Charge ratio, polyplex

Among non-viral vectors, the lipoplex and polyplex systems [69,70], in which cationic Hpids and polycations, respectively, associate with DNA through an electrostatic interaction, are most widely studied for both in vitro and in vivo transfection. Their assets are that they can carry various size ranges of DNA, ease in manufacturing and mass production, a variety of chemical designs with smart fimctions, and their surface properties can be readily controlled by changing the charge ratio between the cationic polymer and DNA. 

Fig. 6 Basic characterization and transfection activities of PEG-PLL/pDNA micelle, a Size distribution of the PIC micelle (PEG-PLL (12-48)/pDNA, charge ratio 1.0) obtained from histogram analysis of dynamic light scattering (DLS). b Nuclease resistance as a function of PLL length evaluated by an increase in absorbance at 260 nm by the addition of DNase I in 10 mM tris-HCL buffer, pH 7.4 (i) Native DNA+ 11 U DNase I, (ii) PEG-PLL12-7/DNA complex + 110 U DNase I, (iii) PEG-PLL12-19/DNA complex+ 110 U DNase I, (iv) PEG-PLL12-42/DNA complex + 110 U DNase I), c Charge ratio dependency of transfection activity of PIC micelles with varying compositions (12-7, 12-19, 12-48) against 293 cells (n = 4, S.D. + 100 p.M HCQ). d Influence of preincubation with serum on transfection activity of PIC micelles (12-48, r = 2), polyplex (PLL/pDNA, r = 2), and lipoplex system (LipofectAMINE/pDNA complex). The preincubation of these complexes in 20% serum was done for 30 min prior to transfection ( = 4 SD). (Fig. 6a,c,d Reprinted with permission from [87] and Fig. 6b from [81])...

Condensates of polycatimi with DNA (polyplexes) can adopt various shapes, the most commonly observed being toroidal, rod-like, and globular (examples of some of these structures are presented in Scheme 7) [68-71]. The different structures that IPECs can adopt can be categorized into different subtypes water-soluble, colloidally stable, and insoluble. The type of complex formed is governed by all the factors mentioned in the previous paragraphs. Moreover, it should be noted that the polycation/DNA charge ratio influences the size, charge, and solubility of the polyplexes. As a cmisequence, in some cases, the polyplexes can be consecutively water soluble, then colloidally stable, and eventually precipitate. 

At mixing charge ratio N P of 1 [190], the polydispersity of the complexes of PEG272- -PLLy 19 4g (Fig. 17a) with pDNA decreased dramatically before increasing again, whereas nearly complete condensation seemed to occur at N P of 2 1 (EtBr exclusion assay), where the diameter of all the polyplexes was inferior to 100 nm. Note that condensation of a linearized pDNA by the same polymer was effective at lower N P ratio. The explanation given by the authors is that native pDNA is in a super-coiled circular form, which certainly has a higher molecular... 

Quatemized or partially quatemized derivatives of poly(4-vinylpyridine) (DP = 1,600, Mw = 168 kDa) were synthesized by the group of Izumrudov [210]. Among them, four different series were synthesized quartemized poly(4-vinylpyridine) with V-alkyl ester substituents (C -PVP, Fig. 20b), polycarboxybetaine with alkyl spacer (C -PCB, Fig. 20c), poly[(4-vinylpyridine)-co-(V-alkyl-4-vinylpyridinium)] and poly[(iV-methyl-4-vinylpyridine)-c )-(V-alkyl-4-vinylpyridinium)] both with various alkylation degree p (respectively Cn-PVP-p, Fig. 20d and Me-Cn-PVP-p, Fig. 20e). Unfortunately, relatively few comparisons between these polymers were presented in this publication regarding the physico-chemical characteristics of their polyplexes. At a charge ratio of 5, Cn-PVP-based polyplexes with short V-alkyl... 

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