Journal: ACS Biomaterials Science & Engineering

Article Title: Encoding Hydrogel Mechanics via Network Cross-Linking Structure

doi: 10.1021/acsbiomaterials.5b00064

Figure Lengend Snippet: Lys(alloc) amino acids alter hydrogel cross-linking. (a) Both peptide sequences contained the MMPsensitive PQ sequence (green box and font). PQ(alloc) contained a Lys(alloc) (red circle and font) spaced from the PQ sequence and C-terminus by glycine residues. Terminal amine groups could be reacted with an acrylate-PEG-SVA to generate the PEG-peptide-PEG diacrylate macromer. (b) PEG−PQ macromers can undergo photopolymerization to form acrylate-based cross-links which impart mechanical stiffness to the hydrogel. However, PEG–PQ(alloc) macromers offer an extra cross-linking site within the peptide sequence, allowing the macromers to terminate at acrylate groups or alloc groups to control the hydrogel mechanics.

Article Snippet: PEG–PQ and PEG–PQ(alloc) macromers were dissolved at different ratios (100/0, 75/25, 50/50.

Techniques: Sequencing, Control

Journal: ACS Biomaterials Science & Engineering

Article Title: Encoding Hydrogel Mechanics via Network Cross-Linking Structure

doi: 10.1021/acsbiomaterials.5b00064

Figure Lengend Snippet: Incorporation of Lys(alloc) amino acids influences the resulting hydrogel mechanical properties. (a) Different polymer densities of PEG–PQ and PEG–PQ(alloc) hydrogels were mechanically tested to determine their compressive moduli. PEG–PQ(alloc) hydrogels exhibited significantly lower (∼10 fold) compressive moduli as compared to PEG–PQ. (b, c) In rheological measurements, PEG–PQ(alloc) had a significantly lower storage modulus ( G ′) compared to PEG–PQ yet displayed a nearly identical loss modulus ( G ″) to PEG–PQ. (d) Holding the overall prepolymer density at 5% PEG, the two macromers could be mixed at ratios of 100/0, 75/25, 50/50, 25/75, or 100/0 PEG–PQ/PEG–PQ(alloc) to create a continuum of mechanics between the minimal and maximal values, exhibiting an exponential relationship between the measured compressive modulus and PEG–PQ(alloc) content. (* indicates statistical significance, in all cases p < 0.001).

Article Snippet: PEG–PQ and PEG–PQ(alloc) macromers were dissolved at different ratios (100/0, 75/25, 50/50.

Techniques: Polymer