Drug resistant superbug infection is one of topmost threats to human health for our society. Plasmonic nanoparticles can be used for ultrasensitive bio-imaging and photothermal killing through the amplification of electromagnetic fields at nanoscale “hot spots”. One of the main challenges in plasmonic imaging and phothermal killing is the designing of plasmonic substrate with large number of “hot spots”. Driven by the need, this article reports the design of three dimensional (3D) plasmonic “hot spots” based substrate using gold nanoparticle attached hybrid graphene oxide (GO) which breaks the traditional 2D limitation. Experimental result shows that the 3D substrate has the capability for highly sensitive label-free sensing and it generates high photothermal heat. Reported data using p-aminothiophenol conjugated 3D substrate shows that the surface enhanced Raman spectroscopy (SERS) enhancement factor for 3D “hot spots” based substrate is more than two orders of magnitude higher than the two dimensional (2D) substrate and five orders of magnitude higher than zero dimensional (0D) p-aminothiophenol conjugated gold nanoparticle. 3D- Finite-Difference Time-Domain (3D-FDTD) simulation calculations indicate that the SERS enhancement factor can be greater than 104 due to the bent assembly structure in 3D substrate. Reported experimental results demonstrated that 3D-substrate based SERS can be used for finger-print identification for several multi-drug resistant superbugs with detection limits of 5 colony forming unit /mL. Experimental data show that 785 nm near infrared (NIR) light generate around 2 times more photothermal heat for 3D substrate with respect to 2D substrate and it allows the rapid and effective killing of 100% of the multi-drug resistant superbugs within 5 minutes of 785 nm NIR light exposure.

Three dimensional (3D) plasmonic hot spot for label-free sensing and effective photothermal killing of multiple drug resistant superbugs

253rd National Meeting (2017)

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