| 1. |
- Malmberg, Per, 1974, et al.
(författare)
-
Imaging mass spectrometry for novel insights into contact allergy - a proof-of-concept study on nickel
- 2018
-
Ingår i: Contact Dermatitis. - : Wiley. - 0105-1873 .- 1600-0536. ; 78:2, s. 109-116
-
Tidskriftsartikel (refereegranskat)abstract
- Background. In spite of extensive regulation to limit exposure, nickel remains the main cause of contact allergy in the general population. More detailed knowledge on the skin uptake of haptens is required. So far, no method exists for the visualization of this clinically relevant hapten and its distribution in the skin. Objectives. To show, in terms of a proof of concept, that imaging mass spectrometry [time of flight secondary ion mass spectrometry (ToF-SIMS)] can be applied for investigation of the penetration and distribution of nickel in human skin. Method. Full-thickness human skin obtained from breast reduction surgery was exposed to nickel sulfate (5% in deionized water) for 24 h in Franz-type diffusion cells. Biopsies were obtained from nickel-treated samples and control (deionized water). The tissue was sliced, and analysed with ToF-SIMS, generating high-resolution images of ion distribution in the epidermis and upper dermis. Results. The skin layers could be discerned from the ToF-SIMS data, particularly on the basis of the collagen signal. Nickel ions were localized to the stratum corneum and upper epidermis. Conclusions. This is the first time that ToF-SIMS has been applied to trace the distribution of a hapten in human skin. Proof of principle was shown for nickel, and the technique can, in the future, be expanded for investigation of the skin distribution of clinically relevant sensitizers in general.
|
|
| 2. |
- Westas, Emma, 1982, et al.
(författare)
-
Using QCM-D to study the adhesion of human gingival fibroblasts on implant surfaces
- 2015
-
Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 103:10, s. 3139-3147
-
Tidskriftsartikel (refereegranskat)abstract
- Sealing the soft tissue-implant interface is one of the key issues in preventing transcutaneous implant-associated infections. A promising surface modification for improving osseointegration and possibly soft tissue integration is to coat the implant surface with hydroxyapatite (HA) nanoparticles. When new implant materials are developed, their ability to facilitate cell attachment and spreading are commonly investigated in vitro to establish their potential for good in vivo performance. However, commonly used techniques, such as microscopy methods, are time consuming, invasive, and subjective. This is the first study using quartz crystal microbalance with dissipation monitoring, where the real-time adhesion of biopsy-derived human gingival fibroblasts onto titanium and nanostructured HA was investigated. Experiments were performed for at least 16 h, and we found that cellular attachment and spreading kinetics can be followed in situ by observing the change in dissipation and frequency with time. Interestingly, a correlation between cell coverage and the magnitude of dissipation shift reached at the end of the experiment was found, but no such trend was observed for the frequency. Furthermore, the level of cell coverage was found to influence the cellular attachment and spreading behavior. No difference in cell response to the two surface types, Ti and nanostructured HA, was found.
|
|
| 3. |
- Borglin, Johan, 1986, et al.
(författare)
-
Annular Beam Shaping in Multiphoton Microscopy to Reduce Out-of-Focus Background
- 2017
-
Ingår i: International Journal of Spectroscopy. - : Hindawi Limited. - 1687-9449 .- 1687-9457.
-
Tidskriftsartikel (refereegranskat)abstract
- Despite the inherent spatial confinement of multiphoton processes that arises from focusing through an objective, the maximum imaging depth in conventional multiphoton microscopy is ultimately limited by noise from out-of-focus fluorescence. This is particularly evident when imaging beyond shallow depths in highly scattering tissue as increased laser powers are necessary. The out-of-focus signal originates from multiphoton processes taking place primarily at shallow depths and deteriorates contrast and limits imaging depth. In this paper, annular laser beams are explored as a concept to reduce this background signal in multiphoton microscopy. The approach is theoretically verified by data from simulations and proof of principle is demonstrated on a custom-built experimental multiphoton microscopy platform. Annular laser beams were created by adopting wavefront control using a spatial light modulator and implemented for imaging tissue phantoms simulating turbid media and human skin ex vivo. The signal-to-background ratios were calculated and compared to images acquired with a traditional, filled-aperture Gaussian beam. Experiments in tissue phantom show an improvement in signal-to-background ratio of about 30% when using annular beam illumination in comparison to Gaussian illumination at specific depths. When laser power is not the limiting factor, this approach is expected to provide even greater benefits.
|
|
| 4. |
- Borglin, Johan, 1986, et al.
(författare)
-
Insights on proximity effect and multiphoton induced luminescence from gold nanospheres in far field optical microscopy
- 2015
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 107:23
-
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.
|
|
| 5. |
- Borglin, Johan, 1986, et al.
