MXene quantum dot functionalized bimetallic MOFs as a label-free aptasensor for highly sensitive detection of exosomes

Abstract

Exosomes have attracted increasing attention in the early diagnosis of tumors due to their participation in physiological and pathological processes. Herein, a novel label-free aptasensor based on the CuNi bimetallic metal–organic frameworks (MOFs) that was decorated with MXene quantum dots (MQDs) was fabricated for exosome sensing. The CuNi-MOFs functionalized with dual specific aptamers, CD63 and MUC1, served as an ideal nanocarrier and catalyst for efficient recognition and capture of target exosomes. Meanwhile, the MQDs with excellent electron transfer can promote the electrochemical catalytic performance of this designed aptasensor. It is noteworthy that the large specific surface area of 2D bimetallic CuNi-MOF nanosheets can offer plenty of exposed active sites and facilitate the connection of aptamers, thereby achieving the goal of specific capture and detection of exosomes. The as-prepared electrochemical aptasensor possesses a wide linear range of 1 × 10¹ to 1 × 10⁶ particles μL⁻¹ for exosome detection and a low detection limit of 5 particles μL⁻¹ (S/N = 3). Besides, the as-prepared aptasensor exhibited satisfactory electrochemical stability for the detection of exosomes, which can provide new ideas for clinical detection and tumor diagnosis.