Well-dispersed Nanophosphors for Cathodoluminescence Microscopy Produced by using Laser Ablation Method T. Furukawa 1 , H. Niioka 2 , M. Ichimiya 1,3 , T. Nagata 4 , M. Ashida 1 , T. Araki 1 and M. Hashimoto 1 Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan 1 , Institute for NanoScience Design, Osaka University 2 , Osaka Dental University 3 , Tukuba Institute for Super Materials, ULVAC Inc. 4 E-mail: [email protected] KEY WORDS: Cathodoluminescence, SEM, Nanophosphors, Laser Ablation, Bioimaging, High-spatial-resolution, Cathodoluminescence (CL) imaging is promising method which can distinguish specific molecular species and has high-spatial-resolution for biological samples. Multi-color CL imaging for cells have already carried out with using rare-earth doped three kinds of Y 2 O 3 -based nanophosphors contained in cells [1]. CL microscopy has a potential to enable high-resolution imaging of individual biomolecular distributions at a resolution of 10 nm. Thus many groups have studied biological CL imaging using such as organic and inorganic phosphors [2]-[3]. To obtain high-spatial-resolution, the size of individual phosphor have to be small. In this study, aggregated Y 2 O 3 :Eu nanophosphors were dispersed by using laser ablation method in water to overcome the size-problem. Femto second laser at 800 nm, 1 kHz was used for laser ablation. Y 2 O 3 :Eu / water solution was stirred up with magnetic stirrer and was treated with laser ablation for 1 hour. Fig. 1 (a) and (b) shows the SEM images of Y 2 O 3 :Eu nanophosphors on Si substrate before and after ablation. Nanophosphors were well dispersed via laser ablation. SEM image and CL image of ablated Y 2 O 3 :Eu nanophosphors on Si substrate are shown in Fig. 2. Emission from laser ablated Y 2 O 3 :Eu nanophosphors had enough intensity for imaging, though the diameter was as small as 100 nm. It indicates that these laser ablated nanophosphors seem to be a candidate for molecular imaging with CL at the high-spatial-resolution using immunostaining. REFERENCES: [1] H. Niioka et al., Appl. Phys. Express, 4, 112402 (2011). [2] P. J. Fisher et al., Opt. Commun., 281, 1901-1908 (2008). [3] Y. Nawa et al., Ext. Abstr. 58th Spring Meet. JSAP, 27p-BH-2 (2011) [in Japanese]. Fig. 1 SEM images before (a) and after (b) laser ablation. Fig. 2 SEM (a) and CL (b) images after laser ablation. (a) Before ablation (b) After ablation 2 μm 2 μm (a) SEM 200 nm (b) CL 200 nm
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Well-dispersed Nanophosphors for Cathodoluminescence Microscopy Produced by using Laser Ablation Method
T. Furukawa1, H. Niioka2, M. Ichimiya1,3, T. Nagata4, M. Ashida1, T. Araki1 and M. Hashimoto1
Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan1 ,
Institute for NanoScience Design, Osaka University2, Osaka Dental University3, Tukuba Institute for Super Materials, ULVAC Inc.4
E-mail: [email protected] KEY WORDS: Cathodoluminescence, SEM, Nanophosphors, Laser Ablation, Bioimaging, High-spatial-resolution,
Cathodoluminescence (CL) imaging is promising method which can distinguish specific molecular species and has high-spatial-resolution for biological samples. Multi-color CL imaging for cells have already carried out with using rare-earth doped three kinds of Y2O3-based nanophosphors contained in cells [1]. CL microscopy has a potential to enable high-resolution imaging of individual biomolecular distributions at a resolution of 10 nm. Thus many groups have studied biological CL imaging using such as organic and inorganic phosphors [2]-[3]. To obtain high-spatial-resolution, the size of individual phosphor have to be small. In this study, aggregated Y2O3:Eu nanophosphors were dispersed by using laser ablation method in water to overcome the size-problem.
Femto second laser at 800 nm, 1 kHz was used for laser ablation. Y2O3:Eu / water solution was stirred up with magnetic stirrer and was treated with laser ablation for 1 hour. Fig. 1 (a) and (b) shows the SEM images of Y2O3:Eu nanophosphors on Si substrate before and after ablation. Nanophosphors were well dispersed via laser ablation. SEM image and CL image of ablated Y2O3:Eu nanophosphors on Si substrate are shown in Fig. 2. Emission from laser ablated Y2O3:Eu nanophosphors had enough intensity for imaging, though the diameter was as small as 100 nm. It indicates that these laser ablated nanophosphors seem to be a candidate for molecular imaging with CL at the high-spatial-resolution using immunostaining. REFERENCES: [1] H. Niioka et al., Appl. Phys. Express, 4, 112402 (2011). [2] P. J. Fisher et al., Opt. Commun., 281, 1901-1908 (2008). [3] Y. Nawa et al., Ext. Abstr. 58th Spring Meet. JSAP, 27p-BH-2 (2011) [in Japanese].
Fig. 1 SEM images before (a) and after (b) laser ablation.
Fig. 2 SEM (a) and CL (b) images after laser ablation.
(a) Before ablation (b) After ablation
2 µm 2 µm (a) SEM 200 nm (b) CL 200 nm
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