Hi all , I am trying to transfect 293T cells using 2M CaCl2 , 2X HBSS , Tris HCl EDTA buffer and Buffered water. I can't seem to achieve a successful transfection .I do not observe any fluorscence after 24 hours .The cells are well and all my buffers have a suitable pH.The amount of transfer vector and helper vectors are suitable too. I do not know what is the problem?