CRISPR Diagnostics | CRISPR Based Tests I Mechanism I SHERLOCK & DETECTR I Biotech I Molecular Bio

Summary

CRISPR diagnostics use CRISPR’s ability to recognize a specific genetic sequence to detect whether it is present in a sample. Unlike gene editing, diagnostic CRISPR tests do not alter genetic material; they use CRISPR as a programmable detection system.

How the detection mechanism works

• Scientists design a guide RNA to match a genetic sequence associated with a target, such as a virus, bacterium, or cancer-related mutation.
• A CRISPR enzyme carrying the guide RNA scans genetic material in the sample.
• If the enzyme finds the matching target, it binds to it and becomes activated.
• The activated enzyme can then cut nearby reporter molecules, a process described in the video as collateral cleavage.
• The reporters produce a detectable signal when cut, such as fluorescent light. Depending on the test, a device may read the result, or it may appear as a line on a paper strip.
• A signal indicates that the target was detected; no signal indicates that it was not detected.

Typical testing workflow

1. Collect a sample, such as saliva or blood.
2. Extract genetic material—DNA or RNA—from the sample.
3. Amplify the genetic material to make the target easier to detect.
4. Add the CRISPR system programmed for the target.
5. If the target is present, the enzyme activates and cuts the reporter molecules.
6. Read the result using a portable device or paper test strip.

Advantages and comparison with other tests

The video presents CRISPR diagnostics as combining strengths of laboratory and rapid tests:

• Speed: The narrator says results can be available in less than an hour.
• Cost and access: The video states that materials for a test may cost less than $5 in large-scale production, potentially making testing more accessible in clinics, homes, and remote areas.
• Readout flexibility: Results may be detected with a portable reader or a paper strip.
• Comparison: RT-PCR is described as highly sensitive and specific, but slower, more expensive, and dependent on laboratory equipment. Rapid antigen tests are described as convenient and inexpensive, but less sensitive. CRISPR diagnostics are presented as aiming to combine high accuracy with speed and convenience.

Named CRISPR diagnostic platforms

• SHERLOCK uses Cas13 to detect RNA targets.
• DETECTR uses Cas12 to detect DNA targets.

Both platforms use target recognition to trigger a detectable signal.

Potential future uses

The video imagines smartphone-connected home tests, with a phone camera reading results and an app sharing them with a doctor. It also describes possible wearable sensors that could monitor for early signs of infection.

For pandemic response, the narrator suggests that once a new pathogen’s genetic sequence is known, a CRISPR test could potentially be designed quickly and distributed soon afterward.

Speakers and sources featured

• Speaker: An unnamed narrator providing an educational explanation.
• Sources or organizations: No specific researchers or organizations are identified. The narrator refers generally to research groups and discusses SHERLOCK, DETECTR, RT-PCR, and rapid antigen tests.