@article{SchuermannNagelJuergensenetal.2022,
  author    = {Sch{\"u}rmann, Robin and Nagel, Alessandro and Juergensen, Sabrina and Pathak, Anisha and Reich, Stephanie and Pacholski, Claudia and Bald, Ilko},
  title     = {Microscopic understanding of reaction rates observed in plasmon chemistry of nanoparticle-ligand systems},
  series = {The journal of physical chemistry : C, Nanomaterials and interfaces},
  volume    = {126},
  journal   = {The journal of physical chemistry : C, Nanomaterials and interfaces},
  number    = {11},
  publisher = {American Chemical Society},
  address   = {Washington},
  issn      = {1932-7447},
  doi       = {10.1021/acs.jpcc.2c00278},
  pages     = {5333 -- 5342},
  year      = {2022},
  abstract  = {Surface-enhanced Raman scattering (SERS) is an effective and widely used technique to study chemical reactions induced or catalyzed by plasmonic substrates, since the experimental setup allows us to trigger and track the reaction simultaneously and identify the products. However, on substrates with plasmonic hotspots, the total signal mainly originates from these nanoscopic volumes with high reactivity and the information about the overall consumption remains obscure in SERS measurements. This has important implications; for example, the apparent reaction order in SERS measurements does not correlate with the real reaction order, whereas the apparent reaction rates are proportional to the real reaction rates as demonstrated by finite-difference time-domain (FDTD) simulations. We determined the electric field enhancement distribution of a gold nanoparticle (AuNP) monolayer and calculated the SERS intensities in light-driven reactions in an adsorbed self-assembled molecular monolayer on the AuNP surface. Accordingly, even if a high conversion is observed in SERS due to the high reactivity in the hotspots, most of the adsorbed molecules on the AuNP surface remain unreacted. The theoretical findings are compared with the hot-electron-induced dehalogenation of 4-bromothiophenol, indicating a time dependency of the hot-carrier concentration in plasmon-mediated reactions. To fit the kinetics of plasmon-mediated reactions in plasmonic hotspots, fractal-like kinetics are well suited to account for the inhomogeneity of reactive sites on the substrates, whereas also modified standard kinetics model allows equally well fits. The outcomes of this study are on the one hand essential to derive a mechanistic understanding of reactions on plasmonic substrates by SERS measurements and on the other hand to drive plasmonic reactions with high local precision and facilitate the engineering of chemistry on a nanoscale.},
  language  = {en}
}
@article{GuptaPathakShrivastav2022,
  author    = {Gupta, Banshi D. and Pathak, Anisha and Shrivastav, Anand},
  title     = {Optical Biomedical Diagnostics Using Lab-on-Fiber Technology},
  series = {Photonics : open access journal},
  volume    = {9},
  journal   = {Photonics : open access journal},
  number    = {2},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {2304-6732},
  doi       = {10.3390/photonics9020086},
  pages     = {40},
  year      = {2022},
  abstract  = {Point-of-care and in-vivo bio-diagnostic tools are the current need for the present critical scenarios in the healthcare industry. The past few decades have seen a surge in research activities related to solving the challenges associated with precise on-site bio-sensing. Cutting-edge fiber optic technology enables the interaction of light with functionalized fiber surfaces at remote locations to develop a novel, miniaturized and cost-effective lab on fiber technology for bio-sensing applications. The recent remarkable developments in the field of nanotechnology provide innumerable functionalization methodologies to develop selective bio-recognition elements for label free biosensors. These exceptional methods may be easily integrated with fiber surfaces to provide highly selective light-matter interaction depending on various transduction mechanisms. In the present review, an overview of optical fiber-based biosensors has been provided with focus on physical principles used, along with the functionalization protocols for the detection of various biological analytes to diagnose the disease. The design and performance of these biosensors in terms of operating range, selectivity, response time and limit of detection have been discussed. In the concluding remarks, the challenges associated with these biosensors and the improvement required to develop handheld devices to enable direct target detection have been highlighted.},
  language  = {en}
}