Increasing Crosslinker Concentration Research Articles

Shape memory properties and unusual optical behaviour of an interpenetrating network of poly(ethylene oxide) and poly(2‐hydroxyethyl methacrylate)

AbstractAn interpenetrating polymer network (IPN) with shape memory properties was prepared by using poly(2‐hydroxyethyl methacrylate) (PHEMA) and poly(ethylene oxide) (PEO). PHEMA acts as a fixed phase and PEO as a switching phase. The switching action of PEO is due to the reversible process of melting and crystallization. It was observed that the shape recovery of the IPN increases with increasing crosslinker concentration up to an optimum value and decreases thereafter. In addition to the shape memory property, the IPNs show a reversible change in optical properties from translucent to opaque. The change in optical properties is quite different from that observed in a semicrystalline polymer system where the transparency increases as a result of the melting of crystals. This behaviour of the IPN is explained in terms of H‐bonding of PEO with PHEMA. Fourier transform infrared spectroscopy was used to study the H‐bonding between PEO and PHEMA. © 2019 Society of Chemical Industry

Preparation and characterization of PVA/SA/HA composite hydrogels for wound dressing

A composite hydrogel based on, by introducing, polyvinyl alcohol, sodium alginate, and hyaluronic acid was fabricated using CaCl2 as a cross-linker. The physical properties including morphology, water vapor transmission rate, and hydrophilicity were investigated. All PVA/SA/HA composite hydrogels with different compositions had highly homogeneous and interconnected pores, and the morphologies of the PVA/SA/HA hydrogels ranged from fibrous structure to irregular structure with increasing content of SA. The introduction of sodium alginate enhanced the hydrophilicity and water vapor transmission capacity of the hydrogel; however, the hydrophilicity of the composite hydrogels decreased with the increasing cross-linker content.

Formulation development and characterization of cefazolin nanoparticles-loaded cross-linked films of sodium alginate and pectin as wound dressings

The present study focuses on the preparation of nanoparticles-loaded ionic cross-linked films for the topical delivery of cefazolin. The aim of the study was to prepare a dosage form which can provide local effect of cefazolin along with sustained delivery at the site of application. Cefazolin was loaded into chitosan nanoparticles to mask the burst release of the drug and they were optimized based on particle size, PDI, % EE and zeta potential. Finally, the prepared nanoparticles were loaded into the films comprising of sodium alginate and pectin which were then subjected to cross-linking via calcium chloride to improve the mechanical strength of the hydrogel films upon exposure to wound fluid. The films were assessed for physical and mechanical properties, swelling behavior, water transmission rate, mucoadhesion, FTIR, DSC, percent inhibition assay and in vitro release profile. Optimized formulation with Cefazolin nanoparticles in the size range of 227 nm and 0.5% CL films showed significantly better results (p < 0.05) as compared to the films with increased cross-linker concentration. Therefore, 0.5% CL films were considered more suitable for the treatment of infections when applied as wound dressing.

Characterization and Evaluation of Prudent Liquid Natural Rubber-Based Foam for Oil Spill Control Application

Oil spills have caused adverse effects on the environment calling for more efficient oil removal techniques. This study highlights the use of liquid natural rubber (LNR) as the main raw material to produce competitive and effective oil absorbents. The absorbents were produced via vulcanization with the aid of foaming agents and were then characterized in terms of morphology and oil absorption capacity. The morphology analysis shows that the absorbents formed have irregular pores of 450–500 \(\upmu \)m in diameter. It was found that the oil absorption capacities of the absorbents decrease with increasing crosslinker concentration and when subjected to higher-viscosity oils. The sorption capacity of the absorbent is capped at 7.67 g g \(^{-1}\), while the reusability of the absorbents is up to 13 times. These LNR-based absorbents open up new opportunities for potential designs of better and renewable oil absorbents.

