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Xiuli Hu, Yuqi Zhang, Zhigang Xie, Xiabin Jing, Adriano Bellotti, Zhen Gu
Polymersomes, the structural analogues of liposomes, are hollow structures enclosed by a bilayer membrane made from amphiphilic copolymers. Polymersomes have been proposed to mimic the structure and properties of cellular membranes and viral capsids. Excellent robustness and stability, chemical versatility for tunable membrane properties and surface functionalization make polymersomes attractive candidates for drug delivery, diagnostic imaging, nanoreactor vessels, and artificial organelles. In further biomimetic strategies, stimuli-responsive polymersomes that can recognize various external physical or internal biological environmental stimuli and conduct "on demand" release in dose-, spatial-, and temporal-controlled fashions have been widely developed...
February 17, 2017: Biomacromolecules
Barbara Tabisz, Werner Schmitz, Michael Schmitz, Tessa Luehmann, Eva Heusler, Jens-Christoph Rybak, Lorenz Meinel, Juliane E Fiebig, Thomas D Mueller, Joachim Nickel
The regenerative potential of bone is strongly impaired in pathological conditions, such as nonunion fractures. To support bone regeneration various scaffolds have been developed in the past, which have been functionalized with osteogenic growth factors such as bone morphogenetic proteins (BMPs). However, most of them required supra-physiological levels of these proteins leading to burst releases, thereby causing severe side effects. Site-specific, covalent coupling of BMP2 to implant materials might be an optimal strategy in order to overcome these problems...
February 17, 2017: Biomacromolecules
Aleeza Farrukh, Julieta I Paez, Marcelo Salierno, Wenqiang Fan, Benedikt Berninger, Aránzazu Del Campo
Biomaterials for cell culture allowing simple and quantitative presentation of instructive cues enable rationalization of the interplay between cells and their surrounding microenvironment. Poly(acrylamide) (PAAm) hydrogels are popular 2D-model substrates for this purpose. However, quantitative and reproducible biofunctionalization of PAAm hydrogels with multiple ligands in a trustable, controlled, and independent fashion is not trivial. Here, we describe a method for bifunctional modification of PAAm hydrogels with thiol- and amine- containing biomolecules with controlled densities in an independent, orthogonal manner...
February 17, 2017: Biomacromolecules
Chu-Harn Chiang, Yi-Hsuan Fu, Jia-Cherng Horng
Most of natural collagens are heterotrimers composed of two (AAB) or three (ABC) different peptide chains, and thus heterotrimeric constructs are preferable to mimic natural collagens. Exploring the forces to assemble synthetic collagen-mimetic peptides (CMPs) into heterotrimers has been an attractive topic in preparing collagen-related biomaterials. Here we designed and synthesized two cationic CMPs (CR and CK) in which multiple Arg or Lys residues are installed in their C-terminal region, and one aromatic CMP (CF) whose C-terminal end contains multiple Phe residues...
February 16, 2017: Biomacromolecules
Sunting Xuan, Sudipta Gupta, Xin Li, Markus Bleuel, Gerald J Schneider, Donghui Zhang
Well-defined polypeptoids bearing oligomeric ethylene glycol side chains (PNMe(OEt)nG, n = 1-3) with a controlled molecular weight (3.26-28.6 kg/mol) and narrow molecular weight distribution (polydispersity index, PDI = 1.03-1.10) have been synthesized by ring-opening polymerization of the corresponding N-carboxyanhydrides having oligomeric ethylene glycol side chains (Me(OEt)n-NCA, n = 1-3) using primary amine initiators. Kinetic studies of polymerization revealed a first-order dependence on the monomer concentration, consistent with living polymerization...
February 16, 2017: Biomacromolecules
Mary C Regier, Sara I Montanez-Sauri, Michael P Schwartz, William L Murphy, David J Beebe, Kyung Eun Sung
As a result of improved relevance to in vivo physiology, in vitro studies are increasingly performed in diverse, three-dimensional (3D) biomaterials. However, material-cell type pairing effects on cytokine availability remain unclear. We cultured five cell types in agarose, alginate, collagen, Matrigel, or RGD-functionalized polyethylene glycol (PEG) hydrogels. We measured 21 cytokines in the conditioned media, and we identified differences in measured cytokine levels that were cell-type- or material-dependent...
February 16, 2017: Biomacromolecules
Jason Burke, Roberto Donno, Richard d'Arcy, Sarah Cartmell, Nicola Tirelli
This study focuses on the comparative evaluation of star (branched) and linear poly(l,d-lactic acid) (PDLLA) as degradable materials employed in controlled release. The polymers were prepared via ring-opening polymerization initiated by decanol (linear), pentaerythritol (4-armed star) and dipentaerythritol (6-armed star), and processed both in the form of films and nanoparticles. Independent of the length or number of their arms, star polymers degrade slower than linear polymers, possibly through a surface (vs bulk) mechanism...
