Dear Simon,

what concentration of agarose did you use?

And, are you sure that agarose evaporated? Agarose covers to slides by very thin layer after drying and it can be difficult to see it.

I agree with previous post, maybe you don't see it because it dries and it looks transparent. What could happen is when you dip it and the agarose doesn't stick..therefore you might need to clean up the slides with methanol and then flame them before dipping them in agarose

Hi, It d be transparent once it dries so it might be the case. Use 1% normal melting agar solution for base slides, i use very frequently and works fine. prepare in PBS or distilled water both works fine. Take precaution while selecting slides, preferably clean by burning with methanol twice.

After you add the normal melting agarose, how long are letting it set for? What conditions do you use for it to set? Once you apply your low melting point agarose suspension, do the gels remain fixed to the slide? Personally, I use specialized glass slides that do not require pre-treatment with normal melting agarose. For low melting point agarose, I use 0.75-1%. Although I do not pre-treat, many papers I have read recommend using 1% normal melting point agarose for pre-coating the slide.