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Porous structures have emerged as a breakthrough of shape-morphing hydrogels to achieve a rapid response. However, these porous actuators generally suffer from a lack of complexity and diversity in obtained 3D shapes. Herein, a simple yet versatile strategy is developed to generate shape-morphing hydrogels with both fast deformation and enhanced designability in 3D shapes by combining two promising technologies: electrospinning and 3D printing. Elaborate patterns are printed on mesostructured stimuli-responsive electrospun membranes, modulating in-plane and interlayer internal stresses induced by swelling/shrinkage mismatch, and thus guiding morphing behaviors of electrospun membranes to adapt to changes of the environment. With this strategy, a series of fast deformed hydrogel actuators are constructed with various distinctive responsive behaviors, including reversible/irreversible formations of 3D structures, folding of 3D tubes, and formations of 3D structures with multi low-energy states. It is worth noting that although poly(N-isopropyl acrylamide) is chosen as the model system in the present research, our strategy is applicable to other stimuli-responsive hydrogels, which enriches designs of rapid deformed hydrogel actuators.

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Preparation of novel antibacterial and cytocompatible polyurethane membranes as occlusive dressing, which can provide moist and sterile environment over mild exudative wounds is considered in this work. In this regard, an epoxy-terminated polyurethane (EPU) prepolymer based on castor oil and glycidyltriethylammonium chloride (GTEAC) as a reactive bactericidal agent were synthesized. Polyurethane membranes were prepared through cocuring of EPU and different content of GTEAC with 1,4-butane diamine. The physical and mechanical properties, as well as cytocompatibility and antibacterial performance of prepared membranes were studied. Depending on their chemical formulations, the equilibrium water absorption and water vapor transmission rate values of the membranes were in ranges of 3-85% and 53-154g m(-2) day(-1), respectively. Therefore, these transparent membranes can maintain for a long period the moist environment over the wounds with low exudates. Detailed cytotoxicity analysis of samples against mouse L929 fibroblast and MCA-3D keratinocyte cells showed good level of cytocompatibility of membranes after purification via extraction of residual unreacted GTEAC moieties. The antibacterial activity of the membranes against Escherichia coli and Staphylococcus aureus bacteria was also studied. The membrane containing 50% GTEAC exhibited an effective antibacterial activity, while showed acceptable cytocompatibility and therefore, can be applied as an antibacterial occlusive wound dressing.

Preparation of polyurethanes derived from novel 1,2,3triazole-functionalized soybean oil-based polyols and assessment of their possible biocidal activities were considered. Epoxidized soybean oil was reacted with sodium azide to produce an azide-containing polyol. The product was subjected to the cycloaddition reaction with various alkynes. Alkylation of tertiary amine-containing polyol with methyl iodide was also performed to prepare a quaternary ammonium salt (QAS)-containing polyol. The polyols and their mixtures with PEG1000 were reacted with isophorone diisocyanate to prepare polyurethane coatings. The influence of embedded functional groups on physical, mechanical, thermal and biological properties of polyurethanes was studied. Incorporation of 1,2,3-triazole groups within the polyol backbone resulted in higher storage modulus at glassy state, glass transition temperature, thermal stability and hardness of corresponding polyurethanes, while it led to lower adhesion strength and hydrophilicity. Although QAS-containing polyurethanes displayed better physical and mechanical properties, but their thermal stability were reduced. Studying the interaction of fibroblast cells with polyurethanes derived merely from oil-based polyols revealed their good cells viability (60− 110%). Moderate to high biocidal activity was detected for polyols and polyurethanes containing tertiary amine and QAS groups. Improving the hydrophilicity of polyurethanes via incorporation of PEG1000 improved their biocidal activity, while it reduced their cytocompatibility.

Preparation and evaluation of new polyurethane membranes for wound dressing application was considered in this work. The membranes were prepared through amine curing reaction of epoxy-terminated polyurethane prepolymers and an antibacterial epoxy-functional quaternary ammonium compound (glycidyltriehtylammonium chloride, GTEACl. To render the prepared membranes to be highly absorptive of wound exudates, poly (ethylene glycol) polyols were introduced into the polyurethane networks. Evaluation of biocompatibity via both MTT assay and direct contact with two different cell lines (fibroblast and epidermal keratinocytes) reveled that membranes with appropriate loading of GTEACl showed proper biocompatibility. Promising antibacterial activity of the prepared membranes against Staphylococcus aureus and Escherichia coli bacteria was confirmed by both agar diffusion and shaking flask methods. The membranes with balanced crosslink density and ionic groups' concentration possessed appropriate hydrophilicity and water vapor transmission rate; therefore, they could prevent the accumulation of exudates and decrease the surface inflammation in the wounded area.

Preparation of antibacterial polyurethane coatings from novel functional soybean oil was considered in this work. First, epoxidized soybean oil (ESBO) as a low price and widely available renewable resource raw material was subjected to the reaction with aniline using an ionic liquid as a green catalyst. The intermediate phenylamine containing polyol (SAP) was then methylated by reaction with methyl iodide to produce a polyol (QAP) with pendant dimethylphenylammonium iodide groups. To regulate the physical and mechanical properties as well as biological characteristics of final coatings, QAP was mixed with different portions of a similar soybean oil-based polyol (MSP) without quaternary ammonium groups. The mixtures were reacted with isophorone diisocyanate to produce crosslinked polyurethane coatings. Evaluation of viscoelastic properties by DMA method revealed single phase structure with Tg in the range of 50-82°C. Stress-strain analysis of the prepared polyurethanes showed initial modulus, tensile strength, and elongation at break in the ranges of 13-299 MPa, 4.5-13.8 MPa, and 16-109%, respectively. Additionally, the coatings showed good adherence to aluminum and PVC substrates. The solvent extracted samples showed excellent biocompatibility as determined by monitoring L929 fibroblast cells morphology and MTT assay. Meanwhile, very promising antibacterial properties against both Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria with bacterial reduction in the range of 83-100% was observed.

Biodegradable, high‐barrier, flexible and transparent food packaging are required to replace current multilayered, metal‐ or halogen‐containing packaging that is nonrecyclable and nondegradable. An “all‐green” solution for food packaging made of a polylactic acid (PLA) foil (25 µm) furnished with a glycol chitosan‐clay nanocomposite coating (1.4 µm) is presented here that surpasses state‐of‐the‐art high‐performance materials like metallized poly(ethylene terephthalate) or poly(vinylidene chloride) even at harsh conditions (OTR = 0.17 cm3 m−2 day−1 bar−1 at 75% relative humidity). While the barrier side of the foil inhibits bacterial colonization, the uncoated PLA side assures biodegradability. Such a Janus feature in combination with the superb barrier performance renders this waterborne bio‐nanocomposite coating a valuable alternative to conventional less eco‐friendly food packaging materials.