Search results for " hydrogels"
showing 10 items of 233 documents
First bisphosphonate hydrogelators: potential composers of biocompatible gels
2020
Recently, investigation of hydrogels has gained ever increasing attention mostly because of their biomedical and pharmaceutical properties, and novel hydrogelators are constantly studied to find functional applications. Bisphosphonates (BPs) are well-known compounds applicable in different fields but are mostly used in clinics as drugs for bone-related diseases. In this study, a novel class of BP-hydrogelators together with a BP-organogelator was found, and the gelating abilities of the compounds were studied. Several techniques to analyze the structure and the properties of the formed gels were used, including solid state 13C and 31P CPMAS and solution state NMR spectroscopy, IR spectrosco…
Hybrid supramolecular gels of Fmoc-F/halloysite nanotubes: Systems for sustained release of camptothecin
2017
Supramolecular gel hybrids obtained by self-assembly of Fmoc-L-phenylalanine (Fmoc-F) in the presence of functionalized halloysite nanotubes (f-HNT) were obtained in biocompatible solvents and employed as carriers for the delivery of camptothecin (CPT) molecules. The synthesis of the new f-HNT material as well as its characterization are described. The properties of the hybrid hydrogels and organogels were analyzed by several techniques. The presence of small amounts of f-HNT allows good dispersion of the tubes and the subsequent formation of homogeneous gels. The experimental results show that f-HNT functions only as an additive in the hybrid gels and does not demonstrate gelator behavior.…
Attachement and spreading of fibroblasts on an RGD peptide-modified injectable hyaluronan hydrogel
2004
Hyaluronan (HA) hydrogels resist attachment and spreading of fibroblasts and most other mammalian cell types. A thiol-modified HA (3,3'-dithiobis(propanoic dihydrazide) [HA-DTPH]) was modified with peptides containing the Arg-Gly-Asp (RGD) sequence and then crosslinked with polyethylene glycol (PEG) diacrylate (PEGDA) to create a biomaterial that supported cell attachment, spreading, and proliferation. The hydrogels were evaluated in vitro and in vivo in three assay systems. First, the behavior of human and murine fibroblasts on the surface of the hydrogels was evaluated. The concentration and structure of the RGD peptides and the length of the PEG spacer influenced cell attachment and spre…
Sepiolite-Hydrogels: Synthesis by Ultrasound Irradiation and Their Use for the Preparation of Functional Clay-Based Nanoarchitectured Materials.
2021
International audience; Sepiolite and palygorskite fibrous clay minerals are 1D silicates featuring unique textural and structural characteristics useful in diverse applications, and in particular as rheological additives. Here we report on the ability of grinded sepiolite to generate highly viscous and stable hydrogels by sonomechanical irradiation (ultrasounds). Adequate drying of such hydrogels leads to low-density xerogels that show extensive fiber disaggregation compared to the starting sepiolite-whose fibers are agglomerated as bundles. Upon re-dispersion in water under high-speed shear, these xerogels show comparable rheological properties to commercially available defibrillated sepi…
Tension Causes Unfolding of Intracellular Vimentin Intermediate Filaments
2020
Intermediate filament (IF) proteins are a class of proteins that constitute different filamentous structures in mammalian cells. As such, IF proteins are part of the load-bearing cytoskeleton and support the nuclear envelope. Molecular dynamics simulations show that IF proteins undergo secondary structural changes to compensate mechanical loads, which is confirmed by experimental in vitro studies on IF hydrogels. However, the structural response of intracellular IF to mechanical load is yet to be elucidated in cellulo. Here, in situ nonlinear Raman imaging combined with multivariate data analysis is used to quantify the intracellular secondary structure of the IF cytoskeletal protein viment…
Biocompatible Hydrogelators Based on Bile Acid Ethyl Amides
2016
Four novel bile acid ethyl amides were synthetized using a well-known method. All the four compounds were characterized by IR, SEM, and X-ray crystal analyses. In addition, the cytotoxicity of the compounds was tested. Two of the prepared compounds formed organogels. Lithocholic acid derivative 1 formed hydrogels as 1% and 2% (w/v) in four different aqueous solutions. This is very intriguing regarding possible uses in biomedicine. peerReviewed
Tension causes structural unfolding of intracellular intermediate filaments
2020
AbstractIntermediate filament (IF) proteins are a class of proteins that constitute different filamentous structures in mammalian cells. As such, IF proteins are part of the load-bearing cytoskeleton and support the nuclear envelope. Molecular dynamics simulations have shown that IF proteins undergo secondary structural changes to compensate mechanical loads, which has been confirmed by experimental in vitro studies on IF hydrogels. However, the structural response of intracellular IF to mechanical load has yet to be elucidated in cellulo. Here, we use in situ nonlinear Raman imaging combined with multivariate data analysis to quantify the intracellular secondary structure of the IF cytoske…
Chemical modification of halloysite nanotubes for controlled loading and release.
2020
Clay minerals have been used for medical purposes from ancient times. Among them, the halloysite nanotube, an aluminosilicate of the kaolin group, is an emerging nanomaterial which possesses peculiar chemical characteristics. By means of suitable modifications, such as supramolecular functionalization or covalent modifications, it is possible to obtain novel nanomaterials with tunable properties for several applications. In this context the covalent grafting of suitable organic moieties on the external surface or in the halloysite lumen has been exploited to improve the loading and release of several biologically active molecules. The resulting hybrid nanomaterials have been applied as drug…
Gellan gum-based delivery systems of therapeutic agents and cells.
2020
The purpose of this review is to make a summary of high quality research trends using gellan gum (GG) as a polymeric constituent for the design of innovative drug delivery systems and devices for biomedical applications, such as cell therapy and regenerative medicine. The use of gellan gum is described both in its native form and as chemically functionalized derivatives or physically mixed with natural or synthetic materials. Starting from a systematic study of recent research works, the main properties of the native polysaccharide have been highlighted and therefore some improvements have been focused thanks to the design of chemically functionalized derivatives and the use of composite ma…
Oxygen permeability of hydrogel contact lenses with organosilicon moieties
2002
Oxygen transport through two extended wear (day and night) hydrogel contact lenses that contain organosilicon moieties (balafilcon A and lotrafilcon A) was studied in the hydrate (hydrogel) and dry (xerogel) states. The water uptake increased the oxygen permeability [(Dk)app] and transmissibility [Dk/L(av)] coefficients of the dry materials by about 70%. The (Dk)app for the hydrated lenses was determined following the so-called stack procedure. The values obtained were 107 +/- 4 barrer for balafilcon A and 141 +/- 5 barrer for lotrafilcon A, about 5-10 times larger than those previously reported for conventional (without organosilicon moieties) extended wear hydrogels contact lenses. The Dk…