Use of HMDS (hexamethyldisilazane) to preserve organic microstructures in etched bivalve mollusk and barnacle shells

B. R. SCHONE 1. D. BENILEY2

1 Department ofGeosciences, University of Arizona, Tucson, AZ 85721 USA,

2 Biotechnology Imaging Facility, University of Arizona, Tucson, AZ 85723 USA

bernd. schoene@excite. corn Fax: +1 520 621 2672
Voice: +1 520 626 5275

Abstract

The organic framework of invertebrate shells yields clues to biocalcification processes. Slight demineralization of the shells reveals the fragile meshwork of insoluble organic fibers and membranes, which tend to collapse, \\orinkle and shrink when air-dried from water. Chemical drying can reduce most of these adverse effects. Commonly, the critical point drying (CPD) method is employed, which requires expensive equipment and constant monitoring during preparation. Nation (1983) introduced HMDS as an alternative drying agent for the final step in soft tissue preservation. We compared different drying techniques on etched bivalve mollusk and barnacle shells and found that HMDS produced results qualitatively superior to CPD or drying from ethyl alcohol or water. HMDS preserves structural details of the organic meshwork excellently and facilitates the recognition of faint growth increments for growth pattern analysis. The HMDS method is cost-effective, saves time and can be used as a routinely substitute for the preservation of microstructures in slightly etched invertebrate shells.


Abbreviations used in the text: HMDS, hexarnethyldisilazane; CPD, critical point drying; ALC, air-drying from ethyl alcohol; AIR, air-drying from water; EtOH, ethyl alcohol; EDT A. ethylene diamine tetraacetate