Disclosed are heparin conjugates comprising heparin conjugated to a peptide that binds to a protein of the extracellular matrix (ECM) of cellular tissue, such as a collagen-binding peptide that binds to collagen of the ECM. The disclosed heparin conjugates may be utilized in methods that include treating ECM material to incorporate the heparin conjugates and impart anticoagulant activity to the ECM. The disclosed heparin conjugates also may be formulated as pharmaceutical compositions for treating and/or preventing vascular injuries and conditions.