Studying Crosslinker Chemical Structure Effect on the Tuning Properties of HTPB‐Based Polyurethane

AbstractHydroxyl terminated polybutadiene based polyurethanes with various crosslinker compounds have been prepared to investigate the effect of crosslinker content and structure on polyurethanes mechanical properties. Three various crosslinkers have been used in this study, including trimethylolpropane, triethanolamine, and boron trifluoride triethanolamine complex. The results established that increasing crosslinker content increased the polyurethane strength. Moreover, boron trifluoride triethanolamine complex showed better ability in making network polyurethanes. The tensile test revealed that using boron trifluoride triethanolamine complex as crosslinker led to increasing chemical crosslinking bonds in comparison to two other crosslinkers via catalyzing side reaction like chain coupling. Swelling test and dynamical‐mechanical analysis confirmed this result, too.

Micro-Mechanical Viscoelastic Properties of Crosslinked Hydrogels Using the Nano-Epsilon Dot Method.

Engineering materials that recapitulate pathophysiological mechanical properties of native tissues in vitro is of interest for the development of biomimetic organ models. To date, the majority of studies have focused on designing hydrogels for cell cultures which mimic native tissue stiffness or quasi-static elastic moduli through a variety of crosslinking strategies, while their viscoelastic (time-dependent) behavior has been largely ignored. To provide a more complete description of the biomechanical environment felt by cells, we focused on characterizing the micro-mechanical viscoelastic properties of crosslinked hydrogels at typical cell length scales. In particular, gelatin hydrogels crosslinked with different glutaraldehyde (GTA) concentrations were analyzed via nano-indentation tests using the nano-epsilon dot method. The experimental data were fitted to a Maxwell Standard Linear Solid model, showing that increasing GTA concentration results in increased instantaneous and equilibrium elastic moduli and in a higher characteristic relaxation time. Therefore, not only do gelatin hydrogels become stiffer with increasing crosslinker concentration (as reported in the literature), but there is also a concomitant change in their viscoelastic behavior towards a more elastic one. As the degree of crosslinking alters both the elastic and viscous behavior of hydrogels, caution should be taken when attributing cell response merely to substrate stiffness, as the two effects cannot be decoupled.

Comparative Study of the Mechanical Properties of New PEGSSDA Hydrogels, and Their Effect on Embedded Stem Cell Secretome

Hydrogels are hyaluronic acid and collagen‐based polymer networks that mimic the 3D cell microenvironment and can be used as tissue‐engineered scaffolds for therapeutic delivery of embedded stem cells and drugs. Mechanical characteristics determine important features of hydrogels (including rigidity and pore size) and affect their therapeutic efficacy. A key component of hydrogels that dictates many of their mechanical characteristics is the crosslinker used in their construction. Recently, new hydrogel crosslinkers were developed. In this study, we compared hydrogels constructed with different concentrations (2% and 4%) of two different PEG (poly(ethylene glycol)) crosslinkers, including PEGDA (poly(ethylene glycol) diacrylate) and the brand new PEGSSDA (a disulfide‐containing PEGDA). Both crosslinkers have acrylate ends, but PEGSSDA is longer due to the additional disulfide bond. We determined various properties of the hydrogels constructed with each crosslinker, including Young's modulus (measurement of rigidity that can be measured using atomic force microscopy), diffusion efficiency and swelling ratio. In follow up experiments, we examined (using luminex multiplex technology) if the cyto‐/chemokine secretome of endothelial progenitor cells (EPCs) was affected when these cells were embedded in PEGDA and PEGSSDA hydrogels. We hypothesized PEGSSDA hydrogels would have different mechanical properties and rigidities than PEGDA hydrogels, an effect that alters the secretome of embedded stem cells presumably due to the altered tension placed on the embedded cells. There was a significant difference in hydrogel swelling ratios between hydrogels constructed with the different crosslinkers and when different crosslinker concentrations were used. The PEGSSDA hydrogels were 15% more permeable than PEGSSDA hydrogels. The measured Young's modulus for 2% and 4% PEGDA hydrogels were 2204 Pa and 4239 Pa, respectively, whereas those of PEGSSDA were 2069 Pa and 2261 Pa, respectively. In general, the cyto‐/chemokine secretome was lower for hydrogel embedded EPCs, as compared to non‐embedded EPCs. EPCs embedded in PEGDA hydrogels, as compared to PEGSSDA hydrogels, had greater release of LIX, VEGF and IP‐10. Upon increased concentration of either crosslinker, hydrogel embedded EPCs released reduced levels of IL‐10, VEGF, GM‐CSF, MIP‐1b and IP‐10. Our results indicate a difference in hydrogel mechanical properties when crosslinked with PEGDA, as compared to PEGSSDA. PEGDA crosslinker creates hydrogels that are more rigid. Furthermore, PEGDA hydrogels enhance cyto‐/chemokine release from embedded EPCs, as compared to PEGSSDA hydrogels. However, upon increased crosslinker concentration of either PEGDA or PEGSSDA from 2% to 4%, hydrogel rigidity was enhanced while cyto‐/chemokine release from embedded EPCs was reduced.Support or Funding InformationAHA grant 12SDG9080006, ASN grant 010973–101, The New York Community Trust Renal Clinical Fund (B.B.R.)