February 16, 2017: Biomacromolecules
Jiaqi Guo, Ilari Filpponen, Leena-Sisko Johansson, Pezhman Mohammadi, Mika Latikka, Markus B Linder, Robin H A Ras, Orlando J Rojas
We present an efficient approach to synthesize cellulose nanocrystal (CNC) hybrids with magnetically responsive Fe3O4 nanoparticles that were synthesized using the (Fe3+/Fe2+) co-precipitation. After TEMPO-catalyzed oxidation of CNC, carbodiimide (EDC/NHS) was used for coupling amine-containing iron oxide nanoparticles that were achieved by dopamine ligand exchange (NH2-Fe3O4 NPs). The as prepared hybrids (Fe3O4@CNC) were further complexed with Cu(II) ions to produce specific protein binding sites. The performance of magnetically responsive Cu-Fe3O4@CNC hybrid was assessed by selectively separating lysozyme from aqueous media...
February 15, 2017: Biomacromolecules
Alexander Raup, Hui Wang, Christopher V Synatschke, Valerie Jerome, Seema Agarwal, Dmitry V Pergushov, Axel H E Mueller, Ruth Freitag
Polycations are popular agents for non-viral delivery of DNA to mammalian cells. Adding hydrophobic, biodegradable, or cell penetrating functions could help to improve their performance, which at present is below that of viral agents. A crucial first step in gene delivery is the complexation of the DNA. The characteristics of these 'polyplexes' presumably influence or even determine the subsequent steps of membrane passage, intracellular travelling / DNA release, and nuclear up-take. Herein, polyplexes formed with linear poly(ethylenimine) (l-PEI) are compared to complexes generated with functionalized diblock copolymers...
February 15, 2017: Biomacromolecules
JooChuan Ang, Benson T Jung, He Dong, Ting Xu
A subtle but highly pertinent factor in the self-assembly of hierarchical nanostructures is the kinetic landscape. Self-assembly of a hierarchical multicomponent system requires the intricate balance of noncovalent interactions on a similar energy scale that can result in several self-assembly processes occurring at different time scales. We seek to understand the hierarchical assemblies within an amphiphilic 3-helix peptide-PEG-lipid conjugate system in the formation process of highly stable 3-helix micelles (3HMs)...
February 15, 2017: Biomacromolecules
Jun Jie Loke, Akshita Kumar, Shawn Hoon, Chandra S Verma, Ali Miserez
Marine snail egg capsules are shock-absorbing bio-elastomers made from precursor "egg case proteins" (ECPs) that initially lack long-range order. During capsule formation, these proteins self-assemble into coiled-coil filaments that subsequently align into microscopic layers, a multi-scale process which is crucial to the capsules' shock-absorbing properties. In this study, we show that the self-assembly of ECPs into their functional capsule material is mediated by a bundling protein that facilitates the aggregation of coiled-coil building blocks and their gelation into a pre-final capsule prior to final stabilization...
February 14, 2017: Biomacromolecules
Congyue Annie Peng, Julia A Russo, Todd A Lyda, William Richard Marcotte
Spider dragline silk is a proteinaceous material that combines superior toughness and biocompatibility, a promising bio-material. The distinct protein structure and the fiber formation process contribute to the superior toughness of dragline silk. Previously, we have produced recombinant spider silk-like proteins in transgenic tobacco that are readily purified from plant extracts. The plant-derived spidroin-like proteins consisted of native major ampullate spidroin 1 or spidroin 2 N- and C-termini flanking 8, 16, or 32 copies of their respective consensus block repeats (mini-spidroins)...
February 14, 2017: Biomacromolecules
Vinh X Truong, Kelly M Tsang, John S Forsythe
Swelling of hydrogels leads to a decrease in mechanical performance coupled with complications in solute diffusion. In addition, hydrogel swelling affects patient safety in biomedical applications such as compression of tissue and fluid blockage. A conventional strategy for suppressing swelling is to introduce a thermoresponsive polymer with a lower critical solution temperature (LCST) within the network structure to counter the water uptake at elevated temperature. However, altering the gels mechanical strength via modification of the network structure often affects the water uptake behavior and thus a non-swelling platform with tunable mechanical properties suitable for various biomedical applications is desirable...
February 14, 2017: Biomacromolecules
Greta Becker, Lisa-Maria Ackermann, Eugen Schechtel, Markus Klapper, Wolfgang Tremel, Frederik R Wurm
Numerous catechol-containing polymers, including biodegradable polymers, are currently heavily discussed for modern biomaterials. However, there is no report combining poly(phosphoester)s (PPEs) with catechols. Adhesive PPEs have been prepared via acyclic diene metathesis polymerization. A novel acetal-protected catechol phosphate monomer was homo- and copolymerized with phosphoester comonomers with molecular weights up to 42000 g/mol. Quantitative release of the catechols was achieved by careful hydrolysis of the acetal groups without backbone degradation...
