Deep-elliptical-silver-nanowell arrays (d-EAgNWAs) fabricated by stretchable imprinting combining colloidal lithography: A highly sensitive plasmonic sensing platform

Elliptical metallic nanohole arrays possess much higher transmission and enhanced sensitivity compared with circular nanohole arrays. However, fabricating elliptical metallic nanohole arrays in large area with highly tunable aspect ratio remains a challenge. Herein, a brand-new method combining stretchable imprinting with colloidal lithography is figured out to fabricate deep-elliptical-silver-nanowell arrays (d-EAgNWAs). In this method, large area highly ordered silicon nanopillar arrays fabricated by colloidal lithography were taken as a master to transfer large area polydimethylsiloxane (PDMS) nanohole arrays. Benefit from the high elasticity of PDMS mold, the aspect ratio of d-EAgNWAs achieved can be facilely regulated from 1.7 to 5.0. Through optimization of polarization direction and the structural parameters including nanowell depth, aspect ratio, and hole size, the sensing performance of d-EAgNWAs was finally improved up to 1, 414.1 nm/RIU. The best sensing behaved d-EAgNWAs were employed as an immunoassay platform finally to prove their great potential in label-free biosensing.