3-Aminopropyltriethoxysilane (APES): a new advance in section adhesion.

Various adhesives have been used to increase the adherence of tissue sections to glass slides and to prevent separation during staining. Traditionally glycerin albumin' and gelatin2 solutions have been widely used in routine histology. More recently poly-L-lysine has been used to improve section adhesion, particularly in immunocytochemistry.3 This method has been of great value but it is time consuming and slides cannot be stored. For the simultaneous immunostaining of T6 and SIOO in tissue sections, we have found it necessary to use frozen sections of tissue fixed in formol calcium.4 With poly-L-lysine used as the adhesive, there was a high loss of sections after initial protease digestion. An alternative method for increasing adhesion was therefore sought. For over 20 years alkoxysilanes have been used in an industrial context as coupling agents in coating and dyeing a variety of materials.5 Weetall et al67 described their use as coupling agents for insolubilising enzymes on inert surfaces, emphasising that the strong covalent bonding effect between the aminoalkyl groups and aldehyde or ketone functions of a reactive surface would withstand repeated washings with a variety of inorganic solvents. More recently aminoalkylsilane has been used as an adhesive for enhancing chromosome spreading on glass slides,8 and for in situ hybridisation of frozen sections.9 In this paper we describe a new modification to the coating method for hybridisation originally introduced by Rentrop et al.9 The modified method is simple, cheap, and can be used in the routine laboratory, whenever improved adhesion of sections is necessary.