larger particles with diameter i.e. 60–70 nm [58] are usually unstable therefore have
limited applications.
In current literature, gold NPs have been extensively used for detection of water
pollutants, especially, toxic metal ions and pathogenic micro-organisms in contaminated water as given in Table 1. ICS based nanosensors utilizing DNA probes
and gold NPs are developed for the detection of mercuric ions [59–64]. In the
working principle of this nanosensor, DNA was designed in such a way that initially thymine-thymine base mismatch were there, and due to the specific interactions of mercury with the thymine bases, mercury stabilize these mismatches and
thus mercury-thymine complex is formed [65].
4.2 Quantum Dots (QDs)
These are semiconductor nanocrystals having size in the ranges of 2–10 nm. They
are used as fluorescent labels for performing better sensitivity of lateral flow assays.
QDs possess properties such as broad UV excitation band, high quantum yield,
Table 1 Gold NPs based ICA
Analyte
Biorecognition
element
ICA type
Linear range Detection
limit
Reference
Hg
2+
Antibody
Sandwich
0.1–
1000 ppb
0.1 ppb
[48]
Hg
2+
Antibody
Competitive 8–14.8 nM
5.2 nM
[49]
Cd
2+
Antibody
Competitive 6–11.5 nM
4.4 nM
Pb
2+
Antibody
Competitive 6–11.5 nM
4.4 nM
Influenza A
virus
Antibody
Sandwich
102–107
copies
102 copies [50]
E. coli O157:
H7
Aptamer
Sandwich
0–108 cfu/
mL
10 cfu/mL
[51]
Ochratoxin A
Aptamer
Sandwich
0.18 ng/mL
0–25 ng/
mL
[52]
Brevetoxins
Antibody
Sandwich
10–4000 ng/
mL
20 ng/mL
[53]
Streptococcus
suis
Antibody
Sandwich
103–
106 cfu/mL
104 cfu/mL [54]
Clenbuterol
Antibody
Competitive 0–10 ng/mL 0.08 ng/mL [55]
Triazophos
Antibody
Competitive –
4 ng/mL
[56]
Vibrio cholerae
O1
Antibody
Sandwich
–
–
108 cfu/mL
107 cfu/mL
[57]
Immunochromatographic Strip Based Sensor for the Detection …
243
limited applications.
In current literature, gold NPs have been extensively used for detection of water
pollutants, especially, toxic metal ions and pathogenic micro-organisms in contaminated water as given in Table 1. ICS based nanosensors utilizing DNA probes
and gold NPs are developed for the detection of mercuric ions [59–64]. In the
working principle of this nanosensor, DNA was designed in such a way that initially thymine-thymine base mismatch were there, and due to the specific interactions of mercury with the thymine bases, mercury stabilize these mismatches and
thus mercury-thymine complex is formed [65].
4.2 Quantum Dots (QDs)
These are semiconductor nanocrystals having size in the ranges of 2–10 nm. They
are used as fluorescent labels for performing better sensitivity of lateral flow assays.
QDs possess properties such as broad UV excitation band, high quantum yield,
Table 1 Gold NPs based ICA
Analyte
Biorecognition
element
ICA type
Linear range Detection
limit
Reference
Hg
2+
Antibody
Sandwich
0.1–
1000 ppb
0.1 ppb
[48]
Hg
2+
Antibody
Competitive 8–14.8 nM
5.2 nM
[49]
Cd
2+
Antibody
Competitive 6–11.5 nM
4.4 nM
Pb
2+
Antibody
Competitive 6–11.5 nM
4.4 nM
Influenza A
virus
Antibody
Sandwich
102–107
copies
102 copies [50]
E. coli O157:
H7
Aptamer
Sandwich
0–108 cfu/
mL
10 cfu/mL
[51]
Ochratoxin A
Aptamer
Sandwich
0.18 ng/mL
0–25 ng/
mL
[52]
Brevetoxins
Antibody
Sandwich
10–4000 ng/
mL
20 ng/mL
[53]
Streptococcus
suis
Antibody
Sandwich
103–
106 cfu/mL
104 cfu/mL [54]
Clenbuterol
Antibody
Competitive 0–10 ng/mL 0.08 ng/mL [55]
Triazophos
Antibody
Competitive –
4 ng/mL
[56]
Vibrio cholerae
O1
Antibody
Sandwich
–
–
108 cfu/mL
107 cfu/mL
[57]
Immunochromatographic Strip Based Sensor for the Detection …
243