| 1. |
- Borglin, Johan, 1986, et al.
(författare)
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Insights on proximity effect and multiphoton induced luminescence from gold nanospheres in far field optical microscopy
- 2015
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 107:23
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Tidskriftsartikel (refereegranskat)abstract
- Goldnanoparticles can be visualized in far-field multiphoton laser-scanning microscopy (MPM) based on the phenomena of multiphoton induced luminescence (MIL). This is of interest for biomedical applications, e.g., for cancer diagnostics, as MPM allows for working in the near-infrared(NIR) optical window of tissue. It is well known that the aggregation of particles causes a redshift of the plasmon resonance, but its implications for MIL applying far-field MPM should be further exploited. Here, we explore MIL from 10nm goldnanospheres that are chemically deposited on glass substrates in controlled coverage gradients using MPM operating in NIR range. The substrates enable studies of MIL as a function of inter-particle distance and clustering. It was shown that MIL was only detected from areas on the substrates where the particle spacing was less than one particle diameter, or where the particles have aggregated. The results are interpreted in the context that the underlying physical phenomenon of MIL is a sequential two-photon absorption process, where the first event is driven by the plasmon resonance. It is evident that goldnanospheres in this size range have to be closely spaced or clustered to exhibit detectable MIL using far-field MPM operating in the NIR region.
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| 2. |
- Ericson, Marica B, 1974, et al.
(författare)
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Exploring plasmonic coupling as a stimuli responsive contrast mechanism in multiphoton microscopy
- 2018
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Ingår i: Proceedings Volume 10509, Plasmonics in Biology and Medicine XV. - : SPIE. - 1605-7422. - 9781510615045 - 9781510615038
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Konferensbidrag (refereegranskat)abstract
- A novel approach for optical biosensing can be obtained based multiphoton induced luminescence (MIL) and its dependence on plasmonic coupling. It has been shown that the proximity of spherical AuNPs determines the generation of MIL in far-field multiphoton laser scanning microscopy (MPM). A stimuli responsive contrast mediator with high sensitivity can be created by controlling the aggregated state of AuNP. In this study we explore a system based on spherical AuNPs functionalized with beta-cyclodextrin and multiple beta-D-lactose units (lacto-CD-AuNP). The aim of the beta-D- lactose units is to target cancer cells, based on overexpression of galectin3 (Gal-3) receptors. The results demonstrate that clustering of particles, and thereby MIL signal, was only acquired from tumor cell lines, i.e., SK-MEL-28 and A431, while not from normal keratinocytes (HEKn). Thus further studies should be undertaken to translate the concept to a preclinical setting.
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| 3. |
- Fraix, Aurore, et al.
(författare)
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A Three-Color Fluorescent Supramolecular Nanoassembly of Phototherapeutics Activable by Two-Photon Excitation with Near-Infrared Light.
- 2019
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Ingår i: Chemistry. - : Wiley. - 1521-3765. ; 25:29, s. 7091-7095
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Tidskriftsartikel (refereegranskat)abstract
- A supramolecular nanoassembly, of about 30nm in diameter, that consists of a green-fluorescent, β-cyclodextrin-based, branched polymer co-encapsulating a red-emitting singlet oxygen (1 O2 ) photosensitizer and a nitric oxide (NO) photoreleaser, which comprises a blue fluorescent reporter, is here reported. The system exhibits "five-in-one" photofunctionalities. All components can be simultaneously excited in the phototherapeutic window with two-photons by using near-infrared light at 740nm and despite their close proximity, behave as independent units. This allows for their in vitro visualization in carcinoma cancer cells, due to their distinct green, red, and blue fluorescence, and for the production of both cytotoxic 1 O2 and biofunctional NO.
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| 4. |
- Guldbrand, Stina, 1970, et al.
(författare)
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Two-photon fluorescence correlation spectroscopy as a tool for measuring molecular diffusion within human skin
- 2013
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Ingår i: European Journal of Pharmaceutics and Biopharmaceutics. - : Elsevier BV. - 0939-6411. ; 84:2, s. 430-436
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Tidskriftsartikel (refereegranskat)abstract
- There is a need for tools enabling quantitative imaging of biological tissue for pharmaceutical applications. In this study, two-photon fluorescence microscopy (TPM) has been combined with fluorescence correlation spectroscopy (FCS), demonstrating proof-of-principle providing quantitative data of fluorophore concentration and diffusion in human skin. Measurements were performed on excised skin exposed to either rhodamine B (RB) or rhodamine B isothiocyanate (RBITC), chosen based on their similarity in fluorescence yield and molecular weight, but difference in chemical reactivity. The measurements were performed at tissue depths in the range 0 and 20 pm, and the diffusion coefficients at skin depths 5 and 10 mu m were found to be significantly different (P < 0.05). Overall median values for the diffusion coefficients were found to be 4.0 x 10(-13) m(2)/s and 2.0 x 10(-13) m(2)/s for RB and RBITC, respectively. These values correspond to the diffusion of a hard sphere with a volume eight times larger for RBITC compared to RB. This indicates that the RBITC have bound to biomolecules in the skin, and the measured signal is obtained from the RBITC-biomolecule complexes, demonstrating the potential of the TPM-FCS method to track molecular interactions in an intricate biological matrix such as human skin.
