Near-infrared fluorescence imaging of cancer cells and tumors through specific biosynthesis of silver nanoclusters

Abstract

Human life toll by cancer, one of the highest among most dreaded diseases in advanced societies, could be reduced by implementing evidence-based strategies for its prevention, early diagnosis and assessment of the progress and suitability of therapies by fast and non-invasive methods. In this contribution, a novel strategy is reported for highly sensitive recognition and in vivo imaging of cancer cells taking advantage of their spontaneous ability to generate silver nanoclusters (NCs) with high near-infrared fluorescence emission by intracellular reduction of innocuous silver salts. Both ex vivo experiments comparing cancer cell models to normal cells and in vivo imaging of subcutaneous xenografted tumor (cervical carcinoma model) in nude mice established the validity of this strategy for precise and selective imaging of cells and tumors. Furthermore, it was observed that the spontaneous self-generation of Ag NCs by tumors in their inside led to drastic reduction of their sizes and often to complete remission, thus providing important hope for new therapy strategies based on cheap and readily available agents.

In-situ green synthesis of highly active GSH-capped Pt-Au-Ag-hybrid nanoclusters

“…The binding energy of Au 4f 5/2 and Au 4f 7/2 were located at 87.11 and 83.39 eV. The binding energy of Ag 3d 3/2 and Ag 3d 5/2 emerged at 373.18 and 367.14 eV, which matched previous reports for Pt(0) [24], Au(0) [38], and Ag(0) [39] nanoparticles. The binding energy of S 2p 3/2 at 161.9 eV could be assigned to the binding of the sulfur atom to the hybrid and metal−S charge transfer in the thiol-coated Pt-Au-Ag-hybrid NCs.…”

In situSynthesis of Fluorescent Gold Nanoclusters by Nontumorigenic Microglial Cells

“…The first in situ synthesis of green fluorescent P:AuNCs was demonstrated in tumorigenic cells by Wang et al in 2013 (7). Very recently, the in 4 situ synthesis of protein stabilized silver, zinc, and platinum nanoclusters in tumorigenic cells have also been published (2,8,19). Interestingly, the synthesis of near IR emitting AgNCs was non-spontaneous and necessitated the development of new protocols requiring additional steps for stable cluster formation (8).…”

“…Protein stabilized noble metal nanoclusters (P:NC) present an exciting option as an intracellular fluorescent marker (1)(2)(3)(4)(5)(6)(7)(8). P:NCs are small clusters of atoms ranging from 5 to 25 atoms which are comprised of an Au 0 core surrounded by a shell of Au + atoms that are bound to the stabilizing protein (9)(10)(11).…”

Reversible Size Control of Silver Nanoclusters via Ligand-Exchange

“…≤ 2 nm) noble metal nanoparticles [1][2][3][4] protected with monolayers of organic molecules (typically, thiolates, ─SR, and phosphines, PR 3 ) yields unique size-and structure-dependent optical, [5][6][7] chemical, 8,9 and biological properties. 10 Nanoparticles in this size range exhibit discrete electronic transitions in their optical spectra, akin to molecules, and are often denoted by their molecular formula, rather than their core diameter.…”