Decoupled Roles of DNA–Surfactant Interactions: Instant Charge Inversion, Enhanced Colloidal and Chemical Stabilities, and Fully Tunable DNA Conjugation of Shaped Plasmonic Nanocrystals

Abstract

Surfactant-dictated syntheses of nanomaterials with well-defined shapes offer an extra dimension of control beyond nanoparticle size and chemical composition on the properties and selfassembly behaviors of colloidal materials. However, the surfactant bilayers on nanocrystals often cause great difficulty toward DNA grafting due to their unfavorable electrostatic charges and dense surface packing. Herein a revisit to this dilemma unveils a rapid charge inversion and enhanced colloidal/chemical stabilities of cationicbilayer-covered nanocrystals upon DNA adsorption. Decoupling this hidden scenario provides a rationale to significantly improve DNA functionalization of surfactant-capped nanocrystals. Accordingly, fully tunable DNA conjugation (via Au−S bonding) on up to seven classes of surfactant-coated metal nanounits is easily and consistently achievable. The DNA−nanocrystal complexes featuring a continuously variable DNA density function well in DNA-guided nanoassembly. Our method opens the door to a wealth of material building blocks derived by surfactant-directed nanosyntheses toward DNA-programmable, extremely diversified, and highly complicated structures and functions.

Assembly and Healing: Capacitive and Conductive Plasmonic Interfacing via a Unified and Clean Wet Chemistry Route

“…The overall effect is a directional transport of gold atoms from a convex (spherical) surface to a concave (gapped) region. , The thermodynamic driving force for the two distinct pathways follows the same interface-cancelation rule. Gold oxidization usually happens for NPs bearing protruding features including vertexes, edges, and spikes. , The commonly adopted oxidants are HAuCl 4 and H 2 O 2 . We found that flowerlike AuNPs were easily etched into spherical ones by H 2 O 2 oxidation, accompanied by a color transition from blue to red (Figure S22).…”

“…In this case, it was found that FSDNA adsorption could passivate the spiky gold surface against gold leaching (Figure S23). This fact was also consistent with previous reports . In fact, both FSDNA and other chemicals, such as buffer salts, were found to decelerate CTP reshaping of the BDP-coupled AuNP dimers (Figure S24).…”

“…This fact was also consistent with previous reports. 102 In fact, both FSDNA and other chemicals, such as buffer salts, were found to decelerate CTP reshaping of the BDP-coupled AuNP dimers (Figure S24). It was also found that the removal of H 2 O 2 from the system immediately slowed the CTP reshaping (Figures S25 and S26).…”

“…Gold oxidization usually happens for NPs bearing protruding features including vertexes, edges, and spikes. 101,102 The commonly adopted oxidants are HAuCl 4 and H 2 O 2 . 102 We found that flowerlike AuNPs were easily etched into spherical ones by H 2 O 2 oxidation, accompanied by a color transition from blue to red (Figure S22).…”

“…101,102 The commonly adopted oxidants are HAuCl 4 and H 2 O 2 . 102 We found that flowerlike AuNPs were easily etched into spherical ones by H 2 O 2 oxidation, accompanied by a color transition from blue to red (Figure S22). In this case, it was found that FSDNA adsorption could passivate the spiky gold surface against gold leaching (Figure S23).…”