Preparation, Properties and Cell Biocompatibility of Room Temperature LCST-Hydrogels Based on Thermoresponsive PEO Stars.
Ontology highlight
ABSTRACT:
SUBMITTER: Santoso B
PROVIDER: S-EPMC8293143 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:The utility of thermoresponsive hydrogels, such as those based on poly(N-isopropylacrylamide) (PNIPAAm), is severely limited by their deficient mechanical properties. In particular, the simultaneous achievement of high strength and stiffness remains unreported. In this work, a thermoresponsive hydrogel is prepared having the unique combination of ultrahigh compressive strength (≈23 MPa) and excellent compressive modulus (≈1.5 MPa). This is accomplished by employing a double network (DN) design comprised of a tightly crosslinked, highly negatively charged 1st network based on poly(2-acrylamido-2-methylpropane sulfonic acid (PAMPS) and a loosely crosslinked, zwitterionic 2nd network based on a copolymer of thermoresponsive NIPAAm and zwitterionic 2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (MEDSAH). Comparison to other DN designs reveals that this PAMPS/P(NIPAAm-co-MEDSAH) DN hydrogel's remarkable properties stem from the intra- and internetwork ionic interactions of the two networks. Finally, this mechanically robust hydrogel retains the desirable thermosensitivity of PNIPAAm hydrogels, exhibiting a volume phase transition temperature of ≈35 °C.
| S-EPMC5878684 | biostudies-literature
Project description:Most polymeric thermoresponsive hydrogels contract upon heating beyond the lower critical solution temperature (LCST) of the polymers used. Herein, we report a supramolecular hydrogel system that shows the opposite temperature dependence. When the non-thermosesponsive hydrogel NaphtGel, containing dialkoxynaphthalene guest molecules, becomes complexed with the tetra cationic macrocyclic host CBPQT4+ , swelling occurred as a result of host-guest complex formation leading to charge repulsion between the host units, as well as an osmotic contribution of chloride counter-ions embedded in the network. The immersion of NaphtGel in a solution of poly(N-isopropylacrylamide) with tetrathiafulvalene (TTF) end groups complexed with CBPQT4+ induced positive thermoresponsive behaviour. The LCST-induced dethreading of the polymer-based pseudorotaxane upon heating led to transfer of the CBPQT4+ host and a concomitant swelling of NaphtGel. Subsequent cooling led to reformation of the TTF-based host-guest complexes in solution and contraction of the hydrogel.
| S-EPMC5113761 | biostudies-literature
Project description:The utility and efficacy of thermoresponsive poly(N-isopropylacrylamide) (PNIPAAm) hydrogels as smart materials is limited by their physical properties. In this study, we sought to design PNIPAAm nanocomposite hydrogels which displayed enhanced mechanical properties as well as deswelling-reswelling kinetics but without reducing equilibrium swelling or altering the convenient volume phase transition temperature (VPTT) of PNIPAAm. PNIPAAm hydrogels were formed as double networks (DN) comprised of a tightly crosslinked 1st network and a loosely crosslinked 2nd network. In addition, polysiloxane nanoparticles of two different average diameters (~50 nm and ~200 nm) were incorporated during formation of the 1st or 2nd network. The influence of the hydrogel composition on VPTT, morphology, equilibrium swelling, deswelling-reswelling kinetics and mechanical properties was evaluated. We observed that DN hydrogels formed with ~200 nm polysiloxane nanoparticles introduced during formation of the 1st network achieved the best combination of the desired properties.
