Detection of Lignin Motifs with RuO₂-DNA as an Active Catalyst via Surface-Enhanced Raman Scattering Studies

Abstract

Biomass-derived lignin derivatives are significant biodegradable plant materials which produce a variety of valueadded products by oxidation/oxidative cleavage methods. These value-added products constitute important materials for the sustainable production of biofuels. The ultralevel quantitative detection of feedstock carbonyls on metal surfaces is possible with surface-enhanced Raman spectroscopy (SERS) technique. Considering environmental friendly protocols for activation of molecular oxygen in both valorization methods of biomass, the corresponding SERS detection protocols are rare.Here, for the very first time, RuO 2 -DNA nanochains aggregate as an efficient catalyst for oxidation/oxidative cleavage of biomass-derived lignin mimics and their subsequent in-situ SERS detection. Notably, both reactions are carried out in aqueous medium. For the controlled oxidation study, veratryl alcohol and cinnamyl alcohol were used as lignin mimics, and the respective carbonyls were detected by the SERS method by activating molecular oxygen. Also, by changing the oxidant from molecular oxygen to peroxide, the respective acids were seen to be formed for veratryl alcohol. We extend this protocol to oxidative cleavage of lignin-derived olefins, and diols, such as cinnamyl alcohol and 1-phenyl-1,2-ethanediol, and corresponding acids were formed and detected by SERS technique. This oxidation protocol could also be scaled-up for large-scale synthesis and recyclability experiments to prove the robustness of the catalyst under green conditions.

Engineered Rh Nano-networks on DNA for SERS Applications

“…Moreover, the prepared Rh nano-networks were analyzed and shows the strong peaks at 268 nm was further evidenced the strong interaction of DNA with the metal ion (curve d) [25]. This kind of interaction was studied in detail previously [11,15,31].…”

“…It works, when the incident light hits on rough metal surface adsorbed on the probe molecule gets increased Raman signal in a few orders of magnitude [7,8]. The noble metal-based nanomaterials (NMs) such as Ag [9], Au [10], Pt [11], Pd [12], Re [13], Os [14], Ir [15], and RuO 2 [16] having the remarkable surface plasmon resonance (SPR) nature in the visible region. Many factors that are influencing the enhancement of such SERS signal mainly, wavelength, polarization, and incidence angle of the laser light [17][18][19].…”

“…Therefore, fabricating closely packed nanomaterial to ensure more hot-spots is highly desirable using the biomolecule DNA [9]. In addition, the presence of DNA can stabilize the NMs in the aqueous solution over long period [15,31]. At first, the metal ion makes an electrostatic interaction with the negative moieties in the double-helix of DNA [26,[32][33][34].…”

Bio-Mediated Synthesis of Metal Nanomaterials for SERS Application

“…There are several reports in the development of DNA based nanomaterials for diverse applications such as in catalysis, sensors, SERS and so on. Our group also highlighted DNA based NMs for multiple applications including SERS, catalysis, electrocatalysis, supercapacitor, and for feedstock conversions [41][42][43][44]. We have prepared aquasols and organosols of various noble metals such as Au, Ag, Pd, Pt, Os, Ir, Rh, Ru and Re with their molecular self-assembly with DNA [41][42][43][44].…”

“…Our group also highlighted DNA based NMs for multiple applications including SERS, catalysis, electrocatalysis, supercapacitor, and for feedstock conversions [41][42][43][44]. We have prepared aquasols and organosols of various noble metals such as Au, Ag, Pd, Pt, Os, Ir, Rh, Ru and Re with their molecular self-assembly with DNA [41][42][43][44]. The presence of DNA in the aqueous and organosol results in an increase in stability and long-lasting property of the material [41,43].…”