TABLE 2.

Binding types and their effect on the conjugate quality and overall sensitivity of LFIA.

Type of interaction	Particle	Effect	Target	LOD	References
Electrostatic interaction	Gold nanoparticle	High rate of bound antibody, but poor orientation	17β-estradiol	500 ng/ml	Oliveira et al. (2019)
Covalent binding	Gold nanoparticle	Lower rate o bound antibody, with good orientation	17β-estradiol	200 ng/ml
Physical adsorption	Gold nanoparticle	Not available	Erwinia amylovora	104 CFU/ml	Razo et al. (2021)
Physical adsorption	Au core—Pt shell nanoparticle	Not available	Erwinia amylovora	103 CFU/ml
Covalent binding	Latex nanoparticle	Not available	Erwinia amylovora	104 CFU/ml
Covalent binding	Magnetic nanoparticle	Not available	Erwinia amylovora	105 CFU/ml
Streptavidin-biotin coupling	Gold nanoparticle	Increased sensitivity for the larger particles (35–50 nm)	Escherichia coli	101 CFU/ml	You et al. (2020)
			Legionella pneumophila
Physical adsorption (nanobodies)	Gold nanoparticle	Salt induced aggregation	Not available	Not available	Goossens et al. (2017)
Physical adsorption	Carbon nanoparticle	Stable conjugates	Influenza A	3.5 × 102 TCID50 mL−1	Wiriyachaiporn et al. (2017)
Covalent binding	Gold nanoparticle	Au-S bound	Staphylococcal enterotoxin A	5 ng/ml	Ben Haddada et al. (2017)
Covalent binding	Gold nanoparticle	Bound between surface alkyne and azido modified proteins	Not available	Not available	Finetti et al. (2016)
Physical adsorption	Carbon nanoparticle	Not available	β–lactams	1–30 ng/ml for most antibiotics and 100 ng/ml cephalexin	Zhang X. et al. (2020)
Covalent binding	Europium III chelate nanoparticle	The binding of the protein did not affect the optical properties	Cystatin C	24,54 ng/ml	Bian et al. (2022)
Covalent binding	Latex microparticles	Not available	Bisphenol A	10 ng/ml	Raysyan and Schneider, (2021)