Table 1. Electrostatic surface modifications of particles for gene delivery.

Base Material	Modification	Drug	Zeta- potential (mV)	Size (nm)	Application	Cell Viability (relative to control)	Activity (relative to control)	Notes	Ref.
PLGA	CTAB	pDNA-HIV p55	+36±6	1540±200	Balb/c mice		∼ ≥ ×100 (PLGA, DNA)	Improved serum antibody and CTL response	60	Singh, 2000
b-PEI	Chondroitin Sulfate	pDNA-Luc	-29.2±0.2	77.0±3.2	B16-F10 cells in vitro (Opti-MEM)	∼ ×5 (pDNA/PEI)	∼ ×1 (b-PEI)	Reduces RBC agglutination	68	Kurosaki, 2009
b-PEI	Poly(acrylic acid)	pDNA-Luc	(approx. neutral)	∼ 500	A549 cells in vitro (100% serum)		∼ ×100 - ×1000 (b-PEI)	Increased in vivo transfection and reduced in vivo toxicity	69	Trubetskoy, 2003
Baculovirus (BV)	PEI	pDNA-Luc	∼ +30	∼ 350	Human U87 and HepG2 cells	∼ 95% up to MOI of 100	up to ∼ ×1000 (uncoated BV) in serum	Increased in vivo transfection as well	72	Yang, 2009
PBAE	E12-RGD peptide	pDNA-GFP	∼ -5	∼ 200	HUVEC in vitro (12% serum)	∼ 80-100%	∼ ×3 (PBAE/E12-RDG); ∼ ×50 (b-PEI); ∼ ×1 (Lipo2000)	Targeted delivery at specific material ratios	74	Green, 2007
Gold nanoparticle	PBAE	siRNA	∼ +13	∼ 100	Luc modified HeLa cells in vitro (10% serum)	∼ 85-100%	∼ ×6 (Lipo2000); ∼ ×20 (AuNP)	Greater than 95% knock down	78	Lee, 2009
Core-shell fluorescent silica nanoparticles	PEI	pDNA-Luc	+31.2±2.7	117±1.1	COS-7 in vitro (Opti-MEM)	∼ 100%	∼ ×1 (PEI)	Particles can be used for imaging and delivery	79	Fuller, 2008
PBAE	Poly(glutamic acid)	pDNA-Luc	∼ -10	∼ 200	Swiss Webster mice	No lethality (mice died with uncoated)	∼ ×10 liver (PBAE); ∼ ×30-40 spleen, marrow	Varying coating affects tissue specificity	80	Harris, 2009

CTAB = cetyltrimethylammonium bromide; CTL = cytotoxic T lymphocyte; MOI = multiplicity of infection (number of viral particles per cell); pDNA-GFP = GFP coding plasmid; pDNA-Luc = luciferase coding plasmid