Development of site-specific antibody-conjugated immunoliposomes for sensitive detection of disease biomarkers

• Published in: Nanoscale Vol. 13; no. 41; pp. 17648 - 17654
• Main Authors: Zhang, Xiao-Kun, Yang, Hong-Ming, Li, Meng-Ran, Gao, Xiao-Yi, Sun, Xiao-Wei, Sun, Xi-Feng, Tang, Jin-Bao
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 28.10.2021
• Subjects: Antibodies; Antigens; Biomarkers; Chemiluminescence; Conjugates; Conjugation; Encapsulation; Immunoassay; Liposomes; Peroxidase
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/d1nr04659d

Liposome-based immunoassay (LIA) is an attractive protocol for amplifying the detection signals because of the excellent ability of liposomes to encapsulate signal marker compounds. The antigen-binding activity of the conjugated antibodies on the liposomal surface is crucial for the specificity and sensitivity of LIA. We present here a general platform to ensure that antibodies can conjugate onto the surface of liposomes in a site-specific and oriented manner. A His-handle-modified antibody with Fc region-specific and covalent conjugation was first fabricated using a photoactivatable Z Bpa -His tag that was engineered using the aminoacyl-tRNA synthetase/suppressor tRNA technique. Based on the high affinity between the His tag and divalent metal ions, the novel His-modified antibody was oriented onto the surface of nickel ion-modified liposomes encapsulating horseradish peroxidase. With the prostate-specific antigen as a model, the detection efficiency of the new immunoliposomes was evaluated by chemiluminescence immunoassay. The immunoliposomes exhibited a limit of detection of 0.2 pg mL −1 , which was a six time improvement compared with that of the chemical-coupled antibody-liposome conjugates. Thus, the proposed immunoliposomes are expected to hold potential applications for the sensitive detection of various biomarkers in complicated serum samples. Schematic diagram of the proposed Fc-specific conjugated immunoliposomes for sensitive detection of disease biomarkers.