Silver nanoparticle surface enabled self- assembly of organic dye molecules

Patent metadata

Field	Value
Publication number	US-12455217-B2
Application number	US-202117401985-A
Country	US
Kind code	B2
Filing date	Aug 13, 2021
Priority date	Aug 13, 2020
Publication date	Oct 28, 2025
Grant date	Oct 28, 2025

Abstract

Fluorescence titration of methylene blue, rhodamine B and rhodamine 6G (R6G) by silver nanoparticle (AgNP) all resulted in an initial steep quenching curve followed with a sharp turn and a much flatter quenching curve. At the turn, there are about 200,000 dye molecules per a single AgNP, signifying self-assembly of approximately 36 layers of dye molecules on the surface of the AgNP to form a micelle-like structure. These fluorescence-quenching curves fit to a mathematical model with an exponential term due to molecular self-assembly on a AgNP surface, or “self-assembly shielding effect”, and a Stern-Volmer term (nanoparticle surface enhanced quenching). Such a “super-quenching” by AgNP can only be attributed to “pre-concentration” of the dye molecules on the nanoparticle surface that yields the formation of micelle-like self-assembly, resulting in great fluorescence quenching. Overall, the fluorescence quenching titration reveals three different types of interactions of dye molecules on AgNP surface: 1) self-assembly (methylene blue, rhodamine B and R6G), 2) absorption/tight interaction (tryptamine and fluorescein), and 3) loose interaction (eosin Y). We attribute the formation of micelle-like self-assembly of these three dye molecules on AgNP to their positive charge, possession of nitrogen atoms, and with relatively large and flat aromatic moieties.

First claim

The invention claimed is:

1. A self-assembling nano-particle-based micelle composition, comprising a silver nanoparticle core and a plurality of layers of positively charged aromatic nitrogen-containing compounds wherein the positively charged aromatic nitrogen-containing compounds are selected from the group consisting of Rhodamine B and Methylene Blue.

2. A self-assembling nano-particle-based micelle composition according to claim 1 , wherein the silver nanoparticle is citrate-coated.

3. A self-assembling nano-particle-based micelle composition according to claim 1 , wherein the silver nanoparticle is present in solution at a concentration of about 1 μM or less, and the positively charged aromatic nitrogen-containing compounds are present in solution at a concentration of about 1 μM or less.

Assignees

• Morgan State Univ

Inventors

• Deng Hua
• Yu Hongtao

Classifications

• C09K11/06 Primary

  containing organic luminescent materials · CPC title

• C09K2211/1007

  Non-condensed systems · CPC title

• C09K2211/1018

  Heterocyclic compounds · CPC title

• G01N2001/302

  Stain compositions · CPC title

• C09B62/44

  with the reactive group not directly attached to a heterocyclic ring · CPC title