Swellographic Study of Peptide Resin Swelling Behavior during Solid Phase Peptide Synthesis

Morphology and aggregation of RADA‐16‐I peptide Studied by AFM, NMR and molecular dynamics simulations

“…Solvent and reagent volumes used for the SPS operation corresponded to about 5 mL/0.5 g of starting MBHA resin. Those amounts were gradually increased to minimize the effects of peptide resin gradual swelling resulted from synthesized material accumulation . Unconditional double coupling Boc‐SPPS protocols were repeated 16 times, while the 1st coupling lasted for 3 h and the 2nd coupling was incubated overnight.…”

Investigation of Parameters that Affect Resin Swelling in Green Solvents

“…Resin 7 with a hydroxymethyl loading of 3.1 mmol g À 1 was found to give moderate swelling (2.8-3.1 mL g À 1 ) in all of the lower molecular weight alcohols, but poor swelling (1.8 mL g À 1 ) in 1-pentanol (S9) and 1-heptanol (S5). This suggests that for resin 7 to experience at least moderate swelling, a primary alcoholic solvent can have a wider range of δ H values (15)(16)(17)(18)(19)(20)(21)(22)(23). Taken together, the swelling of resins 5-7 in various solvents again clearly indicate that even small and subtle changes to the structure of a resin can have a significant effect on the ability of a particular solvent to swell it.…”

“…To investigate the effect of protecting groups and amino acid sidechains, two tripeptides were assembled directly onto aminomethyl cross-linked polystyrene which had a loading of 0.8 mmol g À 1 . The swelling of the resin-tripeptide conjugate was studied both before and after removal of one or both protecting groups, giving a total of six polystyrene supported tripeptide sequences (17)(18)(19)(20)(21)(22) as shown in Figure 10. Tripeptides 17 and 18 contain only unfunctionalised aromatic and aliphatic amino acids.…”

“…[17] Related work by Rodionov et al subsequently confirmed this trend and provided a theoretical basis for it. [18] Rana et al studied the swelling of Merrifield resin with degrees of cross-linking between 0.3 and 6 % in 15 solvents and three solvent mixtures. [19] The highest swelling was observed for the least cross-linked resins in chlorinated solvents.…”

Real-time monitoring of solid-phase peptide synthesis using a variable bed flow reactor

“…Originally, the reaction was monitored by measuring the movement of a piston placing a constant force upon the resin bed. [12][13][14][15] Since other variables alter these measurements, pressure fluctuations more accurately correlate with structural changes of the internal polymer matrix. 12 A differential pressure sensing VBFR was applied to monitor pressure changes across the reaction bed caused by resin swelling (peptide elongation) and shrinking (on-resin aggregation and Fmoc removal).…”