Aging and degeneration of human tissue come with the loss of tissue water retention and associated changes in physical properties partially due to degradation and subsequent loss of proteoglycans. We demonstrated a novel method of fabrication of biomimetic proteoglycans, which mimic the three-dimensional bottlebrush architecture and physical behavior of natural proteoglycans responsible for tissue hydration and structural integrity. Biomimetic proteoglycans are synthesized by an end-on attachment of natural chondroitin sulfate bristles to a synthetic poly(acryloyl chloride) backbone. Atomic force microscopy imaging suggested three-dimensional core-bristle architecture, and hydrodynamic size of biomimetic proteoglycans was estimated at 61.3 ± 12.3 nm using dynamic light scattering. Water uptake results indicated that biomimetic proteoglycans had a ∼50% increased water uptake compared to native aggrecan and chondroitin sulfate alone. The biomimetic proteoglycans are cytocompatible in the physiological ranges of concentrations and could be potentially used to repair damaged or diseased tissue with depleted proteoglycan content.