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Enzyme hydrogel

Ling Dong, Junchao Qian, Zijuan Hai, Jinyong Xu, Wei Du, Kai Zhong, Gaolin Liang
Alkaline phosphatase (ALP) is an important enzyme but using ALP-instructed self-assembly of gadolinium nanofibers for enhanced T2-weighted magnetic resonance imaging (MRI) of tumor has not been reported. In this work, we rationally designed a hydrogelator Nap-FFFYp-EDA-DOTA(Gd) (1P) which, under the catalysis of ALP, was able to self-assemble into gadolinium nanofibers to form hydrogel Gel I for enhanced T2-weighted MR imaging of ALP activity in vitro and in tumor. T2 phantom MR imaging indicated that the transverse relaxivity (r2) value of Gel I was 33...
June 21, 2017: Analytical Chemistry
Kun Shi, Zhuang Liu, Chao Yang, Xiao-Ying Li, Yi-Min Sun, Yi Deng, Wei Wang, Xiao-Jie Ju, Rui Xie, Liang-Yin Chu
Poly(N-vinyl caprolactam) (PVCL) hydrogels usually suffer from the imporous structure and poor mechanical characteristics as well as the toxicity of crosslinkers, although PVCL itself is biocompatible. In this paper, novel biocompatible thermo-responsive poly(N-vinyl caprolactam)/clay nanocomposite (PVCL-Clay) hydrogels with macro-porous structure and improved mechanical characteristics are developed for the first time. The macro-porosity in the hydrogel is introduced by using Pickering emulsions as templates, which contain N-vinyl caprolactam (VCL) monomer as dispersed phase and clay sheets as stabilizers at the interface...
June 12, 2017: ACS Applied Materials & Interfaces
Rafael A Bini, Mônica F Silva, Laudemir C Varanda, Marcelo A da Silva, Cécile A Dreiss
We developed a nanocomposite gel composed of gelatin and poly(3-hydroxybutyrate) polymeric nanoparticles (PNP) to be used as an injectable gel for the contemporaneous, dual sustained release of bioactive molecules. The hydrogel matrix was formed by a very simple process, using either the physical gelation of gelatin or the natural enzyme transglutaminase to covalently cross-link the gelatin chains in the presence of embedded PNP. Oscillatory rheological measurements showed that the addition of the PNP induced an increase in the storage modulus compared to pure gelatin gels, for both physical and chemical gels...
May 22, 2017: Colloids and Surfaces. B, Biointerfaces
A Márquez, C Jiménez-Jorquera, C Domínguez, X Muñoz-Berbel
Simple and disposable point of care systems are usually the best solution for chronic patients to get a rapid diagnosis in home care context. However, their main drawback relies on the poor reliability derived from the low stability of the bio-recognition elements and low quality of the transducers. In the current work, we study the use of electrodeposited calcium alginate hydrogels as a biocompatible matrix in the development of enzymatic amperometric biosensors for whole blood analysis, to enhance the enzymes stability and to protect the transducer from biofouling...
May 30, 2017: Biosensors & Bioelectronics
Joana Marto, Cecilia Sangalli, Priscilla Capra, Paola Perugini, Andreia Ascenso, Lídia Gonçalves, Helena Ribeiro
N-Acetyl-d-glucosamine (NAG) has been recently considered for topical treatment of hyperpigmentation disorders due to its inhibitory effect on thyrosinase enzymes in melanocytes. NAG is a precursor of hyaluronic acid, increasing its amount in skin, and consequently, preserving the skin hydration and elasticity. It may also act as an emulsion stabilizer. Solid lipid nanoparticles (SLN) are advanced delivery systems successfully used in pharmaceutical and cosmetic formulations for the improvement of active molecules penetration into the skin...
June 21, 2017: Drug Development and Industrial Pharmacy
Jingwei Fan, Richen Li, Hai Wang, Xun He, Tan P Nguyen, Rachel A Letteri, Jiong Zou, Karen L Wooley
A polypeptide-based hydrogel system, when prepared from a diblock polymer with a ternary copolypeptide as one block, exhibited thermo-, mechano- and enzyme-responsive properties, which enabled the encapsulation of naproxen (Npx) during the sol-gel transition and its release in the gel state. Statistical terpolymerizations of l-alanine (Ala), glycine (Gly) and l-isoleucine (Ile) NCAs at a 1 : 1 : 1 feed ratio initiated by monomethoxy monoamino-terminated poly(ethylene glycol) afforded a series of methoxy poly(ethylene glycol)-block-poly(l-alanine-co-glycine-co-l-isoleucine) (mPEG-b-P(A-G-I)) block polymers...
