Thermoresponsive Hydrogels from Physical Mixtures of Self‐Assembling Peptide and its Conjugate with PNIPAAm

Abstract

The phase behavior and rheology of a range of physical mixtures of self‐assembling octapeptide FEFEFKFK and its conjugate with the thermoresponsive polymer poly(N‐isopropylacrylamide) (PNIPAAM) have been studied. These systems typically combined the thermo‐responsive character of PNIPAAM and the gelling property of octapeptides where both the elastic behavior and macroscopic melting of the system could be controlled by varying the ratio of pure peptide to peptide‐polymer conjugate.

Nanofibrillar Peptide Hydrogels for the Immobilization of Biocatalysts for Chemical Transformations

“…This reduction is most likely due to the peptide component present in the conjugate incorporating within the peptide fibers, thus tethering PETNR to the fiber surface. Such behavior is commensurate with our previous work where peptide–polymer conjugates were incorporated homogeneously throughout a pure peptide matrix. Nearly a tenth of all PETNR present was released, however, and could represent a small quantity of conjugate that had not been incorporated into the network, hence it was free to diffuse into the buffer.…”

“…The chemically coupled VKVKVEVK–PETNR conjugate (SPep–PETNR) was synthesized using a three‐step process, as outlined in Scheme A. Firstly, VKVKVEVK (1) was prepared using standard solid‐phase peptide synthesis protocols, as described previously . A maleoyl linker was attached using standard amino acid coupling conditions, while the peptide was still protected and attached to the solid support (2) .…”

Supramolecular Peptide/Polymer Hybrid Hydrogels for Biomedical Applications

“…Mechanical testing of the hydrogel was in agreement with two temperature transitions. Increasing of temperature resulted in two transition points in the behavior of the storage modulus (a sharp drop at 31 °C and a rapid increase at 61 °C) . Compared to the melting point of the peptide hydrogel (50 °C), the peptide/conjugate mixed hydrogel had an increase in the melting point suggesting supramolecular interactions between peptide and conjugate .…”

“…Using different peptide:conjugate ratios, they created a series of hydrogels that gelled upon mixing, which became cloudy at increasing temperatures (over LCST of NIPAAm, 40 °C) due to the collapse of NIPAAm chains. [94] The thermo-responsive behavior of the hydrogels were reversible and upon cooling samples became transparent again. At higher temperatures (80 °C) the hydrogel sample shrank in the water content, which is related to the typical behavior of aggregated NIPAAm chains.…”

“…The co‐assembly of the aforementioned octapeptide‐PNIPAAm conjugate with the peptide (peptide/peptide‐polymer) was also investigated. Using different peptide:conjugate ratios, they created a series of hydrogels that gelled upon mixing, which became cloudy at increasing temperatures (over LCST of NIPAAm, 40 °C) due to the collapse of NIPAAm chains . The thermo‐responsive behavior of the hydrogels were reversible and upon cooling samples became transparent again.…”