TABLE 3.

Delivery strategies for various CRISPR–Cas formats

	Viral delivery				Physical delivery			Chemical delivery			Other emerging nonviral delivery
Strategy	AAVs	AVs	LVs	Bacteriop‐hages	Microinjection	Electroporation	Hydrodynamic injection	Cationic vectors	CCPs	AuNPs	GO	BP	DNA nanostructure	EVs
Delivery formats	DNA	DNA	DNA	DNA	DNA, mRNA or protein	DNA, mRNA or protein	DNA, mRNA or protein	DNA, mRNA or protein	Protein	Protein	Protein	Protein	Protein	Protein
Delivery efficiency	++	++	+++	++	+	+++	+++	+	+	++	+++	+++	+++	++
Safety concern	+	++	+++	+	+	+	++	+	+	+	+	+	+	+
Cost	++	++	+	++	+++	+++	++	+	+	++	++	++	++	+
Technical requirement	++	+++	+	++	+++	+	+++	+	++	++	++	+++	+++	+
Major applications	in vivo	in vivo	in vitro and ex vivo	in vivo and in vivo	in vitro and ex 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	in vitro and in vivo	in vitro and in vivo	in vitro and in vivo	in vitro, ex vivo and in vivo

Abbreviations: + denotes low; ++ denotes medium; +++ denotes high; AAV, adeno‐associated virus; AuNPs, gold nanoparticles; AV, adenovirus; BP, black phosphorus; CCPs, cell penetrating peptides; EVs, extracellular vesicles; GO, graphene oxide; LV, lentivirus.