Molar‐Mass Analysis of Dendrigraft Poly(l‐lysine) (DGL) Polyelectrolytes by SEC‐MALLS: The “Cornerstone” Refractive Index Increment

Abstract

Dendrigraft poly(l‐lysine) (DGL) polyelectrolytes, obtained by iterative polycondensation of N‐trifluoroacetyl‐l‐lysine‐N‐carboxyanhydride, constitute very promising candidates in many biomedical applications. In order to get a better understanding of their structure–property relationships in these applications, their absolute average molecular weights have to be accurately measured. Size‐exclusion chromatography coupled to a multi‐angle laser‐light‐scattering detector (SEC‐MALLS) is known to be the most appropriate analytical tool. These measurements require the determination of the refractive index increment, dn/dc, of these highly branched polycationic macromolecules in aqueous solution. This optical property has to be measured in the same aqueous conditions as SEC‐MALLS eluents. Consequently, data are determined and discussed as a function of different aqueous SEC‐MALLS eluents, as well as different counter‐ions of the many ammonium groups of DGL (generation 3, DGL‐3, used as a model herein). The resulting number‐average molecular weights, trueM¯normaln, are found to be very dissimilar when the measured dn/dc values are directly considered. In contrast, very close trueM¯normaln values are obtained (average trueM¯normaln = 18 700, standard error of 1110 g mol−1) with a low coefficient of variation for such data (ca. 6% for six analyses), when the dn/dc are corrected by the exact lysine amount (measured by the total Kjeldahl nitrogen method).

Versatile lysine dendrigrafts and polyethylene glycol hydrogels with inherent biological properties: in vitro cell behavior modulation and in vivo biocompatibility

“…Dense hydrogels of different ratios of DGL/PEG were prepared by adding the desired concentration of PEG‐bis(N‐succinimidyl succinate) (PEG‐NHS, 2000 g/mol, Sigma–Aldrich) in anhydrous dimethyformamide (DMF, Sigma–Aldrich), to a solution of DGL (third generation, 22,000 g/mol, COLCOM) 31 in phosphate‐buffered saline (PBS), at 4°C. For mechanical and swelling testing, 800 μl hydrogels were prepared in 2 ml conic tubes (Maxymum Recovery, Axygen).…”

Synthesis, structure, and function of internally functionalized dendrimers

“…92 Colcom, a French start-up, has commercialized a dendrimer-like structure first discovered by Collet et al and known as "lysine dendrigrafts," which display primary amine functionalities along its backbone and surface ( Figure 11). [77][78][79][80][81][82][83][84][85][86][87][88][89][90][91][92][94][95][96][97][98][99][100][101][102][103][104][105][106][127][128][129][130][131][132][133][134][135][136][137][138] Lysine dendrigrafts are primarily utilized for drug 89 and gene delivery. 107 but have also been investigated for their potential as a coagulant, 108 imaging agent, 95 and substrates for tissue engineering.…”

Everything You Always Wanted to Know about Poly‐l‐lysine Dendrigrafts (But Were Afraid to Ask)

“…Various analytical techniques were used to extensively characterize the poly-l-lysine dendrigrafts, including NMR spectrometry, [12] dynamic light scattering, Ta ylor dispersion analysis, size Synthetic routet oward first-to fourth-generation DGLs G1-G4,and their respective schematic representation (eachdot represents a l-lysine residue, pending free amino groups are not represented).The synthesis of each generation involves the following sequence:polycondensation in water,centrifugation for collecting the precipitate, alkaline deprotection of the side chains, and concentration in vacuo. exclusion chromatography, [13] refractometry, [14] capillary isotachophoresis, [15] potentiometry, [16] colorimetry, [17] cyclic voltammetry, [18] and Ramans pectroscopy. [19] Ta ble 1g athers few selected physicochemical properties for DGLs G1-G4.I ts hould be highlighted that such as imple synthetic procedure exerts an unexpected control on the molecular weighta nd diversity of the resulting dendrigrafts.I ndeed, poly-dispersity indexes measured for DGLs (1.20-1.46) are below those of both LPLs and HPLs( 1.3-2.6 and 1.8-2.6,r espectively), and are comparable to those of genuine DPLs (1.1-1.5), which are only accessible through al aboriousm ultistep process.…”

“…Various analytical techniques were used to extensively characterize the poly‐ l ‐lysine dendrigrafts, including NMR spectrometry, dynamic light scattering, Taylor dispersion analysis, size exclusion chromatography, refractometry, capillary isotachophoresis, potentiometry, colorimetry, cyclic voltammetry, and Raman spectroscopy . Table gathers few selected physicochemical properties for DGLs G1 – G4 .…”