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:

Dendrimeric bowties featuring hemispheric-selective decoration of ligands for microRNA-based therapy. Dendrimers feature a defined number of terminal groups that may bind RNA or be functionalized with bioactive molecules. These competing uses of terminal groups may create an impasse if the requisite density of ligands depletes the number of terminal groups for binding sufficient RNA, or vice versa. A novel dendrimeric platform is needed that maintains high ligand density while retaining sufficient microRNA-binding terminal groups. Here we present a dendrimeric "bowtie" consisting of one-half devoted to microRNA binding and the other half to ligand presentation. We demonstrate its suitability as a transfection agent by delivering miR-126 to human vascular endothial cells (HUVECs) via polyarginine- and RGD-modified bowties and evaluating the downstream effects on proliferation and tube formation. Our findings indicate that the bowtie elicits desired responses and may possess superior delivery properties compared to nondecorated dendrimeric materials. The bowtie system thereby provides a new design model for developing dendrimeric delivery vehicles for RNAi therapeutics.
{"Chemical": ["polyarginine"]}