Poly(2-oxazoline) as a polymer carrier for cellular and brain delivery of therapeutic proteins and fullerene.

摘要

Diseases in the central neuron system (CNS) have become one of the most threatening and challenging problems for the global healthcare system. Delivery of therapeutic agents especially biotherapeutics to the brain is difficult due to the formidable obstacle formed with the blood brain barrier (BBB) and the complexity of the CNS environment. To address this problem we propose to use poly(2-oxazoline)s (POx) as a polymer carrier to enhance neuronal and brain delivery of therapeutic proteins as well as small molecules.;Conjugation with amphiphilic POx block copolymer was developed to enhance cellular and brain delivery of proteins. Amphiphilic POx block copolymers were synthesized and conjugated with model or therapeutic proteins including Horseradish Peroxidase (HRP), Superoxide Dismutase 1 (SOD1) and Leptin using a two-step conjugation method. These protein-POx conjugates were purified and characterized with a variety of analytical and biophysical techniques. They contained a mixture of conjugates with different numbers of POx attached and partially maintained bioactivity of native proteins. HRP-POx exhibited significantly enhanced cellular uptake in MDCK and Caco-2 cells compared to native HRP. SOD1-POx exhibited significantly enhanced cellular uptake in CATH.a neurons and effectively scavenged intracellular superoxide induced by a free radical stimulant Angiotensin II (Ang II). In vivo study indicated that SOD1-POx had increased circulation stability and crossed the BBB to reach brain parenchyma using a non-saturable mechanism. Leptin-POx also showed increased circulation time and enhanced influx rate to the brain.;Nanocomplex with POx was developed to solubilize and deliver a water-insoluble small molecule fullerene. Water-soluble fullerene-POx nanocomplex was prepared and characterized with multiple techniques. This complex displayed low cytotoxicity, dose-dependent antioxidant activity and enhanced neuronal uptake compared to a commercial formulation full erene-PVP complex. Fullerene-POx effectively scavenged intracellular superoxide induced by free radical stimulants such as Ang II.;Altogether, we developed protein-POx conjugation for enhanced neuronal and brain delivery and fullerene-POx nanocomplex formulation for enhanced neuronal delivery and intracellular superoxide scavenging. These results demonstrated that POx is a powerful polymer carrier to deliver therapeutic proteins and small molecules for the treatment of CNS diseases.