Abstract
The recognition that nucleic acids can be used as polymeric materials led to the blossoming of the field of DNA nanotechnology, with a broad range of applications in biotechnology, biosensors, diagnostics, and drug delivery. These applications require efficient methods to synthesize and chemically modify high molecular weight DNA. Here, we discuss terminal deoxynucleotidyl transferase (TdT)-catalyzed enzymatic polymerization (TcEP) as an alternative to conventional enzymatic and solid-phase DNA synthesis. We describe biochemical requirements for TcEP and provide step-by-step protocols to carry out TcEP in solution and from surfaces.