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Fengyang Xu, Jie Liu, Jian Tian, Lingfeng Gao, Xiaju Cheng, Yue Pan, Ziling Sun, Xinming Li
In this work, we reported the generation of a novel supramolecular hydrogelator from a peptide derivative which consisted of a structural motif (e.g., Fc-FF) for supramolecular self-assembly and a functional moiety (e.g., RGD) for integrin binding. Following self-assembly in water at neutral pH, this molecule firstly tended to form metastable spherical aggregates, which subsequently underwent a morphological transformation to form high-aspect-ratio nanostructures over 2 h when aged at room temperature. More importantly, because of the presence of nanoscale RGD clusters on the surface of nanostructures, the self-assembled nanomaterials (e...
October 19, 2016: ACS Applied Materials & Interfaces
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
Alondra Escudero-Castellanos, Blanca E Ocampo-García, Ma Victoria Domínguez-García, Jaime Flores-Estrada, Miriam V Flores-Merino
Hydrogels are suitable materials to promote cell proliferation and tissue support because of their hydrophilic nature, porous structure and sticky properties. However, hydrogel synthesis involves the addition of additives that can increase the risk of inducing cytotoxicity. Sterilization is a critical process for hydrogel clinical use as a proper scaffold for tissue engineering. In this study, poly(ethylene glycol) (PEG), poly(ethylene glycol)-chitosan (PEG-CH) and multi-arm PEG hydrogels were synthesized by free radical polymerization and sterilized by gamma irradiation or disinfected using 70 % ethanol...
December 2016: Journal of Materials Science. Materials in Medicine
Jack R Staunton, Wilfred Vieira, King Leung Fung, Ross Lake, Alexus Devine, Kandice Tanner
One of the hallmarks of the malignant transformation of epithelial tissue is the modulation of stromal components of the microenvironment. In particular, aberrant extracellular matrix (ECM) remodeling and stiffening enhances tumor growth and survival and promotes metastasis. Type I collagen is one of the major ECM components. It serves as a scaffold protein in the stroma contributing to the tissue's mechanical properties, imparting tensile strength and rigidity to tissues such as those of the skin, tendons, and lungs...
September 2016: Cellular and Molecular Bioengineering
Muhammad Faheem Akhtar, Muhammad Hanif, Nazar Muhammad Ranjha
Hydrogels are being investigated recently for the bioactive molecules (in particular pharmaceutical proteins) controlled release, such as matrices, and for the living cells encapsulation. Biodegradable nature of hydrogels has created much interest for drug delivery systems. The original three-dimensional structure disintegrates into nontoxic substances to ascertain an excellent biocompatibility of the gel. Chemical cross-linking is the highly resourceful method for the formation of hydrogels having an excellent mechanical strength...
September 2016: Saudi Pharmaceutical Journal: SPJ: the Official Publication of the Saudi Pharmaceutical Society
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
O V Kim, R I Litvinov, J Chen, D Z Chen, J W Weisel, M S Alber
Fibrin and collagen as well as their combinations play an important biological role in tissue regeneration and are widely employed in surgery as fleeces or sealants and in bioengineering as tissue scaffolds. Earlier studies demonstrated that fibrin-collagen composite networks displayed improved tensile mechanical properties compared to the isolated protein matrices. Unlike previous studies, here unconfined compression was applied to a fibrin-collagen filamentous polymer composite matrix to study its structural and mechanical responses to compressive deformation...
October 14, 2016: Matrix Biology: Journal of the International Society for Matrix Biology
Jinwoo Ma, Jaehun Lee, Sang Sub Han, Kyu Hwan Oh, Ki Tae Nam, Jeong-Yun Sun
Protein-based hydrogels have received attention for biomedical applications and tissue engineering because they are biocompatible and abundant. However, the poor mechanical properties of these hydrogels remain a hurdle for practical use. We have developed a highly stretchable and notch-insensitive hydrogel by integrating casein micelles into polyacrylamide (PAAm) networks. In the casein-PAAm hybrid gels, casein micelles and polyacrylamide chains synergistically enhance the mechanical properties. Casein-PAAm hybrid gels are highly stretchable, stretching to more than 35 times their initial length under uniaxial tension...
