TY - JOUR
T1 - Template-stripped smooth Ag nanohole arrays with silica shells for surface plasmon resonance biosensing
AU - Im, Hyungsoon
AU - Lee, Si Hoon
AU - Wittenberg, Nathan J.
AU - Johnson, Timothy W.
AU - Lindquist, Nathan C.
AU - Nagpal, Prashant
AU - Norris, David J.
AU - Oh, Sang Hyun
PY - 2011/8/23
Y1 - 2011/8/23
N2 - Inexpensive, reproducible, and high-throughput fabrication of nanometric apertures in metallic films can benefit many applications in plasmonics, sensing, spectroscopy, lithography, and imaging. Here we use template-stripping to pattern periodic nanohole arrays in optically thick, smooth Ag films with a silicon template made via nanoimprint lithography. Ag is a low-cost material with good optical properties, but it suffers from poor chemical stability and biocompatibility. However, a thin silica shell encapsulating our template-stripped Ag nanoholes facilitates biosensing applications by protecting the Ag from oxidation as well as providing a robust surface that can be readily modified with a variety of biomolecules using well-established silane chemistry. The thickness of the conformal silica shell can be precisely tuned by atomic layer deposition, and a 15 nm thick silica shell can effectively prevent fluorophore quenching. The Ag nanohole arrays with silica shells can also be bonded to polydimethylsiloxane (PDMS) microfluidic channels for fluorescence imaging, formation of supported lipid bilayers, and real-time, label-free SPR sensing. Additionally, the smooth surfaces of the template-stripped Ag films enhance refractive index sensitivity compared with as-deposited, rough Ag films. Because nearly centimeter-sized nanohole arrays can be produced inexpensively without using any additional lithography, etching, or lift-off, this method can facilitate widespread applications of metallic nanohole arrays for plasmonics and biosensing.
AB - Inexpensive, reproducible, and high-throughput fabrication of nanometric apertures in metallic films can benefit many applications in plasmonics, sensing, spectroscopy, lithography, and imaging. Here we use template-stripping to pattern periodic nanohole arrays in optically thick, smooth Ag films with a silicon template made via nanoimprint lithography. Ag is a low-cost material with good optical properties, but it suffers from poor chemical stability and biocompatibility. However, a thin silica shell encapsulating our template-stripped Ag nanoholes facilitates biosensing applications by protecting the Ag from oxidation as well as providing a robust surface that can be readily modified with a variety of biomolecules using well-established silane chemistry. The thickness of the conformal silica shell can be precisely tuned by atomic layer deposition, and a 15 nm thick silica shell can effectively prevent fluorophore quenching. The Ag nanohole arrays with silica shells can also be bonded to polydimethylsiloxane (PDMS) microfluidic channels for fluorescence imaging, formation of supported lipid bilayers, and real-time, label-free SPR sensing. Additionally, the smooth surfaces of the template-stripped Ag films enhance refractive index sensitivity compared with as-deposited, rough Ag films. Because nearly centimeter-sized nanohole arrays can be produced inexpensively without using any additional lithography, etching, or lift-off, this method can facilitate widespread applications of metallic nanohole arrays for plasmonics and biosensing.
KW - atomic layer deposition
KW - biosensing
KW - microfluidics
KW - nanohole array
KW - nanoimprint lithography
KW - plasmonics
KW - supported lipid bilayer
KW - surface plasmon resonance
KW - template-stripping
UR - http://www.scopus.com/inward/record.url?scp=80052048867&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=80052048867&partnerID=8YFLogxK
U2 - 10.1021/nn202013v
DO - 10.1021/nn202013v
M3 - Article
C2 - 21770414
AN - SCOPUS:80052048867
SN - 1936-0851
VL - 5
SP - 6244
EP - 6253
JO - ACS nano
JF - ACS nano
IS - 8
ER -