Search results for "Gels"

Disulfide-crosslinked hyaluronan-gelatin hydrogel films: a covalent mimic of the extracellular matrix for in vitro cell growth

2003

A new disulfide crosslinking method was developed for the preparation of blended hyaluronan (HA)-gelatin hydrogels to form a synthetic, covalently linked mimic of the extracellular matrix (ECM). The HA and gelatin were chemically modified using 3,3′-dithiobis(propionic hydrazide) (DTP). After reduction with dithiothreitol (DTT), the thiol derivatives of HA (HA-DTPH) and gelatin (gelatin-DTPH) were obtained and characterized. To minimize interference with biological function, the degree of substitution of HA-DTPH and gelatin-DTPH was kept below 50%. Solutions of HA-DTPH and gelatin-DTPH in varying blends (20%, 40%, 60%, 80% gelatin) were prepared in 1% w/v NaCl and crosslinked by disulfide b…

Cooperative onset of a different state of water in the presence of macromolecules.

1973

Self-assembling and auto-crosslinkable hyaluronic acid hydrogels with a fibrillar structure

2008

Abstract A hyaluronic acid derivative bearing pendant l -benzoyl-cysteine portions (with a derivatization degree equal to 10 mol.%) was synthesized by linking N,N′-dibenzoyl- l -cystine to the polysaccharide and then reducing its disulfide bridge to thiol groups. The formation of π–π stacking interactions between the benzoyl moieties was studied by fluorescence spectroscopy as a function of polymer concentration and oxidation time. The efficiency of oxidation of thiol groups to disulfide bridges occurring in phosphate buffer pH 7.4, was determined by colorimetric assays. The hydrogel formed by means of oxidative crosslinking has shown the presence of fibrillar aggregates as detected by ligh…

Melatonin protects rats from radiotherapy-induced small intestine toxicity

2017

Radiotherapy-induced gut toxicity is among the most prevalent dose-limiting toxicities following radiotherapy. Prevention of radiation enteropathy requires protection of the small intestine. However, despite the prevalence and burden of this pathology, there are currently no effective treatments for radiotherapy-induced gut toxicity, and this pathology remains unclear. The present study aimed to investigate the changes induced in the rat small intestine after external irradiation of the tongue, and to explore the potential radio-protective effects of melatonin gel. Male Wistar rats were subjected to irradiation of their tongues with an X-Ray YXLON Y.Tu 320-D03 irradiator, receiving a dose o…

Nose-to-brain delivery of insulin enhanced by a nanogel carrier.

2018

Recent evidences suggest that insulin delivery to the brain can be an important pharmacological therapy for some neurodegenerative pathologies, including Alzheimer disease (AD). Due to the presence of the Blood Brain Barrier, a suitable carrier and an appropriate route of administration are required to increase the efficacy and safety of the treatment. Here, poly(N-vinyl pyrrolidone)-based nanogels (NG), synthetized by e-beam irradiation, alone and with covalently attached insulin (NG-In) were characterized for biocompatibility and brain delivery features in a mouse model. Preliminarily, the biodistribution of the "empty" nanocarrier after intraperitoneal (i.p.) injection was investigated b…

An in vitro and in vivo study of peptide-functionalized nanoparticles for brain targeting: The importance of selective blood-brain barrier uptake

2017

Targeted delivery of drugs across endothelial barriers remains a formidable challenge, especially in the case of the brain, where the blood-brain barrier severely limits entry of drugs into the central nervous system. Nanoparticle-mediated transport of peptide/protein-based drugs across endothelial barriers shows great potential as a therapeutic strategy in a wide variety of diseases. Functionalizing nanoparticles with peptides allows for more efficient targeting to specific organs. We have evaluated the hemocompatibilty, cytotoxicity, endothelial uptake, efficacy of delivery and safety of liposome, hyperbranched polyester, poly(glycidol) and acrylamide-based nanoparticles functionalized wi…

Power of lower extremities is most important determinant of agility among physically inactive or active adult people

2018

OBJECTIVE The purpose of this cross-sectional study was to determine the relationships between agility, running speed, jumping height and length, body mass index, self-report pain in back and in lower extremities, personal factors as self-report health and fitness, and leisure time physical activity in physically inactive or active adult people. METHODS Altogether, 233 healthy subjects, 149 women (43.0 ± 7.3 years) and 84 men (44.0 ± 7.7 years), participated into study. Outcome measures were described in the International Classification of Functioning, Disability and Health domains. RESULTS Multiple regression analysis showed that jumping length explained 24.6% and 15.3% of the variance ass…

Collagen-low molecular weight hyaluronic acid semi-interpenetrating network loaded with gelatin microspheres for cell and growth factor delivery for …

2015

Intervertebral disc (IVD) degeneration is one of the main causes of low back pain. Current surgical treatments are complex and generally do not fully restore spine mobility. Development of injectable extracellular matrix-based hydrogels offers an opportunity for minimally invasive treatment of IVD degeneration. Here we analyze a specific formulation of collagen-low molecular weight hyaluronic acid (LMW HA) semi-interpenetrating network (semi-IPN) loaded with gelatin microspheres as a potential material for tissue engineering of the inner part of the IVD, the nucleus pulposus (NP). The material displayed a gel-like behavior, it was easily injectable as demonstrated by suitable tests and did …

In situ crosslinkable hyaluronan hydrogels for tissue engineering

2003

We describe the development of an injectable, cell-containing hydrogel that supports cell proliferation and growth to permit in vivo engineering of new tissues. Two thiolated hyaluronan (HA) derivatives were coupled to four alpha,beta-unsaturated ester and amide derivatives of poly(ethylene glycol) (PEG) 3400. The relative chemical reactivity with cysteine decreased in the order PEG-diacrylate (PEGDA)>>PEG-dimethacrylate>PEG-diacrylamide>PEG-dimethacrylamide. The 3-thiopropanoyl hydrazide derivative (HA-DTPH) was more reactive than the 4-thiobutanoyl hydrazide, HA-DTBH. The crosslinking of HA-DTPH with PEGDA in a molar ratio of 2:1 occurred in approximately 9 min, suitable for an in situ cr…

A randomized clinical trial compared the effect of intra-alveolar 0.2 % Chlorohexidine bio-adhesive gel versus 0.12% Chlorohexidine rinse in reducing…

2014

Objectives: To evaluate socket healing, incidence of acute alveolar ostieitis (AO) and associated pain following single molar tooth extraction in patients who receive intra-alveolar 0.2% chlorhexidine (CHX) gel, and those who rinsed with 0.12 % CHX rinse. Study Design: A prospective randomized clinical trial was conducted on two parallel groups of patients. Group1 (141 patients): Rinsed with 0.12 % CHX rinse from the second postoperative day, two times daily for a week. Group2 (160 patients): Who had direct intra-alveolar application of 0.2% CHX gel and day 3 post-operatively. The socket was evaluated 3 and 7 day postoperatively for the presence of AO by checking probing tenderness in the s…