October 17, 2016: ACS Applied Materials & Interfaces
Muhammad Sallouh, Marvin Jarocki, Omar Sallouh, Patrick Degen, Andreas Faissner, Ralf Weberskirch
This article reports the behavior of embryonic neural stem cells on a hydrogel that combines cationic, non-specific cell adhesion motifs with glycine-arginine-glycine-aspartic acid-serine-phenylalanine (GRGDSF)-peptides as specific cell adhesion moieties. Therefore, three hydrogels are prepared by free radical polymerization that contains either a GRGDSF-peptide residue (P1), amino ethylmethacrylate as a cationic residue (P2), or a combination of both motifs (P3). For each gel, cross linker concentrations of 8 mol% is used to have a comparable gel stiffness of 8-9 kPa...
October 17, 2016: Macromolecular Bioscience
Andre Childs, Hao Li, Daniella M Lewittes, Biqin Dong, Wenzhong Liu, Xiao Shu, Cheng Sun, Hao F Zhang
Contact lenses are increasingly used in laboratories for in vivo animal retinal imaging and pre-clinical studies. The lens shapes often need modification to optimally fit corneas of individual test subjects. However, the choices from commercially available contact lenses are rather limited. Here, we report a flexible method to fabricate customized hydrogel contact lenses. We showed that the fabricated hydrogel is highly transparent, with refractive indices ranging from 1.42 to 1.45 in the spectra range from 400 nm to 800 nm...
October 17, 2016: Scientific Reports
Zhijun Chen, Yubing Xiong, Roberto Etchenique, Si Wu
Near-infrared light can be used to manipulate the pH of aqueous solutions by using upconverting nanoparticle-assisted photocleavage of a ruthenium complex photobase. Upconverting nanoparticles and the photobase were also introduced into a pH-responsive hydrogel, in which near-infrared irradiation induced swelling of the hydrogel.
October 17, 2016: Chemical Communications: Chem Comm
Andreas Pinegger, Selina C Wriessnegger, Josef Faller, Gernot R Müller-Putz
One important aspect in non-invasive brain-computer interface (BCI) research is to acquire the electroencephalogram (EEG) in a proper way. From an end-user perspective, it means with maximum comfort and without any extra inconveniences (e.g., washing the hair), whereas from a technical perspective, the signal quality has to be optimal to make the BCI work effectively and efficiently. In this work, we evaluated three different commercially available EEG acquisition systems that differ in the type of electrodes (gel-, water-, and dry-based), the amplifier technique, and the data transmission method...
2016: Frontiers in Neuroscience
Wing-Fu Lai, Zhen-Dan He
Hydrogels are swellable polymer networks which can imbibe a substantial amount of fluids while retaining their internal network structure. Compared to bulk hydrogels, hydrogel nanoparticles exhibit added values in drug delivery because they can be internalized into cells to deliver pharmaceutical agents into the cytosol. Their large surface area also allows for multivalent conjugations, making optimization of the nanoparticles towards in vivo and clinical applications possible. These features, together with the tunable properties and biocompatibility of hydrogels, account for the widespread use of hydrogel-based nanoparticulate systems in drug formulation...
October 13, 2016: Journal of Controlled Release: Official Journal of the Controlled Release Society
Zhicheng Wang, Jia Nong, Robert B Shultz, Zhiling Zhang, Veronica J Tom, Ravi K Ponnappan, Yinghui Zhong
Many mechanisms contribute to the secondary injury cascades following traumatic spinal cord injury (SCI). However, most current treatment strategies only target one or a few elements in the injury cascades, and have been largely unsuccessful in clinical trials. Minocycline hydrochloride (MH) is a clinically available antibiotic and anti-inflammatory drug that has been shown to target a broad range of secondary injury mechanisms via its anti-inflammatory, anti-oxidant, and anti-apoptotic properties. However, MH is only neuroprotective at high concentrations...
