Table 5.

A summary of the studies relevant to the evaluation of electrochemical impedance spectroscopy for assessment of bone quality, osseointegration, and infection

Assessment	References	Experimental system	Electrode configuration	Material	Duration	Primary result
Bone quality	Schaur et al. [117]	Ex vivo calf femur	2 electrode	Not specified	N/A	Position dependent change in impedance based on tissue type
	Teichmann et al. [125]	Ex vivo calf femur	2 electrode	Gold	N/A	Detect differences in bone quality during craniotomy
	Balmer et al. [126]	In vivo sheep model	2 electrode	304 stainless steel	In situ	Distance and bone quality between electrodes effects impedance measurement
	Collins et al. [127]	In vivo canine model	3 electrode	Titanium cathode	12 weeks	Cathodic stimulation did not increase impedance around the cathode
	Gupta et al. [128]	In vivo human trial	2 electrode	Steel ex fix pins	8 weeks	Mean increase in impedance increase with healing time, sharp increase with union
	Lin et al. [129]	In vivo mouse model	2 electrode	Gold and platinum interdigitated electrode array	0–28 days and 0–26 days	Measure time course of nonunion fracture healing with implantable microdevice
	Kozhevnikov et al. [130]	In vivo rabbit model	2 electrode	Ag/AgCl	12 weeks	EIS monitored the healing of bone CSD over 12 weeks with bone scaffold treatment
Osseointegration	Clemente et al. [124]	Human in vivo trial	3 electrode	Titanium (working electrode), silver (reference electrode)	90 days	Osseointegration corresponds to an increase in impedance, while clinical complications can cause a decrease in impedance during the healing process
	Fox et al. [131]	In vivo baboon tibia model	3 electrode	Titanium (working electrode), silver (reference electrode)	1 h	No short term changes in impedance during implantation
	Cosoli et al. [132]	In vivo human dental implant	2 electrode	Titanium implant, stainless steel electrode	In situ	Determine difference between healthy, inflamed, and infected dental implants with EIS
	Duan et al. [133]	In vivo cat model	2 electrode	Platinum band electrode	60 days	Impedance increase with 6 month implantation time
	Arpaia et al. [134]	Ex vivo cow femur	2 electrode	Titanium screw electrodes	N/A	Number of screw cycles decreased bone/electrode contact, which decreased impedance
Infection	Farrow et al. [138]	In vitro simulated wound fluid	2 electrode	Ag/AgCl	16 h	Impedance normalization is a useful technique for monitoring bacterial attachment
	Ward et al. [136]	In vitro simulated wound fluid	2 electrode	Screen printed carbon	24 h	Normalized phase angle can determine presence of P. aeruginosa, and distinguish between mucoid and non-mucoid strains
	Kim et al. [140]	In vitro simulated wound fluid	2 electrode	Gold interdigitated electrode array	1 h	Bacterial attachment decreased capacitance in interdigitated electrode array; single frequency can be used in real time
	Paredes et al. [141]	96 well plate	2 electrode	Gold interdigitated electrode array	24 h	Biofilm formation causes 35% increase in resistance after a few hours
	Paredes et al. [142]	In vitro venous catheter phantom	2 electrode	Gold interdigitated electrode array	48 h	55% maximum change in impedance parameters after 10 h
	Hoyos-Nogués et al. [146]	In vitro	2 electrode	Antimicrobial peptide functionalized interdigitated electrode array	5 h	Linear increase in resistance to S. sanguinis in artificial saliva
	Ahmed et al. [147]	In vitro	2 electrode	Antibody functionalized gold interdigitated electrode array	30 min	Sensitive detection of S. pyogenes