Table 1.

Comparison of sensors for DNA detection

Detection method	Strategy	Detection limit	Existing problems
Colorimetric (this work)	AuNP & conjugated polyelectrolyte	1 pM (naked eyes)	Not applicable for colored samples
Colorimetric (28)	AuNP & salt	4.3 nM (naked eyes)	Detect limit not applicable for colored samples
Colorimetric (50)	Enzyme amplification magnetic separation	100 pM (naked eyes)	Multistep process, cumbersome preparation of functionalized gold nanoparticles and magnetic bead. Time-consuming (> 1 day), not applicable for colored samples
Electrochemistry (51)	Electron transfer	10 pM	Dual-labeled oligos. Time-consuming (≈5 hours)
Electrochemistry (52)	Enzyme Amplification & PNA Probe & AgNP	10 fM	Multistep process, stability of enzyme, dual label of DNA, reagent intensive. Time-consuming (≈5 hours)
Fluorescence (35)	Conjugated Polyelectrolyte FRET	2.14 pM	Using expensive and complicated instruments for detection. Time-consuming (≈3 hours)