Polysaccharide carbon nanogels and anticoagulants and antioxidants comprising the same

Provided is a nanogel exhibiting anticoagulation and antioxidation activities, including a graphene-like nanosheet and a polysaccharide, which are complexed to form a cross-linked supramolecular structure. Also provided is a method of preparing the nanogel, including carbonizing the polysaccharide by dry heating. By the heating process, at least a portion of the polysaccharide is conversed into the graphene-like nanosheet, thereby forming a graphene-like nanosheet-embedded phenolic-polysaccharide nanogel that has exceptional polyphenolic structure and high binding affinity toward thrombin. Further provided is a method of preventing or treating a disease or a condition susceptible to amelioration by anticoagulants or antioxidants by using the nanogel.