Development of clustered regularly interspaced short palindromic repeats/CRISPR-associated technology for potential clinical applications

Table 1 Features of clustered regularly interspaced short palindromic repeats/CRISPR-associated system

CRISPR type		Specific cleavage	Collateral cleavage	Secondary messenger	CRISPR inhibitors	Ref.
Class 1	I (Cas8)	DNA	Not identified to date	Not identified to date	Yes	[4]
	III (Cas10)	RNA	RNA, ssDNA	cOA	Not identified to date	[6-8]
	IV (Csf1)	Not studied yet	Not studied yet	Not studied yet	Not studied yet	[16]
Class 2	II (Cas9)	DNA	Not identified to date	Not identified to date	Yes	[4,5,16-20]
	V (Cas12, Cas14)	DNA	ssDNA	Not identified to date	Yes	[21-23]
	VI (Cas13)	RNA	RNA	Not identified to date	Not identified to date	[24-26]

CRISPR: Clustered regularly interspaced short palindromic repeats; ssDNA: Single-stranded DNA; cOA: Cyclic oligoadenylate.

Table 2 Clustered regularly interspaced short palindromic repeats-based pathogen nucleic acid detection system

Nucleic acid detection system	Cas	Target DNA	Amplification method	Test method	Time	Sensitivity	Specificity	Ref.
SHERLOCK	Cas13a	Zika virus etc.	RPA	Fluorescence	2-5 h	2 × 10-8 M	High	[26]
SHERLOCKv2	Cas13a, Cas12a, Csm6	Zika virus, Gordon fever virus, yellow fever virus, etc.	RPA	FluorescenceTest strip	0.5-4.0 h	8 × 10-21 M	High	[29]
DETECTR	Cas12a	HPV	RPA	Fluorescence	1 h	10-18 M	High	[30]
STOP	Cas12b	2019-nCoV	LAMP	Fluorescence	1 h	100 copies	High	[31]
CADD	Cas9	HPV	-	Fluorescence	30 min	10-15 M	High	[32]
CARVER	Cas13a	Influenza A	RPA	Test strip	2 h	-	High	[33]
Smartphone testing	Cas13a	2019-nCoV	-	Fluorescence	15-30 min	10-4 M	High	[34]
Tandem nuclease	Cas13a + Csm6	2019-nCoV	-	Fluorescence	20 min	3.1 × 10-5 M	High	[35]

Cas: CRISPR-associated protein; RPA: Recombinase Polymerase Amplification; SHERLOCK: Specific high-sensitivity enzymatic reporter unlocking; STOP: SHERLOCK Testing in One Pot; CADD: CRISPR-Cas9-assisted DNA detection; CARVER: LAMP: Loop-mediated isothermal amplification; 2019-nCoV: 2019 novel coronavirus; HPV: Human papillomavirus.

Table 3 Clustered regularly interspaced short palindromic repeats-based tumor diagnostic system

System	Cas	Tumor type	Sensitivity	Specificity	Ref.
RCH	Cas9	NSCLC	10-15 M	High	[40]
CUT	Cas9	Colorectal cancer	< 0.01%	High	[41]
SHERLOCK	Cas13a	NSCLC	0.1%	High	[26]
SHERLOCKv2	Cas13a, Cas12a, Csm6	NSCLC	8 × 10-21 M	High	[29]
DETECTR	Cas12a	HPV	10-18 M	High	[30]

RCH: RCA-CRISPR-split-HRP; NSCLC: Non-small cell lung cancer; HPV: Human papillomavirus; CUT: CRISPR-mediated Ultrasensitive Detection of Target DNA-PCR; SHERLOCK: Specific high-sensitivity enzymatic reporter unlocking; DETECTR: DNA endonuclease-targeted CRISPR trans reporter.