I have been trying neuronal differentiation from human embryonic stem cells (hESCs; H9) via the hESC aggregate method according to http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2948208/ and http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0024027 (doing in parallel), however, I have a problem that the EBs do not attach to the laminin-coated plates.

The laminin I used was purchased 2-3 years ago and stored in -80C. However, there was one time it dropped out of the freezer and thawed to RT for sometime (not sure how long) until my lab mate saw it and put it back into the freezer. Do you think it would affect the performance of laminin? I am considering if I should purchase new laminin as it is very expensive (we use the human placental laminin, not sure if the cheaper mouse laminin would work for neural differentiation)

Thanks!