Tuning mechanical reinforcement and bioactivity of 3D printed ternary nanocomposites by interfacial peptide-polymer conjugates.

We present a study on ternary nanocomposites consisting of medical grade poly(ε-caprolactone) (mPCL) matrix, hydroxyapatite nanopowder (nHA) and compatibilized magnesium fluoride nanoparticle (cMgF) fillers. MgF nanoparticles were compatibilized by following a design approach based on the material interfaces of natural bone. MgF-specific peptide-poly(ethylene glycol) conjugates were synthesized and used as surface modifiers for MgF nanoparticles similarly to the non-collagenous proteins (NPC) of bone which compatibilize hydroxyapatite nanocrystallites.

Via precise interface engineering towards bioinspired composites with improved 3D printing processability and mechanical properties.

Precise interface engineering in inorganic-organic hybrid materials enhances both the elastic moduli and toughness of a biodegradable composite, which is of relevance for load-bearing applications in bone tissue engineering. Tailor-made MgF-binding peptide-polymer conjugates (MBC) are utilized as precision compatibilizers, having sequence-specific affinity for the surfaces of the inorganic MgF fillers to stabilize these particles and to contribute to the interactions with the continuous polymer matrix. The effects of the coupling agents are investigated in additively biomanufactured scaffolds from composites composed of MBC compatibilized magnesium fluoride nanoparticles (cMgF) and poly(ε-caprolactone).

Generic Biocombinatorial Strategy to Select Tailor-Made Stabilizers for Sol-Gel Nanoparticle Synthesis.

A generic route for the selection of nanoparticle stabilizers via biocombinatorial means of phage display peptide screening is presented, providing magnesium fluoride nanoparticle synthesis as example. Selected sequence-specific MgF2 binders are evaluated for their adsorption behavior. Peptide-polymer conjugates derived from the best binding peptide are used for the stabilization of MgF2 sol nanoparticles, yielding fully redispersable dry states and improoving processability significantly.

Deoxygenative [1,2]-hydride shift rearrangements in nucleoside and sugar chemistry: analogy with the [1,2]-electron shift in the deoxygenation of ribonucleotides by ribonucleotide reductases.

A variant of the semipinacol rearrangement that was observed in our laboratory has been applied to the synthesis of several furanose and pyranose derivatives. The process consists of an "orchestrated" [1,2]-hydride shift with departure of a leaving group from the opposite face. Transient formation of a C=O group is followed by rapid transfer of a hydride-equivalent from the same face from which the leaving group departed, which results in double inversion of stereochemistry at the two vicinal carbon atoms.

Oxachelin, a novel iron chelator and antifungal agent from Streptomyces sp. GW9/1258.

During a screening campaign for new antimicrobial and antifungal secondary metabolites from several thousand actinomycetes, a novel compound, isolated by activity guided fractionation, was oxachelin (1) from the new Streptomyces sp. GW9/1258. Oxachelin shows strong antibiotic activities against several fungi and Gram(+) bacteria.