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Enzyme hydrogel

Kaixuan Ren, Haitao Cui, Qinghua Xu, Chaoliang He, Gao Li, Xuesi Chen
Bone marrow-derived mesenchymal stem cells (BMSCs) possess vast potential for tissue engineering and regenerative medicine. In this study, an injectable hydrogel comprising poly(L-glutamic acid)-graft-tyramine (PLG-g-TA) with tunable microenvironment was developed via enzyme-catalyzed crosslinking, and used as artificial extracellular matrix (ECM) to explore the behaviors of BMSCs during three dimensional (3D) culture. It was found that the mechanical property, porous structure as well as degradation process of the hydrogels could be tuned by changing the copolymer concentration...
October 24, 2016: Biomacromolecules
David P Hickey
Enzymatic glucose biosensors and biofuel cells make use of the electrochemical transduction between an oxidoreductase enzyme, such as glucose oxidase (GOx), and an electrode to either quantify the amount of glucose in a solution or generate electrical energy. However, many enzymes including GOx are not able to electrochemically interact with an electrode surface directly, but require an external electrochemical relay to shuttle electrons to the electrode. Ferrocene-modified linear poly(ethylenimine) (Fc-LPEI) redox polymers have been designed to simultaneously immobilize glucose oxidase (GOx) at an electrode and mediate electron transfer from their flavin adenine dinucleotide (FAD) active site to the electrode surface...
2017: Methods in Molecular Biology
Hung-Yi Liu, Tanja Greene, Tsai-Yu Lin, Camron S Dawes, Murray Korc, Chien-Chi Lin
: The complex network of biochemical and biophysical cues in the pancreatic desmoplasia not only presents challenges to the fundamental understanding of tumor progression, but also hinders the development of therapeutic strategies against pancreatic cancer. Residing in the desmoplasia, pancreatic stellate cells (PSCs) are the major stromal cells affecting the growth and metastasis of pancreatic cancer cells by means of paracrine effects and extracellular matrix protein deposition. PSCs remain in a quiescent/dormant state until they are 'activated' by various environmental cues...
October 18, 2016: Acta Biomaterialia
Zhi Zhao, Nasser Hamdan, Li Shen, Hanqing Nan, Abdullah Almajed, Edward Kavazanjian, Ximin He
We have developed a novel method to synthesize a hyper-branched bio-mimetic hydrogel network across a soil matrix to improve the mechanical strength of the loose soil and simultaneously mitigate potential contamination due to a harmful by-product. This method successfully yielded a hierarchical structure that possesses the water retention, ion absorption, and soil aggregation capabilities of plant root systems in a chemically controllable manner. Inspired by the robust organic-inorganic composites found in many living organisms, we have combined this hydrogel network with a calcite biomineralization process to stabilize soil...
October 20, 2016: Environmental Science & Technology
Jingjing Hu, Yihua Chen, Yunqi Li, Zhengjie Zhou, Yiyun Cheng
The development of thermo-degradable hydrogels is of great importance in drug delivery. However, it still remains a huge challenge to prepare thermo-degradable hydrogels with inherent degradation, reproducible, repeated and tunable dosing. Here, we reported a thermo-degradable hydrogel that is rapidly degraded above 44 °C by a facile chemistry. Besides thermo-degradability, the hydrogel also undergoes rapid photolysis with ultraviolet light. By embedding photothermal nanoparticles or upconversion nanoparticles into the gel, it can release the entrapped cargoes such as dyes, enzymes and anticancer drugs in an on-demand and dose-tunable fashion upon near-infrared light exposure...
October 11, 2016: Biomaterials
Heidi Stoll, Heidrun Steinle, Katharina Stang, Silju Kunnakattu, Lutz Scheideler, Bernd Neumann, Julia Kurz, Ilka Degenkolbe, Nadja Perle, Christian Schlensak, Hans Peter Wendel, Meltem Avci-Adali
Hemocompatibility and cytocompatibility of biomaterials codetermine the success of tissue engineering applications. DNA, the natural component of our cells, is an auspicious biomaterial for the generation of designable scaffolds with tailorable characteristics. In this study, a combination of rolling circle amplification and multiprimed chain amplification is used to generate hydrogels at centimeter scale consisting solely of DNA. Using an in vitro rotation model and fresh human blood, the reaction of the hemostatic system on DNA hydrogels is analyzed...
