Bovine Omasum-Inspired Interfacial Carbon-Based Nanocomposite for Saliva Metabolic Screening of Gastric Cancer

Gastric cancer is one of the most common malignant digestivecancers,and its diagnostic has still faced challenges based on metabolic analysisdue to complex sample pretreatment and low metabolite abundance. Inthis study, inspired by the structure of bovine omasum, we in situ synthesized a novel interfacial carbon-based nanocompositeof graphene supported nickel nanoparticles-encapsulated in the nitrogen-dopedcarbon nanotube (Ni/N-CNT/rGO), which was served as a novel matrixwith enhanced ionization efficiency for the matrix-assisted laserdesorption/ionization time of flight mass spectrometry (MALDI-TOFMS) saliva metabolic analysis of gastric cancer. Benefiting from itshigh sp(2) graphitic degree, large surface area, strong UVabsorption, and rich active sites, Ni/N-CNT/rGO matrix exhibited excellent performances of reproducibility, coverage, salt-tolerance,sensitivity, and adsorption ability in MALDI-TOF MS. The differentialscanning calorimetry (DSC) and thermal conversion behaviors explainedthe highly efficient LDI mechanism. Based on saliva metabolic fingerprints,Ni/N-CNT/rGO assisted LDI MS with cross-validation analysis couldsuccessfully distinguish gastric cancer patients from healthy controlsthrough the screening of four potential biomarkers with an accuracyof 92.50%, specificity of 88.03%, and sensitivity of 97.12%. Thiswork provided a fast and sensitive MS sensing platform for the metabolomicscharacterization of gastric cancer and might have potential valuefor precision medicine in the future.

Automated summary

In this study, a novel interfacial carbon-based nanocomposite (Ni/N-CNT/rGO) was synthesized as a matrix for gastric cancer saliva metabolic analysis. Using matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOFMS), four potential biomarkers were successfully screened from saliva, leading to an accuracy of 92.50%, specificity of 88.03%, and sensitivity of 97.12% for distinguishing gastric cancer patients from healthy controls.