Silver staining method for DNA in polyacrylamide gels using eriochrome black T as a silver-ion sensitizer

A sensitive silver staining method using eriochrome black T as a silver‐ion sensitizer for DNA detection in polyacrylamide gels was developed. The sensitivity of this staining method was significantly improved by the new silver‐ion sensitizer containing a diazo group, which has reducing power. The staining method lasted a total of approximately 15 min following a fixing step for 2×20 min. The detection limit of this staining method was 1–4 pg for ΦX174 DNA/HaeIII in both nondenaturing and denaturing polyacrylamide gels. This staining method was especially effective in low‐base pair DNA, with a sensitivity that was approximately ten‐fold higher than previously published silver staining methods.