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:

Readily accessible fluorescent probes for sensitive biological imaging of hydrogen peroxide. Hydrogen peroxide is a major component of oxygen metabolism in biological systems that, when present in high concentrations, can lead to oxidative stress in cells. Noninvasive molecular imaging of H(2)O(2) using fluorogenic systems represents an effective way to detect and measure the accumulation of this metabolite. Herein, we detail the development of robust H(2)O(2)-sensitive fluorescent probes using a boronic ester trigger appended to the fluorophore through a benzyl ether linkage. A major advantage of the probes presented here is their synthetic accessibility, with only one step needed to generate the probes on the gram scale. The sensitivity of the probes was evaluated in simulated physiological conditions, showing micromolar sensitivity to H(2)O(2). The probes were tested in biological model systems, demonstrating effective imaging of unstimulated, endogenous H(2)O(2) levels in RAW 264.7 cells and murine brain tissue.
{"Chemical": ["boronic ester", "H(2)O(2)", "hydrogen peroxide", "benzyl ether", "Hydrogen peroxide", "oxygen"]}