Peptide nucleic acid (PNA) is a new nucleic acid sequence-specific reagent. Unlike traditional nucleic acids such as DNA and RNA, it replaces the sugar-phosphate main chain with a polypeptide backbone. Its main features and functions are as follows: 1. Unique structure: PNA molecules are composed of multiple amino acid residues connected by hydrogen bonds. Its structure is different from DNA and RNA, and it has a unique double helix structure and spatial configuration. 2. Highly selective recognition: PNA molecules can bind to specific DNA or RNA sequences to form stable complexes. Due to its unique structure, PNA has a higher binding ability to DNA and RNA than traditional nucleic acid probes. 3. Non-radioactive labeling: Compared with traditional radioactive labeling methods, PNA can be labeled by non-radioactive methods such as chemical synthesis, avoiding the potential harm of radiation to the human body. 4. Good stability: PNA molecules are stable in aqueous solution, do not undergo photolysis, hydrolysis and other reactions, and can be stored and used for a long time.