Nanocrescent SERS Probe for Protease Activity Detection

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Solution Overview

Problem

Current methods for detecting proteolytically active prostate-specific antigen (PSA) in prostate cancer diagnosis face challenges due to high false positive rates, limited sensitivity, and the need for large sample volumes, especially in detecting proteolytic activity in small volumes like seminal fluid or biopsy samples.

Innovation Solution

A nanocrescent surface-enhanced Raman scattering (SERS) probe with a peptide-conjugate design is used, allowing for the detection of proteolytic activity in extremely small volumes with nanomolar sensitivity, utilizing a peptide substrate specifically cleaved by PSA, enabling detection of proteolytically active PSA at the single molecule level.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional detection methods are used to detect proteolytically active PSA, then detection can be performed with standard equipment and procedures, but the sensitivity is insufficient and large sample volumes are required

Engineering Contradiction:

Improvedetection sensitivityVSAvoidsample volume required

Core Design Contradiction:

Measurement precisionVSQuantity of substance

Solution Approach 1:

The invention changes the detection parameter from conventional immunostaining to surface-enhanced Raman scattering (SERS), which provides significantly higher sensitivity. The SERS technique enables detection at nanomolar concentrations in femtoliter volumes, resolving the contradiction between detection sensitivity and sample volume requirements

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention introduces peptide substrates as intermediaries that specifically interact with proteolytically active PSA. These peptides serve as mediators between the enzyme and the SERS detection system, enabling selective detection of active protease forms with high sensitivity in minimal sample volumes

Inventive Principle:

Principle #24Intermediary (Mediator)

2Loss of information

If conventional immunostaining methods are used, then the presence of PSA can be detected, but the proteolytic activity of PSA cannot be revealed

Engineering Contradiction:

Improveproteolytic activity informationVSAvoiddetection method complexity

Core Design Contradiction:

Loss of informationVSDevice complexity

Solution Approach 1:

The invention uses peptide substrates as intermediaries that specifically interact with proteolytically active PSA. These peptides serve as mediators between the enzyme and the SERS detection system, enabling selective detection of active protease forms with high sensitivity in minimal sample volumes

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention employs Raman scattering signal changes as a detectable indicator of proteolytic activity. The SERS signal provides a measurable output that reflects the cleavage of peptide substrates by active PSA, preserving information about proteolytic activity while maintaining relatively simple detection procedures

Inventive Principle:

Principle #32Color changes

3Reliability

If plasma PSA concentration measurement is used for diagnosis, then screening can be performed, but the false positive rate is high and cannot differentiate prostate cancer from benign prostatic hyperplasia

Engineering Contradiction:

Improvediagnostic accuracyVSAvoidproteolytic activity discrimination

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the detection parameter from total PSA concentration to proteolytic activity measurement using SERS. This parameter change enables differentiation between malignant and benign conditions by detecting the functional activity of PSA rather than just its presence, thereby improving diagnostic reliability

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables the detection of proteolytically active PSA in femtoliter volumes with high sensitivity, facilitating early cancer screening and clinical applications by providing real-time monitoring of proteolytic activity, which is not feasible with conventional techniques.

Implementation Method 1

Methodology Applied

Scientific EffectSurface-enhanced Raman scattering:

Implementation Method 2

utilizing a peptide substrate specifically cleaved by PSA, enabling detection of proteolytically active PSA at the single molecule level

Methodology Applied

Scientific EffectProteolytic hydrolysis: Hydrolysis

Data Source

PatentUS9145575B2Detection of protease and protease activity using a single nanocrescent SERS probe

Publication Date: 2015.09.29 RGT UNIV OF CALIFORNIA

AI summary

This invention pertains to the in vitro detection of proteases using a single peptide-conjugate nanocrescent surface enhanced Raman scattering (SERS) probes with at least nanomolar sensitivity. The probe enables detection of proteolytic activity in extremely small volume and at low concentration. In certain embodiments the probes comprise an indicator for the detection of an active protease, where the indicator comprises a nanocrescent attached to a peptide, where said peptide comprises a recognition site for the protease and a Raman tag attached to the peptide.