I recommand to mount the stained sections on superfrost plus slides Take a petri dish , fill it with 0.45% NaCl, transfer the sections into this solution and pull them carefully with a painter brush on the slide), air dry and mount them with any mounting medium wich is suitable for IF. The superfrost slides (not PLUS) you have to coat before use. If you are working with crystate sections I recommand to use superfrost frost plus. Hope you can save your sections. Good luck!

Thanks for the advice.

Unfortunately the sections I am talking about are smaller than 1mm so it is really hard to move them. What I did instead was to define the region with sections with Pap pen, then incubate 30 min with PDL 0.1 mg/ml (sections were floating but remained in the region defined by the pen), wash with milliQ water and dry. Post fix with 4% PFA 15 min and rinse with PBS. Then I started my staining and, up to now, sections are still attached. Let's hope for the best!