You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Patterning Surfaces for Controlled Platelet Adhesion and Detection of Dysfunctional Platelets. Platelets play a fundamental role in thrombus formation and in the pathogenesis of arterial thrombosis. Patterning surfaces for controlled platelet adhesion paves the way for adhesion and activation mechanisms in platelets and detection of platelet functional defects. Here, a new and simple method based on controlled polymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) on the surface of styrene-block-(ethylene-co-butylene)-block-styrene (SEBS) is shown. The competition between polymerization and degradation enables platelet adhesion on SEBS to be switched on and off. The adhesive sites of the platelets can be down to single cell level, and the dysfunctional platelets can be quantitatively detected.
{"Chemical": ["MPC", "SEBS", "styrene-block-(ethylene-co-butylene)-block-styrene", "2-methacryloyloxyethyl phosphorylcholine"]}