Sol State Research Articles

Control of rhGH Release Profile from PEG-PAF Thermogel.

Poly(ethylene glycol)-poly(l-alanine-co-l-phenyl alanine) diblock copolymers (PEG-PAF) of 2000-990 Da (P2K) and 5000-2530 Da (P5K) with the different molecular weights of PEGs, but having a similar molecular weight ratio of hydrophobic block to hydrophilic block were synthesized to compare their solution behavior and corresponding protein drug release profiles from their in situ formed thermogels. The PEG-PAF aqueous solutions underwent heat-induced sol-to-gel transition in a concentration range of 18.0-24.0 wt % and 8.0-12.0 wt % for P2K and P5K, respectively. P5K formed bigger micelles than P2K, of a broad distribution, whereas the PAF blocks of P5K developed richer in α-helix than those of P2K in the core of the micelles. As the temperature increased, the micelles underwent dehydration of the PEG, which led to the aggregation of micelles, while the secondary structure of PAF was slightly affected during the sol-to-gel transition. The P5K exhibited higher tendency to aggregate and formed a tighter gel than P2K. Upon injection into the subcutaneous layer of rats, both polymer aqueous solutions formed a biocompatible gel with typical mild inflammatory tissue responses. Recombinant human growth hormone (rhGH) maintained its stability without forming any aggregates in both sol (4 °C) and gel (37 °C) states of the PEG-PAFs. Even though P2K and P5K have a similar molecular weight ratio of hydrophobic block to hydrophilic block, the P5K system exhibited a reduced initial burst release, improved bioavailability, and prolonged therapeutic duration of the rhGH, compared to the P2K system. The current research suggests that a drug release profile is a complex function of self-assembling carriers and incorporated drugs, and thus, a promising protein delivery system could be designed by adjusting the molecular parameters of a thermogel.

Preparation and characterization of к-carrageenan and xyloglucan blends for sustained release of a hydrophilic drug

Tamarind seed xyloglucan (TSX) and к-carrageenan (KC) have been widely used in the food and pharmaceutical industries. Their synergistic effects and the gelation and degelation of the blends, and the release a hydrophilic model drug, nicotinamide, from the blends were investigated. The KC/TSX blend with a ratio of 1 % (w/v) of KC to 1 % (w/v) of TSX (1KC/1TSX) exhibited the highest synergistic effect. The sol–gel and gel–sol transition temperatures of the blends shifted to higher temperatures when compared with KC alone. The interactions between KC and TSX in the gel state were revealed by ATR-FTIR showing the significant differences in the position and intensity of the peaks at 1164, 1124 and 1130 cm−1 for the 1KC/1TSX gel sample. These were probably due to the intermolecular hydrogen bonds between the OH and C–O–C groups of KC and TSX. In addition, the sol and gel states of the KC or KC/TSX blends could be differentiated using ATR-FTIR. Furthermore, the time needed to release 90 % (T 90) of nicotinamide alone and nicotinamide from 2KC, 1.5KC/0.5TSX, 1KC/1TSX and 0.5KC/1.5TSX was 17, 66, 75, 95 and 78 min, respectively. This demonstrated a sustained release of the drug when incorporated into the KC or KC/TSX blends in the freeze-dried samples. Moreover, the blends retarded the release better than KC alone. The blend of 1KC/1TSX, that exhibited the highest synergism, provided the most effective retardation of the compounds.

