Enhanced electron transfer and stability via hetero-interface engineering of MXene@MOF: Electrochemical sensors for direct detection of GPNMB in serum of PD

The development of analytical tools to contribute to the identification of prognostic and diagnostic biomarkers reflecting the pathophysiology, progression, and severity of Parkinson's Disease (PD) is of paramount importance. Glycoprotein Nonmetastatic Melanoma Protein B (GPNMB) is a candidate biomarker for PD development and therapy targeting. However, the low content and the complexity of the testing environment caused the detection of GPNMB to be difficult. In this work, an MXene@MOF-enhanced electrochemical biosensor was developed for label-free, ultra-sensitive detection of GPNMB in serum from PD patients directly for the first time. 2D MOFs with morphology matching were loaded onto MXene via hetero-interface engineering to prevent oxidation of MXene by H2O/O2. MXene@MOF, which possesses excellent oxidation resistance, high conductivity, and a multi-layered folded structure, is used to enhance the sensitivity and stability of the biosensor by increasing the electroactive surface area. The GPNMB electrochemical sensor has an LOD as low as 180.33 pg/mL and demonstrates an excellent ability to discriminate between PD-positive and negative patient samples (AUC=0.91). This direct, sensitive, and simple GPNMB sensor has enormous potential for clinical diagnosis and personalized treatment of PD, as well as related scientific research.