Dual Stimuli-Responsive Nanogels by Self-Assembly of Polysaccharides Lightly Grafted with Thiol-Terminated Poly(<i>N</i>-isopropylacrylamide) Chains

Morimoto, Nobuo; Qiu, Xing Ping; Winnik, Françoise M.; Akiyoshi, Kazunari

doi:10.1021/ma801332x

Cited by 123 publications

(96 citation statements)

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“…Stimuli-sensitive nanohydrogels containing bioactive specific ligands seem to be an effective strategy [11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Polymeric Nanohydrogels of Poly(N-Isopropylacrylamide) Combined with Others Functionalized Monomers: Synthesis and Characterization

Luztonó¹,

Donates²,

Ramirez³

et al. 2014

JBNB

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Nanohydrogels from inverse microemulsion (w/o) polymerization, at 25˚C, of N-isopropylacrylamide (NIPA) and functionalized monomers are described. The functionalized monomers were: N-(pyridine-4-ylmethyl) acrylamide (NP4MAM) and tert-butyl 2-acrylamidoethyl carbamate (2AAECM). The polymeric nanohydrogel obtained was characterized by attenuated total reflectance Fourier-transformed infrared spectroscopy (ATR-FTIR) and proton nuclear magnetic resonance spectrometry ( 1 HNMR), while their morphology and particle size was assessed by scanning electron microscopy (SEM) and dynamic light scattering. Their thermal properties were studied by Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). As a preliminary measure of biocompatibility, in vitro evaluations of the nanohydrogels were carried out by cellular toxicity (colon carcinoma cells, CT-26) and hemocompatibility tests. These evaluations showed that these nanohydrogels were not toxic in the examined concentration range and exhibited preliminary blood compatibility; therefore they could be used in biomedical applications.

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“…Stimuli-sensitive nanohydrogels containing bioactive specific ligands seem to be an effective strategy [11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Polymeric Nanohydrogels of Poly(N-Isopropylacrylamide) Combined with Others Functionalized Monomers: Synthesis and Characterization

Luztonó¹,

Donates²,

Ramirez³

et al. 2014

JBNB

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“…Thermoresponsive nanogels that enable heat-induced association and dissociation of polysaccharides partially grafted with short poly(N-isopropylacrylamide) (PNIPAM) chains (NipP) have been prepared. 27 Above the LCST, PNIPAM-g-polysaccharides form nanogels that are physically crosslinked by the hydrophobic nanodomains generated by dehydration of PNIPAM (Figure 3). Biocompatible heat-induced nanogels have also been obtained by grafting poly(2-isopropyl-2-oxazoline) (PipP), which is a biocompatible, thermoresponsive crystalline molecule, onto a polysaccharide.…”

Section: ç Introductionmentioning

confidence: 99%

“…6 These nanogels can be obtained by using disulfide bonds as a crosslinking point. 27 More recently, redox-sensitive metal-coordinative crosslinked nanogels were prepared by introducing a metalligand to CHP (CHPIm). 29 As a metal ligand, imidazolyl groups were conjugated with pullulan.…”

Section: ç Introductionmentioning

confidence: 99%

“…A dual stimuli-responsive nanogel that responds to changes in both environmental temperature and redox potential has also been reported. 27 That nanogel was developed by associating a redox-responsive polymer containing a thiol group with the terminus of the PNIPAM chain, which forms a disulfide bond after nanogel formation. More recently, we reported a cyclodextrin-responsive nanogel regarded as an example of chemicalresponsive systems for use in an artificial molecular chaperone.…”

Section: ç Introductionmentioning

confidence: 99%

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Self-assembled Nanogel Engineering for Advanced Biomedical Technology

