Polylactic acid (PLA) is a key biopolymer with potential uses in numerous sectors, since it is biocompatible and both biobased and biodegradable. However, brittleness limits its industrial applications where plastic deformation at high impact rates or high elongation is required, for instance, flexible food packaging. In order to overcome this drawback and potentially expand the PLA market, we developed flexible PLA materials plasticized with renewable and biodegradable epoxidized soybean oil methyl ester reaching elongations at break of almost 800%. The use of amorphous PLA in combination with the lubricating effect of the plasticizer allowed the more sustainable extrusion at a low temperature of 140 °C, preventing the degradation of PLA and at the same time saving energy. Moreover, plasticized films produced, upon handling, significantly less acoustic noise than pure PLA, which is of great importance for food packaging applications. Morphology, thermomechanical and barrier properties, and migration levels were evaluated as a function of plasticizer content.

Responsive materials that change conformation with varying pH have been prepared from a range of amphiphilic block co-polymers. The individual blocks are composed of (a) permanently hydrophilic chains with neutral functionality and (b) acrylate polymers with weakly basic side-chains. Variation in co-monomer content, molar mass and block ratios/compositions leads to a range of pH-responses, manifest through reversible self-assembly into micelles and/or polymersomes. These transitions can be tuned to achieve environmental responses in a pH range from 5–7, as shown by turbidimetric analysis, NMR and dynamic light scattering measurements (DLS). Further characterization by transmission electron microscopy (TEM) indicates that polymersomes with diameters of 100–200 nm can be formed under certain pH-ranges where the weakly basic side-chains are deprotonated. The ability of the systems assembled with these polymers to act as pH-responsive containers is shown by DNA encapsulation and release studies, and their potential for application as vehicle for drug delivery is proved by cell metabolic activity and cell uptake measurements

Combination switchable polymer-DNA hydrogels have been synthesized to respond to both a specific oligonucleotide recognition signal and a non-specific but biorelevant environmental trigger. The hydrogels exhibit rheological properties that can be modulated through interaction with complementary DNA strands and/or reduction. Furthermore, individual and combined oligonucleotide recognition and reduction responses allow control over pore sizes in the gel, enabling programmable release and transport of objects ranging from the nano-to micro-scale. Materials and methods Materials All oligonucleotides (HPLC purified, Table 1) were purchased from Biomers.net GmbH (Ulm, Germany) and used without † Electronic supplementary information (ESI) available: Detailed methods for synthesis, rheology and further figures depicting particle transport across gels.

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