FTIR spectra of ZnO-MTCP, cysteine, and MTCP. The peaks around 3,000 cm−1 are attributed to the stretching vibration of the N–H group present in MTCP. The strong peak around 1,380 cm−1 aroused from vibration of the amide bond. Elimination of the peak around 3,000 cm−1, and exhibition of strong peak around 1,380 cm−1, demonstrates the formation of the amide bond between MTCP and the cysteine arm on ZnO nanoparticles.