| S-EPMC3535461 | biostudies-literature
Project description:We report the development of thermoresponsive magnetic hydrogels based on poly(N-isopropylacrylamide) encapsulation of Fe3O4 magnetic nanostructures (MNS). In particular, we examined the effects of hydrogels encapsulated with poly-ethylene glycol (PEG) and polyhedral oligomeric silsesquioxane (POSS) surface modified Fe3O4 MNS on magnetic resonance (MR) T2 (transverse spin relaxation) contrast enhancement and associated delivery efficacy of absorbed therapeutic cargo. The microstructural characterization reveal the regular spherical shape and size (?200 nm) of the hydrogels with elevated hydrophilic to hydrophobic transition temperature (?40 °C) characterized by LCST (lower critical solution temperature) due to the presence of encapsulated MNS. The hydrogel-MNS (HGMNS) system encapsulated with PEG functionalized Fe3O4 of 12 nm size (HGMNS-PEG-12) exhibited relaxivity rate (r2) of 173 mM(-1) s(-1) compared to 129 mM(-1) s(-1) obtained for hydrogel-MNS system encapsulated with POSS functionalized Fe3O4 (HGMNS-POSS-12) of the same size. Further studies with HGMNS-PEG-12 with absorbed drug doxorubicin (DOX) reveals approximately two-fold enhance in release during 1 h RF (radio-frequency) field exposure followed by 24 h incubation at 37 °C. Quantitatively, it is 2.1 ?g mg(-1) (DOX/HGMNS) DOX release with RF exposure while only 0.9 ?g mg(-1) release without RF exposure for the same period of incubation. Such enhanced release of therapeutic cargo is attributed to micro-environmental heating in the surroundings of MNS as well as magneto-mechanical vibrations under high frequency RF inside hydrogels. Similarly, RF-induced in vitro localized drug delivery studies with HeLa cell lines for HGMNS-PEG-12 resulted in more than 80% cell death with RF field exposures for 1 h. We therefore believe that magnetic hydrogel system has in vivo theranostic potential given high MR contrast enhancement from encapsulated MNS and RF-induced localized therapeutic delivery in one nanoconstruct.
| S-EPMC4025575 | biostudies-literature
Project description:Thermoresponsive poly(N-isopropylacrylamide) (PNIPAAm) hydrogels are widely studied smart materials, particularly for biomedical applications, but are limited by their mechanical strength. In this study, double network (DN) hydrogels were prepared with an asymmetric crosslink design and inclusion of an electrostatic co-monomer, 2-acrylamido-2-methylpropane sulfonic acid (AMPS). These P(NIPAAm-co-AMPS)/PNIPAAm DN hydrogels were sequentially formed with a tightly crosslinked 1st network comprised of variable levels of AMPS (100 : 0 to 25 : 75 wt% ratio of NIPAAm:AMPS) and a loosely crosslinked 2nd network comprised of PNIPAAm. The impact of AMPS content in the 1st network on the volume phase transition temperature (VPTT), morphology, deswelling-reswelling kinetics and mechanical properties was evaluated. Without substantially altering the VPTT of conventional PNIPAAm hydrogels but with improving thermosensitivity, the DN hydrogel formed with 25 : 75 wt% of NIPAAm:AMPS achieved exceptional strength, high modulus and high %strain at break.
| S-EPMC7740108 | biostudies-literature
Project description:Fluorescence/temperature-sensitive hydrogels, thanks to their properties in fluorescence and temperature sensitivity, have shown a promising outlook in the fields of drug delivery, cell imaging, etc., and thus become the focus of present research. This paper reports the preparation of green-fluorescence/temperature-sensitive hydrogels through one-step radical polymerization with green fluorescence-emissioned carbon dots as fluorescence probes and N-isopropylacrylamide as a monomer. UV-vis spectra, fluorescence spectra, and fluorescence microscope imaging have been used to characterize the prepared hydrogel, and to study their optical and temperature-sensitive properties. It was discovered that the emission of prepared hydrogel is excitation wavelength-dependent, pH responding, and excellent temperature-sensitive, as well as having good biocompatibility. The prepared hydrogel can also be applied as fluorescence ink in the fields of anti-counterfeit identification and appraisal.
