Fibronectin is a critical component of the extracellular matrix (ECM) and plays an important role in various biological processes, including cell adhesion, growth, migration, and differentiation. In fibrotic tissues, fibronectin can activate fibroblasts, inducing their differentiation into myofibroblasts, leading to excessive accumulation of ECM proteins. A fibronectin-binding peptide has shown potential as an antifibrotic agent. However, the peptide often suffers from rapid renal clearance, limiting their systemic circulation and therapeutic potential. To address this limitation, we generated peptide-polymer conjugates using a cysteine-engineered peptide. The engineered peptide maintained its binding affinity for fibronectin, as confirmed by in vitro binding tests. Using size-exclusion chromatography, we successfully separated the polymer-conjugated peptide from the unconjugated form. Based on these results, we are currently characterizing the peptide-polymer conjugates and investigating their potential for ECM-targeted therapeutic applications.