June 28, 2017: Organic & Biomolecular Chemistry
Timothy E L Douglas, Agata Łapa, Sangram Keshari Samal, Heidi A Declercq, David Schaubroeck, Ana C Mendes, Pascal Van der Voort, Agnieszka Dokupil, Agnieszka Plis, Karel De Schamphelaere, Ioannis S Chronakis, Elżbieta Pamuła, Andre G Skirtach
Mineralization of hydrogel biomaterials is considered desirable to improve their suitability as materials for bone regeneration. Calcium carbonate (CaCO3 ) has been successfully applied as a bone regeneration material, but hydrogel-CaCO3 composites have received less attention. Magnesium (Mg) has been used as a component of calcium phosphate biomaterials to stimulate bone-forming cell adhesion and proliferation and bone regeneration in vivo, but its effect as a component of carbonate-based biomaterials remains uninvestigated...
June 1, 2017: Journal of Tissue Engineering and Regenerative Medicine
Li Zhou, Mathieu Morel, Sergii Rudiuk, Damien Baigl
DNA micro- and nanogels-small-sized hydrogels made of a crosslinked DNA backbone-constitute new promising materials, but their functions have mainly been limited to those brought by DNA. Here a new way is described to prepare sub-micrometer-sized DNA gels of controllable crosslinking density that are able to embed novel functions, such as an enzymatic activity. It consists of using proteins, instead of traditional base-pairing assembly or covalent approaches, to form crosslinks inside individual DNA molecules, resulting in structures referred to as intramolecularly protein-crosslinked DNA gels (IPDGs)...
May 31, 2017: Small
Hai-Yue Yu, Dan-Dan Ma, Bu-Ling Wu
OBJECTIVE: To evaluate the cytotoxicity of gelatin/alginate hydrogel scaffolds prepared by 3D bioprinting in human dental pulp cells (HDPCs) and compare the cell adhesion and proliferation of the cells seeded in the biomaterial using two different methods. METHODS: HDPCs isolated by tissue block culture and enzyme digestion were cultured and passaged. Gelatin/alginate hydrogel scaffolds were printed using a bioplotter, and the cytotoxicity of the aqueous extracts of the scaffold material was tested in the third passage of HDPCs using cell counting kit-8...
May 20, 2017: Nan Fang Yi Ke da Xue Xue Bao, Journal of Southern Medical University
Celia Ruiz-Palomero, Sandra Benítez-Martínez, M Laura Soriano, Miguel Valcárcel
A novel low-cost fluorimetric platform based on sulfur, nitrogen-codoped graphene quantum dots immersed into nanocellulosic hydrogels is designed and applied in detecting the laccase enzyme. Although most of methods for detecting laccase are based on their catalytic activity, which is strongly dependent on environmental parameters, we report a sensitive and selective method based on the fluorescence response of hydrogels containing graphene quantum dots (GQDs) acting as luminophore towards laccase. The easily-prepared gel matrix not only improves the fluorescence signal of GQDs by avoiding their self-quenching but also stabilizes their fluorescence signal and improves their sensitivity towards laccase...
June 29, 2017: Analytica Chimica Acta
Fanfan Fu, Zhuoyue Chen, Ze Zhao, Huan Wang, Luoran Shang, Zhongze Gu, Yuanjin Zhao
Biologically inspired self-healing structural color hydrogels were developed by adding a glucose oxidase (GOX)- and catalase (CAT)-filled glutaraldehyde cross-linked BSA hydrogel into methacrylated gelatin (GelMA) inverse opal scaffolds. The composite hydrogel materials with the polymerized GelMA scaffold could maintain the stability of an inverse opal structure and its resultant structural colors, whereas the protein hydrogel filler could impart self-healing capability through the reversible covalent attachment of glutaraldehyde to lysine residues of BSA and enzyme additives...
June 6, 2017: Proceedings of the National Academy of Sciences of the United States of America
Hiroyuki Kintsu, Taiga Okumura, Lumi Negishi, Shinsuke Ifuku, Toshihiro Kogure, Shohei Sakuda, Michio Suzuki
Biomineralization, in which organisms create biogenic hard tissues, with hardness or flexibility enhanced by organic-inorganic interaction is an interesting and attractive focus for application of biomimetic functional materials. Calcites in the prismatic layer of Pinctada fucata are tougher than abiotic calcites due to small crystal defects. However, the molecular mechanism of the defect formation remains unclear. Here, chitin and two chitinolytic enzymes, chitinase and chitobiase, were identified as organic matrices related to for the formation of small crystal defects in the prismatic layer...
May 17, 2017: Biochemical and Biophysical Research Communications
Jia-Wei Tay, Mark S Hoddle, Ashok Mulchandani, Dong-Hwan Choe
BACKGROUND: Insecticide sprays used for ant control cause environmental contamination. Liquid bait is a safe and effective alternative, but it requires bait stations to dispense the toxicant. We developed a biodegradable hydrogel to deliver liquid bait obviating the need for bait stations. RESULTS: Alginate hydrogel beads with preferred rigidity and maximum hydration in 25% sucrose solution were engineered by optimizing a crosslinking process. The moisture content of the substrate on which the beads were placed and the relative atmospheric humidity significantly influenced water loss dynamics of the hydrated hydrogel beads...
