Poly-β-cyclodextrin strengthen Pr 6 O 11 porous oxidase mimic for dual-channel visual recognition of bioactive cysteine and Fe 2 .

To conveniently monitor bioactive cysteine (Cys) and Fe 2+ in practice, a kind of poly-β-cyclodextrin strengthen praseodymium oxide (Pr 6 O 11 ) porous oxidase mimic (p-β-CD@Pr 6 O 11 ) was constructed by virtue of the strong coordination between nano Pr 6 O 11 and poly-β-cyclodextrin substrate. After its microstructure and physicochemical property were characterized in detail, it was noted that porous p-β-CD@Pr 6 O 11 exhibited excellent enzyme-like catalytic activity to accelerate the oxidation of 3,3',5,5,'-tetramethylbanzidine (TMB) and 2,2'-azinobis (3-ethylbenzo-thiazoline-6-sulfonic acid) ammonium salt (ABTS) with significant color-enhancement effect in the air. Based on the signal amplification, trace Cys could exclusively deteriorate the UV-vis absorbance at 653 nm of p-β-CD@Pr 6 O 11 -TMB and Fe 2+ alter the one at 729 nm of p-β-CD@Pr 6 O 11 -ABTS with visual color changes. Under the optimized conditions, the proposed p-β-CD@Pr 6 O 11 -TMB and p-β-CD@Pr 6 O 11 -ABTS systems were successfully applied for dual-channel monitoring of Cys in Cys capsules and fetal bovine serum and Fe 2+ in agricultural products with quite low detection limits, i.e., 7.8×10 -9 mol·L -1 for Cys and 6.93×10 -8 mol·L -1 (S/N=3) for Fe 2+ , respectively. The synergetic-enhancement detection mechanisms to Cys and Fe 2+ were also proposed.