peg macromer peg-pq(alloc)  (Alloc Modulo LTD)

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: Here, 5%, 7.5%, and 10% PEG w/v corresponded to 61.1, 91.65, and 122.2 mg/mL PEG–PQ macromer and 62.3, 93.45, and 124.6 mg/mL PEG–PQ(alloc) macromer, respectively.

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: Effects of hydrogel compliance on EC spreading. (a) Average circularity values for cells encapsulated in 5% PEG hydrogels with ratios of 100/0, 75/25, 50/50, 25/75, or 0/100 PEG–PQ/PEGPQ(alloc). Cell spreading, as assessed by lower circularity, increased as the hydrogels became more compliant. 25/75 and 0/100 PEG–PQ/PEG–PQ(alloc) exhibited significantly lower circularities than the other formulations and ECs in the 100% PEG–PQ(alloc) hydrogel were the most spread ( p < 0.005). (b-f) Histograms that summarize the measured circularity for all the cells assessed in each hydrogel formulation. While a population of highly rounded cells (circularity ∼0.8) can be found in all hydrogels, populations of spread cells begin to emerge as the compliance decreases. Nuclear (DAPI, blue) and actin (green) staining of characteristic cells show more developed actin networks with identifiable stress fibers in highly spread cells as compared to diffuse bands surrounding the nucleus in rounded cells (inset). Scale bar represents 30 μm.

Article Snippet: Here, 5%, 7.5%, and 10% PEG w/v corresponded to 61.1, 91.65, and 122.2 mg/mL PEG–PQ macromer and 62.3, 93.45, and 124.6 mg/mL PEG–PQ(alloc) macromer, respectively.

Techniques: Formulation, Staining

Journal: ACS Biomaterials Science & Engineering

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

doi: 10.1021/acsbiomaterials.5b00064

Figure Lengend Snippet: Visualization and analysis of HUVEC:HBVP coculture in PEG–PQ or PEG–PQ(alloc) hydrogels. (a) Gels were fixed and stained for PECAM (green) and αSMA (red) then counterstained with DAPI (blue) after 1, 3, or 6 days of culture. Within 24 h of coculture, PEG–PQ(alloc) hydrogels had begun to form HUVEC networks as can be seen by the PECAM staining. The PEG–PQ hydrogels, however, exhibited no networks and minimal cell–cell contacts. After 3 days in coculture, the PEG–PQ hydrogels showed increasing cell–cell contacts and short networks with some HBVP incorporation (as seen by αSMA staining), whereas PEGPQ(alloc) hydrogels had highly developed HUVEC networks with HBVP support. At the 6 day time point, both PEG–PQ and PEG–PQ(alloc) hydrogels had well developed HUVEC networks that had directly interacting HBVPs. Scale bar represents 100 μm. (b) Total tubule length was measured for z-projection for each time point in both hydrogels. At all time points, PEG–PQ(alloc) exhibited significantly more tubule-like networks. (c) The number of branch points was counted for each field-of-view (image). Significantly more branch points were identified after 1 and 6 days of culture. (d) Comparisons of the total cell volume to cell network volume indicated significantly more cellular integration in PEG–PQ(alloc) hydrogels at all time points. (*indicates statistical significance: * p < 0.05, ** p < 0.01, *** p < 0.001).

Article Snippet: Here, 5%, 7.5%, and 10% PEG w/v corresponded to 61.1, 91.65, and 122.2 mg/mL PEG–PQ macromer and 62.3, 93.45, and 124.6 mg/mL PEG–PQ(alloc) macromer, respectively.

Techniques: Staining

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