Highly sensitive detection of DNA methyltransferase1 triggered by methylation protection

Type 2 diabetes is on the rise year by year, and 80 % of patients with type 2 diabetes die from cardiovascular complications. Strict control of blood glucose can significantly reduce the occurrence and development of diabetic microvascular complications, but can not effectively prevent the occurrence of diabetic macrovascular lesions. DNA methyltransferase 1 (DNMT1) plays an important role in developing phenotypic switching and secretion of inflammatory factors in vascular smooth muscle cells(VSMC), leading to the deregulation of vascular function. In this work, a biosensor based on methylation protection was designed. In the presence of the target DNMT 1, the formed methylation sites protect the dsDNA from being digested by the Hpa II restriction enzyme. At the same time, a large number of G-quadruplex are produced by the catalyzed hairpin assembly (CHA) reaction cycle, and the peroxidase-like activity of G-tetraplex and hemin is used to continuously catalyze the color change of substrate ABTS, thus realizing dual signal amplification. The binding of magnetic beads to dsDNA effectively reduces the background signal and enables a highly selective and sensitive analysis of the target DNMT 1 in complex biological samples, with a detection limit as low as 0.22 UmL −1 , showing a good linear relationship in the range of 0.22–10 UmL −1 . A new approach for the study of macrovascular damage is provided in type 2 diabetes.