A Colorimetric Enzyme-Linked Immunosorbent Assay with CuO Nanoparticles as Signal Labels Based on the Growth of Gold Nanoparticles In Situ

Abstract

A colorimetric immunoassay has been reported for prostate-specific antigen (PSA) detection with CuO nanoparticles (CuO NPs) as signal labels. The method is based on Cu2+-catalyzed oxidation of ascorbic acid (AA) by O2 to depress the formation of colored gold nanoparticles (AuNPs). Specifically, HAuCl4 can be reduced by AA to produce AuNPs in situ. In the presence of target, CuO NPs-labeled antibodies were captured via the sandwich-type immunoreaction. After dissolving CuO nanoparticles with acid, the released Cu2+ catalyzed the oxidation of AA by O2, thus depressing the generation of AuNPs. To demonstrate the accuracy of the colorimetric assay, the released Cu2+ was further determined by a fluorescence probe. The colorimetric immunoassay shows a linear relationship for PSA detection in the range of 0.1~10 ng/mL. The detection limit of 0.05 ng/mL is comparable to that obtained by other CuO NPs-based methods. The high throughput, simplicity, and sensitivity of the proposed colorimetric immunoassay exhibited good applicability for assays of serum samples.

Designed Metal-ATCUN Derivatives: Redox- and Non-redox-Based Applications Relevant for Chemistry, Biology, and Medicine

“…For example, Cu II is a paramagnetic species whereas Cu I is a diamagnetic species. Based on this spectroscopic advantage, Cu II -ATCUN state has been studied extensively as a paramagnetic probes and sensors ( Donaldson et al., 2001 ; Maiti et al, 2017b ; Deng et al., 2019a , 2019b ; Torrado et al., 1998 ). Significantly, this review is mainly focused on stable Cu II -ATCUN derivatives as spectroscopic probe and positron emission tomography (PET) imaging ( Miyamoto et al., 2016 ).…”

“…Over the last few decades, the research on designed metal-ATCUN derivatives (ATCUN; amino terminal copper and nickel binding motif possessing H 2 N–X-X-His sequence; X = any amino acid) has greatly progressed due to the wide range of applications envisaged, relevant for biology and chemistry, which include DNA ( Harford and Sarkar, 1997 ; Mack and Dervan, 1992 ; Jin and Cowan, 2005 , 2007 ; Agbale et al., 2016 ; Yu and Cowan, 2017a , 2017b ; Gonzalez et al., 2018 ), RNA ( Yu and Cowan, 2017a , 2017b ; Gonzalez et al., 2018 ; Ross et al., 2017 ), proteins ( Agbale et al., 2016 ; Yu and Cowan, 2017a , 2017b ; Gonzalez et al., 2018 ; Pinkham et al., 2018a , 2018b ), sugar ( Yu and Cowan, 2017a , 2017b ), and lipids cleavage ( Alexander et al., 2017 ), antitumor ( Kimoto et al., 1983 ), and antimicrobial activity ( Alexander et al., 2018 , 2019 ), inhibition of enzyme activity ( Gokhale et al., 2008 ), telomere shortening ( Yu et al., 2015 ), aggregation of amyloid-β peptides ( Zhang et al., 2016 ), nitration of tyrosine ( Maiti et al., 2019 ), protein-protein cross-linking ( Horowitz et al., 2012 ; Brown et al., 1998 ), water oxidation ( Deng et al., 2018 ), hydrogen evolution ( Kandemir et al., 2016 ), nitrite to NH 3 ( Guo et al., 2018 ), useful in spectroscopic probes ( Donaldson et al., 2001 ; Maiti et al, 2017b ; Deng et al., 2019a , 2019b ; Torrado et al., 1998 ), and imaging ( Miyamoto et al., 2016 ).…”

“…Therefore, the design of ATCUN motif is of interest for mimicking the structure and function of naturally occurring proteins and peptides, as well as for other new performances. Many efforts are being made in designing ATCUN motifs with amino acid variants, as well as its conjugation with protein, peptide, or fluorophore for fulfilling the needs of various practical and biological relevant usages ( Gonzalez et al., 2018 ; Pinkham et al., 2018a , 2018b ; Donaldson et al., 2001 ; Maiti et al, 2017a ; Deng et al., 2019a , 2019b ; Torrado et al., 1998 ; Miyamoto et al., 2016 ). The designed parameters include stereochemistry, position, and charge of amino acid, modulating the redox potential of the metal center in M-ATCUN derivatives (M = Cu II , Ni II , and Co II ), leading to catalytic efficiency ( Jin and Cowan, 2005 , 2007 ).…”

“…Due to high stability of Cu II -ATCUN complex, the ATCUN motif can be used as a Cu-chelation therapy, such as inhibition of aggregation of amyloid-β peptides ( Zhang et al., 2016 ). The combination of ATCUN motif with selected recombinant proteins, peptides, or fluorophores are also used in order to understand the structure and function of biomolecules ( Donaldson et al., 2001 ; Maiti et al, 2017b ; Deng et al., 2019a , 2019b ; Torrado et al., 1998 ; Miyamoto et al., 2016 ).…”

Nanomaterials-Based Colorimetric Immunoassays

“…Lai’s group developed a colorimetric immunoassay for CEA detection based on a copper chromogenic reaction, in which Cu(II) released from CuO NPs coordinates with a synthesized chromogenic of 1,2-diphenyl-2-(2-(pyridin-2-yl)hydrazono)ethanone, together with the colorimetric signal change from colorless to red [164]. We have demonstrated that the released Cu(II) from the captured CuO NPs labels can catalyze the oxidation of AA by O 2 , thus depressing the AA-guided formation of colored AuNPs [165]. The colorimetric assay with an LOD of 0.05 ng/mL showed good applicability for the assay of PSA in serum samples.…”