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Author: Singh, Smriti × DDC: 540 ×

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    Approach to Obtain Electrospun Hydrophilic Fibers and Prevent Fiber Necking
    (New York, NY [u.a.] : Wiley InterScience, 2019) Fischer, Thorsten; Möller, Martin; Singh, Smriti
    Solution electrospinning of a blend containing a hydrophobic polymer with a hydrophilic functional polymer as an additive is a simple and straight-forward route to obtain functional and hydrophilic fibers accompanied by the mechanical properties of the hydrophobic polymer. However, this process of thermodynamically unfavored surface segregation of the hydrophilic additive is not well understood. To understand the process the dependencies of the surface hydrophilization on type of hydrophilic polymers, the solvent, and the process, using poly(caprolactone) (PCL) as the matrix polymer is explored. The results show that hydrophilic fibers can be obtained using different additive hydrophilic polymers. The combination of polymer blends which show this effect can be predicted using the Flory–Huggins interaction parameter. In addition mechanical and micromechanical properties of PCL fibers blended with NCO-terminated star-shaped poly(ethylene glycol) (sPEG-NCO) as additive are investigated. In this context blending with sPEG-NCO turns out to be a powerful tool to prevent fiber necking rendering this method an interesting candidate for tissue engineering application, where it is mandatory to retain the surface properties under mechanical stress.
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    3D-Printing of Structure-Controlled Antigen Nanoparticles for Vaccine Delivery
    (Columbus, Ohio : American Chemical Soc., 2020) Nishiguchi, Akihiro; Shima, Fumiaki; Singh, Smriti; Akashi, Mitsuru; Moeller, Martin
    Targeted delivery of antigens to immune cells using micro/nanocarriers may serve as a therapeutic application for vaccination. However, synthetic carriers have potential drawbacks including cytotoxicity, low encapsulation efficiency of antigen, and lack of a morphological design, which limit the translation of the delivery system to clinical use. Here, we report a carrier-free and three-dimensional (3D)-shape-designed antigen nanoparticle by multiphoton lithography-based 3D-printing. This simple, versatile 3D-printing approach provides freedom for the precise design of particle shapes with a nanoscale resolution. Importantly, shape-designed antigen nanoparticles with distinct aspect ratios show shape-dependent immune responses. The 3D-printing approach for the rational design of nanomaterials with increasing safety, complexity, and efficacy offers an emerging platform to develop vaccine delivery systems and mechanistic understanding.
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    Physical gels of poly(vinylamine) by thermal curing
    (Cambridge : Royal Society of Chemistry, 2020) Fischer, Thorsten; Köhler, Jens; Möller, Martin; Singh, Smriti
    Physical gels are a versatile class of materials which can find application in sensors, electrochemistry, biomedicine or rheological modifiers. Herein, we present a hydrogen-bonded physical gel which is based on the interaction between phenylcarbonate telechelic poly(ethylene glycol) (PEG-PC) and poly(vinyl amine-co-acetamide) (p(VAm-co-VAA)). The critical gelation concentration was found to be 10 wt% by rheology and NMR. UV-vis spectroscopy and dynamic light scattering reveal the formation of aggregates in the gel. Rheology and differential scanning calorimetry (DSC) was used to show the effect of thermal curing on the mechanical properties of the physical gel. © The Royal Society of Chemistry 2020.