Membrane shows irregular signal distribution with visible fingerprints, fold marks, or forceps imprints. Signal intensity varies across membrane surface in non-biological pattern.
Common Causes
1Direct contact with membrane surface using fingers or gloves depositing proteins and oils
2Membrane folded or creased during handling, blocking, or antibody incubation
3Forceps with sharp tips damaging or marking membrane surface
4Membrane drying during incubation due to insufficient buffer volume
Solutions
1Always wear clean powder-free gloves; handle membrane only at edges or corners using blunt-end forceps
2Keep membrane flat during all procedures; use appropriate size containers to prevent folding
3Use only blunt-end stainless steel forceps for membrane handling
4Ensure buffer volumes completely cover membrane during blocking, antibody incubations, and washes; use rocking platform for even distribution