October 5, 2016: Biomaterials
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
Luis M De Leon-Rodriguez, Yacine Hemar, Guang Mo, Alok K Mitra, Jillian Cornish, Margaret A Brimble
We report the synthesis and characterization of multifunctional peptides comprised of a hydrogel forming β-sheet peptide segment and a matrix metalloproteinase 2 substrate containing a propargylglycinyl linker that is further derivatized with a RGD peptide sequence via "click" chemistry. In contrast to currently known systems, these multifunctional peptides formed gels that are stiffer than those formed by their respective precursors. All the peptides showed reversible thermoresponsive properties, which render them as suitable lead systems for a variety of possible biomedical applications...
October 12, 2016: Acta Biomaterialia
Leise Riber, Mette Burmølle, Martin Alm, Stefan M Milani, Peter Thomsen, Lars H Hansen, Søren J Sørensen
The spread of antimicrobial resistance, usually mediated by horizontal transfer of plasmids, limits the options of treating bacterial infections and thereby poses a crucial human health problem. The disturbance of plasmid stability within bacterial species in clinical environments serves as a novel strategy to reduce the development and dissemination of antibiotic resistance. We tested the ability of irgasan to destabilize plasmids from Escherichia coli K-12 cells when added directly into liquid growth medium at concentrations below levels of marked bacterial growth inhibition, or when released into liquid growth medium from irgasan-impregnated Interpenetrating Polymer Network (IPN) silicone hydrogel objects, a novel technology developed as drug-delivery platform...
October 12, 2016: Plasmid
Hongmei Xia, Yinxiang Xu, Zhiqing Cheng, Yongfeng Cheng
Tetramethylpyrazine (TMP) was extracted from Ligusticum chuanxiong hort. The compound is known to have a variety of medicinal functions; in particular, it is used for the treatment of cerebral ischemic diseases. TMP-loaded hydrogels offer an excellent preparation with the capacity to bypass the blood-brain barrier, allowing treatment of the brain through intranasal administration. We prepared TMP-loaded hydrogels using carbomer 940 and evaluated the release of TMP from the hydrogel. We determined the release rate using Franz-type diffusion cell experiments with a subcutaneous-mucous-membrane model and also by a molecular dynamics (MD) simulation...
October 14, 2016: AAPS PharmSciTech
Christopher Hernandez, Natalia Gawlik, Monika Goss, Haoyan Zhou, Selva Jeganathan, Danielle Gilbert, Agata A Exner
In situ forming implants (ISFIs) have shown promise as a sustained, local drug delivery system for therapeutics in a variety of applications.However, development of ISFIs has been hindered by poor correlation between in vitro study results and in vivo performance.In contrast to oral dosage forms, there is currently no clear consensus on a standard for in vitro drug dissolution studies for parenteral formulations. Recent studies have suggested that the disparity between in vivo and in vitro behavior of phase-inverting ISFIs may be, in part, due to differences in injection site stiffness...
October 11, 2016: Journal of Controlled Release: Official Journal of the Controlled Release Society
Dragica Spasojević, Danica Zmejkoski, Jasmina Glamočlija, Miloš Nikolić, Marina Soković, Verica Milošević, Ivana Jarić, Marijana Stojanović, Emilija Marinković, Talin Barisani-Asenbauer, Radivoje Prodanović, Miloš Jovanović, Ksenija Radotić
Nowadays bacterial resistance to known antibiotics is a serious health problem. In order to achieve more efficient treatment, lately there is an effort to find new substances, such as certain biomaterials, that are non-toxic to humans with antibiotic potential. Lignins and lignin-derived compounds have been proposed to be good candidates for use in medicine and health maintenance. In this study, the antibacterial activity of the lignin model polymer dehydrogenate polymer (DHP) in alginate hydrogel (Alg) was studied...
September 30, 2016: International Journal of Antimicrobial Agents
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