Designable nanoplasmonic biomarkers for direct microscopy cytopathology diagnostics

Abstract

Direct microscopy interpretation of fineneedle biopsy cytological samples is routinely used by practicing cytopathologists.Adding possibility to identify selective and multiplexed biomarkers on the same samples and with the same microscopy technique can greatly improve diagnostic accuracy. In this article, we propose to use biomarkers based on designable plasmonic nanoparticles (NPs) with unique optical properties and excellent chemical stability that can satisfy the above-mentioned requirements. By finely controlling the size and composition of gold-silver alloy NPs and gold nanorods, the NPs plasmonic resonance properties, such as scattering efficiency and resonance peak spectral position, are adjusted in order to provide reliable identification and chromatic differentiation by conventional direct microscopy. Efficient darkfield NPs imaging is performed by using a novel circular side illumination adaptor that can be easily integrated into any microscopy setup while preserving standard cytopathology visualization method. The efficiency of the proposed technology for fast visual detection and differentiation of three spectrally distinct NP-markers is demonstrated in different working media, thus confirming the potential application in conventional cytology preparations. It is worth emphasizing that the presented technology does not interfere with standard visualization with immunohistochemical staining, but should rather be considered as a second imaging modality to confirm the diagnostics. K E Y W O R D S

Multiplexed Plasmonic Nano-Labeling for Bioimaging of Cytological Stained Samples

“…The other plasmonic NPs (Table 1), including the gold-silver Alloy NPs (50/50 and 10/90 vol. ), were synthesized based on a seeded-growth approach (Turkevich method), and their optical properties match the SI microscopy adaptor [10,16,22,24]. Cytology sample preparation: Two types of cytology samples were prepared by using the same breast cancer cell line (MDA-MB-453).…”

“…The other plasmonic NPs ( Table 1 ), including the gold-silver Alloy NPs (50/50 and 10/90 vol. ), were synthesized based on a seeded-growth approach (Turkevich method), and their optical properties match the SI microscopy adaptor [ 10 , 16 , 22 , 24 ].…”

“…However, these diagnostic approaches still have some disadvantages and limitations, which should be addressed [ 8 ]. The preparation of histo-cytopathological specimens includes treatment with cytological fixatives, and other embedded components that affect the antigenicity of cells, thereby reducing the effectiveness and reliability of immunohistochemistry [ 9 , 10 ]. Although the two-color IHC protocol was developed by labeling two antigens located in different cellular compartments, antigens are usually identified one at a time, making it difficult to confirm the presence of multiple overexpressed receptors in the same cells [ 11 ].…”

“…Existing technology to fine-tune NPs physicochemical properties (e.g., geometry, size, and composition) allows for the generation of a multitude of NPs with spectrally distinguishable absorption/scattering peaks in the visible or near infrared, thereby enabling multispectral imaging and multiplex immunolabeling [ 20 , 21 , 22 ]. Moreover, direct observation and analysis of even single plasmonic NPs can be performed using conventional dark-field or backscattering microscopy, which are readily available in research laboratories [ 10 , 23 ].…”

Formation Pathways of Porous Alloy Nanoparticles through Selective Chemical and Electrochemical Etching

“…To understand the effect of the composition on pore formation and overall structural evolution, we chose two types of AuAg NPs: i) Au‐core and AuAg‐alloy‐shell (Au–AuAg) [ 35,36 ] and ii) uniform AuAg alloy NPs [ 37 ] (see Section S1 in the Supporting Information for the protocol of their synthesis). Furthermore, to test how the NP dealloying is impacted by the Ag dissolution rate, we extended our study to both selective chemical and electrochemical etching.…”