Chiral Plasmonic Nanochains via the Self-Assembly of Gold Nanorods and Helical Glutathione Oligomers Facilitated by Cetyltrimethylammonium Bromide Micelles.
Gold nanorods are excellent anisotropic building blocks for plasmonic chiral nanostructures. The near-infrared plasmonic band of nanorods makes them highly desirable for biomedical applications such as chiral bioimaging and sensing, in which a strong circular dichroism (CD) signal is required. Chiral assemblies of gold nanorods induced by self-associating peptides are especially attractive for this purpose as they exhibit plasmonic-enhanced chiroptical activity. Here, we showed that the presence of cetyltrimethylammonium bromide (CTAB) micelles in a gold nanorod solution promoted the self-association of l-/d-glutathione (GSH) and significantly enhanced the chirality of the resulting plasmonic nanochains. Chiroptical signals for the ensemble in the presence of CTAB micelles were 20 times greater than those obtained below the critical micelle concentration of CTAB. The strong optical activity was attributed to the formation of helical GSH oligomers in the hydrophobic core of the CTAB micelles. The helical GSH oligomers led the nanorods to assemble in a chiral, end-to-end crossed fashion. The CD signal intensities were also proportional to the fraction of nanorods in the nanochains. In addition, finite-difference time-domain simulations agreed well with the experimental extinction and CD spectra. Our work demonstrated a substantial effect from the CTAB micelles on gold nanoparticle assemblies induced by biomolecules and showed the importance of size matching between the inorganic nanobuilding blocks and the chiral molecular templates (i.e., the GSH oligomers in the present case) in order to attain strong chiroptical activities.
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, P.R. China.
Jun
J
Lu
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, P.R. China.
Yi-Xin
YX
Chang
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, P.R. China.
Ning-Ning
NN
Zhang
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, P.R. China.
Ying
Y
Wei
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, P.R. China.
Ai-Ju
AJ
Li
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, P.R. China.
Jia
J
Tai
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, P.R. China.
Yao
Y
Xue
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, P.R. China.
Zhao-Yi
ZY
Wang
Department of Chemistry and Biochemistry and Department of Materials Science and Engineering, University of Maryland , College Park, Maryland 20742, United States.
Yang
Y
Yang
School of Life Sciences, Jilin University , Changchun 130012, P.R. China.
Li
L
Zhao
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, P.R. China.|State Key Laboratory of Supramolecular Structure and Materials, Institute of Theoretical Chemistry, Jilin University , Changchun 130023, P.R. China.
Zhong-Yuan
ZY
Lu
State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University , Changchun 130012, P.R. China.
Kun
0000-0003-2940-9814
K
Liu
cetyltrimethylammonium bromide; chirality; glutathione oligomer; gold nanorods; plasmonic