Scalable Fabrication of Low Elastic Modulus Polymeric Nanocarriers With Controlled Shapes for Diagnostics and Drug Delivery

Abstract

A new process, decoupled functional imprint lithography (D-FIL), is presented for fabricating low elastic modulus polymeric nanocarriers possessing Young's modulus of bulk material as low as sub-1 MPa. This method is employed to fabricate sub-50 nm diameter cylinders with >3:1 aspect ratio and other challenging shapes from low elastic modulus polymers such as N-isopropylacrylamide (NIPAM) and poly(ethylene glycol) di-acrylate (PEGDA), possessing Young's modulus of bulk material <10 MPa which is cannot otherwise be imprinted in similar size and pitch using existing imprint techniques. Standard imprint lithography polymers have Young's modulus >1 GPa, and so these polymers used in nanocarrier fabrication in comparison have very low elastic modulus. Monodispersed, shape- and size-specific nanocarriers composed of NIPAM with material elastic modulus of <1 MPa have been fabricated and show thermal responsive behavior at the lower critical solubility temperature (LCST) of ∼32 °C. In addition, re-entrant shaped nanocarriers composed of PEGDA with elastic modulus <10 MPa are also fabricated. Nanocarriers fabricated from PEGDA are shown with model imaging agent and anticancer drug (Doxorubicin) encapsulated in as small as 50 nm cylindrical nanocarriers.