Combined Imaging and Chemical Sensing of Fertilization-Induced Acid Release from Single Sea Urchin Eggs

• Published in: Analytical biochemistry Vol. 273; no. 2; pp. 168 - 178
• Main Authors: Michael, Karri L., Walt, David R.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 10.09.1999
• Subjects: Animals; Cell Division; Female; Fertilization - physiology; Fiber Optic Technology - instrumentation; Hydrogen-Ion Concentration; Image Processing, Computer-Assisted - instrumentation; Light; Male; Microscopy - instrumentation; Microscopy, Fluorescence - instrumentation; Ovum - physiology; Sea Urchins - physiology; Sodium-Hydrogen Exchangers - metabolism
• ISSN: 0003-2697; 1096-0309
• DOI: 10.1006/abio.1999.4173

We demonstrate a microarray sensor capable of obtaining both chemical and visual information on multiple cells simultaneously with single-cell resolution. The array was fabricated by covalently immobilizing a thin, pH-sensitive polymer layer on the distal end of an optical imaging fiber. The sensor's ability to measure localized chemical dynamics in real-time was evaluated using sea urchin fertilization biochemistry as a model system. Following sea urchin fertilization, the Na+/H+ transporter is activated to exchange extracellular sodium ions for intracellular hydrogen ions, causing a release of hydrogen ions at the egg's surface. By placing the pH sensor proximal to the egg and switching between a fluorescence image and a white light image, we were able to observe both localized pH changes following fertilization as well as morphological transformations during cell division.