(författare)
-
Peptide Functionalized Gold Nanoparticles as a Stimuli Responsive Contrast Medium in Multiphoton Microscopy
- 2017
-
Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 17:3, s. 2102-2108
-
Tidskriftsartikel (refereegranskat)abstract
- There is a need for biochemical contrast mediators with high signal-to-noise ratios enabling noninvasive biomedical sensing, for example, for neural sensing and protein protein interactions, in addition to cancer diagnostics. The translational challenge is to develop a biocompatible approach ensuring high biochemical contrast while avoiding a raise of the background signal. We here present a concept where gold nanoparticles (AuNPs) can be utilized as a stimuli responsive contrast medium by chemically triggering their ability to exhibit multiphoton-induced luminescence (MIL) when performing multiphoton laser scanning microscopy (MPM). Proof-of-principle is demonstrated using peptide-functionalized AuNPs sensitive to zinc ions (Zn2+). Dispersed particles are invisible in the MPM until addition of millimolar concentrations of Zn2+ upon which MIL is enabled through particle aggregation caused by specific peptide interactions and folding. The process can be reversed by removal of the Zn2+ using a chelator, thereby resuspending the AuNPs. In addition, the concept was demonstrated by exposing the particles to matrix metalloproteinase-7 (MMP-7) causing peptide digestion resulting in AuNP aggregation, significantly elevating the MIL signal from the background. The approach is based on the principle that aggregation shifts the plasmon resonance, elevating the absorption cross section in the near-infrared wavelength region enabling onset of MIL. This Letter demonstrates how biochemical sensing can be obtained in far-field MPM and should be further exploited as a future tool for noninvasive optical biosensing.
|
|
| 6. |
- Conte, C., et al.
(författare)
-
Monitoring the release of a NO photodonor from polymer nanoparticles: Via Förster resonance energy transfer and two-photon fluorescence imaging
- 2018
-
Ingår i: Journal of Materials Chemistry B. - : Royal Society of Chemistry (RSC). - 2050-7518 .- 2050-750X. ; 6:2, s. 249-256
-
Tidskriftsartikel (refereegranskat)abstract
- Core-shell polymeric nanoparticles (NPs) made of either di-block or tri-block poly-ϵ-caprolactone and polyethylene glycol copolymers, covalently integrating Rhodamine B in the core or the shell have been prepared and a green fluorescent NO photodonor entrapped therein. One- and two-photon fluorescence experiments demonstrate that effective Förster Resonance Energy Transfer (FRET) occurs exclusively in the di-block NPs having the Rhodamine in the core, accounting for a localization of the NO photoreleaser in the inner part of the polymeric nanocarrier. These di-block NPs are stable in the presence of human serum albumin and their cargo release NO under exclusive excitation with visible light. Two-photon imaging experiments carried out using 900 nm NIR light, demonstrate that the release of the NO photodonor can be monitored in biological tissue, herein human skin, and provide insights into the integrity and penetration depth of the NPs. Toxicity experiments performed on NCTC keratinocyte cell lines in the dark and upon visible light irradiation show good biocompatibility of the polymeric system that therefore has a great potential in light of the multifaceted therapeutic role of NO. © The Royal Society of Chemistry.
|
|
| 7. |
- Ericson, Marica B, 1974, et al.
(författare)
-
Exploring plasmonic coupling as a stimuli responsive contrast mechanism in multiphoton microscopy
- 2018
-
Ingår i: Proceedings Volume 10509, Plasmonics in Biology and Medicine XV. - : SPIE. - 1605-7422. - 9781510615045 - 9781510615038
-
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.
|
|
| 8. |
- Ericson, Marica B, 1974, et al.
(författare)
-
Imaging of Photosensitizers in Skin
- 2017
-
Ingår i: Imaging in Photodynamic Therapy. Eds: Michael R. Hamblin, Yingying Huang. - Boca Raton : Taylor & Francis Group, CRC Press. - 9781498741453
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)
|
|
| 9. |
- Fraix, Aurore, et al.
(författare)
-
A Three-Color Fluorescent Supramolecular Nanoassembly of Phototherapeutics Activable by Two-Photon Excitation with Near-Infrared Light.
- 2019
-
Ingår i: Chemistry. - : Wiley. - 1521-3765. ; 25:29, s. 7091-7095
-
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.
|
|
| 10. |
- Gatenholm, Paul, 1956, et al.
(författare)
-
3D Bioprinting of Human Skin
- 2015
-
Ingår i: Tissue Engineering Part A. - 1937-3341 .- 1937-335X. ; 21:Supplement 1
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
