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ABSTRACT: Highly fluorescent organic nanoparticles with size of about 300 nm were prepared by nanosecond laser ablation of micrometer-sized
powder of dendronized perylenediimide dispersed in water. The nanoparticle colloidal solution provided a fluorescence quantum
yield of 0.58. The absorption and emission spectral studies demonstrated that the bulky dendron groups at the side bays of
perylenediimide chromophore efficiently suppress the interchromophoric interactions in the nanoparticles. Fluorescence measurement
on several single nanoparticles underlines that the prepared nanoparticles are bright and photo-stable enough to be auseful
probe for single particle fluorescence investigation.
Applied Physics A 04/2012; 93(1):5-9. · 1.63 Impact Factor
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ABSTRACT: Quinacridone nanoparticles with a mean size of about 200nm are successfully prepared using nanosecond near-infrared (NIR)
laser ablation of its microcrystalline powders in heavy water. The absorption spectra of the formed colloidal solutions depend
on the excitation wavelengths, which is eventually ascribed to number and energy of absorbed photons. β-carotene has low photostability and is easily decomposed upon UV/VIS laser ablation of its solid, while its nanoparticles
are prepared utilizing this NIR laser ablation technique. The advantage of nanoparticle preparation by NIR laser ablation
is discussed.
Applied Physics A 04/2012; 101(4):591-596. · 1.63 Impact Factor
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ABSTRACT: The discovery of small molecular compounds that expand cartilage is needed. We searched for small molecular compounds that expand cartilage or enhance the actions of bone morphogenetic proteins (BMPs) on cartilage.
Metatarsal primordial cartilage explants prepared from 14.5 days postcoitum (d.p.c.) mouse embryos were organ-cultured in the presence or absence of BMPs and/or 4-(5-Benzol[1,3]dioxol-5-yl-4-pyrldin-2-yl-1H-imidazol-2-yl)-benzamide hydrate (BPIB) and its related molecules. The perichondrium was removed from some of the cartilage explants by partial digestion with collagenase. BPIB aqueous solution was prepared by fragmenting BPIB crystals in water with laser irradiation and then added to cartilage explants in organ culture.
We found that small molecular compounds, BPIB, available as SB431542 from Sigma and its related molecules, expand primordial cartilage explants in organ culture. These molecules are transforming growth factor-β (TGF-β) inhibitors, and the addition of excess TGF-β reduced cartilage expansion induced by these molecules. The co-administration of BPIB and BMPs synergistically expanded cartilage explants. Removal of the perichondrium abolished BIPB-induced cartilage expansion but not BMP-induced cartilage-expansion, suggesting that BPIB, but not BMPs, expands cartilage through the perichondrium. Furthermore, we used the laser-ablation technique to generate BPIB aqueous solution in the presence of 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) without the use of hazardous dimethyl sulfoxide (DMSO). The laser-ablation-generated BPIB aqueous solution was more stable, expanded cartilage explants more effectively than BPIB colloidal solution prepared with DMSO, and synergistically enhanced BMP-induced cartilage expansion.
A small molecular compound, BPIB, expands primordial cartilage explants. A BPIB aqueous solution was created by laser-ablation without using DMSO and proved to be biologically active.
Osteoarthritis and Cartilage 02/2011; 19(2):233-41. · 3.90 Impact Factor
