An example of a bottlebrush polymer has a polymer backbone and a plurality of individual brush moieties bonded to the polymer backbone. The individual brush moieties respectively include a crosslinked oxyamine moiety, a hydrophilic segment, and a surface adhesive terminal group.

Disclosed are methods, compositions, reagents, systems, and kits to prepare and utilize branched multi-functional macromonomers, which contain a ring-opening metathesis polymerizable norbornene group, one or more reactive sites capable of undergoing click chemistry, and a terminal acyl group capable of undergoing a coupling reaction; branched multi-cargo macromonomers; and the corresponding polymers are disclosed herein. Various embodiments show that the macromonomers and polymers disclosed herein display unprecedented control of cargo loading of agents. These materials have the potential to be utilized for the treatment of diseases and conditions such as cancer and hypertension.

The present disclosure provides, in some aspects, macromonomers of Formula (I), and salts thereof; methods of preparing the macromonomers, and salts thereof; Brush prodrugs (polymers); methods of preparing the Brush prodrugs; compounds of Formula (II); conjugates of Formula (III), and salts thereof; pharmaceutical compositions comprising a Brush prodrug, or a conjugate or a salt thereof; kits comprising: a macromonomer or a salt thereof, a Brush prodrug, a compound, a conjugate or a salt thereof, or a pharmaceutical composition; methods of using the Brush prodrugs, or conjugates or salts thereof; and uses of the Brush prodrugs, and conjugates or salts thereof. These chemical entities may be useful in delivering pharmaceutical agents to a subject or cell.