Tetraplex Immunophenotyping of Cell Surface Proteomes via Synthesized Plasmonic Nanotags and Portable Raman Spectroscopy

Abstract

Multiplex immunophenotyping of cell surface proteomes is useful for cell characterization as well as providing valuable information on a patient’s physiological or pathological state. Current methods for multiplex immunophenotyping of cell surface proteomes still have associated technical pitfalls in terms of limited multiplexing capability, challenging result interpretation, and large equipment footprint limited to use in a laboratory setting. Herein, we presented a portable surface-enhanced Raman spectroscopy (SERS) assay for multiplex cell surface immunophenotyping. We synthesized and functionalized customizable SERS nanotags for cell labeling and subsequent signal measurement using a portable Raman spectrometer. We extensively evaluated and validated the analytical assay performance of the portable SERS immunophenotyping assay in two different cellular models (red blood cells and breast cancer cells). In terms of analytical specificity, the cell surface immunophenotyping of both red blood cells and breast cancer cells correlated well with flow cytometry. The portable SERS immunophenotyping assay also has comparable analytical repeatability to flow cytometry, with coefficient of variation values of 21.89–23.33% and 6.88–17.32% for detecting red blood cells and breast cancer cells, respectively. The analytical detection limits were 77 cells/mL for red blood cells and 1–17 cells/mL for breast cancer cells. As an alternative to flow cytometry, the portable SERS immunophenotyping assay demonstrated excellent analytical assay performance and possessed advantages such as quick sample-to-result turnaround time, multiplexing capability, and small equipment footprint.

Nanophotonic immunoarray with electrochemically roughened surfaces for handheld detection of secreted PD-L1 to predict immuno-oncology efficacy

“…The handheld Metrohm Instant Raman Analyzer (MIRA) DS equipped with a right-angle attachment (Metrohm Switzerland) was used for SERS measurements. 26 Each measurement was taken with a 785 nm laser with a laser power of 100 mW for 1 s integration time. The collected SERS spectra were background-corrected using the MIRA Cal DS software.…”

The Emerging Role of Raman Spectroscopy as an Omics Approach for Metabolic Profiling and Biomarker Detection toward Precision Medicine

“…The accuracy of SERS assays can be comparable to flow cytometry but at a fraction of the cost because Raman reporters are inexpensive relative to fluorescent tags. 253 In such proteomic assays, multiple factors control the overall sensitivity and detection limits that can be achieved. These include: (i) the choice of the metal used where low-loss metals with strong radiative properties, such as Ag, Au, and, more recently Al, is highly desirable.…”

“…In ex vivo SERS, because the limitation of imaging a living subject is not involved, these assays can be optimized to show ultralow detection limits, allow multiplexing of >30 molecular targets and enable quantitative response. The accuracy of SERS assays can be comparable to flow cytometry but at a fraction of the cost because Raman reporters are inexpensive relative to fluorescent tags . In such proteomic assays, multiple factors control the overall sensitivity and detection limits that can be achieved.…”

Four-Color SERS Monitoring of Size-dependent Nanoparticle Delivery in the Same Tumor

“…Therefore, SERS tags have recently been intensively investigated for biomedical applications, especially for disease diagnosis/prognosis by detecting the corresponding biomarker molecules through conjugating the NPs with the specific antibodies . Up to now, 6-color immuno-SERS imaging of HER2 on a single SK-BR3 breast cancer cell, tetraplex phenotyping of surface proteins on cancer cells/excised tumor tissues, − and 5-color quantification of SERS NPs in vivo has been realized. However, utilizing SERS tags to encode NPs with different physiochemical characteristics and directly evaluating their delivery efficiencies in the same tumor cell/tissue have not been reported.…”