Systemic modulation of the stability of pluronic hydrogel by a small amount of graphene oxide

Thermo-sensitive and injectable hydrogels have been widely investigated for drug delivery, tissue engineering, and other biomedical applications. Pluronic copolymers can form thermo-sensitive physical gel state, thus applicable for injectable hydrogels. However, they are not stable in vivo, showing a very fast dissolution, which limits their applications. We propose a novel Pluronic-based physical hydrogel with enhanced stability by simply adding a small quantity of graphene oxide (GO) which has a large surface area and can make strong interactions with Pluronic. Further carboxylated GO could act as a more efficient additive. The addition of GO increased the moduli of hydrogels, but more importantly, it enhanced the stability of Pluronic gel dramatically. The in vitro dissolution rate of Pluronic hydrogel could be systematically modulated by increasing GO content. Upon subcutaneous injection at a sol state, GO-containing hydrogel induced a stable gel state, and was maintained over several weeks whereas very fast degradation was observed without the addition of GO. Furthermore, histological analyses demonstrated that the GO-containing Pluronic hydrogel was biocompatible and showed no severe inflammatory response. Similarly, GO-containing hydrogel resulting from the packing of Pluronic-based nanogel also showed the more enhanced stability by the addition of GO both in vitro and in vivo. In both systems, hydrogels with remarkably enhanced stability by the addition of GO were also effective for the sustained release of loaded protein, and the release rates were mainly determined by the degradation rates of hydrogels. Thus, these GO-containing Pluronic systems can be used as a thermo-sensitive injectable system with a sufficient stability in vivo.

Synthesis of nanosized platinum based catalyst using sol-gel process

The nano-sized platinum based catalysts using high surface area silica support have been prepared by sol-gel method. Tetramethoxysilane (TMOS) diluted in methanol was hydrolyzed to form a porous silica gel. Platinum (2%) was loaded at sol state using platinum chloride solution. After gelation, the solvent from the gel pores was extracted at ambient temperature which resulted in porous silica matrix incorporated with nanosized platinum. X-ray diffraction studies indicated the presence of elemental platinum in the silica-platinum composites. Transmission electron microscopy of the platinum -silica composites revealed that nanosized platinum particles of about 5-10 nm are homogeneously dispersed in silica matrix. Chemisorptions studies showed high dispersion (more than 50%) of platinum on silica support with specific surface area of 400 m2/g which puts them as promising candidates as catalyst in heterogeneous reactions.

Influence of Molar Mass and Concentration on the Thermogelation of Methylcelluloses

In this study, thermogelation of methylcelluloses is investigated in relation to the molar mass and concentration in aqueous medium. A large hysteresis between heating and cooling ramps was observed whatever the conditions. The heating process in particular was studied to analyze the two steps of gelation using rheometry. At low temperature, in the sol state, viscosity depends on the concentration and molar mass. Over 30°C a gel-like behavior was observed including two steps (the second step is a strong gel with phase separation) having storage moduli that are nearly independent of polymer molar mass but are directly related to polymer concentration.

Dynamics of CoFe2O4 Single-Core Nanoparticles in Viscoelastic Media

The dynamics of single-core CoFe2O4 nanoparticles in viscoelastic media was studied utilizing ac susceptibility and fluxgate magnetorelaxometry measurements. As viscoelastic medium aqueous gelatin suspensions with gelatin contents between 2.5 wt% and 10 wt% were used. Specifically, the gelation kinetics after cooling the sample from the sol state (313K) to 296K was investigated. It is shown that the measurement results can be analyzed with the Voigt-Kelvin model thus providing information on local dynamic viscosity and shear modulus.

Electrospinning of gelatin nanofiber scaffolds with mild neutral cosolvents for use in tissue engineering

