Table 3.

Comparison of different physical technologies used for drug delivery.

Physical energy	Electric field	Magnetic field	Temperature	Ultrasound	Light
Poration	Electroporation	MNP	Thermoporation	Sonoporation	Optoporation
Limitations	Narrow range of clinically safe electric field parameters (refer to current standards for safety levels)	Limited drug carrying capacity of magnetic field due to their biodistribution	Low penetration depth (since only applied topically so far)	Sonoporation devices have poor calibration in terms of the amount of ultrasound energy emitted	Limited time duration between optoporation and drug delivery
		Narrow range of magnetic field
Disadvantages	Irreversible electroporation, cell death with high fields	Aggregation of MNP can cause embolization	Excess heat can induce thermohemolysis	Shear forces may induce rupture of cells	Excessive inflammation, postinflammatory, and hyperpigmentation
	Electromechanical coupling effect	Cytotoxicity increases with the increased concentrations of MNP	Relies on electric field to heat up the filaments; therefore, the disadvantages of electric field applies	Temperature increases as a function of frequency and eventually disrupts cells	Laser usage and ultrastructural changes in epidermis
Advantages	Inexpensive and simple to perform	Noninvasive nature of the magnetic field	Noninvasive nature of low heat compared to EP	Less invasive compared to EP	Remote operation with less cellular damage
	Drugs are easy to overcome the cell membrane barrier	Field modulated externally without electrode contacts unlike EP	Selective irreparable cellular damage	Instant impermeabilization after ultrasound exposure	Enhanced optofection efficiency compared with regular gene delivery
		High efficiency of drugs delivery compared with that without the magnetic field			Deep penetration; key nanosurgical tool to the microscopist

EP = electroporation, MNP = magnetoporation.