February 14, 2017: Biomacromolecules
Jun Yang, Feng Xu, Chun-Rui Han
Utilization of reversible interactions as sacrificial bonds in biopolymers is critical for the integral synthesis of mechanically superior biological materials. In this work, cellulose nanofibrils (CNFs) reinforced covalent polyacrylamide (PAAm) composite hydrogels are immersed into multivalent cation (Ca2+, Zn2+, Al3+, and Ce3+) aqueous solution to form ionic association among CNFs, leading to the ionic-covalent cross-linked hydrogels. The cations promote the formation of porous networks of nanofibrils by screening the repulsive negative charges on CNF surface and dominate the mechanical properties and self-recovery efficiency of the hydrogels, resulting in mechanically reinforced ionic hydrogels with stiff (Young's modulus 257 kPa) and tough properties (fracture toughness 386 kJ/m3)...
February 13, 2017: Biomacromolecules
Ji Yang, Fangyu Cheng, Huimin Yu, Junting Wang, Guo Zhi Gang, Gregory Stephanopoulos
The essential pathophysiological roles of hyaluronic acid (HA) strongly depend on HA binding and HA size. Here we deployed the atomic vision of molecular dynamics (MD) simulation to experimentally investigate the influence of C-terminal mutations of Streptococcus equisimilis hyaluronan synthase (SeHAS) on HA product synthesis in Escherichia coli. R413 was vital for HA production, as the removal or mutation of R413 led to inactivation of SeHAS. MD simulations indicated that R406-R413 constituted an HA-binding pattern that stabilized the HA-SeHAS complex...
February 13, 2017: Biomacromolecules
Edith Oyen, Charlotte Martin, Vicky Caveliers, Annemieke Madder, Bruno Van Mele, Richard Hoogenboom, Sophie Hernot, Steven Ballet
Hydrogels are promising materials for biomedical applications such as tissue engineering and controlled drug release. In the last two decades, the subclass of peptide hydrogels is gaining increasing interest from the scientific community thanks to their numerous advantages, such as biocompatibility, biodegradability and most importantly, injectability. Here, we report on a hydrogel consisting of the amphipathic hexapeptide H-FEFQFK-NH2, which has previously shown promising in vivo properties in terms of releasing morphine...
February 13, 2017: Biomacromolecules
Linnea Nilebäck, Jesper Niels Hedin, Mona Widhe, Lotta S Floderus, Annika Krona, Helena Bysell, My Hedhammar
Functionalization of biomaterials with biologically active peptides can improve their performance after implantation. By genetic fusion to self-assembling proteins, the functional peptides can easily be presented on different physical formats. Herein, a chemical-free coating method based on self-assembly of the recombinant spider silk protein 4RepCT is described and used to prepare functional coatings on various biomaterial surfaces. The silk assembly on surfaces was studied in real-time, revealing occurrence of continuous assembly of silk proteins onto surfaces and formation of nanofibrillar structures...
February 13, 2017: Biomacromolecules
Calogero Fiorica, Nicolò Mauro, Giovanna Pitarresi, Cinzia Scialabba, Fabio S Palumbo, Gaetano Giammona
Here, we reported the production of hyaluronic acid/polyaspartamide-based double-network nanogels for the potential treatment of colorectal carcinoma. Graphene oxide, thanks to the huge aromatic surface area, allows to easily load high amount of irinotecan (33.0 % w/w) and confers to the system hyperthermic properties when irradiated with a near infrared (NIR) laser beam. We demonstrate that the release of antitumor drug is influenced both by the pH of the external medium and the NIR irradiation process. In vitro biological studies, conducted on human colon cancer cells (HCT 116), revealed that nanogels are uptaken by the cancer cells and, in the presence of the antitumor drug, can produce a synergistic hyperthermic/cytotoxic effect...
February 13, 2017: Biomacromolecules
Hang Zhang, Jinlong Chen, Xiaojie Zhang, Chunsheng Xiao, Xuesi Chen, Youhua Tao, Xianhong Wang
We describe here the synthesis of multidentate comb-shaped polypeptides bearing trithiocarbonate functionality and their application in the preparation of water-soluble quantum dots (QDs). A new l-lysine-based N-carboxyanhydride monomer containing trithiocarbonate functionality was designed and synthesized. Ring-opening polymerization of the resulting monomer initiated by hexamethyldisilazane affords polypeptides bearing pendent trithiocarbonate groups (P(TTCLys)) with controllable molecular weights. P(TTCLys) was then applied to mediate the reversible addition-fragmentation chain-transfer polymerization of oligo(ethylene glycol)acrylate for the metal-free preparation of hydrophilic comb-shaped polypeptides...
February 13, 2017: Biomacromolecules
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