October 19, 2016: Macromolecular Bioscience
Thavasyappan Thambi, V H Giang Phan, Doo Sung Lee
Stimuli-sensitive injectable polymeric hydrogels are one of the promising delivery vehicles for the controlled release of bioactive agents. In aqueous solutions, these polymers are able to switch sol-to-gel transitions in response to various stimuli including pH, temperature, light, enzyme and magnetic field. Therapeutic agents, including chemotherapeutic agents, protein drugs or cells, are easily mixed with the low-viscous polymer solution at room temperature. Therapeutic-agents-containing solutions are readily injected into target sites through syringe or catheter, which could form hydrogel depot and serve as bioactive molecules release carriers...
October 18, 2016: Macromolecular Rapid Communications
Jamal Mohammadi Ayenehdeh, Bahareh Niknam, Seyed Mahmoud Hashemi, Hossein Rahavi, Nima Rezaei, Masoud Soleimani, Nader Tajik
BACKGROUND: Islet transplantation could be an ideal alternative treatment to insulin therapy for type 1 diabetes Mellitus (T1DM). This clinical and experimental field requires a model that covers problems such as requiring a large number of functional and viable islets, the optimal transplantation site, and the prevention of islet dispersion. Hence, the methods of choice for isolation of functional islets and transplantation are crucial. METHODS: The present study has introduced an experimental model that overcomes some critical issues in islet transplantation, including in situ pancreas perfusion by digestive enzymes through common bile duct...
October 18, 2016: Iranian Biomedical Journal
Hao Meng, Yuan Liu, Bruce P Lee
: Mussel adhesive moiety, catechol, has been utilized to design a wide variety of biomaterials. However, the biocompatibility and biological responses associated with the byproducts generated during the curing process of catechol has never been characterized. An in situ curable polymer model system, 4-armed polyethylene glycol polymer end-capped with dopamine (PEG-D4), was used to characterize the production of hydrogen peroxide (H2O2) during the oxidative crosslinking of catechol. Although PEG-D4 cured rapidly (under 30s), catechol continues to polymerize over several hours to form a more densely crosslinked network over time...
October 12, 2016: Acta Biomaterialia
Satyavrata Samavedi, Patricia Diaz-Rodriguez, Joshua Dean Erndt-Marino, Mariah Hahn
The goal of the present study was to develop a fully 3D co-culture system that would allow for systematic investigation of the interplay between activated macrophages and chondrocytes in osteoarthritic disease progression. Toward this end, our 3D co-culture system was first validated against existing in vitro osteoarthritis models, which have generally cultured healthy normal chondrocytes (NCs) ─ in 2D or 3D ─ with 2D classically activated macrophages (AMs). In the current work, NCs and AMs were both encapsulated within poly(ethylene glycol) diacrylate hydrogels to better mimic the native 3D environments of both cell types within the osteoarthritic joint...
October 13, 2016: Tissue Engineering. Part A
Celine A Mandon, Loïc Jacques Blum, Christophe Andre Marquette
3D printing technologies will impact in a near future the biosensor community, both at the sensor prototyping level and the sensing layer or-ganization level. The present study aimed at demonstrating the capacity of one 3D printing technique, the Digital Light Processing (DLP), to produce hydrogel sensing layers with 3D shapes unreachable using conventional molding procedures. The first model of sensing layer was com-posed of a sequential enzymatic reaction (glucose oxidase and peroxidase) which generated chemiluminescent signal in the presence of glucose and luminol...
October 11, 2016: Analytical Chemistry
Gabriel S Longo, Monica Olvera de la Cruz, Igal Szleifer
The swelling/deswelling transition of pH-sensitive, electrode-grafted, hydrogel nanofilms when exposed to electric fields is studied by theoretical analysis. In acidic conditions, the response of these films to changes in pH is dominated by network-surface interactions, while intra-network electrostatic repulsions, which are highly modulated by the adsorption of salt ions, determine material response at a higher pH. Film thickness is a non-monotonic function of solution pH and displays a local maximum, a local minimum or both, depending on the salt concentration and the applied voltage...
October 12, 2016: Soft Matter
Justine J Roberts, Pratibha Naudiyal, Khoon S Lim, Laura A Poole-Warren, Penny J Martens
BACKGROUND: Dityrosine crosslinking in proteins is a bioinspired method of forming hydrogels. This study compares oxidative enzyme initiators for their relative crosslinking efficiency and cytocompatibility using the same phenol group and the same material platform. Four common enzyme and enzyme-like oxidative initiators were probed for resulting material properties and cell viability post-encapsulation. RESULTS: All four initiators can be used to form phenol-crosslinked hydrogels, however gelation rates are dependent on enzyme type, concentration, and the oxidant...
2016: Biomaterials Research
Julia Schückel, Stjepan Krešimir Kračun, William G T Willats
Carbohydrates active enzymes (CAZymes) have multiple roles in vivo and are widely used for industrial processing in the biofuel, textile, detergent, paper and food industries. A deeper understanding of CAZymes is important from both fundamental biology and industrial standpoints. Vast numbers of CAZymes exist in nature (especially in microorganisms) and hundreds of thousands have been cataloged and described in the carbohydrate active enzyme database (CAZy). However, the rate of discovery of putative enzymes has outstripped our ability to biochemically characterize their activities...
