Search results for "Gels"

Rational Design of Thermoresponsive Microgel Templates with Polydopamine Surface Coating for Microtissue Applications.

2021

Functional microgels provide a versatile basis for synthetic in vitro platforms as alternatives to animal experiments. The tuning of the physical, chemical, and biological properties of synthetic microgels can be achieved by blending suitable polymers and formulating them such to reflect the heterogenous and complex nature of biological tissues. Based on this premise, this paper introduces the development of volume-switchable core-shell microgels as 3D templates to enable cell growth for microtissue applications, using a systematic approach to tune the microgel properties based on a deep conceptual and practical understanding. Microscopic microgel design, such as the tailoring of the microg…

Reversible Hydrogels with Switchable Diffusive Permeability

2021

Hydrogels are polymer networks swollen in water that are characterized by soft mechanics and high permeability. This makes them good candidates for separation and membrane technologies. The diffusion is controlled by the mesh size of the network, and this can be made tunable through the introduction of thermoresponsive polymers. However, this is still a developing field. To contribute to this development, a dual dynamic network is formed composed of four-arm polyethylene glycol precursors in which each arm is functionalized with both a terpyridine moiety capable of forming reversible metal–ligand complexes along with branches of poly(N-isopropylacrylamide) (pNIPAAm), which can be swit…

Acid‐Cleavable Poly(ethylene glycol) Hydrogels Displaying Protein Release at pH 5

2020

Abstract PEG is the gold standard polymer for pharmaceutical applications, however it lacks degradability. Degradation under physiologically relevant pH as present in endolysosomes, cancerous and inflammatory tissues is crucial for many areas. The authors present anionic ring‐opening copolymerization of ethylene oxide with 3,4‐epoxy‐1‐butene (EPB) and subsequent modification to introduce acid‐degradable vinyl ether groups as well as methacrylate (MA) units, enabling radical cross‐linking. Copolymers with different molar ratios of EPB, molecular weights (M n) up to 10 000 g mol−1 and narrow dispersities (Đ<1.05) were prepared. Both the P(EG‐co‐isoEPB)MA copolymer and the hydrogels showed pH‐…

METHOD TO PRODUCE HYALURONIC ACID FUNCTIONALIZED DERIVATIVES AND FORMATION OF HYDROGELS THEREOF

2009

Positive effects of an extracellular matrix hydrogel on rat anterior cruciate ligament fibroblast proliferation and collagen mRNA expression

2015

Summary Background/Objective We have previously shown that an extracellular matrix (ECM) bioscaffold derived from porcine small intestine submucosa (SIS) enhanced the healing of a gap injury of the medial collateral ligament as well as the central third defect of the patellar tendon. With the addition of a hydrogel form of SIS, we found that a transected goat anterior cruciate ligament (ACL) could also be healed. The result begs the research question of whether SIS hydrogel has positive effects on ACL fibroblasts (ACLFs) and thus facilitates ACL healing. Methods In the study, ECM-SIS hydrogel was fabricated from the digestion of decellularised and sterilised sheets of SIS derived from αGal-…

Metronidazola kvantitatīvā noteikšana farmaceitiskā preparātā

2016

Metronidazola kvantitatīvā noteikšana farmaceitiskā preparātā. Lazdāne L., zinātniskais vadītājs Dr. Ķīm. Nakurte, I. Maģistra darbs, 54 lappuses, 23 attēli, 20 tabulas, 45 literatūras avoti, 2 pielikumi. Latviešu valodā. Veikts literatūras apkopojums par farmaceitiski aktīvo vielu metronidazolu un tā farmakoloģiskajām īpašībām. Noskaidrotas metronidazola ekstrakcijas un analītiskās noteikšanas metodes. Balstoties uz ICH vadlīnijām veikta metronidazola kvantitatīvās noteikšanas metodes Metronidazola 7,5 mg/g gelā validācija. Validācijas ietvaros noteikta hromatogrāfiskās metodes linearitāte, noteikšanas robežas, pareizība un precizitāte, atkārtojamība, robustums. Pārbaudīta metronidazola st…

Temperature effects on the IR absorption bands of hydroxyl and deuteroxyl groups in silica glass

2009

Abstract In this report we will show the changes of the band shape of the hydroxyl group (SiOH) infrared (IR) absorption band (∼3670 cm −1 ) in silica glass induced by lowering temperature in the range from 290 to 20 K. This band is considered as the overlap of several spectral components associated to the vibrational activity of hydroxyl groups in different bond configurations. By a suitable analysis of the experimental band profile in terms of different sub-bands, we studied the thermal evolution of each component and we reconsidered their assignations. For comparison we examined the SiOD absorption band (∼2710 cm −1 ) as a function of temperature as well. Our data can be interpreted as a…

Contribution of IL-17-producing {gamma}{delta} T cells to the efficacy of anticancer chemotherapy.

2011

IL-17 production by γδ T cells is required for tumor cell infiltration by IFN-γ–producing CD8+ T cells and inhibition of tumor growth in response to anthracyclines.

Differences in platelet growth factor release and leucocyte kinetics during autologous platelet gel formation.

2006

Three commercial systems for whole blood separation were compared to obtain the buffy coat composed of platelet-rich plasma (BC-PRP) and leucocytes . These samples of the buffy coat were used to make a platelet gel (PG), which was used to measure platelet growth factor (PGF) release, to perform a white blood cell (WBC) count and to measure myeloperoxidase (MPO) release from WBCs. Aliquots of whole blood obtained from ten volunteers were distributed either to a blood cell separator (The Electa Cell-Separator (TM), E-CS) or to a tabletop centrifuge (Gravitational Platelet Sequestration System (TM), GPS) to prepare the BC-PRP. The third system combines the BC-PRP production by E-CS with a micr…

Growth factor levels in platelet-rich plasma and correlations with donor age, sex, and platelet count.

2002

Abstract Introduction: Platelet-rich plasma contains autologous thrombocyte growth factors and might be promising for acceleration of dentoalveolar bone regeneration. In this study, it was analysed for platelet counts and growth factor concentrations. Material and method: Platelet-rich plasma was isolated by discontinuous cell separation from 158 healthy men and 55 women aged 17–62 years. One hundred and fifteen specimens (stratified for age and gender of the donor) were analysed for growth factor concentrations and platelet count. Results: The platelet count in platelet-rich plasma (1,407,640±320,100/μl) was 5 times higher than in donor blood (266,040±60,530/μl). Platelet-derived growth fa…