# US 2025/0084459 A1 · Expanding the Molecular Processing and Biosensing Capabilities of a Single-Construct Quantum Dot-Based Biosensor By Selectively Controlling Energy Transfer Pathways

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- Number: US 2025/0084459 A1
- Document ID: US20250084459A1
- Status: Published application
- Kind: A1
- Application number: 18/776,176
- Filed: 2024-07-17
- Published: 2025-03-13
- Earliest claimed: 2023-09-12
- Assignees: The Government of the United States of America, as represented by the Secretary of the Navy
- Applicants: The Government of the United States of America, as represented by the Secretary of the Navy
- Inventors: Igor L Medintz; Matthew Chiriboga; Shelby L. Hooe; David A. Hastman; Niko Hildebrandt; Sebastian A. Diaz; Kimihiro Susumu
- Web page: https://patentgrep.com/patent/US20250084459A1

## CPC

- C12Q 1/6818: involving interaction of two or more labels, e.g. resonant energy transfer
- C12Q 1/37: involving peptidase or proteinase
- C12Q: MEASURING OR TESTING PROCESSES INVOLVING ENZYMES, NUCLEIC ACIDS OR MICROORGANISMS (immunoassay G01N33/53); COMPOSITIONS OR TEST PAPERS THEREFOR; PROCESSES OF PREPARING SUCH COMPOSITIONS; CONDITION-RESPONSIVE CONTROL IN MICROBIOLOGICAL OR ENZYMOLOGICAL PROCESSES

## Abstract

An energy transfer platform involves a CdSe/ZnS core-shell quantum dot (QD) scaffold having four additional components: terbium metal chelate, ruthenium(II)-phenanthroline, AlexaFluor 647, and Cy5.5. These are positioned in a self-assembled fashion on the QD surface through the utilization of peptide-PNA and DNA bioconjugate linkers. The modular platform can operate to sense multiple different events or targets simultaneously, including sensing of genetic moieties and enzymatic targets.

## Claims

### Claim 1

A modular energy transfer platform comprising:
a CdSe/ZnS core-shell quantum dot (QD) scaffold having four additional components bound thereto, the additional components comprising terbium, ruthenium, AlexaFluor 647, and Cy5.5, wherein
each of the additional components are bound to the QD scaffold via an arm, each arm comprising a peptide-PNA strand comprising (1) a peptide nucleic acid (PNA) comprising a PNA sequence and (2) a peptide comprising a polyhistidine sequence effective to bind the peptide-PNA strand to the QD; and
the arm comprising ruthenium features the ruthenium conjugated to the PNA sequence via a modified peptide derivative.

### Claim 2 (depends on 1)

The modular energy transfer platform of claim 1 wherein the arm comprising ruthenium features the ruthenium conjugated to the PNA sequence via a modified peptide derivative substituted for an arm comprising ruthenium featuring the ruthenium conjugated to a DNA sequence.

### Claim 3 (depends on 1)

The modular energy transfer platform of claim 1 wherein the CdSe/ZnS core-shell quantum dot (QD) is substituted for a QD that emits at a wavelength and FRET dye acceptors and donors along with electron transfer acceptors selected based on desired results.

### Claim 4 (depends on 1)

A method of preparing a modular energy transfer platform, the method comprising:
heating a mixture of anchor, template, and probe strands under conditions sufficient to denature DNA found within, and allowing them to assemble into arms, and then
without further purification, allowing these arms to bind to a quantum dot to form the modular energy platform of claim 1.

### Claim 5 (depends on 4)

The method of preparing a modular energy transfer platform of claim 4 further comprising the steps of:
assembling components to the quantum dot;
controlling ratios of the components assembled to the quantum dot; and
controlling the relative rate of FRET or electron transfer.

### Claim 6 (depends on 1)

A method of analysis comprising:
contacting a modular energy transfer platform of claim 1 with a sample comprising (1) nucleic acids operable to displace the terbium, AlexaFluor 647, and/or Cy5.5 from the scaffold; and/or (2) a protease operable to separate the ruthenium from the scaffold; and
measuring a change in the optical properties of the scaffold as a result of the contacting.

### Claim 7 (depends on 6)

The method of analysis of claim 6 further comprising:
inserting a target molecule between the QD and the dye, Tb, or Ru; and
detecting a hydrolytic substance.

### Claim 8 (depends on 6)

The method of analysis of claim 6 further comprising:
detecting a complex multistep biological process wherein a protease site on a peptide is phosphorylated or dephosphorylated for cleavage to happen, thus providing an indirect sensor for that activity or coupled activity.