regex - mysql regexp varchar value which contains \0 -

i'm testing regexp feature, , met problem. sql statement likes:

select field table field regexp '^[a-z][a-z0-9\\.]*[a-z0-9]$' limit 1; 

it matches row, field contains more a-z0-9. characters. in hex, value is:

61 726d 0000 00ab 003f 3f00 

i want let such rows filtered out. what's correct sql statement can write?