2016: Journal of Visualized Experiments: JoVE
Pasquale Picone, Giovanna Navarra, Chiara Peres, Marco Contardi, Pier Luigi San Biagio, Marta Di Carlo, Daniela Giacomazza, Valeria Militello
Proteolytic resistance is a relevant aspect to be tested in the formulation of new nanoscale biomaterials. The action of proteolytic enzymes is a very fast process occurring in the range of few minutes. Here, we report data concerning the proteolytic resistance of a heat-set BSA hydrogel obtained after 20-hour incubation at 60 °C prepared at the pH value of 3.9, pH at which the hydrogel presents the highest elastic character with respect to gel formed at pH 5.9 and 7.4 "Heat-and pH-induced BSA conformational changes, hydrogel formation and application as 3D cell scaffold" (G...
December 2016: Data in Brief
Gomaa F El-Fawal, Abdelrahman M Yassin, Nehal M El-Deeb
Material barrier properties to microbes are an important issue in many pharmaceutical applications like wound dressings. A wide range of biomaterials has been used to manage the chronic inflamed wounds. Eight hydrogel membranes of poly vinyl alcohol (PVA) with κ-carrageenan (KC) and Lactobacillus bulgaricus extract (LAB) have been prepared by using freeze-thawing technique. To evaluate the membranes efficiency as wound dressing agents, various tests have been done like gel fraction, swelling behavior, mechanical properties, etc...
September 12, 2016: AAPS PharmSciTech
Raluca Vulpe, Didier Le Cerf, Virginie Dulong, Marcel Popa, Catalina Peptu, Liliana Verestiuc, Luc Picton
The elaboration of chemically crosslinked hydrogels based on collagen (C), hyaluronanic acid (HA) and sericin (S) with different polymer ratios was investigated by in-situ rheology. This reaction was performed via amide or ester bond reaction activated by carbodiimide, in pure water. Prior to molecule crosslinking, the rheological behaviour of the biopolymers (alone or in mixture) was characterized in a semi-dilute concentration regime. Both flow and dynamic measurements showed that uncrosslinked collagen alone appears to be rather elastic with yield stress properties, whereas uncrosslinked HA alone appears to be rather shear thinning and viscoelastic in agreement with entangled polymer behaviour...
December 1, 2016: Materials Science & Engineering. C, Materials for Biological Applications
Shaohua Zhang, Zhongyi Jiang, Jiafu Shi, Xueyan Wang, Pingping Han, Weilun Qian
Design and preparation of high-performance immobilized biocatalysts with exquisite structures and elucidation of their profound structure-performance relationship are highly desired for green and sustainable biotransformation processes. Learning from nature has been recognized as a shortcut to achieve such an impressive goal. Loose connective tissue, which is composed of hierarchically organized cells by extracellular matrix (ECM) and is recognized as an efficient catalytic system to ensure the ordered proceeding of metabolism, may offer an ideal prototype for preparing immobilized biocatalysts with high catalytic activity, recyclability, and stability...
September 28, 2016: ACS Applied Materials & Interfaces
Meiling Lian, Xu Chen, Yanluo Lu, Wensheng Yang
A self-assembled peptide nanofibrous hydrogel composed of N-fluorenylmethoxycarbonyl-diphenylalanine (Fmoc-FF) was used to construct a smart biointerface. This biointerface was then used for enzyme-based electrochemical biosensing and cell monitoring. The Fmoc-FF hydrogel had two functions. One was as a matrix to embed an enzyme model, horseradish peroxidase (HRP), during the self-assembly of Fmoc-FF peptides. The other was use as a robust substrate for cell adhesion. Experimental data demonstrated that HRP was immobilized in a stable manner within the peptide hydrogel, and that HRP retained its inherent bioactivity toward H2O2...
September 28, 2016: ACS Applied Materials & Interfaces
Kusum Solanki, Walaa Abdallah, Scott Banta
Alcohol dehydrogenase D (AdhD) is a monomeric thermostable alcohol dehydrogenase from the aldo-keto reductase (AKR) superfamily of proteins. We have been exploring various strategies of engineering the activity of AdhD so that it could be employed in future biotechnology applications. Driven by insights made in other AKRs, we have made mutations in the cofactor-binding pocket of the enzyme and broadened its cofactor specificity. A pre-steady state kinetic analysis yielded new insights into the conformational behavior of this enzyme...
September 5, 2016: Biotechnology Journal
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