Escape Depth of Gold Ions in Tissue Sections
- PDF / 2,068,212 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 85 Downloads / 205 Views
Escape Depth of Gold Ions in Tissue Sections Yasuro Niidome,1,2,† Masanori Fujii,1 Naotoshi Nakashima,1,2 and Takuro Niidome3 1
Department of Applied Chemistry, Faculty of Engineering, Kyushu University, 744 Motooka,
Nishi-ku, Fukuoka 819-0395, Japan 2
World Premier International (WPI) Research Center, International Institute for
Carbon-Neutral Energy Research (I2CNER), Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan 3
Department of Applied Chemistry and Biochemistry, Graduate School of Science and
Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan. JST-CREST, 5 Sanbancho, Chiyoda-ku, Tokyo 102-0075, Japan †
Present Affiliation: Department of Chemistry and Bioscience, Kagoshima University, 1-21-35
Korimoto, Kagoshima 890-8580, Japan ABSTRACT Desorption of gold ions from liver tissue sections, in which intravenously injected gold nanorods were accumulated, were studied to evaluate properties of gold nanorods as a "mass-tag". Gold ions were sensitively detected by using a conventional MALDI-MS machine. When 50-µm-thick blank sections without gold nanorods were placed on or beneath a sample section, desorption of gold ions was almost suppressed. It was found that the escape depth of gold ions from liver tissue sections was less than 50 µm. It was found that we do not have to take account of the escape depth of gold ions if a section were sliced into 10-20 µm thickness. INTRODUCTION Imaging mass spectroscopy (IMS) is a useful technique to visualize distribution of functional molecules in biological specimens [1,2]. IMS has advantages in high sensitivity, high throughput, and molecular specificity. To make the IMS, we firstly have to ionize target molecules. Matrix assisted laser desorption/ionization (MALDI) is the most popular technique to ionize bio-related molecules. The MALDI can efficiently ionize lipids, oligo-peptides, and some of metabolites; however, it is difficult to ionize larger peptides in a tissue section, such as enzymes
and antibodies. Lipids, which are the major species in a tissue section, frequently suppress the ionization of the other molecules. Removal of lipids from a tissue section is needed to obtain IMS images of the larger peptides. In the removal processes of lipids, we have to retain the original positions of the peptides. This is an issue of IMS using the MALDI method. "Mass-tag", which gives specific fragments, is a possible solution to detect the large molecules in a tissue section. The mass probe invalidates a part of the advantage of mass spectrometry that can distinguish hundreds of molecules in one measurement, but the selective detection of the mass-tag fragments can simplify the pretreatments of specimens and improve the reliability of analysis of mass spectra that would show hundreds peaks of molecular ions and their fragments if the MALDI method were used for a measurement. Previously, a triphenylmethane derivative was reported as a possible candidate of the mass probe [3,4]. Gold nanoparticles have been studied as a pos
Data Loading...
