Efficient generation of recombinant anti‐HER2 scFv with high yield and purity using a simple method

We developed a method to produce a soluble form of a single-chain fragment variable (scFv) targeting human epithelial growth factor receptor 2 (HER2) in Escherichia coli. By optimizing the orientations of the variable heavy (VH) and variable light (VL) domains and the His-tag, we identified the HL-His type antibody with the highest HER2-binding activity. Purification of HL-His yielded 40.7 mg from a 1 L culture, achieving >99% purity. The limit of detection was determined to be 2.9 ng, demonstrating high production yield, purity, and sensitivity. Moreover, we successfully labeled HER2