Sasaki

Akiyoshi

2012

Chemistry Letters

Self Cite

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Nanogels are polymer nanoparticles with three-dimensional networks. Recently, various nanogels have been designed, with a particular focus on biomedical applications. In this review, we describe recent progress in the synthesis of functional nanogels by self-assembly of associating polymers and nanogel engineering for advanced biomedical technology including regenerative medicine and drug delivery systems. Ç IntroductionLiving systems, for example biomembranes which are selforganized assemblies of proteins and lipids, reveal sophisticated biological functions such as signal transduction, energy production, and cellular communication. The concept of supramolecular assembly of biocomponents such as lipids, proteins, nucleic acids, and polysaccharides is central to bottom-up design of advanced biomaterials. For example, molecular organization based on supramolecular assembly enables fabrication of not only materials with well-controllable molecular orientation and arrangement but mechanically controlled nanomaterials and nanosystems 1 or self-assembled micro-and nanoshells for drug delivery applications. Recently, we have proposed nanogel engineering, which involves design of self-assembled nanogel and the construction of functional hierarchical gels or interfaces through their bottomup assembly of nanogels as building units. The bottom-up nanogel engineering provides a new paradigm for development of hydrogel biomaterials with well-organized three-dimensional structures, multiple functions, sensitivity to a range of different stimuli, and programmed responses that can be controlled temporally and spatially. Nanogels are nanometer-sized hydrogel nanoparticles (<100 nm) with three-dimensional networks of crosslinked polymer chains. They have attracted growing interest over the last several years due to their potential for biomedical applications, such as drug delivery system (DDS) and bioimaging.3 Usual polymer nanoparticles, such as nanospheres, have a densely packed polymer inside core structure. In contrast, nanogels are able to stably trap bioactive compounds such as drugs, proteins, and DNA/RNA inside their nanospace with polymer networks. Moreover, nanogels show a rapid response to microenvironmental factors such as temperature and pH because of their nanoscale dimensions. These properties are useful for the controlled release of bioactive compounds.Nanogels have been prepared using various methods, which can be classified into two categories according to their crosslinking structure: chemically (covalent) crosslinked nanogels which form crosslinking points by covalent bonds and physically crosslinked nanogels with noncovalent bonds (such as hydrogen bonds), electrostatic and hydrophobic interactions. 4 Typically, chemically crosslinked nanogels are synthesized under dilute conditions by a crosslinking reaction of polymers modified with reactive groups, such as vinyl and thiol groups. Nano-or microemulsion polymerization methods are often used to obtain nanogels with a well-controlled size.A variety of...

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“…[1][2][3][4][5][6] Self assembly of discrete components has been recognized as an important ''bottomup'' technique to create various functionalized, hierarchical structures, including nanogels. [7][8][9][10][11] Stimuli-responsive polymers are emerging as particularly promising materials due to the capability of reversibly altering of their properties on receiving external signals.…”

mentioning

confidence: 99%

Temperature‐ and Redox‐Directed Multiple Self Assembly of Poly(N‐Isopropylacrylamide) Grafted Dextran Nanogels

Liu

Feng

et al. 2011

Macromol. Rapid Commun.

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Poly(N-isopropylacrylamide) (PNIPAAm) grafted dextran nanogels with dodecyl and thiol end groups have been synthesized by RAFT process. Dodecyl-terminated polymers (DexPNI) can be readily dissolved in water and further self assemble into ordered stable nanostructures through direct noncovalent interactions at room temperature. SEM, AFM and DLS measurements confirm the formation of spherical nanogels at hundred-nanometer scales. The elevation of environment temperature will indirectly result in the formation of collapsed nanostructures due to the LCST phase transition of PNIPAAm side chains. Turbidimetry results show that the phase transition behaviors of DexPNI are greatly dependent on PNIPAAm chain length and polymer concentration: increasing PNIPAAm chain length and polymer concentration both lead to lower LCSTs and sharper phase transitions. Moreover, the dodecyl-terminated polymers can transform into thiol-terminated versions by aminolysis of trithiocarbonate groups, and further into chemical (disulfide) cross-linked versions (SS-DexPNI) by oxidation. SS-DexPNI nanogels have "doubled" chain length of PNIPAAm, and hence sharper phase transitions. In situ DLS measurements of the evolution of hydrodynamic radius attest that the self assembly of SS-DexPNI nanogels can be selectively directed by the change in either external temperature or redox potential. These nanogels thus are promising candidates for triggered intracellular delivery of encapsulated cargo. We can also expect that the polymer can be noncovalently (by dodecyl end groups) or covalently (by thiol end groups) coated on a series of nanomaterials (e.g., carbon nanotubes, graphene, gold nanomaterials) to build a variety of novel smart, and robust nanomaterials.

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Dual Stimuli-Responsive Nanogels by Self-Assembly of Polysaccharides Lightly Grafted with Thiol-Terminated Poly(N-isopropylacrylamide) Chains

Cited by 123 publications

References 28 publications

Polymeric Nanohydrogels of Poly(N-Isopropylacrylamide) Combined with Others Functionalized Monomers: Synthesis and Characterization

Polymeric Nanohydrogels of Poly(N-Isopropylacrylamide) Combined with Others Functionalized Monomers: Synthesis and Characterization

Self-assembled Nanogel Engineering for Advanced Biomedical Technology

Temperature‐ and Redox‐Directed Multiple Self Assembly of Poly(N‐Isopropylacrylamide) Grafted Dextran Nanogels

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