Table 1.

Comparison of common clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 delivery strategies.

Strategy	Viral Delivery				Non-Viral Delivery
	LV	AAV	AV	EV	Microinjection	Electroporation	Cell Penetrating Peptide	Lipid-Based Nanoparticle	Gold Nanoparticle
Cas9 Delivery Format	DNA	DNA	DNA	Protein	DNA, mRNA or protein	DNA, mRNA or protein	Protein	DNA, mRNA or protein	Protein
Delivery Efficiency	+++	++	++	++	+	+++	+	+	++
Safety Concern	+++	+	++	+	+	+	+	+	+
Cost	+	++	++	+	+++	+++	+	+	++
Technical Requirement	+	++	+++	+	+++	+	++	+	++
Major Advantages	Efficient delivery; Large cloning capacity	Non-integrating	Non-integrating	Non-integrating; transient exposure; multiplexible; all-in one format	Direct delivery; Dosage more controllable	Efficient delivery; Easy to operate	No risk of virus	FDA-approved; Low stress to the cells	No risk of virus
Major Limitations	Random integration; Insertional mutagenesis	Limited cloning capacity	immune response	Limited quantification method	Technical challenging; in vivo work not feasible	Cell viability issue; in vivo work difficult	Variable efficiency depends on cell types; requires extensive optimization
Major Applications	in vitro and ex vivo	in vivo	in vivo	in vitro, ex vivo and in vivo	in vitro and ex vivo	in vitro and ex vivo	in vitro and in vivo	in vitro and in vivo	in vitro and in vivo

AV, adenovirus; AAV, adeno-associated virus; EV, extracellular vesicle; LV, lentivirus; + denotes low; ++ denotes medium; +++ denotes high.