Selective Surface Enhanced Raman Scattering for Quantitative Detection of Lung Cancer Biomarkers in Superparticle@MOF Structure

Abstract

Surface enhanced Raman scattering (SERS) is a trace detection technique that extends even to single molecule detection. Its potential application to the noninvasive recognition of lung malignancies by detecting volatile organic compounds (VOCs) that serve as biomarkers would be a breakthrough in early cancer diagnostics. This application, however, is currently limited by two main factors: (1) most VOC biomarkers exhibit only weak Raman scattering; and (2) the high mobility of gaseous molecules results in a low adsorptivity on solid substrates. To enhance the adsorption of gaseous molecules, a ZIF-8 layer is coated onto a self-assembly of gold superparticles (GSPs) in order to slow the flow rate of gaseous biomarkers and depress the exponential decay of the electromagnetic field around the GSP surfaces. Gaseous aldehydes that are released as a result of tumor-specific tissue composition and metabolism, thereby acting as indicators of lung cancer, are guided onto SERS-active GSPs substrates through a ZIF-8 channel. Through a Schiff base reaction with 4-aminothiophenol pregrafted onto gold GSPs, gaseous aldehydes are captured with a 10 ppb limit of detection, demonstrating tremendous prospects for in vitro diagnoses of early stage lung cancer.

Superficial‐Layer‐Enhanced Raman Scattering (SLERS) for Depth Detection of Noncontact Molecules

“…By controlling electromagnetic enhancement generated in medium, we can guide the Raman signal enhancing decay exponentially with distance from the metal surface. There was a 3.68‐fold increase in penetration depth in the perovskite medium on ETHH NP arrays compared to bare ETHH NP arrays, which was calculated by , where ε 1 and ε 2 are the dielectric constant of metal and medium, respectively, and λ is the wavelength of the incident light . The penetration depth was consistent with the variation trend of electromagnetic field intensity of FDTD simulation (Figure e).…”

Cross‐Linked Surface Engineering to Improve Iron Porphyrin Catalytic Activity

“…We proposed an alternate of QTD ultra‐thin metallized film by depositing organic ligands and metal nodes on a hollow skeleton combined with the external cross‐linked surface engineering, typically by post‐synthetic modification (PSM) methodologies, for tuning the chemical and physical properties which determines their performance in catalysis. [ 12–14 ] As a consequence, the heterogeneous catalyst having a QTD film structure combines the merits of homogeneous and heterogeneous catalyst, which can be sufficiently contacted with a reactant and easily separated and recovered. Heterogenization of homogeneous metal complex catalysts occurs in some simple steps due to the coordination mechanism involved, and it provides a method for anchoring specific functional molecules into the catalyst structure without compromising the integrity of the framework structure.…”

Metal–Organic Frameworks for Biomedical Applications

“…Diagrammatic schemes for h) GSPs@ZIF‐8 fabrication and usage of volatile organic compound detection for lung cancer diagnosis by SERS, and i) the selection and the binding strategies for gas molecules with different sizes by GSPs@ZIF‐8 biosensor. Reproduced with permission 83. Copyright 2017, Wiley‐VCH.…”

“…Wang and co‐workers reported a surface‐enhanced Raman scattering method for the diagnosis of lung cancer by detecting volatile organic compound biomarker using core–shell 3D MOF‐based biosensor (Figure 9h). 83 This biosensor called GSPs@ZIF‐8 was composed of Au NPs as core and ZIF‐8 as shell, and the pore size in ZIF‐8 shell could be expanded from 3.4 to over 7.6 Å, which could adsorb small aromatic compounds. After the Raman‐active 4‐ATP molecules were grafted onto the ZIF‐8 surface, 4‐ethylbenzaldehyde reacted with the amino group on 4‐ATP and detected sensitively at the ppb level (Figure 9i).…”