Electrospun gelatin nanofibers are effective tissue engineering scaffolds with high biocompatibility and cell adhesion activity. In gelatin electrospinning, fluorinated alcohols, which are irritants, and acidic organic solvents are used as solvents to prevent gelation. This study established a technique to embed protein reagents into the nanofibers using mild solvents. From 22 mixtures of 50% organic solvent–50% H2O, less denaturing neutral dipolar aprotic solvents (specifically N,N-dimethylacetamide, N,N-dimethylformamide and N-methyl-2-pyrrolidone), were screened to assess their suitability for use in electrospinning of gelatin nanofiber scaffolds by their ability to maintain gelatin in a sol state at room temperature. By selecting the solvents and their concentrations, gelatin nanofibers were electrospun with different structures from a thick, wide, porous nanofibrous structure to a thin, fine, nanofibrous mesh structure. Swiss 3T3 fibroblasts grew well on the gelatin nanofibers. In particular, some cells showed in vivo-like spindle morphologies on the thick porous nanofibers using N,N-dimethylacetamide. Additionally, as a model protein reagent, alkaline phosphatase was embedded in the gelatin nanofibers while maintaining high activity. Considering these results, the gelatin nanofibers in this study are expected to provide effective structural and chemical cues and will be useful for tissue engineering and regenerative medicine. Gelatin nanofibers were electrospun using mild N,N-dimethylacetamide, N,N-dimethylformamide and N-methyl-2-pyrrolidone. Various gelatin nanofibers were fabricated, ranging from a thick, wide, porous nanofibrous structure to a thin, fine, nanofibrous mesh structure, depending on the solvents and their concentrations. In particular, Swiss 3T3 fibroblasts exhibited in vivo-like spindle morphologies on the thick nanofibers. A model protein, alkaline phosphatase, embedded in the gelatin nanofibers maintained high activity.

Spatiotemporal control of synergistic gel disintegration consisting of boroxole- and glyco-based polymers via photoinduced proton transfer.

We demonstrate here a local- and remote-control of gel disintegration by using photoinduced proton transfer chemistry of photoacid generator (PAG). The gels were prepared by simply mixing two polymers, poly(N-isopropylacrylamide-co-5-methacrylamido-1,2-benzoxaborole) (P(NIPAAm-co-MAAmBO)) and poly(3-gluconamidopropyl methacrylamide) (PGAPMA) via the synergistic interaction of benzoxaborole and diol groups. The o-nitrobenzaldehyde (o-NBA) was then loaded into the gel as a PAG. The benzoxaborole-diol interaction was successfully disintegrated upon UV irradiation due to the local pH decrease inside the gel. When the gel was irradiated to a specific gel region, the synergistic interactions were disintegrated only at the exposed region. Of special interest is that the whole material eventually transitioned from gel to sol state, as the generated protons diffused gradually toward the nonilluminated region. The ability of the proposed gel-sol transition system via photoinduced proton diffusion may be beneficial for not only prompt pH changes within the gel but also the design of predictive and programmable devices for drug delivery.

Monopyrrolotetrathiafulvalene-succinamide conjugates and their TCNQ charge transfer complex based supramolecular gels with multiple stimulus responsiveness.

A series of monopyrrolotetrathiafulvalene-succinamide conjugates and their 7,7,8,8-tetracyano-p-quinodimethane (TCNQ) charge transfer (CT) complexes have been synthesized and investigated as new low-molecular mass organogelators. The gelation capability of these conjugates is highly dependent on the length of the alkyl chain of the terminal amide. Thus, only the short alkyl chain derivatives and could efficiently gelate cyclohexane and methylcyclohexane (MCH). Surprisingly, these gelators react with TCNQ to form stable CT complex gels in both cyclohexane and MCH. The FE-SEM images of the native gels reveal the characteristic gelation morphologies of microporous or fibrous structures, whereas the morphologies of CT complex gels show the fibrillar and globular aggregates in cyclohexane and MCH, respectively. SAXS study of the native gel and the CT complex gel of in cyclohexane suggests that the molecules maintain rectangular and hexagonal columnar molecular packing models in the gel phase, respectively. The native gels undergo a reversible gel-sol phase transition upon exposure to external stimuli, such as temperature and chemical oxidation/reduction. Alternatively, the corresponding CT complex gels exhibit a complicated response to external stimuli. Chemical oxidation by I2 results in the destruction of the gel state. However, neither Fe(3+) nor Cu(2+) can induce the collapse of the gel phase. Interestingly, all the gels show an irreversible gel-sol transition on successively triggering with trifluoroacetic acid and triethylamine. The reformation of the gel from the sol state is achieved just by the addition of water, showing the phase-selective gelation of the solvents from their mixtures with water.

