Plasmonic nanoparticle-based expansion microscopy with surface-enhanced Raman and dark-field spectroscopic imaging

Abstract

Fluorescence-based expansion microscopy (ExM) is a new technique which can yield nanoscale resolution of biological specimen on a conventional fluorescence microscope through physical sample expansion up to 20 times its original dimensions while preserving structural information. It however inherits known issues of fluorescence microscopy such as photostability and multiplexing capabilities, as well as an ExM-specific issue in signal intensity reduction due to a dilution effect after expansion. To address these issues, we propose using antigen-targeting plasmonic nanoparticle labels which can be imaged using surface-enhanced Raman scattering spectroscopy (SERS) and dark-field spectroscopy. We demonstrate that the nanoparticles enable multimodal imaging: bright-field, dark-field and SERS, with excellent photostability, contrast enhancement and brightness.

Expansion microscopy: principles and uses in biological research

“…This family of protocols has become rapidly utilized for the nanoscale imaging of protein identity and location in the following contexts in just the last year: examining larval zebrafish brain synaptic connections and nuclear-cytoskeletal organization 16 , imaging glial and gap junction organization in human brain tissue from epilepsy patients 24 , imaging synaptic proteins to characterize novel connections in mouse striatal brain circuitry (Fig. 4C) 25 , mapping the organization of kinesins relative to cytoskeletal proteins at defined points in the cell cycle in cultured cells 26 , visualization of melatonin receptors in purified mitochondria from mouse brain 27 , imaging of the Drosophila synaptonemal complex that helps chromosomes segregate during meiosis 28 , segmenting neurons in the mouse brain labeled with brainbow reagents 29 , visualizing key proteins at active zones of Drosophila synapses 30 , analysis of proteins indicative of a novel glial cell type in a species of planaria 31 , visualization of cytoskeletal filaments in the parasite Giardia 32 , the use of nanoparticles to perform surface-enhance Raman spectroscopy imaging of proteins in mouse brain 33 , and the analysis of sorting tubules in vasculature of the mouse brain 34 , amongst ongoing publication activity.…”

Ultra-bright Raman dots for multiplexed optical imaging

“…Furthermore, SERS signal largely depends on the generation of hotspots, which is difficult to precisely control. Hence, despite the recent advance, immune-SERS has seldom achieved quantitative staining in practice 15 – 17 .…”

Gold Nano-Particle Based Localized Plasmon Resonance Biosensors

“…Çap büyüdükçe, bu küreler daha fazla ışık saçar. Bu yüzden, çapı 40-50 nm den büyük olan altın nanoküreler sıklıkla karanlık alan mikroskopi tekniğinde biyogörüntüleme etiketi olarak kullanılırlar (Artur, C. G. et al 2018). Altın nano-çubuklar (AuNÇ) diğer altın nanoparçacıklar ile kıyaslandığında hacmine göre ışık ile etkileşecek geniş yüzeyleri olmasından dolayı araştırmacılar tarafından özel ilgi görür.…”