Journal: Chemical Science

Article Title: Controlled high-yield assembly of gold nanoparticles via amide bond formation

doi: 10.1039/d5sc08787b

Figure Lengend Snippet: Optimisation of AuNP assembly via amide bond formation. (a) Selection of amine ligands. Assembly yields (green bar graphs) are compared among the assemblies where AHT- or ABT-functionalised AuNC 93 cores are coupled with COOH-functionalised AuNS 35 satellites in the presence of EDC. AHT affords markedly higher yields than ABT. Representative SEM images are shown, with AuNS 35 satellites false-coloured red for clarity. (b) Selection of carboxyl ligands. Three ligands—MUA, dPEG 4 , and dPEG 12 —were tested. (i) Assembly yields increase substantially when residual dPEG 12 is removed from the dPEG 12 + cit-AuNS 35 solution by centrifugation prior to coupling with NH 2 -AuNC 93 . (ii) Stability comparison showing that PEG-based ligands (dPEG 4 , dPEG 12 ) maintain colloidal stability after two centrifugation cycles, whereas MUA-functionalised AuNS 35 destabilise. (c) Optimisation of EDC concentration. (i) SEM images of AuNC 101 @AuNS 35 assemblies formed with 10–200 eq. of EDC relative to surface carboxyl groups. (ii) Quantification of assembly yields and average satellite number per core as a function of EDC concentration. (iii) Normalised UV-vis spectra of assemblies prepared at different EDC concentrations. Red triangles denote plasmon coupling bands. Grey-filled curves show the LSPR spectra of the individual building blocks (AuNC and AuNS) for comparison. Spectra are vertically offset for clarity. Scale bar: 200 nm.

Article Snippet: The structure of the AuNP building blocks was characterised by TEM (JEM-F200, JEOL, Japan).

Techniques: Selection, Centrifugation, Comparison, Concentration Assay

Journal: Chemical Science

Article Title: Controlled high-yield assembly of gold nanoparticles via amide bond formation

doi: 10.1039/d5sc08787b

Figure Lengend Snippet: Assembly of AuNPs through amide bond formation, showing (a–e) the optical and structural properties of representative core@satellite assemblies and (f–h) the extension of the method to diverse AuNP combinations. (a) TEM images of the individual building blocks: AuNC 93 (top), AuNS 35 (middle), and AuNS 69 (bottom). (b and c) Normalised UV-vis extinction spectra of the nanoassemblies (AuNC 93 @AuNS 35 and AuNS 69 @AuNS 35 , red) compared with their corresponding building blocks (COOH-AuNS 35 , cyan; NH 2 -AuNC 93 and NH 2 -AuNS 69 , green). Red arrows mark the plasmon coupling bands. (d and e) SEM images of AuNC 93 @AuNS 35 and AuNS 69 @AuNS 35 assemblies, highlighting their structural characteristics: high yield ( Y ), 1 : 1 stoichiometry, and predominantly on-top satellite adsorption. Satellites are false-coloured red for clarity. Insets show magnified views of individual assemblies. (f–h) SEM images of assemblies with varied shapes and sizes, demonstrating the generality of the amide-bond assembly strategy. Unlabeled scale bars represent 100 nm.

Article Snippet: The structure of the AuNP building blocks was characterised by TEM (JEM-F200, JEOL, Japan).

Techniques: Adsorption