[OPTICAL REVIEW Vol. 13, No. 4 (2006) 288-291]
© 2006 The Optical Society of Japan

Investigation of the Doughnut Effect in Cy3-Labeled Protein Microarrays using Scanning Near-Field Optical Microscope

Anisha GOKARNA, Yong Hwan KIM, Yong-Hoon CHO*, Min Su LEE1, In Cheol KANG2, Hyun Kyu PARK3, Min Gon KIM3 and Bong Hyun CHUNG3

Nano-Bio-Photonics Laboratory, Department of Physics, Chungbuk National University, Cheongju 361-763, Korea
1Chungbuk BIT Research-Oriented University Consortium, Chungbuk National University, Cheongju 361-763, Korea
2Protein Chip Research Laboratory, Department of Biological Science, College of Natural Science, Hoseo University, Asan 336-795, Korea
3Korea Research Institute of Bioscience and Biotechnology, Daejeon 305-333, Korea

(Received November 15, 2005; Accepted March 13, 2006)

We demonstrate the fluorescence mapping of protein microarrays by the technique of scanning near-field optical microscopy (SNOM) and confocal microscopy. Micron sized spots (300 μm) of human Immunoglobulin G (hIgG) protein with and without a Cy3 dye labeling have been fabricated on glass substrates by an immobilization method which makes use of calixcrown derivatives termed Prolinker. We have also tried to probe into the well-known “doughnut effect” observed in fluorescence images of proteins using the SNOM technique. The topographic and fluorescence SNOM images revealed that the number of proteins at the boundary of the spot were more than at the center in the case of the microarray spot which showed brighter luminescence at the edge than at the center in the confocal image.

Key words: scanning near field optical microscopy, fluorescence, protein microarray, protein chip, confocal microscopy

*E-mail address: yonghcho@chungbuk.ac.kr