Intrinsic SERS Fingerprints of Aptamer-Peptide Conjugates for Direct High-Specific Profiling Abnormal Protein Levels in Cancer Patients

Abstract

Surface-enhanced Raman spectroscopy (SERS) with ultrasensitive vibrational fingerprints enables quick identification and trace detection of various kinds of molecules. But proteins usually have low Raman cross sections and are difficult to generate recognizable signals in direct SERS detection. Recently, nucleic acid-peptide conjugates are emerging with great potential in structuring, assembling, catalyzing, sensing, etc., and the coupling of aptamers further enables superior biological recognition and programmability. Here, we develop the aptamer−peptide conjugates as a new kind of SERS probe for direct high-specific profiling abnormal protein levels in cancer patients. The aptamer conjugated with glutathione (GSH) functions as both the recognition element and the SERS reporters that can simultaneously generate SERS fingerprints of both peptides and nucleic acids. This kind of biocompatible probe appears to have excellent performance in high-salt environments and realizes rapid, simple, and multisignal detection of thrombin (TB). Data-driven soft independent modeling of class analogy (DD-SIMCA) is used to distinguish SERS profiles of actual blood samples and realize the identification and classification of cancer patients. Furthermore, the effect of low-temperature storage time on blood samples is analyzed by tracking the changes of SERS profiles; the results hint that plasma samples stored under 4 °C for more than 2 days could generate false negative results due to TB hydrolysis, which has important implications for clinical sample analysis. This kind of nucleic acid-peptide conjugate provides new ideas for SERS sensing strategy in the future.

SERS sensing for cancer biomarker: Approaches and directions

“…The combination of deep learning and label-free SERS offers great promise for the rapid, accurate, and non-invasive detection of cancer, which could greatly improve precise clinical diagnosis. In other work Su and coworkers [ 138 ], introduce aptamer-peptide conjugates as an innovative type of SERS probe, designed for the direct and highly specific profiling of abnormal protein levels in cancer patients. These conjugates consist of an aptamer linked with glutathione (GSH), serving a dual role as the recognition element and the SERS reporters.…”

Data-Driven Version of Multiway Soft Independent Modeling of Class Analogy (N-Way DD-SIMCA): Theory and Application

“…A significant number of practical cases requiring a qualitative response occur across many scientific fields. , Typical examples that need such analysis include medical diagnostics, , detection of counterfeit drugs and food adulteration, , quality control of finished products, outlier detection, , etc. Proper methodologies to be applied in this situation are class modeling or one-class classifiers, − which are meant to distinguish objects of a given target class from all other objects and classes.…”