Serum Metal Ion-Induced Cross-Linking of Photoelectrochemical Peptides and Circulating Proteins for Evaluating Cardiac Ischemia/Reperfusion

Patients having experienced the ischemia-reperfusion process areparticularly vulnerable to subsequent heart attacks because this process can inducemyocardialfibrosis, hallmarked by the release of reactive oxygen species and someproteases, such as cathepsin G, into the circulating blood. If these risk indicators can bemonitored from the peripheral serum, early diagnosis and intervention may become areality. For this purpose, we have designed an assay of free copper ions and cathepsin Gin serum using only synthetic small molecules as the biosensing elements. Noantibodies are needed to recognize the target protein, and no enzymes are needed togenerate and amplify the biosensing signal. In this design, a short peptide can target-specifically recognize protease, while the copper ion in the serum can stimulate thephotoelectrochemical activity of the probe, resulting in cross-linking of the serumproteins in a target protein-specific manner. Using this method, serum cathepsin G andfree copper ion are found to be significantly elevated in the blood samples collectedfrom patients with acute myocardial infarction and successful percutaneous coronary intervention in comparison with healthycontrols, indicating a higher risk of subsequent myocardial injury and cardiovascular events. These results may point to the possibleapplication of the proposed assay to evaluate the severity and prognosis of cardiac ischemia/reperfusion in the near future

Automated summary

Patients who have experienced the ischemia-reperfusion process are at a higher risk of subsequent heart attacks. A novel assay using synthetic small molecules for detecting free copper ions and cathepsin G in serum has shown potential for evaluating the severity and prognosis of cardiac ischemia/reperfusion.