If your example with strrep does not succeed, that would be because the whitespace is actually not a space. You can check what it is for sure by getting its ASCII value with:
double(cell_Array{1}(3))
If it is some other sort of whitespace (maybe a tab), you can use:
cell_Array = regexprep(cell_Array, '\s', '') %\s means any of \t, \f, \n, \r or \v
But if it is not, assuming your text is only letters, numbers or underscore, you can remove anything else with:
cell_Array = regexprep(cell_Array, '\W', '')
