Dopamine-Mediated Assembly of Citrate-Capped Plasmonic Nanoparticles into Stable Core–Shell Nanoworms for Intracellular Applications

Abstract

Plasmonic nanochains, derived from the one-dimensional assembly of individual plasmonic nanoparticles (NPs), remain infrequently explored in biological investigations due to their limited colloidal stability, ineffective cellular uptake, and susceptibility to intracellular disassembly. We report the synthesis of polydopamine (PDA)-coated plasmonic “nanoworms” (NWs) by sonicating citrate-capped gold (Cit-Au) NPs in a concentrated dopamine (DA) solution under alkaline conditions. DA mediates the assembly of Cit-Au NPs into Au NWs within 1 min, and subsequent self-polymerization of DA for 60 min enables the growth of an outer conformal PDA shell that imparts stability to the inner Au NW structure in solution, yielding “core–shell” Au@PDA NWs with predominantly 4–5 Au cores per worm. Our method supports the preparation of monometallic Au@PDA NWs with different core sizes and bimetallic PDA-coated NWs with Au and silver cores. The protonated primary amine and catechol groups of DA, with their ability to interact with Cit anions via hydrogen bonding and electrostatic attraction, are critical to assembly. When compared to unassembled PDA-coated Au NPs, our Au@PDA NWs scatter visible light and absorb near-infrared light more intensely and enter HeLa cancer cells more abundantly. Au@PDA NWs cross the cell membrane as intact entities primarily via macropinocytosis, mostly retain their inner NW structure and outer PDA shell inside the cell for 24 h, and do not induce noticeable cytotoxicity. We showcase three intracellular applications of Au@PDA NWs, including label-free dark-field scattering cell imaging, delivery of water-insoluble cargos without pronounced localization in acidic compartments, and photothermal killing of cancer cells.

Nanomaterials for the Photothermal Killing of Bacteria

“…Metal-based nanomaterials have received great interest due to their unique optical properties, which are size- and shape-dependent [ 22 , 23 , 24 , 25 ]. Therefore, many kinds of metal nanostructures have been produced, such as nanorods [ 26 , 27 , 28 ], nanostars [ 29 ], nanobipyramids [ 30 ], nanowires [ 31 , 32 , 33 ], nanoworms (NWs) [ 34 , 35 , 36 ], nanoflowers [ 37 , 38 ], etc. Liao et al focused on gold NWs (AuNWs) and synthesized them with an average diameter of 5 ± 1.5 nm through a one-step synthesis method, as shown in Figure 1 .…”

A Gold Nanoparticle Bouquet held on plasma membrane: An ultrasensitive dark-field imaging approach for Cancer Cell Analysis

“…In this field, it's worth emphasizing that how flexibility to design new-style AuNP-based photothermal reagents for high sensitivity and selectivity of cancer therapy. On the other hand, taken the clinical trials consideration the clinical trials, it is expected that the photothermal emission of Ivyspring International Publisher absorption of long-wave light in the near-infrared (NIR) region can further penetrate the tissue [15,16]. To accomplish this target, AuNPs of varying forms and sizes have been prepared for NIR illumination and attained a good therapeutic effect [17].…”

Enhanced bactericidal activity of azithromycin‐coated silver nanoprisms in comparison to their spherical‐shaped counterparts

“…Amongst different shapes of nanoparticles, such as nanocubes [19], nanoworms [20], nanoshells [21] etc., silver nanoprisms (AgNPrs) have attracted the attention of many researchers due to their unique optical properties [22–25]. The most fascinating feature of AgNPrs is their sharp edges with remarkable optical and electronic properties [22–24, 26–28].…”