Table 4.

Change of NPs zeta potentials upon covalent crosslinking and varying pH conditions.

NPs a,b	Zeta potential (mV)
	Preparation pHd	pH 1.2d	pH 6.8d	pH 7.4		pH 12.0d
				Aqueous conditions	FBS (10% v/v)
C-TPP	+29.0 ± 1.31	Clear	Aggregate	Aggregate	—e	Aggregate
C-PPA	+25.5 ± 0.92	Clear	Aggregate	Aggregate	—e	Aggregate
C-HMP	+51.5 ± 1.08	+7.6 ± 0.73c	Aggregate	Aggregate	—e	Aggregate
CP-TPP	+14.7 ± 1.92	clear	Aggregate	Aggregate	Aggregate	Aggregate
CP-PPA	+11.0 ± 1.31	clear	Aggregate	Aggregate	Aggregate	Aggregate
CP-HMP	+36.8 ± 1.45	+19.0 ± 1.95c	Aggregate	Aggregate	Aggregate	Aggregate
CPS-TPP	+13.5 ± 0.72	Clear	Aggregate	Aggregate	Aggregate	Aggregate
CPS-PPA	+11.4 ± 1.05	Clear	Aggregate	Aggregate	Aggregate	Aggregate
CPS-HMP	+26.8 ± 1.57	Aggregate	Aggregate	Aggregate	Aggregate	Aggregate
CROSS-CP-TPP	+9.4 ± 0.41	+14.9 ± 2.90	+1.4 ± 0.16	−4.5 ± 0.47	−3.14 ± 0.58	−14.3 ± 0.50
CROSS-CP-PPA	+8.2 ± 1.19	+12.0 ± 0.80	−2.9 ± 0.80	−5.9 ± 0.95	−1.64 ± 0.36	−15.9 ± 0.80
CROSS-CPS-HMP	+20.0 ± 1.64	+16.0 ± 0.76	+2.2 ± 0.50	−5.1 ± 0.47	−7.07 ± 0.37	−12.0 ± 0.69

^aSee Table 2 for pH value at preparation conditions.

^bEach value represents the average of triplicate measurements ± standard deviation.

^cNPs are stable without EDC.

^dAqueous conditions (no FBS).

^eNot tested.