Low temperature embedding with Lowicryl resins: two new formulations and some applications

Area of Science:

• Cryo-electron microscopy
• Biological sample preparation
• Immunocytochemistry

Background:

• Lowicryl K4M and HM20 are established low temperature embedding resins for biological samples.
• These resins are compatible with progressive lowering of temperature (PLT) and freeze-substitution techniques.
• Current resins operate effectively within a temperature range of approximately 220 K to 340 K.

Purpose of the Study:

• To introduce novel low temperature embedding resins (K11M and HM23).
• To extend the applicability of low temperature embedding to even lower temperatures.
• To evaluate the impact of these resins on immunocytochemical sensitivity.

Main Methods:

• Development and application of new methacrylate/acrylate based resins (K11M, HM23).
• Utilizing freeze-substitution in conjunction with low temperature embedding.
• Assessing antigen localization sensitivity on biological sections.

Main Results:

• New resins K11M and HM23 allow embedding at temperatures around 200 K.
• Freeze-substitution combined with low temperature embedding permits minimal or no chemical fixation.
• This approach appears to enhance the sensitivity of immunocytochemical antigen localization.

Conclusions:

• K11M and HM23 resins significantly expand the low temperature range for biological sample embedding.
• The combination of freeze-substitution and low temperature embedding offers a milder preparation method.
• This technique improves the detection sensitivity for antigens in immunocytochemistry.