May 18, 2017: Pest Management Science
Hongjie Dai, Shiyi Ou, Zhijun Liu, Huihua Huang
Hydrogel composites based on pineapple peel carboxymethyl cellulose, polyvinyl alcohol and mesoporous silica SBA-15 were synthesized by an eco-friendly method of repeated freeze-thaw cycles for the application of papain immobilization. The experiment was optimized to obtain an efficient papain immobilization carrier. Simultaneously the immobilization conditions, including enzyme concentration, pH, crosslinker concentration and cross-linking time were optimized. The immobilized papain had maximum activity at low reaction temperature of 40°C and showed pH-sensitivity by exhibiting a rapid decrease of activity within a narrow range from pH 7...
August 1, 2017: Carbohydrate Polymers
Christian Doonan, Raffaele Riccò, Kang Liang, Darren Bradshaw, Paolo Falcaro
Many living organisms are capable of producing inorganic materials of precisely controlled structure and morphology. This ubiquitous process is termed biomineralization and is observed in nature from the macroscale (e.g., formation of exoskeletons) down to the nanoscale (e.g., mineral storage and transportation in proteins). Extensive research efforts have pursued replicating this chemistry with the overarching aims of synthesizing new materials of unprecedented physical properties and understanding the complex mechanisms that occur at the biological-inorganic interface...
May 10, 2017: Accounts of Chemical Research
Manfred F Maitz, Jan Zitzmann, Jasmin Hanke, Claudia Renneberg, Mikhail V Tsurkan, Claudia Sperling, Uwe Freudenberg, Carsten Werner
Feedback-controlled anticoagulant hydrogels were formed by crosslinking the anticoagulant heparin with star-shaped poly(ethylene glycol) using peptide linkers, which are selectively cleaved by different activated blood coagulation factors acting as proteolytic enzymes. Various cleavable peptide units, differing either in their thrombin turnover rates or in their responsiveness to factors activated earlier in the course of blood coagulation, were used for the formation of the biohybrid materials. Release triggered by the early coagulation factors Xa (FXa) or FXIIa/kallikrein was shown to enhance the efficiency of the released anticoagulant...
April 26, 2017: Biomaterials
Evgeny Katz, Maria Gamella, Marina Privman, Saira Bakshi, Artem Melman
Signal-controlled release of DNA from Fe3+-cross-linked alginate hydrogel electrochemically deposited on an electrode surface was studied. The multiple input signals were logically processed with the help of the enzyme biocatalyzed reactions. Boolean logic gates, OR, AND, INH, were realized with the biocatalytic reactions performed by the enzymes entrapped in the alginate film. Hydrogen peroxide produced by the enzymatic reactions resulted in the degradation of the alginate hydrogel and DNA release. The alginate degradation was facilitated by the formation of free radicals in the Fenton-type reaction catalyzed by iron cations cross-linking the alginate hydrogel...
May 3, 2017: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Inês P Moreira, Tomasz K Piskorz, Jan H van Esch, Tell Tuttle, Rein V Ulijn
We report on the biocatalytic activation of a self-assembling (unprotected) tripeptide to stabilize oil-in-water emulsions on-demand. This is achieved by the conversion of a phosphorylated precursor into a hydrogelator using alkaline phosphatase (AP) as the trigger. The rate of conversion, controlled by the amount of enzyme used, is shown to play a key role in dictating the morphology of the nanofibrous networks produced. When these amphiphilic tripeptides are used in biphasic mixtures, nanofibers are shown to self-assemble not only at the aqueous/organic interface but also throughout the surrounding buffer, thereby stabilizing the oil-in-water droplet dispersions...
May 12, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Xin Zhang, Jiayun Xu, Chao Lang, Shanpeng Qiao, Guo An, Xiaotong Fan, Linlu Zhao, Chunxi Hou, Junqiu Liu
Self-healing, one of the exciting properties of materials, is frequently used to repair the damage of biological and artificial systems. Here we have used enzymatic catalysis approaches to develop a fast self-healing hydrogel, which has been constructed by dynamic aldimine cross-linking of pillar[5]arene-derivant and dialdehyde-functionalized PEG followed by encapsulation of glucose oxidase (GOx) and catalase (CAT). In specific, the two hydroxyl groups at terminal of PEG4000 are functionalized with benzaldehydes that can interact with amino-containing pillar[5]arene-derivant through dynamic aldimine cross-links, resulting in reversible dynamic hydrogels...
May 5, 2017: Biomacromolecules
Yanxian Feng, Qiu Li, Dang Wu, Yiming Niu, Cheng Yang, Lei Dong, Chunming Wang
Biomaterials scaffolds designed for many regenerative applications are expected to support neo-vascularisation, which is now being hampered by two limitations - the instability of exogenous growth factors (GFs) that are delivered to promote angiogenesis; and the loss of extracellular matrix components that bind and stabilise GFs. Here, we report the design and evaluation of an injectable hydrogel system aimed at restoring a GF-binding microenvironment to enhance the pro-angiogenic functions of endogenous GFs...
April 25, 2017: Biomaterials
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