Aptamer biorecognition and gold nanoshell-mediated fluorescence quenching for glycoprotein analysis and breast cancer diagnosis

In recent years, glycoproteins have gained increasing attention due to their pivotal roles in cellular chemistry and signal transduction. However, the limited availability of rapid and wash-free analytical tools has impeded their utilization as circulating biomarkers for disease diagnosis in clinical settings. To address this challenge, we developed a gold nanoshell-mediated method for analyzing glycoprotein composition directly in native biofluids. Initially, glycoproteins are captured at the micelle surface through aptamer-protein interactions and were labeled with fluorescent lectin. Subsequently, the fluorescence of the lectin is locally quenched by the in-situ formation of gold nanoshell on micelle surface, while free-floating lectin remains unresponsive throughout this process. After optimizing the HAuCl4 dosage for gold nanoshell formation, we achieved rapid and strong fluorescence quenching against fluorescent lectin captured at micelle surface. Using this method, we analyzed the glycan compositions of CEA, HER2 and MUC1 with fluorescent ConA, Jacalin, LCA and PHA. The analyzing results demonstrated that our method can discriminate between glycoprotein compositions of plasma samples obtained from breast cancer patients and those from healthy donors.