Synthesis and characterization of thermally responsive N-isopropylacrylamide hydrogels copolymerized with novel hydrophobic polyphenolic crosslinkers

Two series of thermosensitive hydrogels were synthesized by copolymerizing N-isopropylacrylamide (NIPAAm) with various contents of novel hydrophobic crosslinkers, curcumin multiacrylate (CMA) and quercetin multiacrylate (QMA). The compositions of the resulting hydrogels were characterized using solid state-NMR (ss-NMR), and the temperature dependent swelling behavior and lower critical solution temperature (LCST) were characterized using swelling studies and differential scanning calorimetry (DSC). Increasing the crosslinker content resulted in a significant decrease in the LCST and swelling ratio of hydrogels, which could be attributed to the increased hydrophobicity introduced by CMA or QMA. All of the hydrogels demonstrated temperature responsive swelling with the extent of swelling decreasing with increasing crosslinker content. The lower crosslinker content gels displayed sharper phase transitions, while the high crosslinker content gels had broader phase transitions.

Experimental investigation of the effects of crosslinking processes on the swelling and hygroscopic performances of a poly(vinyl alcohol) membrane

ABSTRACTPoly(vinyl alcohol) (PVA) membranes crosslinked with L‐malic acid were prepared, and the effects of the heat‐treatment temperature and crosslinker concentration on their swelling and hygroscopic performances were investigated. Both the swelling and hygroscopic performances of the PVA membranes decreased with increasing heat‐treatment temperature; while the former decreased, the latter increased with increasing crosslinker concentration. The PVA membranes were characterized with differential scanning calorimetry (DSC), acid–base titration, and Fourier transform infrared spectrometry. The DSC results indicated that there was freezing and nonfreezing water in the swollen membranes, whereas there was only nonfreezing water in the moistened membranes. In addition, acid–base titration analysis revealed that both increased heat‐treatment temperature and increased crosslinker concentration increased the bilateral ester group levels (crosslinking degree) and decreased the content of freezing water. By contrast, the content of hydrophilic groups decreased and increased with increasing heat‐treatment temperature and crosslinker concentration, respectively; this resulted in decreased and increased levels of nonfreezing water, respectively. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2017,134, 44481.

Formulation of polysaccharide-based nanoparticles for local administration into the oral cavity

The efficacy of treatments for oral ailments is often challenged by a low residence time of the conventional pharmaceutical formulations in the oral cavity. The residence time in the oral cavity could be improved by using bioadhesive formulations, such as preparations based on polysaccharides. This study describes the formulation and the evaluation of polysaccharide-based nanosystems as drug delivery systems addressed to the oral cavity. Nanoparticles based on chitosan, alginate or pectin were prepared through self-assembly by ionotropic gelation using oppositely charged crosslinkers (tripolyphosphate or zinc). Characteristics of nanoparticles at increasing crosslinker concentration provided the basis for selecting the most suitable formulations. The nanoparticles were tested for cytotoxicity against buccal cells (TR146) and for stability in a medium simulating pH, ionic strength, electrolyte composition and concentration of saliva. Alginate nanoparticles were the most stable in the salivary environment, while chitosan nanoparticles were the most cytocompatible. Alginate nanoparticles and pectin nanoparticles revealed possible cytotoxicity due to the presence of zinc. This knowledge is important in the early design of polymer-based nanoparticles for oral usage and for potential improving of the biocompatibility of the investigated nanoparticles with the oral environment.

