Table 2.

Summary of single-molecule biosensors for quantitative analysis of tumor biomarkers.

Target	Combined Amplification Strategy	Assay Time	Linear Range	LOD	Real Sample	Ref.
DNA	no	10 min	1 aM–1 fM	5.00 aM	vaginal secretions; MRSA-spiked milk samples	[26]
Retroviral DNA	no	70 min	100 aM–1 nM	66.1 aM, 82.8 aM	HuT-78 cells; U266B1 cells	[22]
SNP	T7 transcription	1 h	0.1 aM–100 pM	0.0724 × 10 aM; 0.0372 × 10 aM	PANC-1 cells; HCT-116 cells; HL-7702 cells; H358 cells; HLF-1 cells; and A549 cells	[59]
DNA methylation	T7 transcription	4.5 h	1 fM–10 nM	337 aM	A549 cells; HepG2 cells; HT-29 cells; HBE cells; H358 cell; breast cancer patient tissue; healthy individual tissue.	[65]
6mdA-DNA; 4mdC-DNA	TMSD	1 h	10 fM–100 nM	9.80 fM; 9.97 fM	HepG2 cells; E. coli plasmid cloning vector (pUC19)	[71]
8-oxo-7, 8-dihydroguanine		70 min	0.5 aM–5 pM	2.45 aM	A549 cells; HeLa cells; HL-7702 cells	[81]
lncRNA	PER; SDA	40 min	100 aM–1 nM	65.25 aM	MCF-7 cells; HeLa cells; A549 cells; HBE cells; breast cancer patient tissues; healthy individual tissues	[102]
MALAT1; HOTAIR	No	1 h	0.1 aM–1 pM	0.10 aM; 0.031 aM	SW480 cells; MCF-7 cells; A549 cells; HBE cells	[89]
microRNA	No	~3 h	1 fM–100 pM	1.12 fM	Serum	[100]
microRNA	PER		1 fM–100 pM	0.45 fM	H460 cells; H292 cells; H358 cells; A549 cells; and H1975 cells; NSCLC patient tissue and healthy individual tissue	[101]
Human telomerase RNA	No	1 h	10 fM–1 nM	2.10 fM	MCF-7 cells; HL-7702 cells; A549 cells; HeLa cells; breast cancer patient tissue; healthy individual tissue	[106]
piRNA	Loop connection	~5 h	1 fM–10 nM	0.104 fM	MCF-7 cells; A549 cells; HepG2 cells; HeLa cells; HCT-116 cells; breast cancer patient tissue; healthy individual tissue	[111]
circRNAs	EXPAR, RCA	~3 h	100 aM–10 pM	41.3 aM	MCF-7 cells; HepG2 cells; HeLa cells; HL-7702 cells; A549 cells; breast cancer patient tissue; healthy individual tissue	[120]
UDG	SDA	~2.5 h	0.0005–0.5 U/mL	0.00029 U/mL	HeLa cells; HL-7702 cells	[138]
hSMUG1; hAAG	SP-SDA	~4 h	1.00 × 10−9–0.02 U/μL	8.14 × 10−10 U/μL; 4.50 × 10−9 U/μL	A549 cells; HEK-293 cells; HeLa cells	[128]
FTO	RCA	~5 h	1 fM–1 nM	0.596 fM	MDA-MB-231 cells; MCF-10A cells; MCF-7 cells; A549 cells; HeLa cells; breast cancer patient tissue; healthy individual tissue	[121]
APOBEC3A	ERA	~3 h	1 fM–50 pM	0.855 aM	A549 cells; HEK-293 cells; HeLa cells; MCF-7 cells	[144]
telomerase	EDC	100 min	no	no	MCF-7 cells; HeLa cells; HL-7702 cells A549 cells;	[145]
ALP	HCR	~2.5 h	1 × 10−5–1 × 10−2 U/mL	2.61× 10−6 U/mL	HeLa cells; MCF-7 cells; HEK cells; clinical serum samples	[156]
caspase-8; caspase-9	Exo III-mediated amplification	~2.5 h	2.50 × 10−6 –2.50 × 10−3 U/μL	2.08 × 10−6 U/μL; 1.71 × 10−6 U/μL	HeLa cells; MCF-7 cells; Jurkat cells	[166]
FEN1	RCA	2.5 h	0–0.5 U/μL	2.24 × 10−5 U/μL	A549 cells; HeLa cells; MCF-7 cells; HepG2 cells; HL-7702 cells; HEK-293 cells; breast cancer patient tissue; healthy individual tissue	[173]