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| 5. |
- Kandoth, N., et al.
(författare)
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Two-photon fluorescence imaging and bimodal phototherapy of epidermal cancer cells with biocompatible self-assembled polymer nanoparticles
- 2014
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 15:5, s. 1768-1776
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Tidskriftsartikel (refereegranskat)abstract
- We have developed herein an engineered polymer-based nanoplatform showing the convergence of two-photon fluorescence imaging and bimodal phototherapeutic activity in a single nanostructure. It was achieved through the appropriate choice of three different components: a β-cyclodextrin-based polymer acting as a suitable carrier, a zinc phthalocyanine emitting red fluorescence simultaneously as being a singlet oxygen (1O2) photosensitizer, and a tailored nitroaniline derivative, functioning as a nitric oxide (NO) photodonor. The self-assembly of these components results in photoactivable nanoparticles, approximately 35 nm in diameter, coencapsulating a multifunctional cargo, which can be delivered to carcinoma cells. The combination of steady-state and time-resolved spectroscopic and photochemical techniques shows that the two photoresponsive guests do not interfere with each other while being enclosed in their supramolecular container and can thus be operated in parallel under control of light stimuli. Specifically, two-photon fluorescence microscopy allows mapping of the nanoassembly, here applied to epidermal cancer cells. By detecting the red emission from the phthalocyanine fluorophore it was also possible to investigate the tissue distribution after topical delivery onto human skin ex vivo. Irradiation of the nanoassembly with visible light triggers the simultaneous delivery of cytotoxic 1O 2 and NO, resulting in an amplified cell photomortality due to a combinatory effect of the two cytotoxic agents. The potential of dual therapeutic photodynamic action and two-photon fluorescence imaging capability in a single nanostructure make this system an appealing candidate for further studies in biomedical research. © 2014 American Chemical Society.
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| 6. |
- Kirejev, Vladimir, 1984, et al.
(författare)
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A polymer-based nanodevice for the photoregulated release of NO with two-photon fluorescence reporting in skin carcinoma cells
- 2014
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Ingår i: Journal of Materials Chemistry B. - : Royal Society of Chemistry (RSC). - 2050-750X .- 2050-7518. ; 2:9, s. 1190-1195
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Tidskriftsartikel (refereegranskat)abstract
- We have developed a multifunctional biocompatible nanoconstruct based on polymeric nanoparticles encapsulating a molecular conjugate, able to photorelease nitric oxide (NO) with a fluorescent reporting function. We demonstrate that two-photon excitation (TPE) using biofriendly NIR 700 nm laser light can be applied for monitoring as well as triggering the release of NO, wherein the uncaging of a strongly fluorescent co-product acts in turn as a TPE fluorescent reporter for the simultaneous NO release from the nanoassembly. This supramolecular nanodevice internalizes in skin carcinoma cells, induces significant cell death upon light excitation and preserves its TPE properties, allowing the nearly instantaneous quantification of the NO photoreleased in cancer cells by two-photon NIR fluorescence microscopy. © 2014 The Royal Society of Chemistry.
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| 7. |
- Kirejev, Vladimir, 1984, et al.
(författare)
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Contactless Stimulation and Control of Biomimetic Nanotubes by Calcium Ion Gradients
- 2018
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Ingår i: Small. - : Wiley. - 1613-6810 .- 1613-6829. ; 14:21
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Tidskriftsartikel (refereegranskat)abstract
- Membrane tubular structures are important communication pathways between cells and cellular compartments. Studying these structures in their native environment is challenging, due to the complexity of membranes and varying chemical conditions within and outside of the cells. This work demonstrates that a calcium ion gradient, applied to a synthetic lipid nanotube, triggers lipid flow directed toward the application site, resulting in the formation of a bulge aggregate. This bulge can be translated in a contactless manner by moving a calcium ion source along the lipid nanotube. Furthermore, entrapment of polystyrene nanobeads within the bulge does not tamper the bulge movement and allows transporting of the nanoparticle cargo along the lipid nanotube. In addition to the synthetic lipid nanotubes, the response of cell plasma membrane tethers to local calcium ion stimulation is investigated. The directed membrane transport in these tethers is observed, but with slower kinetics in comparison to the synthetic lipid nanotubes. The findings of this work demonstrate a novel and contactless mode of transport in lipid nanotubes, guided by local exposure to calcium ions. The observed lipid nanotube behavior can advance the current understanding of the cell membrane tubular structures, which are constantly reshaped during dynamic cellular processes.
