Small Gold Nanorods with Tunable Absorption for Photothermal Microscopy in Cells

TL;DR

This paper discusses the development of small gold nanorods with tunable absorption properties for enhanced photothermal microscopy in live cells, aiming to improve molecular imaging with better stability and tissue penetration.

Contribution

The authors introduce a method to synthesize small gold nanorods with adjustable absorption, enabling improved photothermal imaging in cellular environments.

Findings

Small gold nanorods exhibit tunable absorption properties.

Enhanced photothermal imaging sensitivity in live cells.

Potential for improved molecular diagnostics in biological tissues.

Abstract

Over the last decade, single-molecule optical microscopy has become the gold-standard approach to decipher complex molecular processes in cellular environments. [1-3] Single-molecule fluorescence microscopy has several advantages such as ease of application, high sensitivity, low invasiveness and versatility due the large number of available fluorescent probes. It bears however some drawbacks related to the poor photostability of organic dye molecules [4] and auto-fluorescent proteins [5-7] and and to the relatively large size of semiconductor nanoparticles in the context of live cell applications. [4,8,9] The overall size of the functional biomarkers is a general issue for any imaging approach because of steric hindrance effects in confined cell regions. Small red-shifted nano-emitters that are highly photostable are not currently available, while they would combine the best physical and optical penetration properties in biological tissues. Although single-molecule absorption microscopy was early used to detect single-molecules [10] at cryogenic temperatures, it is only with the advent of photothermal microscopy [11,12] that practical applications of absorption microscopy were developed in single-molecule research. Photothermal imaging (PhI)