Enzymatically triggered peptide hydrogels for 3D cell encapsulation and culture

Abstract

We have investigated the possibility of using enzymatically triggered peptide hydrogels for the encapsulation and culture of cells. Based on recent work done on the enzymatically triggered gelation of FEFK (F, phenylalanine; E, glutamic acid; K, lysine) using thermolysin, a protease enzyme from Bacillus Thermoproteolyticus Rokko, we have investigated the possibility of using this gelation triggering mechanism to encapsulate cells within a 3D hydrogel matrix. First, the properties of enzymatically triggered hydrogels prepared in phosphate buffer solution were investigated and compared with the properties of hydrogels prepared in HPLC grade water from our previous work. We showed that the use of phosphate buffer solution allowed the production of hydrogels with very high shear moduli (>1 MPa). The gelation kinetics was also investigated, and the mechanical properties of the system were shown to closely follow the synthesis of the octapeptide by the enzyme through reverse hydrolysis. In a second phase, we developed, on the basis of information acquired, a facile protocol for the encapsulation of cells and plating of the hydrogel. Human dermal fibroblasts were then used to exemplify the use of these materials. FEFEFKFK octapeptide hydrogels prepared under the same conditions and with the same mechanical properties were used as a control. We showed that no significant differences were observed between the two systems and that after a decrease in cell number on day 1, cells start to proliferate. After 5 days of culture, the cells can be seen to start to adopt a stretched morphology typical of fibroblasts. The results clearly show that the protocol developed minimises the potential detrimental effect that thermolysin can have on the cells and that these enzymatically triggered hydrogels can be used for the 3D encapsulation and culture of cells.

A Metallogel Based on a Zwitterionic Spirocyclic Meisenheimer Complex: Sensing of Fluoride Ions in Water and Moisture Content in Organic Solvents

“…Gels derived from conventional synthetic materials such as peptides and carbohydrates have already been explored a lot ,. Different biomedical applications have been achieved utilizing these gels because of their inherent biocompatibility . But the interest in designing these gelators has declined due to their lack of stimuli‐responsiveness.…”

“…[3][4][5][6][68][69] Different biomedical applications have been achieved utilizing these gels because of their inherent biocompatibility. [7][8] But the interest in designing these gelators has declined due to their lack of stimuli-responsiveness. However, people have become interested in designing smart gels where a nongelator is transformed into a gel via encapsulation of a guest molecule.…”

In vivo characterisation of a therapeutically relevant self‐assembling 18F‐labelled β‐sheet forming peptide and its hydrogel using positron emission tomography

“…F9 is one of a family of amphipathic peptides with alternating hydrophobic and hydrophilic residues that self-assembles into β-sheet fibres that above a critical gelation concentration (CGC) associates to form a hydrogel. The properties of the hydrogels can be tailored through peptide design, concentration, media pH and ionic strength 9 ; as such, they have been shown to hold promise for application in the biomedical field as 3D cell culture matrices 10 and/or drug delivery vehicles. 5 Positron emission tomography (PET) is a quantitative imaging modality boasting high levels of sensitivity.…”

Logic‐Gate Functions in Chemomechanical Materials

“…[30] Sol-gel transitions triggered by pH variation rely on LMWGs containing,for example, carboxyl groups, whichd ecrease the solubility of the LMWG at lower pH and induce self-assembly into gels;w ith amino LMWGs the same occurs when the pH is raised above the pK a value of the LMWG base. [31] Besides pH changes, salts, [32] metal ions, [33] and enzymes [34] are also capable of triggerings elf-assembly.O ther chemoresponsivem aterials that can also be used in, for example, drug delivery,i nclude silica nanoparticles, [35,36] corresponding membranes, [37,38] imprinted polymers, [39,40] and polymer brushes. [41][42][43]…”