For example, a polymer-based supramolecular hydrogel prepared from α-CD and methoxy polyethylene glycol-poly(caprolactone)-(dodecanedioic acid)-poly(caprolactone)-methoxy polyethylene glycol triblock polymer (α-CD/MPEG-PCL-MPEG) was used to deliver erythropoietin (EPO), a hormone reported to have a positive role in myocardial infarction (MI, to reduce the systemic side effect of thrombosis and hypertension [101,102]. The gene discussed is EPO; the disease is myocardial infarction.