The effect of the water-soluble polymer released from Botryococcus braunii Showa strain on solvent extraction of hydrocarbon

Hydrocarbons are easily extracted by organic sol- vents such as n-decane from wet samples of Botryococcus braunii by thermal pretreatment at 90 °C even after being cooled to room temperature. However, hydrocarbon recover- ies are not as readily achieved at room temperature from samples pretreated at temperatures lower than 80 °C. This suggests that there is the point of no return for pretreatment temperature that enables effective solvent extraction of hydro- carbons at room temperature from wet algal samples of B. braunii. To elucidate the mechanism of hydrocarbon re- covery from B. braunii following thermal pretreatments, we investigated the thermophysical properties of the water phase separated from heated algal slurry. Differential scanning cal- orimetry (DSC) measurements revealed sol-gel transitions in the water phase of algal slurry after protein denaturation at 64 °C in samples that was pretreated at 70 or 80 °C but not in those pretreated at 90 °C. Furthermore, the pretreated >70 °C water-soluble polymers revealed polysaccharides composed of galactose, arabinose, and uronic acid. These results suggest that the transition from sol state to gel state of water-soluble polysaccharides in algal slurry prevented hydrocarbon recov- ery with organic solvents since hydrocarbons were easily recovered from sol state samples pretreated at 70 or 80 °C when the extraction temperature was kept the same as the pretreatment temperature. These results reveal that the pres- ence of water-soluble polymers with gelation ability in the water phase and removal of these polymers in sol state enable effective recovery of hydrocarbons at room temperature after thermal pretreatments.

A co-assembled gel of a pyromellitic dianhydride derivative and polyaniline with optoelectronic and photovoltaic properties.

5,5'-(1,3,5,7-Tetraoxopyrrolo[3,4-f]isoindole-2,6-diyl)diisophthalic acid (PMDIG) is used to produce a supramolecular hydrogel via acid-base treatment. The field emission scanning electron micrograph and atomic force microscopy micrographs exhibit a fibrillar network structure from intermolecular supramolecular interaction, supported from Fourier transform infrared (FTIR) and UV-vis spectra. The fluorescence intensity of the PMDIG gel is 16 times higher than that of the sodium salt of PMDIG with a 42 nm red shift of the emission peak. Upon addition of an anilinium chloride solution to the PMDIG gel, it transforms into the sol, and when a solid ammonium persulfate is spread over it, a stable hydrogel is produced. The co-assembled PMDIG-polyaniline (PANI) gel exhibits a fibrillar network morphology, and the co-assembly is formed by the supramolecular interaction between the polyaniline (donor) and the PMDIG (acceptor) molecules, which is evident from FTIR spectra and wide angle X-ray scattering results. The UV-vis spectrum of the PMDIG-PANI hydrogel exhibits the characteristic peaks of polaron band transitions of the doped PANI. The PMDIG-PANI co-assembled hydrogel has a 51-fold higher storage modulus, a 52-fold higher elasticity, a 1.4-fold increase in stiffness, and a 5-fold increase of fragility compared to the values of the PMDIG hydrogel. The PMDIG-PANI xerogel exhibits a 4 order of magnitude increase in dc conductivity compared to that of PMDIG, and the I-V characteristic curve exhibits a rectification property under white light illumination showing photocurrent rectification, a new phenomenon reported here for the supramolecular gel systems. A dye-sensitized solar cell fabricated with an ITO/PMDIG-PANI/graphite device shows a power conversion efficiency (η) of 0.1%. A discussion of the mechanism of gel formation and the sol state of the PMDIG-aniline system is included considering the contact angle values of the xerogels.

