Metal–Polymer Heterojunction in Colloidal-Phase Plasmonic Catalysis

[EN] Plasmonic catalysis in the colloidal phase requires robust surface ligands that prevent particles from aggregation in adverse chemical environments and allow carrier flow from reagents to nanoparticles. This work describes the use of a water-soluble conjugated polymer comprising a thiophene moiety as a surface ligand for gold nanoparticles to create a hybrid system that, under the action of visible light, drives the conversion of the biorelevant NAD+ to its highly energetic reduced form NADH. A combination of advanced microscopy techniques and numerical simulations revealed that the robust metal-polymer heterojunction, rich in sulfonate functional groups, directs the interaction of electron-donor molecules with the plasmonic photocatalyst. The tight binding of polymer to the gold surface precludes the need for conventional transition-metal surface cocatalysts, which were previously shown to be essential for photocatalytic NAD+ reduction but are known to hinder the optical properties of plasmonic nanocrystals. Moreover, computational studies indicated that the coating polymer fosters a closer interaction between the sacrificial electron-donor triethanolamine and the nanoparticles, thus enhancing the reactivity.This work was supported by grant PID2019-111772RB-I00 funded by MCIN/AEI/10.13039/501100011033 and grant IT 1254-19 funded by Basque Government. The authors acknowl- edge the financial support of the European Commission (EUSMI, Grant 731019). S.B. is grateful to the European Research Council (ERC-CoG-2019 815128). The authors acknowledge the contributions by Dr. Adrian Pedrazo Tardajos related to sample support and electron microscopy experiments

Chemotermally fueled transient self-assembly of gold nanoparticles

Resumen del póster presentado a la XXXVIII Reunión Bienal de la Real Sociedad Española de Química, celebrada en el Palacio de Congresos de Granada, del 27 de junio al 30 de junio de 2022.Inspired by biology, the field of supramolecular self-assembly evolved over the years from thermodynamical equilibrium structures towards dissipative assemblies, where molecular building blocks assemble out-of-equilibrium for the time being of fuel consumption. These dissipative assemblies in nature fulfill actions like transport, movement, and catalysis among others. More recently, controlling transient states of nanoparticles using chemical fuel is an emerging field for the creation of active matter, and gives the possibility to exploit new materials with unusual and adaptive properties (e.g. optical, electrical, mechanical). Examples in literature are still rare, due to difficulties of bridging different length scales with the fuel being on the molecular and building blocks on the nanoscopic scale. We report here on coupling a chemothermal cycloaddition reaction with thermosensitive DNA-coated gold nanoparticles[2] (AuDNA) (Figure 1: Coupling chemothermal reaction cycle with thermosensitive DNA coated gold nanoparticles). AuDNA undergo transient redispersion for the time of heat production by the exothermic reaction. After the excessive heat dissipates, AuDNA spontaneously cluster due to DNA rehybridization. Through adjusting the amount of fuel added, different transient states could be accessed as well as their lifetime could be controlled. To the best of our knowledge, this is the first example of coupling thermosensitive nano building blocks with a chemical reaction cycle. Our results expand the existing list of nanoscale constructs sensitive to the outcome of a chemical reaction.Peer reviewe

Coupling reversible clustering of DNA-coated gold nanoparticles with chemothermal cycloaddition reaction

Stimuli-responsive, optically-active colloidal systems are convenient signal transducers capable of monitoring environmental changes at the nanoscale. We report on the coupling of chemo-thermal cycloaddition reaction with temperature-sensitive, DNA-coated gold nanoparticles. We found that the concentration of chemical fuel, dictating the temperature of the mixture, is a primary ingredient in controlling the extent of the reversible clustering of gold nanoparticles. Our results show that rational coupling of chemical and colloidal systems can open up new possibilities in tracking the change of local temperature using aggregation/redispersion of nanoparticles.This work was supported by grant PID2019-111772RB-I00 funded by MCIN/AEI/10.13039/501100011033.Peer reviewe

Metal-polymer heterojunction in colloidal-phase plasmonic catalysis

[Image: see text] Plasmonic catalysis in the colloidal phase requires robust surface ligands that prevent particles from aggregation in adverse chemical environments and allow carrier flow from reagents to nanoparticles. This work describes the use of a water-soluble conjugated polymer comprising a thiophene moiety as a surface ligand for gold nanoparticles to create a hybrid system that, under the action of visible light, drives the conversion of the biorelevant NAD(+) to its highly energetic reduced form NADH. A combination of advanced microscopy techniques and numerical simulations revealed that the robust metal–polymer heterojunction, rich in sulfonate functional groups, directs the interaction of electron-donor molecules with the plasmonic photocatalyst. The tight binding of polymer to the gold surface precludes the need for conventional transition-metal surface cocatalysts, which were previously shown to be essential for photocatalytic NAD(+) reduction but are known to hinder the optical properties of plasmonic nanocrystals. Moreover, computational studies indicated that the coating polymer fosters a closer interaction between the sacrificial electron-donor triethanolamine and the nanoparticles, thus enhancing the reactivity