Synthesis of defective microporous/mesoporous MOF-808.

Growth factors (GF) are critical cytokines in wound healing. However, the direct delivery of these biochemical cues into a wound site significantly increases the cost of wound dressings and can lead to a strong immunological response due to the introduction of a foreign source of GFs. To overcome this challenge, we designed a poly(ethylene glycol) diacrylate (PEGDA) hydrogel with the potential capacity to sequester autologous GFs directly from the wound site. We demonstrated that synthetic peptide sequences covalently tethered to PEGDA hydrogels physically retained human transforming growth factor beta 1 (hTGFβ1) and human vascular endothelial growth factor (hVEGF) at 3.2 and 0.6 ng/mm2, respectively. In addition, we demonstrated that retained hTGFβ1 and hVEGF enhanced human dermal fibroblasts (HDFa) average cell surface area and proliferation, respectively, and that exposure to both GFs resulted in up to 1.9-fold higher fraction of area covered relative to the control. After five days in culture, relative to the control surface, non-covalently bound hTGFβ1 significantly increased the expression of collagen type I and hTGFβ1 and downregulated vimentin and matrix metalloproteinase 1 expression. Cumulatively, the response of HDFa to hTGFβ1 aligns well with the expected response of fibroblasts during the early stages of wound healing.

Polymeric emulsifiers based on glycerol and oleic acid were developed and their properties evaluated in palm oil and water solutions. Developed polymeric emulsifiers were polyglycerol-esters. Polymerization degree of polyglycerol-esters at different dosages (from 0.2 to 3% w/v) had a significant effect over emulsion stability, water surface tension, droplet size, and viscosity. Polyglycerol-ester with highest polymerization degree behaved more efficiently as emulsifier. A dosage of 0.5% w/v was required to maintain emulsion stability for a half-life period of 872 min (~14.5 h); which, is 5.6 and 3.6-fold longer stability than with the other two polyglycerol-esters developed. When dosage increased to 3% w/v, the emulsion stability also increased to 3792 min (~2.6 days). Nevertheless, surfactants with lower polymerization degree and molecular weight did not behave the same way. Emulsifier with highest polymerization degree reduced water surface tension by 70% and the mean particle diameter decreased when emulsifier polymerization degree increased. For the viscosity parameter, there were two interesting regions: for shear rates up to 1 s −1 the emulsion behaved as Non-Newtonian fluid type Shear-thinning; while, higher shear rates, the viscosity exhibited a Newtonian profile.

Polymer and surfactant flooding are widely applied processes in enhanced oil recovery (EOR) in which viscous polymers or surfactants aqueous solutions are introduced in oil reservoirs to rise the recovery of the remaining oil. In this regard, one of the challenges of EOR practices is the use of efficient but low-cost viscosifier and surfactant polymers. This work is aimed at synthesizing a polyglycerol derived from the biodegradable and nontoxic monomer, glycerol, and evaluating the effect of its copolymerization on rheological and interfacial properties, which were tested in water and brine for the former and in the water/oil system for the last properties. The copolymers were synthesized using a polyglycerol backbone, acrylic acid, lactic acid, and oleic acid. The chemical structure of copolymers was characterized by Fourier transform infrared spectroscopy (FT-IR), thermogravimetry (TG), and differential scanning calorimetry (DSC). The viscosity and the interfacial tension (IFT) of polymeric solutions were tested. Thus, the viscosity and surface performance of the prepared polymer solutions in distilled water and brine were analyzed according to the structure of the synthesized polymers. The results showed that the synthesized polymers modified water viscosity and surface tension between water and oil. The developed polymers could be candidates for applications in enhanced oil recovery and related applications.