| S-EPMC6680904 | biostudies-literature
Project description:Electrospinning is a versatile process used to prepare micro- and nano- sized fibers from various polymers dissolved in volatile solvents. In this report, cellulose and cellulose-heparin composite fibers are prepared from nonvolatile room temperature ionic liquid (RTIL) solvents by electrospinning. RTILs are extracted from the biopolymer fiber after the fiber formation using a cosolvent. Micron to nanometer sized, branched fibers were obtained from 10% (w/w) concentration of polysaccharide biopolymer in RTIL solution with an applied voltage of 15-20 kV. Cellulose-heparin composite fibers showed anticoagulant activity, demonstrating that the bioactivity of heparin remained unaffected even on exposure to a high voltage involved in electrospinning.
| S-EPMC4777308 | biostudies-literature
Project description:There is an increasing need to develop conducting hydrogels for bioelectronic applications. In particular, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hydrogels have become a research hotspot due to their excellent biocompatibility and stability. However, injectable PEDOT:PSS hydrogels have been rarely reported. Such syringe-injectable hydrogels are highly desirable for minimally invasive biomedical therapeutics. Here, an approach is demonstrated to develop injectable PEDOT:PSS hydrogels by taking advantage of the room-temperature gelation property of PEDOT:PSS. These PEDOT:PSS hydrogels form spontaneously after syringe injection of the PEDOT:PSS suspension into the desired location, without the need of any additional treatments. A facile strategy is also presented for large-scale production of injectable PEDOT:PSS hydrogel fibers at room temperature. Finally, it is demonstrated that these room-temperature-formed PEDOT:PSS hydrogels (RT-PEDOT:PSS hydrogel) and hydrogel fibers can be used for the development of soft and self-healable hydrogel bioelectronic devices.
| S-EPMC6946856 | biostudies-literature
Project description:Vocal folds are connective tissues housed in the larynx, which can be subjected to various injuries and traumatic stimuli that lead to aberrant tissue structural alterations and fibrotic-induced biomechanical stiffening observed in patients with voice disorders. Much effort has been devoted to generate soft biomaterials that are injectable directly to sites of injury. To date, materials applied toward these applications have been largely focused on natural extracellular matrix-derived materials such as collagen, fibrin or hyaluronic acid; these approaches have suffered from the fact that materials are not sufficiently robust mechanically nor offer sufficient flexibility to modulate material properties for targeted injection. We have recently developed multiple resilin-inspired elastomeric hydrogels that possess similar mechanical properties as those reported for vocal fold tissues, and that also show promising in vitro cytocompatibility and in vivo biocompatibility. Here we report studies that test the delivery of resilin-based hydrogels through injection to the subcutaneous tissue in a wild-type mice model; histological and genetic expression outcomes were monitored. The rapid kinetics of crosslinking enabled facile injection and ensured the rapid transition of the viscous resilin precursor solution to a solid-like hydrogel in the subcutaneous space in vivo; the materials exhibited storage shear moduli in the range of 1000-2000 Pa when characterized through oscillatory rheology. Histological staining and gene expression profiles suggested minimal inflammatory profiles three weeks after injection, thereby demonstrating the potential suitability for site-specific in vivo injection of these elastomeric materials. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2229-2242, 2018.
| S-EPMC6030450 | biostudies-literature
Project description:This study describes an integrated NH3 sensor based on a hydrogenated nanocrystalline diamond (NCD)-sensitive layer coated on an interdigitated electrode structure. The gas sensing properties of the sensor structure were examined using a reducing gas (NH3) at room temperature and were found to be dependent on the electrode arrangement. A pronounced response of the sensor, which was comprised of dense electrode arrays (of 50 µm separation distance), was observed. The sensor functionality was explained by the surface transfer doping effect. Moreover, the three-dimensional model of the current density distribution of the hydrogenated NCD describes the transient flow of electrons between interdigitated electrodes and the hydrogenated NCD surface, that is, the formation of a closed current loop.
| S-EPMC4273209 | biostudies-literature