Table 1. Magnetic, SPR and EIS sensors based on magnetic nanoparticles.

Sensor	MP composition	NP size	Bacterial target	Detection limit (cell/mL)	Detection range (cell/mL)	Ref.
MP: superparamagnetic particle; NP: nanoparticle; ND: no data; GMR: giant magnetoresistive; SQUID: superconducting quantum interference device; MRS: magnetic relaxation switching; SPR: surface plasmon resonance; LRSPR: long-range SPR; EIS: electrochemical impedance spectroscopy; L. monocytogenes: Listeria monocytogenes; P. aeruginosa: Pseudomonas aeruginosa; S. enterica: Salmonella enterica; S. enteritidis: Salmonella enteritidis; E. coli: Escherichia coli.
GMR	Streptavidin conjugated MPs	1 µm	ND	104	ND	[41]
SQUID	Biotin conjugated MPs	50 nm	L. monocytogenes	~108	ND	[42]
MRS	Carboxyl group modified Fe3O4 MPs	~10 nm	P. aeruginosa	50	102−106	[43]
MRS	Carboxyl group modified Fe2O3/Fe3O4 MPs	30 nm and 250 nm	S. enterica	102	104−108	[19]
SPR	Carboxyl group modified Fe3O4 MPs	6 nm	S. enteritidis	14	14–1.4×109	[44]
LRSPR	Polysaccharide conjugated MPs	200 nm	E. coli	50	102−107	[23]
EIS	Carboxyl group modified Fe3O4 MPs	2.7 µm	E. coli	102	102−104	[8]