Despite the success of galvanic replacement in preparing hollow nanostructures with diversified morphologies via the replacement reaction between sacrificial metal nanoparticles (NPs) seeds and less active metal ions, limited advances are made for producing branched alloy nanostructures. In this paper, we report an extended galvanic replacement for preparing branched Au-Ag NPs with Au-rich core and Ag branches using hydroquinone (HQ) as the reductant. In the presence of HQ, the preformed Ag seeds are replaceable by Au and, in turn, supply the growth of Ag branches. By altering the feed ratio of Ag seeds, HAuCl4, and HQ, the size and morphology of the NPs are tunable. Accordingly, the surface plasmon resonance absorption is tuned to near-infrared (NIR) region, making the branched NPs as potential materials in photothermal therapy. The branched NPs are further coated with polydopamine (PDA) shell via dopamine polymerization at room temperature. In comparison with bare NPs, PDA-coated branched Au-Ag (Au-Ag@PDA) NPs exhibit improved stability, biocompatibility, and photothermal performance. In vitro experiments indicate that the branched Au-Ag@PDA NPs are competitive agents for photothermal ablation of cancer cells.

Nanocomposites based on hollow Au nanostructures have gained considerable attention in theranostics applications because of their unique plasmonic structures and attractive physicochemical properties. The exploration of feasible and facile methods for constructing multifunctional nanocomposites combined with bioactive molecules is greatly needed for the development of multifunctional theranostics platforms. In this work, resveratrol, a natural polyphenol with antioxidant activity and cancer-chemopreventive propertyies is employed as the reducing agent cum coating agent for the surfactant-free preparation of Au@resveratrol hollow NPs (Au@Res HNPs). The as-prepared Au@Res HNPs were found to present good photothermal performance and chemical inhibition for cancer therapy. In vitro experiments indicated that the Au@Res HNPs can block cell cycles to inhibit cell division and lead to cell apoptosis after 808-nm laser irradiation. Because no toxic surfactants are introduced, the current protocol avoids the tedious surfactant separation and surface modification processes that are necessary for most theranostics materials.

The amphiphilic star-like copolymer polyethylenimine-block-poly(ε-caprolactone) (PEI-b-PCL) was utilized to transfer the pre-synthesized citrate-capped noble metal nanoparticles (NMNPs) from an aqueous layer to an organic layer without any additional reagents. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) were utilized to study the assembly of the polymers coated on the surface of the citrate-capped NMNPs. After removing the organic solvent, the polymer-coated NMNPs in powder form (PCP-NMNPs) were obtained. The excellent solubility of the PEI-b-PCL allows the PCP-NMNPs to be easily dispersed in most of the organic solvents without any significant aggregation. Moreover, the good thermal stability and long-term stability make PCP-NMNPs an excellent NMNP-containing hybrid system for different specific applications, such as surface coating, catalysis and thermoplastic processing of nanocomposite materials.

Gold nanorods (GNRs) attract extensive attention in current diagnostic and therapeutic applications which require the synthesis of GNRs with high yields, adjustable aspect ratio, size monodispersity, and easy surface decoration. In the seed-mediated synthesis of GNRs using cetyl trimethyl ammonium bromide (CTAB) micelles as templates, the additives of aromatic compounds have been found to be important for improving the size monodispersity of the as-synthesized GNRs; this is hopeful in terms of the further optimization of the synthetic methodology of GNRs. In this work, resveratrol, a natural polyphenol in grapes with an anti-oxidization behavior, is employed as the reductant for the seedless synthesis of GNRs with a good size monodispersity and a tunable aspect ratio. Accordingly, the longitudinal localized surface plasmon resonance (LSPR) peak is tunable from 570 to 950 nm. The success of our approach is attributed to the aromatic structure and mild reducibility of resveratrol. The embedment of resveratrol into CTAB micelles strengthens the facet-selective adsorption of CTAB, and therewith facilitates the anisotropic growth of GNRs. In addition, the mild reducibility of resveratrol is capable of supporting GNR growth by avoiding secondary nucleation, thus allowing the seedless synthesis of GNRs with a good size monodispersity. As a chemopreventive agent, the combination of resveratrol in GNR synthesis will consolidate the theranostic applications of GNRs.

A series of supramolecular dendritic multiarm polymers (SDMPs) are fabricated by simply mixing the hyperbranched polyethylenimine (PEI, 10K) and carboxylic acid-terminated carbazolecontaining dendrons. Carbazole-containing dendrons with different generations, i.e. generation zero (G0), generation one (G1), and generation two (G2), are employed for the formation of the nanocomplexes. The formation of SDMPs is demonstrated by the use of dynamic light scattering (DLS) and water contact angle (WCA) measurement. The ionic bonding between the PEIs and the surrounding carbazole-containing dendrons is also confirmed by the 1 H nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR) spectra. The encapsulation capability of SDMPs is tested by monitoring the phase transfer process of anionic guests by UV−vis spectroscopy. The effect of the dendron generation on the encapsulation capability of SDMPs is evaluated as well. Without any additional reducing agent, the SDMPs are also utilized as the nanoreactors for the formation of the noble metal nanoparticle (NMNPs) while cross-linking the periphery carbazole shells simultaneously. The electrochemically active SDMPs, with the simple fabrication method and their utilization as the nanocarriers to encapsulate anionic guests and nanoreactors to generate conjugated polymer shells surrounded NMNPs, are expected to be ideal building blocks for the optoelectronic devices and intelligent materials. ■ INTRODUCTIONBy analogue with biomolecules that self-organize into the welldefined 3-D hierarchical structures with unique properties and functionalities, the synthesized polymers can also be programmed to self-assemble into functional supramolecular nanoobjects, i.e., supramolecular polymers (SPs). 1−4 The SPs have attracted broad interest in both academic and industrial fields due to their broad applications in catalysis, 5 drug delivery, 2,6 nanopattern fabrication, 7 information storage, 8 actuators, 9 liquid crystals, 10,11 self-healing material, 12,13 and optoelectronic devices. 14 Compared with the covalently bonded polymers, they enjoyed several advantages, such as simple preparation and purification, tunable structure and morphology, and stimulus response. 15 With a three-dimensional global architecture, supramolecular dendritic polymers (SDPs) exhibit good solubility, lower solution viscosity, and higher degree of functionality than their linear analogues. 15 With one multifunctional dendritic polymer as core and numerous linear polymers or dendrons with one complementary unit as shells, supramolecular dendritic multiarm copolymers (SDMPs) usually possess two chemically distinct components. As a unique class of SDPs, SDMPs exhibit great potentials in drug delivery, 2,16 templated polymerization, 17 nanoparticle formation, 18,19 and catalysis. 5 The dendritic polymer and surrounding linear polymers or dendrons are held together by the secondary interactions, such as hydrogen bonding, 14 electrostatic interactions, 18,20 and host−guest complexation. 21 The ionic bond...