Recent Advances in Quenchbody, a Fluorescent Immunosensor

Dong, Jinhua; Ueda, Hiroshi

doi:10.3390/s21041223

Cited by 40 publications

(26 citation statements)

References 54 publications

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“…Fluorescent molecules modified near antigen recognition sites (CDRs) are known to have their fluorescence quenched by photoinduced electron transfer (PET) with conserved tryptophan residues in the antibody structure. In contrast, when the modified antibody binds to the antigen, the fluorescent molecules are expelled from the hydrophobic pocket of the antibody, thereby resolving the PET and restoring fluorescence 104,105) (Fig. 3C).…”

Section: Enzyme-catalyzed Tyrosine Clickmentioning

confidence: 99%

Protein Chemical Modification Using Highly Reactive Species and Spatial Control of Catalytic Reactions

Sato

2022

Chem. Pharm. Bull.

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Protein bioconjugation has become an increasingly important research method for introducing artificial functions in to protein with various applications, including therapeutics and biomaterials. Due to its amphiphilic nature, only a few tyrosine residues are exposed on the protein surface. Therefore, tyrosine residue has attracted attention as suitable targets for site-specific modification, and it is the most studied amino acid residue for modification reactions other than lysine and cysteine residues. In this review, we present the progress of our tyrosine chemical modification studies over the past decade. We have developed several different catalytic approaches to selectively modify tyrosine residues using peroxidase, laccase, hemin, and ruthenium photocatalysts. In addition to modifying tyrosine residues by generating radical species through single-electron transfer, we have developed a histidine modification method that utilizes singlet oxygen generated by photosensitizers. These highly reactive chemical species selectively modify proteins in close proximity to the enzyme/catalyst. Taking advantage of the spatially controllable reaction fields, we have developed novel methods for site-specific antibody modification, detecting hotspots of oxidative stress, and target identification of bioactive molecules.

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Section: Enzyme-catalyzed Tyrosine Clickmentioning

confidence: 99%

Protein Chemical Modification Using Highly Reactive Species and Spatial Control of Catalytic Reactions

Sato

2022

Chem. Pharm. Bull.

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“…In the labeled immunoassay, target molecules are detected using an antibody labeled with a substance showing a binding signal. Fluorescent molecules, such as green fluorescent protein [2,3], nanoparticles such as quantum dots and gold nanoparticles [4,5], and enzymes have been widely used in these applications as substances [6,7]. Among them, enzymes are advantageous because they can easily amplify signals and can be applied for electrochemical detection.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of Fragment Antibody–Enzyme Complex as a Sensing Element for Immunosensing

Oda

Asano

2022

IJMS

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Antibody–enzyme complexes (AECs) are ideal molecular recognition elements for immunosensing applications. One molecule possesses both a binding ability to specific targets and catalytic activity to gain signals, particularly oxidoreductases, which can be integrated into rapid and sensitive electrochemical measurements. The development of AECs using fragment antibodies rather than intact antibodies, such as immunoglobulin G (IgG), has attracted attention for overcoming the ethical and cost issues associated with the production of intact antibodies. Conventionally, chemical conjugation has been used to fabricate AECs; however, controlling stoichiometric conjugation using this method is difficult. To prepare homogeneous AECs, methods based on direct fusion and enzymatic conjugation have been developed, and more convenient methods using Catcher/Tag systems as coupling modules have been reported. In this review, we summarize the methods for fabricating AECs using fragment antibodies developed for sensing applications and discuss the advantages and disadvantages of each method.

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“…In contrast, Quenchbody (Q-body), a fluorescent biosensor based on antigen-antibody reactions, is simple to operate, highly specific, and can significantly improve the sensitivity and accuracy of the traditional assay. The Q-body is a recombinant antibody fragment in which the N-terminus is specifically labeled with a fluorescent dye, and the fluorescence is quenched by a tryptophan residue in the variable region of the antibody based on photo-induced electron transfer ( Abe et al, 2011 ; Dong et al, 2020b ; Dong and Ueda, 2021 ). Specific binding of the antigen to the antibody results in quenching of the fluorescent dye inside the antibody.…”

Section: Introductionmentioning

confidence: 99%

Isolation of a Monoclonal Antibody and its Derived Immunosensor for Rapid and Sensitive Detection of 17β-Estradiol

Dong

et al. 2022

Front. Bioeng. Biotechnol.

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Estrogens are effective for stimulating several functions in living organisms and for regulating cancer development by promoting cell proliferation. Estradiol can disrupt the reproductive and endocrine systems, leading to the development of various diseases. In this study, the monoclonal antibody ESC9 was developed by immunizing mice with a 17β-estradiol (E2) conjugate, preparing an antibody phage display library, and screening monoclonal antibodies from the prepared library. An antibody with the same sequence as that of ESC9 has not been reported previously. The equilibrium dissociation constant between ESC9 and E2 was found to be 43.3 nM. Additionally, we generated an ESC9-derived immunosensor named as the ESC9 Quenchbody (Q-body), which can rapidly and sensitively detect E2. The assay can be completed within 2 min with a limit of detection of 3.9 pg/ml and half-maximal effective concentration of 154.0 ng/ml. Serum E2 levels were measured using the ESC9 Q-body without pretreatment with serum and with a high recovery rate of 83.3–126.7%. The Q-body immunosensor shows potential for clinical applications based on its excellent detection speed and sensitivity.

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Recent Advances in Quenchbody, a Fluorescent Immunosensor

Cited by 40 publications

References 54 publications

Protein Chemical Modification Using Highly Reactive Species and Spatial Control of Catalytic Reactions

Protein Chemical Modification Using Highly Reactive Species and Spatial Control of Catalytic Reactions

Fabrication of Fragment Antibody–Enzyme Complex as a Sensing Element for Immunosensing

Isolation of a Monoclonal Antibody and its Derived Immunosensor for Rapid and Sensitive Detection of 17β-Estradiol

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