Gellan gum microspheres crosslinked with trivalent ion: effect of polymer and crosslinker concentrations on drug release and mucoadhesive properties

Gellan gum microspheres were obtained by ionotropic gelation technique, using the trivalent ion Al3+. The percentage of entrapment efficiency ranged from 48.76 to 87.52% and 22 randomized full factorial design demonstrated that both the increase of polymer concentration and the decrease of crosslinker concentration presented a positive effect in the amount of encapsulated drug. Microspheres size and circularity ranged from 700.17 to 938.32 μm and from 0.641 to 0.796 μm, respectively. The increase of polymer concentration (1–2%) and crosslinker concentration (3–5%) led to the enlargement of particle size and circularity. However, the association of increased crosslinker concentration and reduced polymer content made the particles more irregular. In vitro and ex vivo tests evidenced the high mucoadhesiveness of microspheres. The high liquid uptake ability of the microspheres was demonstrated and the pH variation did not affect this parameter. Drug release was pH dependent, with low release rates in acid pH (42.40% and 44.93%) and a burst effect in phosphate buffer pH (7.4). The Weibull model had the best correlation with the drug release data, demonstrating that the release process was driven by a complex mechanism involving the erosion and swelling of the matrix or by non-Fickian diffusion.

Novel Method to Monitor the De-Swelling of PNIPAAm Hydrogels of Different Cross-Link Density

The effect of cross-linker (methylene-bis-acrylamide) (MBA) on the volume phase transition, mechanical properties and de-swelling of Poly(N-isopropyl acrylamide-co-methylene-bis-acrylamide) hydrogel (PNIPAAm/MBA hydrogel) was investigated. A new method, namely isothermal thermo-gravimetry was developed for monitoring de-swelling of PNIPAAm/MBA hydrogel. Monomer/ Cross-linker ratio of the initial monomer composition R = moleNIPAAm/moleMBA was introduced. It has been proven earlier that initial monomer composition is close to the copolymer composition; hence R values may be used to express cross-link density. Hydrogels from R10 to R150 were investigated. The results of DSC analysis revealed that the less the cross-linker ratio in the gel (from R10 to R150) the more sharp the temperature range of volume phase transition and the higher its enthalpy. Cross-link density, namely increasing cross-linker content in the copolymer (R from 150 to 10) does not significantly affect the temperature range of volume phase transition. It sets on at 33°C - 34°C, and ends between 35?C and 38?C. Cross-link density has significant effect on compression modulus. By decreasing the ratio of cross-linker (by increasing R from 10 to 150), the compression modulus increases, goes through a maximum, and then decreases. The highest compression modulus was measured for PNIPAAm/MBA hydrogel R20. Hydrogels with cross-linker content between R100 and 30 are strong enough and have their thermoresponsivity. Isothermal thermograms of de-swelling are of similar character for all the gels with different cross-linker content. During the initial stage of de-swelling for gels with higher cross-linker content (R10 - R15) the solute release is quicker than for gels R20 - 150 and the thermograms are drawn out. In the initial stage of de-swelling, i.e. during the first 40 minutes the rate of solute release is the highest for gels R70 - 150. The cross-linker content effects solute release, especially for gels with high cross-linker content. It is noteworthy that gels R10 - 15 release solute quicker than gels R30 - 50 and their rate of de-swelling is comparable to that of gels R100 - 150. The novel thermogravimetric method enables the selection of gels based on the rate of solute release and it can also be applied for other cross-linked gels.

