Ultrasmall Au and Ag Nanoclusters for Biomedical Applications: A Review.

Jia Tang,Guanyu Ma,Zhenghua Tang,Liangping Luo,Haihong Shi

doi:10.3389/fbioe.2020.01019

Abstract

Noble metal (e.g., Au, Ag, Pt, Pd, and their alloys) nanoclusters (NCs) have emerged as a new type of functional nanomaterial in nanoscience and nanotechnology. Owing to their unique properties, such as their ultrasmall dimension, enhanced photoluminescence, low toxicity, and excellent biocompatibility, noble metal NCs—especially Au and Ag NCs—have found various applications in biomedical regimes. This review summarizes the recent advances made in employing ultrasmall Au and Ag NCs for biomedical applications, with particular emphasis on bioimaging and biosensing, anti-microbial applications, and tumor targeting and cancer treatment. Challenges, including the shared and specific challenges for Au and Ag NC toward biomedical applications, and future directions are briefly discussed at the end.

Highlights

The last decade has witnessed the great achievement of employing noble metal nanoparticles, with sizes typically between 2 and 100 nm, in biomedical applications (Li et al, 2017; Mohanta et al, 2020; Yang et al, 2020)
When the size of metal NPs shrink below 2 nm, the surface plasmon resonance (SPR) peak disappears and discrete step-like absorption bands can be observed in the optical spectrum
This review summarizes the recent progresses made in engineering Au and Ag NCs for biomedical applications, with particular emphasis placed on bioimaging and biosensing, anti-microbial applications, and tumor targeting and cancer treatment

Summary

INTRODUCTION

The last decade has witnessed the great achievement of employing noble metal nanoparticles, with sizes typically between 2 and 100 nm, in biomedical applications (Li et al, 2017; Mohanta et al, 2020; Yang et al, 2020) Such applications are largely relied on for their optical properties, such as absorption, luminescence, surface scattering, and surface-enhancing capabilities. When the size of metal NPs shrink below 2 nm, the SPR peak disappears and discrete step-like absorption bands can be observed in the optical spectrum Such ultrasmall NPs are called nanoclusters (NCs), and NCs exhibit significantly different physiochemical properties from relatively larger counterparts, such as having larger Stokes shift, enhanced fluorescence, excellent photostability, and so on (Tan and Jin, 2013; Chakraborty and Pradeep, 2017). The challenges, including the shared and specific challenges for Au and Ag NC toward biomedical applications, and future research directions in this emerging and promising field are discussed

For Bioimaging and Biosensing

Tumor Targeting and Cancer Treatment

CHALLENGES AND OUTLOOKS

Findings

AUTHOR CONTRIBUTIONS