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:

Self-assembled monolayers with dynamicity stemming from (bio)chemical conversions: from construction to application. Surfaces with "dynamicity" whereby surface properties can be modulated by an external stimulus on user demand have been actively exploited for the past decade. These switchable surfaces with dynamic properties are widely used for a number of applications such as micro/nanoarrays, biomolecule immobilization, basic cell studies, and tissue engineering on a variety of materials. This minireview highlights the dynamic control of surface properties on self-assembled monolayers and focuses on dynamicity that stems from (bio)chemical conversions achieved by electrical potentials, photoillumination, chemical reagents, enzymes, and pH.
{"Chemical": []}