Biotin TUNEL Apoptosis Kit

During apoptosis, certain DNA endonucleases are activated to cleave genomic DNA between nucleosomes, generating 180 bp-200 bp fragments. These fragmented DNA strands expose numerous mucous 3'-OH termini. Under the catalytic action of deoxyribonucleotide terminal transferase (TdT), these fragments bind to biotin-dUTP, then combine with streptavidin-HRP-labeled horseradish peroxidase (HRP) . The HRP-catalyzed DAB coloration ultimately reveals apoptotic cells through optical microscopy. This method is termed Terminal-deoxynucleotidyl Transferase-mediated dUTP nick end labeling (TUNEL) for direct detection of apoptotic cells. This kit demonstrates broad applicability, enabling analysis of apoptosis in both frozen/wax sections and cultured adherent or suspension cells. It selectively detects apoptotic cells rather than necrotic cells or those with DNA strand breaks caused by radiation or drug treatment.