Simultaneous Detection of Molecules Achieved with Innovative Sensor Platform

Recently, scientists from Karamanoglu Mehmetbey University in Turkey, have unveiled a novel sensor platform capable of simultaneously detecting multiple molecules. The research, published in the journal Spectroscopy Letters, introduces a cutting-edge surface-enhanced infrared absorption (SEIRA) sensor based on disk antennas with a double spacer (1). This innovative platform promises significant advancements in the field of biomolecular sensing.

SEIRA is a spectroscopic technique that enhances the detection sensitivity of infrared (IR) absorption signals from molecules adsorbed on or near metallic surfaces. It involves utilizing plasmonic effects to amplify the electromagnetic field near the sample surface, thereby enhancing the interaction between the molecules and incident IR radiation. This enhancement leads to increased absorption signals, making SEIRA a powerful tool for molecular analysis and detection. SEIRA is particularly valuable in the mid-infrared range, where many important molecular vibrations occur. The technique finds applications in various fields, including chemical sensing, bioanalysis, environmental monitoring, and materials science. By harnessing the unique properties of plasmonic materials and their interaction with molecules, SEIRA offers a pathway to improve sensitivity and specificity in infrared spectroscopy for a range of scientific and technological applications.

The detection of biomolecules plays a crucial role in various domains, including medical diagnosis, forensic analysis, biological studies, and food quality assessment. The researchers focused on utilizing the mid-infrared range, which offers a unique opportunity for biomolecular sensing due to its ability to capture the vibrational spectra of essential biochemicals like DNA, RNA, and proteins.

The proposed sensor platform consists of a double band absorbing plasmonic nanoantenna array featuring two gold disk resonators. Through extensive investigations, the team successfully demonstrated the biosensing capabilities of this structure using a protein-goat anti-mouse immunoglobulin G model and a polymethyl methacrylate film.

The study revealed that the protein monolayer exhibited distinctive vibrational signatures, specifically the Amide-I, Amide-II, and Amide-III bonds, detected at wavelengths of 6010 nm (∼1664 cm⁻¹), 6496 nm (∼1539 cm⁻¹), and 6989 nm (∼1431 cm⁻¹), respectively. Additionally, by detecting the C=O and C-H bonds in a polymethyl methacrylate film, the researchers observed a strong absorption deep at 5782 nm (∼1730 cm⁻¹) and relatively lower absorption depths at 3350 nm (∼2985 cm⁻¹) and 3395 nm (∼2946 cm⁻¹) for the C-H bond.

Significantly, the newly developed sensor platform enabled simultaneous detection of the spectral signatures of the protein monolayer and Polymethyl methacrylate film in each band. The double spacer disk configuration allows independent tuning of the dual-band, without affecting the other band. This capability offers a characterization tool for identifying complex molecules by detecting their spectral fingerprints independently in each mode of the dual-band. The implications are vast, as this design strategy could be applied to multi-mode SEIRA platforms for detecting or identifying more intricate chemical molecules in biology, chemistry, and defense-related fields.

The findings of this study pave the way for enhanced molecular detection and identification techniques, with potential applications in various scientific and industrial domains. The team's innovative sensor platform opens doors for improved understanding and analysis of unknown complex molecules, providing valuable insights for future advancements in biology, chemistry, and defense areas.

This breakthrough research signifies a significant step forward in the field of biomolecular sensing and holds great promise for future developments in molecular analysis and detection technologies.

Reference

(1) Erturan, A. M.; Durmaz, H.; Gültekin, S. S. Simultaneous detection of molecules with the surface-enhanced infrared absorption sensor platform based on disk antennas with double spacer. Spectrosc. Lett. 2023, 56 (5), 283–292. DOI: 10.1080/00387010.2023.2208650