Rubaiet Shattique | Bangladesh University of Engineering and Technology (original) (raw)

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Papers by Rubaiet Shattique

Plasmonics, 2019

We have reported the in situ surface–enhanced Raman spectroscopy (SERS) monitoring of repetitive ... more We have reported the in situ surface–enhanced Raman spectroscopy (SERS) monitoring of repetitive surface plasmon–mediated chemical transformation cycles in a conjugate nanobiological system. The nanobiological conjugate comprised a gold-coated plasmonic substrate biofunctionalized with thiolated single–stranded DNA carrying a reduction-oxidation indicator methylthioninium chloride, which is also known as methylene blue (MB), in buffer solution at a neutral pH. Exposure to a 523-nm laser excitation produced pronounced SERS bands of oxidized MB. Continued exposure to the laser resulted in disappearance of the SERS bands, which can be interpreted as a reduction of MB. This occurred in the absence of electrochemical stimulation, chemical agents, or catalysts, suggesting a surface plasmon–mediated mechanism of the transformation. The oxidized form of MB was recovered by an addition of fresh buffer solution on the surface of the sample. Continued laser exposure with periodical addition of...

Nano-biological systems interfacing nano-structured solid surfaces with biological compounds such... more Nano-biological systems interfacing nano-structured solid surfaces with biological compounds such as oligonucleotides or proteins are highly regarded as enabling materials for biosensing and biocatalysis applications. In particular, nanostructures of noble metals such as gold or silver, when exposed to light, exhibit a phenomenon known as surface plasmon resonance. When a proper metal nanostructure (plasmonic substrate) is exposed to light, very efficient absorption of incoming photons is possible, resulting in a buildup of localized high-energy regions, or “hot-spots”, where energetic carriers or “hot carriers” can be created. These hot-carriers can be used to catalyze desired chemical transformations in materials located nearby. Furthermore, plasmonic hot-spots are also known to enhance inelastic scattering of light by the same materials, promising multifunctional applications that combine photo-catalytic stimulation of materials with their ultrasensitive characterization in the s...

We developed a conjugate nano-biological system interfacing plasmonic gold nanostructures with th... more We developed a conjugate nano-biological system interfacing plasmonic gold nanostructures with thiolated single-stranded DNA carrying an important reductionoxidation indicator, methylthioninium chloride, also known as methylene blue. Using surface-enhanced Raman spectroscopy, we have detected characteristic bands of DNA-bound immobilized methylene blue in sub-monolayer quantities. We also have detected reversible reductionoxidation of methylene blue during laser excitation of the samples at neutral pH, in the absense of electrodes or chemical agents.

2014 9th International Forum on Strategic Technology (IFOST), 2014