Air‐drying of human leucocytes for scanning electron microscopy using the GTGO procedure

Abstract

The utilization of tannic acid and guanidine hydrochloride as mordants for better osmium binding was shown to serve as an excellent alternative to metal coating of organ tissue specimens for scanning electron microscopy (SEM). The GTGO [glutaraldehyde-tannic acid-guanidine hydrochloride osmium tetroxide] procedure is described, a modification of the TAO [tannic-acid osmium] technique, which was found successful for the preparation of air dried peripheral blood leukocytes for SEM studies. Air dried, GTGO-treated leukocytes show excellent preservation of surface features with minimal cell shrinkage. When critical point dried, GTGO-treated cells are examined, they also show less shrinkage than cells prepared with standard glutaraldehyde fixation and critical point drying. The potential application of this air drying procedure (GTGO-AD) to other soft biological specimens is currently under investigation. This technique is recommended as a new and effective air drying procedure for the successful preparation of cells for SEM.