Identification and Detection of Volatile Aldehydes as Lung Cancer Biomarkers by Vapor Generation Combined with Paper-Based Thin-Film Microextraction

Abstract

Accurate, sensitive, and selective on-spot screening of volatile aldehydes as lung cancer biomarkers is of vital significance for preclinical diagnosis and treatment guidance of cancers. However, the common methods of sensing biomarkers are limited by the fact that they are time-consuming, require professional personnel, and have complex matrixes. Here, we developed a smart vapor generation paper-based thin-film microextraction system capable of both sensitive on-field fluorescence detection and accurate surface-enhanced Raman spectroscopy (SERS) quantification of volatile benzaldehyde (BA) by utilizing stimuli-responsive core–shell gold nanorod (GNR) quantum dot (QD)-embedded metal–organic framework (MOF) structures. The amino-modified GNRs and carboxyl-capped QDs can directly assemble with each other by electrostatic interaction, which leads to an almost complete emission quenching of QDs. The addition of BA molecules destroys the GNRs-QD assemblies due to the Schiff base reactions between the amine group of 4-mercaptonoaniline and the aldehyde moiety of BA, resulting in the increase of the fluorescence and Raman signal of hybrid systems, which enables the visualization of BA with the naked eye. Moreover, the “cavity-diffusion” effect of porous MOF shells validates the selective concentration of gaseous BA molecules on the GNR surface, allowing the discrimination of BA in exhaled breath rapidly and precisely even at the sub-ppb level with excellent specificity against other volatile organic compounds. This study not only offers a versatile sensing platform for accurate discrimination of lung cancer from controls but also opens an avenue for the design of smart sensors for point-of-care applications.

Recent Advances in the Use of Surface-Enhanced Raman Scattering for Illicit Drug Detection

“…Other techniques, such as the incorporation of microfluidics [ 130 , 131 ] for enhancing the interaction between the analyte and SERS substrate and colorimetric assays [ 132 ] as a prescreening step, have been employed to enhance SERS signals. When used together with other analytical methods, such as fluorescence spectroscopy and colorimetry, SERS can significantly improve the sensitivity and discriminatory power of chemical analysis [ 133 , 134 , 135 ]. Finally, integration of SERS with powerful analytical machine learning techniques helps extract relevant, fast, and more accurate results for on-site drug detection, thus popularizing its use even among non-expert users.…”

Plasmonic Biosensors for the Detection of Lung Cancer Biomarkers: A Review

“…In addition to MOF-based SERS sensing, a dual-mode sensing strategy incorporating fluorescent (FL) and surface-enhanced Raman spectroscopy (SERS) was employed in a move to achieve ultrasensitive detection of volatile benzaldehyde [127]. In that case, a vapour generation paper-based thin-film microextraction (VG-PTFM) platform for FL and SERS sensing of volatile benzaldehyde (BA) was fabricated using core−shell gold nanorodquantum dot (GNRs-QD)@NU-901 structures [127]. The dual-sensing mode enabled the physical visualisation and quantitative detection of analytes.…”

Recent Advances and Applications in Paper-Based Devices for Point-of-Care Testing

“…Through selection of electrode material and electrochemical technique, electrochemical detection was realized with fast response and high sensitivity [29]. Nowadays, to enrich these detection methods and achieve sensitive and accurate signal out-put, various micro-and nano-materials with different signal transduction mechanisms, such as metal nanoparticles [30,31], metal oxide [32,33], graphene or graphene oxide [34,35], quantum dots [36,37], hybrid materials [38,39] and metal-organic frameworks [40][41][42] have brought new breakthroughs in the design of new paper-based sensors. In addition, signal readers tend to be miniaturized.…”