Synthesis and characterization of anisotropic magnetic hydrogels

Hinrichs, Stephan; Nun, Nils; Fischer, Birgit

doi:10.1016/j.jmmm.2016.10.016

Cited by 5 publications

(6 citation statements)

References 20 publications

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“…Apart from all the properties and advantages, just like hydrogels, magnetogels can be designed and fabricated into different types such as spheroid-like structures known as microgels, nanofibrous networks and mesh-like nanocomposites, thus granting more control over the nanosystem, as the optimum structure can be adapted to the desired application [ 50 , 62 , 63 , 64 , 65 , 66 , 67 , 68 ]. For example, an interesting concept to develop microgels is the addition of a silica shell to a magnetic nanoparticle core, which is further grafted with the hydrogelator polymer of interest.…”

Section: Properties and Applications Of Magnetogelsmentioning

confidence: 99%

“…For example, an interesting concept to develop microgels is the addition of a silica shell to a magnetic nanoparticle core, which is further grafted with the hydrogelator polymer of interest. This concept was shown by Hinrichs et al [ 62 ] where silica-coated magnetite or hematite nanoparticles were grafted with N -isopropylacrylamide (NIPAM) by a free radical emulsion polymerization method, which was further cross-linked using N , N -methylenebisacrylamide (BIS) and grafted with amine groups at the nanoparticle surface by addition of acrylic acid (AA). Macrogels can then be attained by reaction of amine groups with the aldehyde moiety of glutaraldehyde (GA) [ 62 ].…”

Section: Properties and Applications Of Magnetogelsmentioning

confidence: 99%

“…This concept was shown by Hinrichs et al [ 62 ] where silica-coated magnetite or hematite nanoparticles were grafted with N -isopropylacrylamide (NIPAM) by a free radical emulsion polymerization method, which was further cross-linked using N , N -methylenebisacrylamide (BIS) and grafted with amine groups at the nanoparticle surface by addition of acrylic acid (AA). Macrogels can then be attained by reaction of amine groups with the aldehyde moiety of glutaraldehyde (GA) [ 62 ]. A common method for the development of magnetogels is the mixture of nanoparticles and a hydrogelator solution followed by its gelation that produces a mesh-like composite, which sometimes might require the nanoparticle surface functionalization to grant it stabilization.…”

Section: Properties and Applications Of Magnetogelsmentioning

confidence: 99%

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Magnetogels: Prospects and Main Challenges in Biomedical Applications

et al. 2018

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Drug delivery nanosystems have been thriving in recent years as a promising application in therapeutics, seeking to solve the lack of specificity of conventional chemotherapy targeting and add further features such as enhanced magnetic resonance imaging, biosensing and hyperthermia. The combination of magnetic nanoparticles and hydrogels introduces a new generation of nanosystems, the magnetogels, which combine the advantages of both nanomaterials, apart from showing interesting properties unobtainable when both systems are separated. The presence of magnetic nanoparticles allows the control and targeting of the nanosystem to a specific location by an externally applied magnetic field gradient. Moreover, the application of an alternating magnetic field (AMF) not only allows therapy through hyperthermia, but also enhances drug delivery and chemotherapeutic desired effects, which combined with the hydrogel specificity, confer a high therapeutic efficiency. Therefore, the present review summarizes the magnetogels properties and critically discusses their current and recent biomedical applications, apart from an outlook on future goals and perspectives.

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Section: Properties and Applications Of Magnetogelsmentioning

confidence: 99%

Section: Properties and Applications Of Magnetogelsmentioning

confidence: 99%

Section: Properties and Applications Of Magnetogelsmentioning

confidence: 99%

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Magnetogels: Prospects and Main Challenges in Biomedical Applications

et al. 2018

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“…Thermoresponsive polymers that undergo a coil-to-globule transition in aqueous solution show lower critical solution temperature (LCST) behavior as the temperature rises (Hinrichs et al 2017). Thermoresponsive polymers with this property have been developed in a wide range of applications, such as drug delivery (Wu et al 2016), targeted drug release (Chen et al 2013), and tissue engineering (Wang et al 2013).…”

Section: Introductionmentioning

confidence: 99%

Tuning of lower critical solution temperature of thermoresponsive 2-hydroxy-3-alkoxypropyl hydroxyethyl cellulose by alkyl side chains and additives

Dai

Tian

Fan

et al. 2019

BioRes

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Two kinds of thermoresponsive 2-hydroxy-3-alkoxypropyl hydroxyethyl celluloses (HAPEC) were prepared by grafting butyl and isopropyl glycidyl ethers onto hydroxyethyl celluloses (HEC). The HAPEC was characterized by 1H NMR, 13C NMR, and 2D HSQC NMR. The lower critical solution temperature (LCST) of HAPEC can be tuned by changing the molar substitution (MS). The LCST decreased with the increasing MS of the alkyl chains. The HAPEC concentration, salt concentration, and organic solvent concentration had a marked influence on LCST. In addition, the differences of thermoresponsive properties between the two kinds of HAPECs were investigated. 2-Hydroxy-3-butoxypropyl hydroxyethyl cellulose (HBPEC), which has longer hydrophobic side chains, demonstrated a lower LCST when both HBPEC and 2-hydroxy-3-isopropoxypropyl hydroxyethyl cellulose (HIPEC) possessed similar MS values. HBPEC, which has longer hydrophobic side chains, exhibited thermoresponsive flocculation behavior, and the critical flocculation temperature (CFT) was adjusted in the range from 27.3 to 51.2 °C by changing the molar substitution.

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“…In addition, the synthesis can be directly used for nanoparticles covered with a silica shell, which is an frequently used method [19]. By incorporating nanoparticles inside the silica core, multi-responsive hydrogels can be prepared with additional optical or magnetic properties [20,21,22,23,24,25].…”

Section: Introductionmentioning

confidence: 99%

Tuning the Size of Thermoresponsive Poly(N-Isopropyl Acrylamide) Grafted Silica Microgels

Nun

Hinrichs

Schroer

et al. 2017

Gels

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Core-shell microgels were synthesized via a free radical emulsion polymerization of thermoresponsive poly-(N-isopropyl acrylamide), pNipam, on the surface of silica nanoparticles. Pure pNipam microgels have a lower critical solution temperature (LCST) of about 32 • C. The LCST varies slightly with the crosslinker density used to stabilize the gel network. Including a silica core enhances the mechanical robustness. Here we show that by varying the concentration gradient of the crosslinker, the thermoresponsive behaviour of the core-shell microgels can be tuned. Three different temperature scenarios have been detected. First, the usual behaviour with a decrease in microgel size with increasing temperature exhibiting an LCST; second, an increase in microgel size with increasing temperature that resembles an upper critical solution temperature (UCST), and; third, a decrease with a subsequent increase of size reminiscent of the presence of both an LCST, and a UCST. However, since the chemical structure has not been changed, the LCST should only change slightly. Therefore we demonstrate how to tune the particle size independently of the LCST.

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Synthesis and characterization of anisotropic magnetic hydrogels

Cited by 5 publications

References 20 publications

Magnetogels: Prospects and Main Challenges in Biomedical Applications

Magnetogels: Prospects and Main Challenges in Biomedical Applications

Tuning of lower critical solution temperature of thermoresponsive 2-hydroxy-3-alkoxypropyl hydroxyethyl cellulose by alkyl side chains and additives

Tuning the Size of Thermoresponsive Poly(N-Isopropyl Acrylamide) Grafted Silica Microgels

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