Table 2.

AuNP-based colorimetric detection based on non-crosslinking aggregation mechanism

Types	Examples	Target of nucleic acids	Shape of AuNPs	Functionalization	Linear Range	LOD	Size of AuNPs	Ref
Bacteria	E. coli	unamplified genomic DNA	spherical	Thiolated DNA probe	215-27 ng	54 ng	20 nm	[131]
	Salmonella spp	Amplified by NASBA	_	Thiolated probe-AuNPs	100-0.5×104 CFUs/mL	5 CFUs	17-23 nm	[137]
	Salmonella typhimurium DT104	mAb-AuNPs	“Popcorn” shaped	mAb-AuNPs	NR	103 CFU/g	30 nm	[138]
Viruses	Dengue virus (DENV)	genomic RNA	-	DDZ-AuNP	1×101-1×106 TCID50 units	1×101 TCID50 units	15 nm	[139]
	Shrimp Taura syndrome virus (TSV)	RT LAMP Products	spherical	Thiolated-TSV oligonucleotide- AuNPs	100 pg–1 fg	1 pg total RNA	10-20 nm	[140]
Cancer biomarkerss	Breast cancer	-	spherical	peptide substrate	0-0.2 μg/mL	0.05 μg/mL	20 nm	[133]
Metal Ions	Hg2+	-	spherical	Ds-DNA	. 25 nM to 1μM,	0.4 nM	12 nm	[141]
	Pb2+	-	Anisotropic AuNPs and spherical AuNPs	DTT-AuNPs	1-1000 nM	∼9 nM	∼47nm	[142]
Fungus	Paracoccidioides brasiliensis	complementary DNA (cDNA)	spherical	Thiolated probe-AuNPs	NR	20 ng/μL−1	23 nm	[143]
Others	SNPs and DNA mutations	complementary DNA	Nanospheres nanorods, nanotriangles	ssDNA- nanoparticles	NR	NR	AuNS: 40 (d) nm, AuNR: 20 (d)×42 nm, AuNR: 15 (d)×45 nm, AuNR: 13 (d)×51 nm, AuNT: 20 (th)×50nm	[134]
	Nitrite	-	nanorods	4-Amino thiophenol-AuNPs (4-ATP)	0.25-5 ppm	<1 ppm	NR	[144]