A saturation binding experiment was conducted in which zeta potential measurements were recorded for a stock MON solution (1 mg/ml in 1.37 mmol PBS w.r.t. NaCl) incubated with various peptide concentrations (Figure ). The Kd for FTVRDLS binding to Hf-BTB-NH2 was calculated to be 74 ± 22 μM. Off-target binding studies of YNYRNLL and NNWWAPA against Hf-BTB-NH2 were also conducted, with the Kd determined to be 285 ± 23 μM and 1393 ± 200 μM respectively. This corresponds to an approximate 4-fold and 19fold increase in the dissociation constant relative to the ontarget binding of FTVRDLS. This is consistent with the phage display identified 12-mer peptide binding studies against MOFs reported by Fan et. al., who found all values lying within the micromolar range. The smaller difference in Kd for YNYRNLL most likely reflects similarities between these arginine-bearing peptides, which leads to strong binding to the anionic MON surfaces. Hence Hf-BTB-NH2 shows a high degree of selectivity for the consensus peptide identified through the biopanning studies, which makes it a promising candidate for use as a sensitive peptide recognition surface.