A nonfouling polypeptide(Poly(D)-K) with poly(aspartic acid) backbone and lysine side chains was developed by polycondensing a covalently bonded dimer of aspartic acid (D) and lysine (K).Gel permeation chromatography (GPC)

nuclear magnetic resonance (NMR)

Fourier transform infrared spectroscopy (FTIR)

X-ray photoelectron spectroscopy(XPS)

circular dichroism (CD) were conducted to determine the molecular weight

structure

secondary structure of the polypeptide and compositions of self-assembling monolayers (SAMs) of the polypeptide on gold chips

respectively.The results show that the polypeptide was successfully prepared

of which the average molecular weight (Mw) is about 3.8103

polydispersity index (PDI) is 1.33

average degree of polymerization (DP) is about 12.4; and secondary conformation of the polypeptide in water solution is random coil.The polypeptide could form SAMs on gold chips by the terminal thiol groups

and the lowest relatively nonspecific protein adsorption on SAMs surface determined by Enzyme-linked Immunosorbent Assay (ELISA) for anti-IgG and Fg was (8.53.6)% and (12.54.8)%

respectively

where the protein adsorption on tissue culture polystyrene (TCPS) surface was set as 100%.The cell viability of the polypeptide determined by MTT assay was (87.64.3)% even its concentration was up to 5 mg/mL.