Prevention of desiccation induced postsurgical adhesion by thermosensitive micelles

Tissue desiccation is a common cause of postsurgical peritoneal adhesion, which leads a variety of adverse consequences in clinic. Until now, many approaches have been advocated to prevent postsurgical adhesions, but the therapeutic effects were not very encouraging. In this work, biodegradable and thermosensitive poly(ɛ-caprolactone)-poly(ethylene glycol)-poly(ɛ-caprolactone) (PCL–PEG–PCL) micelles were prepared and assigned for anti-adhesion studies. The micelles were a free flowing sol at low temperature, but instantly inverted into a non-flowing gel at physiological temperature, which could serve as a potential candidate as anti-adhesion barrier. A novel cecum desiccation rat model was established and used for anti-adhesion studies. The micelles were sol state before use, which could cover the injured cecum unrestrictedly, and then formed gel in body temperature and adhered to the injured sites. All the rats in the control group developed adhesions with score 5 or 4, whereas none in the micelle-treated group developed adhesions with score 5 or 4 (P<0.001, Mann–Whitney U test). Histopathological assessment also confirmed that the micelles exhibited excellent anti-adhesion effects on desiccation-induced peritoneal adhesion. Adhesiveness and degradation behavior of the micelles suggested that the micelles could adhere to the injured cecum and prevent adhesion in the critical time of healing process. The results indicated that the thermosensitive micelles could serve as an effective anti-adhesion barrier.

A novel doxorubicin-loaded in situ forming gel based high concentration of phospholipid for intratumoral drug delivery.

The purpose of this study was to develop a safe and effective drug delivery system for local chemotherapy. A novel injectable in-situ-forming gel system was prepared using small molecule materials, including phospholipids, medium chain triglycerides (MCTs), and ethanol. Thus, this new sustained release system was named PME (first letter of phospholipids, MCT, and ethanol). PME has a well-defined molecule structure, a high degree of safety, and better biocompatible characteristics. It was in sol state with low viscosity in vitro and turned into a solid or semisolid gel in situ after injection. When loaded with doxorubicin (Dox), PME-D (doxorubicin-loaded PME) exhibited notably antitumor efficiency in S180 sarcoma tumors bearing mice after a single intratumoral injection. In vitro, PME-D had remarkable antiproliferative efficacies against MCF-7 breast cancer cells for over 5 days. Moreover, the initial burst effect can hardly be observed from PME system, which was different from many other in-situ-forming gels. The in vivo biodistribution study showed the high Dox concentration in tumors compared with other major organs after PME-D intratumoral administration. The strong signal in tumors was retained for more than 14 days after one single injection. The high concentration of Dox in tumor and long-term retention may explain the superior therapeutic efficacy and reduced side effects. The PME-D in-situ-forming gel system is a promising drug delivery system for local chemotherapy.

Effects of salt concentrations on the structural transitions of peptide-amphiphile solution

ABSTRACTA new peptide amphiphile (PA) called C16-W3K has hierarchical structures, presenting unique solution states, micelle structures, and secondary structures. In this work, the effects of salt (sodium dihydrogenorthophosphate) concentration on the hierarchical structural transitions of the C16-W3K solution due to its active hydrogen bonding in the peptide were discussed. In order to analyze the effects of salt on the structural transitions, the mechanical and structural analyses were conducted by viscosity measurements, transmission electron microscopy (TEM), and circular dichroic (CD) spectroscopy. It was found that the C16-W3K solutions with different salt concentrations presented different multi-scale structural transitions from spherical micelles with α-helix molecular conformations in the sol state to wormlike micelles with β-sheet conformations in the gel state. Additionally, we found that the speed of transition increased as the salt concentration increased and the conformational ratio of β-sheet to α-helix in the solutions increased with the increase in the salt concentration.

