Scalable nanolaminated SERS multiwell cell culture assay

Abstract

This paper presents a new cell culture platform enabling label-free surface-enhanced Raman spectroscopy (SERS) analysis of biological samples. The platform integrates a multilayered metal-insulator-metal nanolaminated SERS substrate and polydimethylsiloxane (PDMS) multiwells for the simultaneous analysis of cultured cells. Multiple cell lines, including breast normal and cancer cells and prostate cancer cells, were used to validate the applicability of this unique platform. The cell lines were cultured in different wells. The Raman spectra of over 100 cells from each cell line were collected and analyzed after 12 h of introducing the cells to the assay. The unique Raman spectra of each cell line yielded biomarkers for identifying cancerous and normal cells. A kernel-based machine learning algorithm was used to extract the high-dimensional variables from the Raman spectra. Specifically, the nonnegative garrote on a kernel machine classifier is a hybrid approach with a mixed nonparametric model that considers the nonlinear relationships between the higher-dimension variables. The breast cancer cell lines and normal breast epithelial cells were distinguished with an accuracy close to 90%. The prediction rate between breast cancer cells and prostate cancer cells reached 94%. Four blind test groups were used to evaluate the prediction power of the SERS spectra. The peak intensities at the selected Raman shifts of the testing groups were selected and compared with the training groups used in the machine learning algorithm. The blind testing groups were correctly predicted 100% of the time, demonstrating the applicability of the multiwell SERS array for analyzing cell populations for cancer research.

Self-sustainable and recyclable ternary Au@Cu2O–Ag nanocomposites: application in ultrasensitive SERS detection and highly efficient photocatalysis of organic dyes under visible light

“…As SERS can offer intrinsic fingerprint information about specific molecules, SERS based on molecular vibrations and/or rotations has been identified as a promising spectral analytical technology 2,3 . In addition to its ultrahigh detection accuracy and trace-level sensitivity, SERS has the advantages of rapidity, specificity, nondestruction of analytes, and in situ identification, resulting in a wide range of applications in the fields of biosensors, analytical chemistry, food safety, and environmental science 4,5 . Given the importance of SERS-active substrates for the enhancement of the Raman signal, a considerable number of studies have been conducted on the design and preparation of various noble metal nanomaterials as SERS substrates due to their unique surface plasmon resonance (SPR) 6 .…”

Plasmonic Electronic Raman Scattering as Internal Standard for Spatial and Temporal Calibration in Quantitative Surface-Enhanced Raman Spectroscopy

“…Here, we first test plasmonic ERS signals, I ERS , as the internal standard for spatial calibration of MRS signals, I MRS , by using nanolaminate SERS substrates functionalized with a self-assembled monolayer of benzenethiol (BZT) molecules (Figure C). Nanolaminate SERS substrates consist of multilayered metal–insulator–metal (MIM) nanocavity arrays and MIM nanohole arrays separated by polymer nanopillar arrays (Figure D,E, and fabrication details in the Supporting Information) and represent a generalized metallo–dielectric plasmonic system that supports multiple localized and delocalized plasmonic modes. − To investigate plasmonic enhancement effects in ERS and MRS processes, we conducted Raman measurements for nanolaminate SERS substrates functionalized with BZT molecules and compared them with measurements on various reference samples, including bare nanolaminate SERS substrates, an unpatterned Au thin film (nominally 150 nm thick) with BZT molecules, and a bare silicon substrate (Figure F). Raman measurements performed under 785 nm laser excitation show several key results.…”

Nanostructured Au-Based Surface-Enhanced Raman Scattering Substrates and Multivariate Regression for pH Sensing

“…Detailed SERS substrate fabrication processes are described elsewhere. ,, Briefly, a composite polydimethylsiloxane stamp (diameter = 120 nm, periodicity = 400 nm, height = 150 nm) was prepared by soft lithography . We used UV-curable polyurethane (PU; NOA83H, Norland Product Inc., USA) to fabricate periodic nanopillar arrays on a flexible and optically transparent polyester (PET) film.…”