Pyruvate Hyperpolarization via SABRE Temperature Cycling
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Solution Overview
Problem
Current methods for hyperpolarizing pyruvate, such as dynamic nuclear polarization (DNP), are limited by high cost, long preparation times, and instrument complexity, while alternative methods like parahydrogen-induced polarization (PHIP) and signal amplification by reversible exchange (SABRE) have not achieved sufficient polarization levels for real-time MRI imaging of metabolic changes in diseases like cancer.
Innovation Solution
A temperature cycling method using SABRE with parahydrogen to modulate substrate and hydride exchange rates, achieving polarization levels greater than 10% in cryogen-free conditions, suitable for in vivo metabolic imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dynamic nuclear polarization (DNP) is used to hyperpolarize pyruvate, then high polarization levels (~60%) are achieved, but the cost is high, preparation time is long, and instrument complexity increases
Solution Approach 1:
The patent extracts the essential function of hyperpolarization from the complex DNP system and implements it through a simplified SABRE approach using parahydrogen and an iridium catalyst, eliminating the need for cryogenic cooling and high-power microwaves while achieving sufficient polarization levels for metabolic imaging
Solution Approach 2:
The patent employs a cost-effective iridium-based SABRE catalyst system that can be used at room temperature with standard NMR equipment, replacing expensive cryogenic infrastructure. The catalyst system is designed for single-use hyperpolarization experiments, eliminating the need for maintenance of complex DNP instrumentation
2Device complexity
If SABRE method is used for pyruvate hyperpolarization, then instrument complexity is reduced, but polarization levels (1.7%) are insufficient for in vivo imaging
Solution Approach 1:
The patent dynamically optimizes the SABRE hyperpolarization process by systematically varying key parameters including iridium catalyst concentration (0.1-10 mM), pyruvate concentration (10-100 mM), parahydrogen pressure (1-100 atm), and temperature (20-100°C) to achieve maximum polarization transfer efficiency and achieve >10% polarization levels
Solution Approach 2:
The patent changes critical reaction parameters from the conventional SABRE setup, specifically optimizing the ratio of pyruvate to catalyst, adjusting parahydrogen flow rates and pressure, and controlling reaction temperature to maximize the polarization transfer from parahydrogen to pyruvate, achieving >10% polarization levels necessary for in vivo imaging
3Manufacturing precision
If dDNP method is used for pyruvate preparation, then high polarization is achieved, but preparation time is long (~30 min) and cost is prohibitive (>2 million)
Solution Approach 1:
The patent replaces the mechanical cryogenic cooling system and high-power microwave generation required in dDNP with a chemical hyperpolarization approach using parahydrogen and an iridium catalyst that operates at room temperature, dramatically reducing both equipment cost and preparation time to under 10 minutes
Solution Approach 2:
The patent performs preliminary optimization of the SABRE reaction conditions including catalyst pre-preparation, substrate purification, and parameter standardization to enable rapid hyperpolarization experiments that can be completed in under 10 minutes, making the technique suitable for clinical translation
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
Enables rapid and cost-effective hyperpolarization of pyruvate and related molecules, allowing for real-time metabolic imaging using low-cost MRI systems, suitable for early cancer diagnosis and other metabolic disorders.
Implementation Method 1
SABRE is a different parahydrogen-based process that uses reversible interactions between p-H2 derived hydrides and target substrates on an organometallic catalyst—in synchronization with substrate exchange on the catalyst—to transfer spin order from p-H2 to a target substrate
Implementation Method 2
A temperature cycling method using SABRE with parahydrogen to modulate substrate and hydride exchange rates, achieving polarization levels greater than 10% in cryogen-free conditions
Data Source
AI summary
Hyperpolarized target molecules and contrast agents comprising the same, methods of making the same, and methods of imaging using same are provided. In a further aspect, imaging performed using the hyperpolarized target molecules and contrast agent can enable real time monitoring and diagnosis of diseases including various cancers and metabolic disorders. The methods are cryogen-free and inexpensive and can be performed in a short time.