative of phosphatidylcholine containing an azobenzene group in its sn2 acyl chain, enables optical control over key properties of supported lipid bilayers (SLBs), such as membrane fluidity and bilayer thickness. However, azobenzenes are well-known for their interaction with various dyes through photo-modulation and -sensitization pathways, presenting a challenge in bilayer characterization by fluorescence microscopy. Label-free tools capable of monitoring the switching process of photolipid SLBs at the nanoscale are therefore highly desired. In this study, the use of dark field scattering spectroscopy on gold nanorods as a highly sensitive approach is demonstrated for analyzing the reversible photo-isomerization dynamics of photolipid SLBs in real time at the single particle level
Postsynthetic Photocontrol of Giant Liposomes via Fusion-Based Photolipid Doping
We report on photolipid
doping of giant unilamellar vesicles
(GUVs) via vesicle fusion with small unilamellar
photolipid vesicles
(pSUVs), which enables retroactive optical control of the membrane
properties. We observe that vesicle fusion is light-dependent, if
the phospholipids are neutral. Charge-mediated fusion involving anionic
and cationic lipid molecules augments the overall fusion performance
and doping efficiency, even in the absence of light exposure. Using
phosphatidylcholine analogs with one or two azobenzene photoswitches
(azo-PC and dazo-PC) affects domain formation, bending stiffness, and
shape of the resulting vesicles in response to irradiation. Moreover,
we show that optical membrane control can be extended to long wavelengths
using red-absorbing photolipids (red-azo-PC). Combined, our findings present
an attractive and practical method for the precise delivery of photolipids,
which offers new prospects for the optical control of membrane function
Postsynthetic Photocontrol of Giant Liposomes via Fusion-Based Photolipid Doping
We report on photolipid
doping of giant unilamellar vesicles
(GUVs) via vesicle fusion with small unilamellar
photolipid vesicles
(pSUVs), which enables retroactive optical control of the membrane
properties. We observe that vesicle fusion is light-dependent, if
the phospholipids are neutral. Charge-mediated fusion involving anionic
and cationic lipid molecules augments the overall fusion performance
and doping efficiency, even in the absence of light exposure. Using
phosphatidylcholine analogs with one or two azobenzene photoswitches
(azo-PC and dazo-PC) affects domain formation, bending stiffness, and
shape of the resulting vesicles in response to irradiation. Moreover,
we show that optical membrane control can be extended to long wavelengths
using red-absorbing photolipids (red-azo-PC). Combined, our findings present
an attractive and practical method for the precise delivery of photolipids,
which offers new prospects for the optical control of membrane function
Postsynthetic Photocontrol of Giant Liposomes via Fusion-Based Photolipid Doping
We report on photolipid
doping of giant unilamellar vesicles
(GUVs) via vesicle fusion with small unilamellar
photolipid vesicles
(pSUVs), which enables retroactive optical control of the membrane
properties. We observe that vesicle fusion is light-dependent, if
the phospholipids are neutral. Charge-mediated fusion involving anionic
and cationic lipid molecules augments the overall fusion performance
and doping efficiency, even in the absence of light exposure. Using
phosphatidylcholine analogs with one or two azobenzene photoswitches
(azo-PC and dazo-PC) affects domain formation, bending stiffness, and
shape of the resulting vesicles in response to irradiation. Moreover,
we show that optical membrane control can be extended to long wavelengths
using red-absorbing photolipids (red-azo-PC). Combined, our findings present
an attractive and practical method for the precise delivery of photolipids,
which offers new prospects for the optical control of membrane function
Postsynthetic Photocontrol of Giant Liposomes via Fusion-Based Photolipid Doping
We report on photolipid
doping of giant unilamellar vesicles
(GUVs) via vesicle fusion with small unilamellar
photolipid vesicles
(pSUVs), which enables retroactive optical control of the membrane
properties. We observe that vesicle fusion is light-dependent, if
the phospholipids are neutral. Charge-mediated fusion involving anionic
and cationic lipid molecules augments the overall fusion performance
and doping efficiency, even in the absence of light exposure. Using
phosphatidylcholine analogs with one or two azobenzene photoswitches
(azo-PC and dazo-PC) affects domain formation, bending stiffness, and
shape of the resulting vesicles in response to irradiation. Moreover,
we show that optical membrane control can be extended to long wavelengths
using red-absorbing photolipids (red-azo-PC). Combined, our findings present
an attractive and practical method for the precise delivery of photolipids,
which offers new prospects for the optical control of membrane function