Graphene quantum dot-based nanocomposites for diagnosing cancer biomarker APE1 in living cells

• Main Authors: Zhang, Hao, Ba, Sai, Yang, Zhaoqi, Wang, Tianxiang, Lee, Jasmine Yiqin, Li, Tianhu, Shao, Fangwei
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2022
• Subjects: Science::Chemistry::Biochemistry; Nanocomposite; Cancer Diagnosis
• Online Access: https://hdl.handle.net/10356/155161
• Institution: Nanyang Technological University

As an essential DNA repair enzyme, apurinic/apyrimidinic endonuclease 1 (APE1) is overexpressed in most human cancers and is identified as a cancer diagnostic and predictive biomarker for cancer risk assessment, diagnosis, prognosis, and prediction of treatment efficacy. Despite its importance in cancer, however, it is still a significant challenge nowadays to sense abundance variation and monitor enzymatic activity of this biomarker in living cells. Here, we report our construction of biocompatible functional nanocomposites, which are a combination of meticulously designed unimolecular DNA and fine-sized graphene quantum dots. Upon utilization of these nanocomposites as diagnostic probes, massive accumulation of fluorescence signal in living cells can be triggered by merely a small amount of cellular APE1 through repeated cycles of enzymatic catalysis. Most critically, our delicate structural designs assure that these graphene quantum dot-based nanocomposites are capable of sensing cancer biomarker APE1 in identical type of cells under different cell conditions and can be applied to multiple cancerous cells in a highly sensitive and specific manners. This work not only brings about new methods for cytology-based cancer screening but also lays down a general principle for fabricating diagnostic probes that target other endogenous biomarkers in living cells.