Abstract:
Background: Surface Enhanced Raman Spectroscopy is a potent and unique spectroscopy
technique for ultrasensitive sensing and trace detection of analyte adsorbed on the SERS substrate.
Light driven technologies have contributed to improving the quality of life for centuries therefore
an optical biosensor based on SERS technology using nanostructures as potential SERS substrate
can be an effective, portable and sensitive analytical device for rapid diagnosis of infectious
diseases. In current study, the potential of gold nanostars to exhibit high SERS spectra and ultra sensitive detection against the target analyte (TB DNA) was evaluated.
Methodology: Gold nanostars were synthesized using seed mediated protocol and were
characterized using UV-Vis spectroscopy and scanning electron microscope (SEM). MPTMS
functionalized glass slides were coated with gold nanostars where thiol groups served as linkage
moieties for immobilization process. Afterwards, single stranded thiolated DNA probes were
drop casted onto the gold nanostars adsorbed glass slides. Eventually, SERS analysis was
performed for the target (TB DNA) and non-target analyte (E.coli DNA) alongwith control group
(without SERS substrate) to analyze the sensitivity of the sensor and for comparative analysis
respectively.
Results: UV-Vis analysis revealed the distinct peak at 664nm attributed to gold nanostars whereas
SEM analysis demonstrated the characteristic morphology of gold nanostars with sharp tips and
branches. FTIR spectra of functionalized glass slides confirmed the glass coating via MPTMS
through the presence of C-H bending, a characteristic of MPTMS. SERS spectra analysis against
the target DNA resulted in high Raman intensity in comparison to non-target analyte (E.coli DNA)
and control thereby successfully demonstrating the specificity and sensitivity of our SERS
biosensor.
Conclusion: These findings suggest that gold nanostars serve as a potential substrate for the
development of SERS based biosensors for more rapid, robust, specific and ultra-sensitive
detection hallmark against and can be used for generating even more potent and versatile SERS
sensors in the future.
