title: Colorimetric assay of lead ions in biological samples using a nanogold-based membrane.
abstract: We have developed a simple paper-based colorimetric membrane for sensing lead ions (Pb(2+)) in aqueous solutions. The nitrocellulose membrane (NCM) was used to trap bovine serum albumin (BSA) modified 13.3-nm Au nanoparticles (BSA-Au NPs), leading to the preparation of a nanocomposite film of a BSA-Au NP-decorated membrane (BSA-Au NPs/NCM). The BSA-Au NPs/NCM operates on the principle that Pb(2+) ions accelerate the rate of leaching of Au NPs induced by thiosulfate (S(2)O(3)(2-)) and 2-mercaptoethanol (2-ME). The BSA-Au NPs/NCM allowed for the detection of Pb(2+) by the naked eye in nanomolar aqueous solutions in the presence of leaching agents such as S(2)O(3)(2-) and 2-ME. We employed the assistance of microwave irradiation to shorten the reaction time (<10 min) for leaching the Au NPs. Under optimal solution conditions (5 mM glycine-NaOH (pH 10), S(2)O(3)(2-) (100 mM), and 2-ME (250 mM), microwaves (450 W)), the BSA-Au NPs/NCM allowed the detection of Pb(2+) at concentrations as low as 50 pM with high selectivity (at least 100-fold over other metal ions). This cost-effective sensing system allowed for the rapid and simple determination of the concentrations of Pb(2+) ions in real samples (in this case, sea water, urine, and blood samples).
authors.affiliation: Institute of Bioscience and Biotechnology, National Taiwan Ocean University, 2, Beining Road, Keelung 20224, Taiwan.
authors.forename: Yen-Fei
authors.initials: YF
authors.lastname: Lee
authors.forename: Chih-Ching
authors.initials: CC
authors.lastname: Huang
mesh_terms: D003124:Colorimetry / Q000379:methods*; D006046:Gold; D007854:Lead / Q000032:analysis*; D008567:Membranes, Artificial; D036103:Nanotechnology; D012710:Serum Albumin, Bovine / Q000737:chemistry
chemical_list: D008567:Membranes, Artificial; D012710:Serum Albumin, Bovine; D007854:Lead; D006046:Gold