1. Introduction
There isa growinginterest in developingnano-biosensors with high
sensitivity and selectivity in the scienti
fi
c community due to its various
advantages
[1
–
2]
. The localized surface plasmon resonance (LSPR)
based sensors offer the bene
fi
t of low cost instrumentation, label free
detection, high sensitivity, speci
fi
c selectivity and easy con
fi
guration
in addition to its ability of real time detection
[3
–
5]
. These optical
nano-biosensors have proved very useful in applications in wide range
fi
eldssuchasdrugscreening,DNArecognition,environmentalmonitor-
ingandvariouschemicaland biomoleculardetection
[6
–
8]
.Researchers
currently are investigating ways of developing an LSPR based sensor
with better performance. The most common method that the scientists
have employed is building the nano-sensor by chemically immobilizing
metalnanoparticlesonafunctionalizedopticallytransparentsurface
[9]
and using an optical transducer that can translate the biomolecular in-
teractionintoaquanti
fi
ablesignalinordertodetectthespeci
fi
cbiomol-
ecule
[5]
. The unique optical property and bio-compatibility of gold has
encouraged scientists to utilize it for biosensing applications
[10
–
11]
.
We have demonstrated an LSPR based gold nano-ripple biosensor that
is produced in a single step process using gas cluster ion beam (GCIB)
system
[12
–
14]