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Background: Spider silk is a tear-resistant and elastic biopolymer that has outstanding mechanical properties. Additionally, exiguous immunogenicity is anticipated for spider silks. Therefore, spider silk represents a potential ideal biomaterial for medical applications. All known spider silk proteins, so-called spidroins, reveal a composite nature of silk-specific units, allowing the recombinant production of individual and combined segments. Results: In this report, a miniaturized spidroin gene, named VSO1 that contains repetitive motifs of MaSp1 has been synthesized and combined to form multimers of distinct lengths, which were heterologously expressed as elastin-like peptide (ELP) fusion proteins in tobacco. The elastic penetration moduli of layered proteins were analyzed for different spidroin-based biopolymers. Moreover, we present the first immunological analysis of synthetic spidroin-based biopolymers. Characterization of the binding behavior of the sera after immunization by competitive ELISA suggested that the humoral immune response is mainly directed against the fusion partner ELP. In addition, cytocompatibility studies with murine embryonic fibroblasts indicated that recombinant spidroin-based biopolymers, in solution or as coated proteins, are well tolerated. Conclusion: The results show that spidroin-based biopolymers can induce humoral immune responses that are dependent on the fusion partner and the overall protein structure. Furthermore, cytocompatibility assays gave no indication of spidroin-derived cytotoxicity, suggesting that recombinant produced biopolymers composed of spider silk-like repetitive elements are suitable for biomedical applications. [ABSTRACT FROM AUTHOR]

Direct compounding injection molding of ternary blends of polylactide (PLA), polybutylene succinate (PBS) and a hydrogenated styrene farnesene block copolymer (HSFC) was investigated for different blend compositions. Morphological analysis by atomic force microscopy and scanning electron microscopy showed a heterogeneous morphology of the ternary blends, with coexisting droplets of HSFC and PLA respectively PBS. Particle sizes analysis of the minor phases in the ternary blends showed mean values in the range of ∼1 μm, which is discussed in correlation to the rheological properties of the blend components as obtained by high pressure capillary rheometry. In result, with increasing HSFC content, the ternary blends showed a significant increase in notched Charpy impact strength (acN). In concrete, for the ternary blends with 15 wt% of HSFC a maximum acN of 15.8 kJ/m2 was found. At the same time, incorporation of the HSFC resulted only in a moderate reduction in elastic modulus and tensile strength. [ABSTRACT FROM AUTHOR]