CRISPR-Cas13 Diagnostics for Kidney Transplant Rejection
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Solution Overview
Problem
Current diagnostics for organ transplantation, such as PCR and biopsies, are costly, invasive, and time-consuming, leading to delayed diagnosis and increased risk of irreversible allograft injury, especially in resource-limited settings, and there is a need for a cost-effective and rapid point-of-care testing method for opportunistic infections and rejection monitoring.
Innovation Solution
The development of CRISPR-based diagnostic tools using the SHERLOCK methodology, which combines isothermal recombinase polymerase amplification and CRISPR-Cas13 technology for rapid detection of BKV DNA and CXCL9/CXCL10 mRNA in urine, enabling a low-cost, non-invasive, and fast point-of-care test for kidney transplant patients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PCR and biopsy methods are used for organ transplant diagnostics, then diagnostic accuracy is improved, but cost and time consumption increase significantly
Solution Approach 1:
The patent combines isothermal recombinase polymerase amplification (RPA) with CRISPR-Cas13a detection in a single integrated assay system. This merging of amplification and detection functions into one unified platform achieves both high diagnostic accuracy through specific target recognition and rapid results within one hour, eliminating the sequential time consumption of separate PCR and analysis steps.
Solution Approach 2:
The patent replaces the thermal cycling mechanism of traditional PCR with isothermal RPA amplification that operates at constant temperature (37-42°C). This substitution eliminates the need for complex thermal cycler equipment and lengthy heating/cooling cycles, reducing time consumption while maintaining amplification efficiency and diagnostic accuracy through the guide RNA-directed Cas13a cleavage mechanism.
2Measurement precision
If PCR and biopsy methods are used for organ transplant diagnostics, then diagnostic accuracy is improved, but cost increases
Solution Approach 1:
The patent employs disposable, single-use diagnostic cartridges containing pre-loaded reagents for RPA amplification and CRISPR-Cas13a detection. This approach replaces expensive, reusable PCR equipment and consumables with affordable, disposable units that can be manufactured at low cost using standard molecular biology reagents, significantly reducing per-test costs while maintaining high diagnostic accuracy through specific guide RNA-target binding.
Solution Approach 2:
The patent changes the operational temperature parameter from the variable thermal cycling of PCR (requiring 95°C denaturation, 55-65°C annealing, 72°C extension) to a constant low temperature of 37-42°C for RPA amplification. This parameter change eliminates the need for expensive thermal cycler equipment and reduces operational costs, while the CRISPR-Cas13a system maintains high diagnostic accuracy through sequence-specific guide RNA recognition and collateral cleavage activity.
3Measurement precision
If biopsy is used for rejection monitoring, then diagnostic accuracy is improved, but patient comfort and accessibility worsen due to invasive procedure
Solution Approach 1:
The patent extracts the detection function from invasive tissue biopsy and applies it to non-invasive or minimally invasive sample types such as urine, blood, or saliva. The CRISPR-Cas13a system detects rejection biomarkers (e.g., donor-derived cell-free DNA, inflammatory cytokines) directly from these accessible samples, eliminating the need for painful and risky surgical biopsies while maintaining diagnostic accuracy through sensitive target recognition.
Solution Approach 2:
The patent introduces cell-free DNA and cytokine biomarkers as intermediary molecules that mediate between the transplant rejection state and the detection system. These intermediaries can be detected in non-invasive body fluids, serving as surrogate markers for tissue rejection without requiring direct tissue sampling. The CRISPR-Cas13a guide RNAs specifically recognize these intermediary biomarkers, enabling accurate rejection monitoring through comfortable, accessible sampling methods.
4Loss of time
If rapid detection methods are developed for point-of-care testing, then time consumption is reduced, but sensitivity and specificity may worsen
Solution Approach 1:
The patent performs preliminary isothermal RPA amplification of target nucleic acids before CRISPR-Cas13a detection, pre-concentrating the signal from low-abundance targets. This preliminary enrichment action ensures that even trace amounts of viral DNA or rejection biomarkers are amplified to detectable levels, maintaining high sensitivity and specificity in the rapid one-hour point-of-care assay without requiring lengthy concentration steps.
Solution Approach 2:
The patent implements a feedback mechanism through the collateral cleavage activity of Cas13a, where initial specific binding of the guide RNA to the target triggers non-specific RNase activity that amplifies the detection signal. This feedback loop generates a strong, easily detectable signal from minimal target binding events, ensuring high sensitivity and specificity in the rapid assay through signal amplification rather than extended incubation times.
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 allows for sensitive and specific detection of BKV infection and kidney allograft rejection within an hour, reducing healthcare costs and improving early intervention, with potential for broader application in resource-limited settings and beyond transplantation medicine.
Implementation Method 1
a CRISPR component comprising: (i) an effector protein; and (ii) a guide RNA, and/or a polynucleotide encoding a guide RNA, that binds or hybridizes to a corresponding target molecule
Implementation Method 2
a guide RNA, and/or a polynucleotide encoding a guide RNA, that binds or hybridizes to a corresponding target molecule
Data Source
AI summary
Described herein are nucleic acid detection systems, devices, and kits having a CRISPR component comprising an effector protein and a guide RNA, and/or a polynucleotide encoding a guide RNA, that binds or hybridizes to a corresponding target molecule. Also described herein are methods that utilize these nucleic acid systems, devices, and kits.