AuNPs/CNC Nanocomposite with A "Dual Dispersion" Effect for LDI-TOF MS Analysis of Intact Proteins in NSCLC Serum Exosomes

Detecting exosomal markers using laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF MS) is a novel approach for examining liquid biopsies of non-small cell lung cancer (NSCLC) samples. However, LDI-TOF MS is limited by low sensitivity and poor reproducibility when analyzing intact proteins directly. In this report, gold nanoparticles/cellulose nanocrystals (AuNPs/CNC) is introduced as the matrix for direct analysis of intact proteins in NSCLC serum exosomes. AuNPs/CNC with "dual dispersion" effects dispersed and stabilized AuNPs and improved ion inhibition effects caused by protein aggregation. These features increased the signal-to-noise ratio of [M+H]+ peaks by two orders of magnitude and lowered the detection limit of intact proteins to 0.01 mg mL-1. The coefficient of variation with or without AuNPs/CNC is measured as 10.2% and 32.5%, respectively. The excellent reproducibility yielded a linear relationship (y = 15.41x - 7.983, R2 = 0.989) over the protein concentration range of 0.01 to 20 mg mL-1. Finally, AuNPs/CNC-assisted LDI-TOF MS provides clinically relevant fingerprint information of exosomal proteins in NSCLC serum, and characteristic proteins S100 calcium-binding protein A10, Urokinase plasminogen activator surface receptor, Plasma protease C1 inhibitor, Tyrosine-protein kinase Fgr and Mannose-binding lectin associated serine protease 2 represented excellent predictive biomarkers of NSCLC risk.

[The prospect and challenge of liquid biopsy in the diagnosis and treatment of chest malignancy]

In recent years, the incidence of chest malignant tumors in China has increased year by year, which has seriously threatened the health problems of people. Among them, early screening and intervention of patients with chest malignancies is the key to cancer prevention. Early detection, early diagnosis, and early treatment as the "three early prevention" of clinical practice are conducive to improve the survival rate of tumor patients. As a non-invasive and real-time reflection of tumor status, liquid biopsy has gradually received attention in clinical diagnosis and treatment. Circulating tumor cells (CTCs), circulating tumor DNA (ctDNA) and exosomes as liquid biopsy "Three carriages" are not only widely used in the diagnosis, monitoring and prognostic evaluation of chest malignancies, but also face many unknown challenges. In this article, the application of liquid biopsy in chest malignancies in recent years is elaborated in detail, which provides a reference for the formulation of clinical tumor prevention and diagnosis and treatment strategies.