Thermoresponsive Synthetic Polymer–Microtubule Hybrids

Thermoresponsive hybrids consisting of synthetic polymers and microtubules (MTs), i.e., assemblies of tubulins, were prepared by bonding MTs covalently to a few reactive units in a macromolecular strand. The hybrids exhibited the gel/sol transition because of the "assembling of tubulins to MTs/disintegrating of MTs to tubulins" by the temperature change between 37 and 4 °C, respectively. The viscoelastic behaviors of the hybrid gels depended upon the quantity of polymer feed and the amount of resulting covalent bonds between the polymers and tubulin units. Furthermore, in a confined space of a thin and long rectangular cell with the temperature gradient from 4 °C (cold terminal) to 37 °C (warm terminal), the sol state hybrid turned to the gel state that propagated from the warm terminal toward the cold terminal to form uniaxially oriented MT arrays. Upon changing the temperature of the whole system between 37 and 4 °C, the uniaxial arrays appeared/disappeared reversibly.

Reconstruction of Active Regular Motion in Amoeba Extract: Dynamic Cooperation between Sol and Gel States

Amoeboid locomotion is one of the typical modes of biological cell migration. Cytoplasmic sol–gel conversion of an actomyosin system is thought to play an important role in locomotion. However, the mechanisms underlying sol–gel conversion, including trigger, signal, and regulating factors, remain unclear. We developed a novel model system in which an actomyosin fraction moves like an amoeba in a cytoplasmic extract. Rheological study of this model system revealed that the actomyosin fraction exhibits shear banding: the sol–gel state of actomyosin can be regulated by shear rate or mechanical force. Furthermore, study of the living cell indicated that the shear-banding property also causes sol–gel conversion with the same order of magnitude as that of shear rate. Our results suggest that the inherent sol–gel transition property plays an essential role in the self-regulation of autonomous translational motion in amoeba.

Discrimination of Sol and Gel states in an aging clay suspension

The dynamical scattered light intensity and multiplicative cascade model was employed to characterize the anisotropic charged colloidal particles suspension during the so-called Sol–Gel transition. Generally we looked for finding a criterion to distinguish the properties of Sol and Gel states systematically. The probability density function (PDF) of the light scattering intensity shows an obvious change with proceeding of the sample aging process (during of gelation state). Our results confirmed that in the so-called Sol state, the value of non-Gaussian parameter, λw2, as a function of time is larger than that of for weak-Gel or in coexistence Sol–Gel state. The number of cascades in the weak-Gel is smaller than the rest of states. In addition, we found out a deviation from Kolmogorov–Obukhov hypothesis concerning the linear dependance of λw2 to the logarithm of scale.

Synthesis of highly porous alumina-based materials

γ-Alumina-based materials with high porous volume, tunable pore size, were synthesized by the addition of both PEO/PPO/PEO triblock copolymers (Pluronics® F127 and P123) and metal nitrates (Al3+, Mn2+, Cu2+) in a boehmite (AlOOH) nanoparticle hydrosol. During the subsequent thermal treatment, the surfactant was removed leaving a highly porous framework.The pore size distribution was strongly dependent on the metal nitrate added and its concentration. By this simple process it was possible to modify the porous volume in the range 0.3–2.6cm3g−1 and the median pore diameter in the range 5–40nm. All these materials presented high surface areas in the range 300–500m2g−1.During the drying AlOOH particles aggregate to form linear objects (flat rods, laths) in order to minimize electrostatic repulsion. We think that the improvement of the textural characteristics of γ-alumina could be explained by the adsorption of copolymer onto these fiber-like objects, preventing the compact rearrangement of the boehmite nanoparticles in a compact “card-pack” microstructure during the drying.The addition of electrolytes induces a reduction of electrostatic repulsions, leading to the formation of both fiber-like objects at lower AlOOH concentration, and a 3D network by bridging these 1D objects. This bridging is reversible since the gel returns to a sol state under shearing, but polymer adsorption can prevent the full collapsing of this network during the drying step and a huge porosity can be maintained after calcination.

