Table 1.

Vectors and systems for gene targeting and myocardial delivery

		Advantages	Disadvantages
Non-Viral	Plasmids	Simplified construction, versatility of expression cassette size, favorable biosafety risk profiles	Low transduction efficiency, transient expression
	Liposomes	Allow for targeting at the cell surface, ultrasound manipulation possible, favorable biosafety risk profiles	More complex construction, usually requires competent blood flow, transient expression
Viral	Replication Deficient Adenoviruses	Large DNA packaging possible, enters both dividing and non-dividing cells, well suited for myocardial delivery	Serotype immunogenicity, potential cytotoxicity, transient expression
	Adeno-associated Virus	Greater stability than Adenovirus, enters both dividing and non- dividing cells, well suited for myocardial delivery, longer periods of expression, reduced immunogenicity	DNA insertion possible causing oncogenic potential, smaller DNA packaging
	Lentivirus	Integrates into host DNA for long term expression, minimal immunogenicity	Smaller DNA packaging, high tropism for dividing cells, insertional mutagenesis