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| 8. |
- Kirejev, Vladimir, 1984
(författare)
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Exploring nanosystems for biomedical applications focusing on photodynamic therapy and drug delivery
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The increasing incidences of cancer and related deaths call for the development of new and improved treatment modalities. Photodynamic therapy (PDT) today is an alternative to conventional treatments, but has limitations. This thesis explores different nanosystems with aim to improve PDT focusing on spectroscopic and ex vivo studies. Nanosystems capable of efficient photodynamic action in anaerobic or hypoxic conditions are gaining much attention. Constructs of cyclodextrin polymer encapsulating anthracene-nitroaniline conjugates, that can release nitric oxide (NO) radicals upon irradiation, were investigated in this thesis. It was demonstrated that concomitant increase of fluorescence can be used for dosimetry of NO release. Pulsed near-infrared laser light can be used for NO photorelease by two-photon excitation process that along with high phototoxicity (observed cell mortality >90%) make this nanosystem a promising technique in PDT (paper I). A multimodal nanosystem consisting of a cyclodextrin polymer, adamantyl-nitroaniline, and zinc phthalocyanine tetrasulfonate was evaluated (paper II). Multiphoton microscopy showed cytosolic distribution of the nanosystem in in vitro cells and the ability of the nanosystem to penetrate into ex vivo skin. In addition, the combinatorial phototoxic effect elicited by singlet oxygen and NO (cell mortality >90%), indicates high potential of this multimodal nanosystem in PDT. Herein, it is demonstrated that conjugation of water non-soluble photosensitizer (mTHPP) to cyclodextrin can enhance its aqueous solubility and monomerization, thereby leading to improved photophysical properties in aqueous environment (paper III).It was also shown that conjugation facilitates skin penetration ex vivo. Fluorescence lifetime imaging demonstrated accumulation of the monomeric conjugate in the cytoplasm in vitro cells. It has been suggested that PDT enhancement can be achieved by a combination of photosensitizer and gold nanoparticles; however, the investigations in this thesis demonstrate a lack of the effect using protoporphyrin IX and PEGylated goldnanorods (paper IV). Cell viability studies were combined with spectroscopic measurements confirming a lack of energy transfer between nanoparticles and photosensitizer. Incubation of cells combining aminolevulinic acid and gold nanorods showed a slightly elevated PDT efficiency, however this effect is most likely attributed to an enhanced delivery of aminolevulinic acid rather than the energy transfer. Finally, a nanosystem consisting of gold nanoparticle labelled with lactose moieties was explored for tumour-specific delivery (Paper V). Multiphoton microscopy was used to visualise the multiphoton-induced luminescence from the particles loaded to epithelial cancer cells and keratinocytes. The study demonstrates that tumour-specific uptake can be obtained by targeting galecin-3, known to be overexpressed in tumour cells. Taken together, the work in this thesis presents several promising nanosystems to improve PDT. Of particular interest are the NO photoreleasing nanosystems for hypoxic conditions. Furthermore, improved biodistribution and targeted delivery can be obtained by clever design of the systems, presenting interesting approaches to aid in restraining the acute problem of increasing worldwide occurrence of cancer.
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| 9. |
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| 10. |
- Kirejev, Vladimir, 1984, et al.
(författare)
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Multiphoton microscopy – a powerful tool in skin research and topical drug delivery science
- 2012
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Ingår i: Journal of Drug Delivery Science and Technology. - 1773-2247. ; 22:3, s. 250-259
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Tidskriftsartikel (refereegranskat)abstract
- Multiphoton microscopy (MPM) has become a powerful complementary tool in biomedical research, enabling non-invasive three-dimensional imaging of tissue with high resolution. The major advantage is that investigations and visualization can be performed without mechanical destruction of the sample through tissue sectioning. This review will give a brief introduction to the technology, accompanied by examples of how the technique can be implemented within the field of skin research. Specifically, MPM has already made it possible to visualize cellular morphology and the cutaneous distribution of topically applied compounds applied to intact skin. MPM provides information that can be used to assess the bioavailability of drugs and to visualize drug penetration pathways into skin. MPM has also been implemented as a tool for obtaining non-invasive tissue biopsy based on skin autofluorescence in connection to diagnostics of skin cancer. We will also briefly present some recent results where MPM has been used to track cyclodextrin based drugs applied topically. Finally, we will discuss some future challenges of the technology, including label-free imaging, multimodal techniques, and quantitative imaging.
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