Salt-mediated, plasmonic field-field/field-lattice coupling-enhanced NIR-II photodynamic therapy using core-gap-shell gold nanopeanuts. Issue 6 (9th May 2022)

• Record Type: Journal Article
• Authors: Kuthala, Naresh; Shanmugam, Munusamy; Kong, Xiangyi; Chiang, Chi-Shiun; Hwang, Kuo Chu
• Is Part Of: Nanoscale horizons. Volume 7:Issue 6(2022)
• Page Start: 589
• Page End: 606
• Publication Date: 2022-05-09
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/d1nh00631b
• Languages: English
• ISSNs: 2055-6756

Abstract

Abstract : It is demonstrated that filling salt in the nanogaps in core-gap-shell Au@gap@AuAg nanopeanuts can enhance their extinction coefficient in the 1000–1300 nm NIR-II region, singlet O2 sensitization QY, and NIR-II PDT efficacy for destroying tumors. Abstract : Plasmonic field-field coupling-induced enhancement of the optical properties of dye molecules in the nanogaps among metal nanoparticle clusters and thin films has attracted significant attention especially in disease-related theranostic applications. However, it is very challenging to synthesize plasmonic core-gap-shell nanostructures with a well-controlled nanogap, uniform shape, and distances to maximize the plasmonic field-field coupling between the core and the shell. Herein, we synthesized Au@gap@AuAg nanopeanut-shaped core-gap-shell nanostructures (Au NPN) and tuned their optical absorption from near-infrared region-I (NIR-I) to near-infrared region-II (NIR-II) by filling their nanogap with a high dielectric NaCl(aq) aqueous solution, which led to a dramatic redshift in the plasmonic absorption band by 320 nm from 660 to 980 nm and a 12.6-fold increase (at 1064 nm) in the extinction coefficient in the NIR region (1000–1300 nm). Upon filling the nanogap with NaCl(aq) aqueous solution, the Au NPN6.5(NaCl) ( i.e., ∼6.5 nm nanogap)-mediated NIR-II photodynamic therapy effect was dramatically enhanced, resulting in a much longer average lifespan of >55 days for the mice bearing a murine colon tumor and treated with Au NPN6.5(NaCl) plus 1064 nm light irradiation compared to the mice treated with Au NPN6.5 + 1064 nm light irradiation (without nanogap filled with dielectric NaCl(aq), 40 d) and the doxorubicin-treated group (23 d). This study demonstrates a simple but effective method to tune and maximize the plasmonic field-field coupling between the metal shell and metal core of core-gap-shell nanostructures, the plasmonic field-lattice interactions, and biomedical applications for the treatment of tumors. Overall, our work presents a new way to enhance/maximize the plasmonic field-field and field-lattice coupling, and thus the performance/sensitivities in nanogap-based bioimaging, sensing, and theranostic nanomaterials and devices.