Sustainable Materials and Chemical Processes for Additive Manufacturing

Unformatted postprintAdditive manufacturing (AM) is energizing the fields of chemistry and materials science to develop new inks for new applications within fields such as aerospace, robotics, and healthcare. AM enables the fabrication of innumerable 3D geometries that cannot be easily produced by other means. In spite of the great promise of AM as an advanced form of future manufacturing, there are still fundamental challenges with respect to sustainability that need to be addressed. Some of the material needs for AM include sustainable sources of printing inks, resins, and filaments, as well as pathways for polymer recycling, upcycling, and chemical circularity. Furthermore, the combination of bio-sourced and biodegradable polymers with additive manufacturing could enable the fabrication of objects that can be recycled back into feedstock or degraded into non-toxic products after they have served their function. Herein, we review the recent literature on the design and chemistry of the polymers to that enable sustainability within the field of AM, with a particular focus on biodegradable and bio-sourced polymers. We also discuss some of the sustainability-related applications that have emerged as a result of AM technologies.E.S.-R. thanks the European funding by the Marie Sklodowska-Curie Individual Fellowships (MSCA-IF-GF) 841879-4D Biogel. H.S. and C.J. thank MINECO for funding through MAT2017-83373-R. A.N. thanks the National Science Foundation for support (1752972)

3D Printed Bioplastics with Shape-Memory Behavior Based on Native Bovine Serum Albumin

Unformatted postprintBio-based plastics that can supplant petroleum-derived materials are necessary to meet the future demands of sustainability in the life cycle of plastic materials. While there are significant efforts to develop protein-based plastic materials for commercial use, their application is limited by poor processability and limitations in mechanical performance. Here, we present a bovine serum albumin (BSA)-based resin for stereolithographic apparatus (SLA) 3D printing that affords bioplastic objects with shape memory behavior. We demonstrate that the native conformation of these globular proteins is largely retained in the 3D printed constructs, and that each protein molecule possesses a “stored length” that could be revealed during mechanical deformation (extension or compression) of the 3D bioplastic objects. While the plastically deformed objects could retain this state for an indefinite period of time, heating the object or submerging in water allowed it to return to its original 3D printed shape.We thank the Center for Research in Education and Simulation Technologies (CREST) at The University of Washington, and in particular Alex Gong for his assistance during the tensile tests. E.S.-R. thanks the European funding by the Marie Sklodowska-Curie Individual Fellowships (MSCA-IF-GF) 841879-4D Biogel. H.S. and A.G.-L. thank MINECO for funding through MAT2017-83373-R. A.N. thanks the National Science Foundation for support (1752972). A.L.C. thanks the European Research Council ERC-CoG-648071-ProNANO, and Agencia Estatal de Investigación, Spain (PID2019-111649RB-I00). This work was performed partially under the Maria de Maeztu Units of Excellence Program from the Spanish State Research Agency – Grant No. MDM-2017-0720 (CIC biomaGUNE)

Template-Directed Olefin Cross Metathesis

A template containing two secondary dialkylammonium ion recognition sites for encirclement by olefin-bearing dibenzo[24]crown-8 derivatives has been used to promote olefin cross metatheses with ruthenium-alkylidene catalysts. For monoolefin monomers, the rates of metatheses and yields of the dimers are both amplified in the presence of the template. Likewise, for a diolefin monomer, the yield of the dimer is enhanced in the presence of the template under conditions where higher oligomers are not formed

Template-Directed One-Step Synthesis of Cyclic Trimers by ADMET

A trifurcated template, containing three secondary dialkylammonium ion recognition sites for encirclement by a dibenzo [24]crown-8-containing acyclic diene, is used to promote acyclic diene metatheses (ADMET) catalyzed by ruthenium−alkylidene complexes, affording a cyclic trimer in 55% yield. Following this one-step, threefold ADMET reaction, the resulting cyclic trimer was isolated by preparative HPLC and characterized by NMR spectroscopy and mass spectrometry

Chemically Defined Sialoside Scaffolds for Investigation of Multivalent Interactions with Sialic Acid Binding Proteins

Four glycodendrons and a glycocluster were synthesized from carbohydrate building blocks to form paucivalent (di- to tetravalent) structures of controlled scaffold architectures. Enzymatic sialylation of the functionalized cluster and dendrons, terminated in lactose residues, generated a library of paucivalent synthetic sialosides displaying sialic acids with different dispositions. These newly constructed bioactive sialic acid-based structures were differentially recognized by sialoadhesin, a mammalian macrophage sialic acid binding protein. The binding of the sialosides to sialoadhesin was evaluated by an enzyme-linked immunosorbant assay to investigate the complementarity of scaffold structure and binding to sialoadhesin. Modulating the interaction between sialoadhesin and its sialic acid ligands has important implications in immunobiology

Multivalency and Cooperativity in Supramolecular Chemistry

Multivalent interactions, which rely upon noncovalent bonds, are essential ingredients in the mediation of biological processes, as well as in the construction of complex (super)structures for materials applications. A fundamental understanding of multivalency in supramolecular chemistry is necessary not only to construct motors and devices on the nanoscale but also to synthesize model systems to provide insight into how biological processes work. This Account focuses on the application of multivalency to supramolecular chemistry in particular and the nanosciences in general