Co-assembled White-Light-Emitting Hydrogel of Melamine

A coassembled light-harvesting hydrogel of melamine (M), 6,7-dimethoxy-2,4[1H, 3H]-quinazolinedione (Q) with riboflavin (R), is used to produce a white-light-emitting hydrogel (W-gel) by mixing with the dye rhodamine B (RhB) in a requisite proportion. Addition of R to the Q solution causes both static and dynamic quenching to the emission of Q as evident from the Stern-Volmer plot and the emission of R shows a gradual increase in intensity. On addition of RhB to an aqueous solution of R, fluorescence resonance energy transfer (FRET) occurs, showing an emission peak at 581 nm. In a solution of constant molar ratio of Q and R, addition of RhB causes a quenching of emission of R with no effect on the emission of Q, indicating that the energy transfer takes place only between R and RhB. In the MQR coassembled hydrogel containing RhB, the gel melting temperature is lower than those of MQ and MQR gel, but the storage modulus remains almost unaffected. The oscillatory stress experiment indicates a gradual decrease of critical stress values for breaking of MQ, MQR, and W-gels attributed to the coassembly. In contrast to the solution of Q and R, energy transfer occurs on addition of RhB to the MQ gel. By varying the RhB and R concentration in the 1:1 MQ gel white light emission is observed for the W-gel composition having molar ratio of M:Q:R:RhB = 100:100:0.5:0.02 with the Commission Internationale de L'eclairage (CIE) coordinates of 0.31 and 0.36 for the excitation at 360 nm. However, in the sol state, the CIE coordinates of the hybrid differ significantly from those of the white light.

Glycol Chitin–based Thermoresponsive Hydrogel Scaffold Supplemented with Enamel Matrix Derivative Promotes Odontogenic Differentiation of Human Dental Pulp Cells

IntroductionHydrogels have been widely studied as tissue engineering scaffolds over the past 2 decades because of their favorable biological properties. Recently, a new biodegradable glycol chitin–based thermoresponsive hydrogel scaffold (GC-TRS) was developed that can be easily applied as a mild viscous solution at room temperature but quickly transforms into a durable hydrogel under physiological conditions. The aim of this study was to investigate the effects of GC-TRS on the proliferation and odontogenic differentiation of colony-forming human dental pulp cells (hDPCs) in the presence of enamel matrix derivative. MethodsGlycol chitin was synthesized by N-acetylation of glycol chitosan. The morphology of the thermoresponsive hydrogel scaffold was observed by using scanning electron microscopy. The sol gel phase transition of the aqueous solution of glycol chitin was investigated by using the tilting method and rheometer studies. hDPCs were isolated based on their ability to generate clonogenic adherent cell clusters. The effect of GC-TRS and collagen on cell viability was examined by performing 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Expression of markers for odontogenic/osteogenic differentiation (ie, dentin sialophosphoprotein, dentin matrix protein-1, osteonectin, and osteopontin) was analyzed by performing real-time polymerase chain reaction. ResultsGC-TRS exhibited a highly macroporous and well-interconnected porous structure. The polymer solution existed in a mildly viscous sol state, but it transitioned to a gel state and did not flow above approximately 37°C. Rheometer studies showed that the glycol chitin solution exhibited a fast sol gel transition approximately at body temperature. GC-TRS and collagen did not inhibit cell viability until 7 days. Dentin sialophosphoprotein and dentin matrix protein-1 were expressed by cells cultured in GC-TRS at a higher level than that in cells cultured in collagen (P < .05). In both the scaffold groups, dentin sialophosphoprotein, dentin matrix protein-1, and osteopontin messenger RNA was up-regulated significantly in EMD-treated hDPCs when compared with the nontreated cells (P < .05). ConclusionsGC-TRS allowed the proliferation and odontogenic differentiation of hDPCs. Furthermore, the differentiation was facilitated by EMD. These results suggest that GC-TRS has the potential to be used in tissue engineering techniques for dentin regeneration.