Controlled release in vitro of icariin from gelatin/hyaluronic acid composite microspheres

To fabricate a controlled release system for icariin for application to tissue engineering, gelatin/hyaluronic acid (Gel/HA) composite microspheres loaded icariin were prepared through emulsion-coagulation method using glutaraldehyde (GA) as cross-linker. The free Gel/HA and Gel/HA-icariin microspheres were characterized by Fourier transforms infrared (FTIR) and scanning electron microscopy (SEM). The influences of cross-linker content on the drug loaded and encapsulation efficiency of the Gel/HA microspheres were investigated, and the effects of cross-linker content, cross-linking time and loaded drug content on the release behavior of icariin in vitro were also studied. Moreover, the in vitro release kinetics of icariin from Gel/HA microspheres was analyzed. The results showed that both Gel/HA and Gel/HA-icariin microspheres are spherical with size ranged from 20 to 60 μm, and the Gel/HA-icariin microspheres showed rougher surface than Gel/HA microspheres. The loaded efficiency and the encapsulation efficiency decreased with increasing cross-linker content. The cumulative release of icariin from the Gel/HA microspheres decreased with increasing GA content and cross-linking time; however, the cumulative release increased with increasing icariin content in the microspheres. The results of icariin release kinetics from Gel/HA microspheres indicated Fickian diffusion. We concluded that it was feasible for Gel/HA to act as carriers of slow release of microspheres, and the release rate of icariin from the microspheres was adjustable.

In vitro release of metformin from iron (III) cross-linked alginate–carboxymethyl cellulose hydrogel beads

In the present study, sodium alginate (NaAlg)/sodium carboxymethyl cellulose (NaCMC) blend hydrogel beads were prepared in ferric chloride solution. The developed hydrogel beads exhibited pH sensitive for deliver Metformin hydrochloride (MH). Preparation conditions of the beads (ferric chloride solution) were significantly affected the encapsulation efficiency, swelling and in vitro release profiles of the beads. Swelling studies were accomplished in gastric and intestine stimuli atmosphere at 37°C. The swelling studies reveal that the beads at pH 7.4 showed higher swelling properties compare to pH 1.2. Exterior morphology of beads was analyzed by scanning electron microscope. SEM indicates the surface of the beads is spherical with smooth surface and size of beads drastically reduced with increasing crosslinker concentration. The crosslinking reaction between NaAlg and NaCMC with ferric chloride was confirmed by FTIR analysis. XRD analysis indicates that MH drug molecularly dispersed in the polymer matrix. In vitro release studies of MH loaded beads showed higher release profiles at pH 7.4 compared to pH 1.2. The polymeric matrices followed slightly deviation with Fickian diffusion and fit for experimental co-relation (r2) values.

Monitoring the internal structure of poly(N-vinylcaprolactam) microgels with variable cross-link concentration.

The combination of a set of complementary techniques allows us to construct an unprecedented and comprehensive picture of the internal structure, temperature dependent swelling behavior, and the dependence of these properties on the cross-linker concentration of microgel particles based on N-vinylcaprolactam (VCL). The microgels were synthesized by precipitation polymerization using different amounts of cross-linking agent. Characterization was performed by small-angle neutron scattering (SANS) using two complementary neutron instruments to cover a uniquely broad Q-range with one probe. Additionally we used dynamic light scattering (DLS), atomic force microscopy (AFM), and differential scanning calorimetry (DSC). Previously obtained nuclear magnetic resonance spectroscopy (NMR) results on the same PVCL particles are utilized to round the picture off. Our study shows that both the particle radius and the cross-link density and therefore also the stiffness of the microgels rises with increasing cross-linker content. Hence, more cross-linker reduces the swelling capability distinctly. These findings are supported by SANS and AFM measurements. Independent DLS experiments also found the increase in particle size but suggest an unchanged cross-link density. The reason for the apparent contradiction is the indirect extraction of the parameters via a model in the evaluation of DLS measurements. The more direct approach in AFM by evaluating the cross section profiles of observed microgel particles gives evidence of significantly softer and more deformable particles at lower cross-linker concentrations and therefore verifies the change in cross-link density. DSC data indicate a minor but unexpected shift of the volume phase transition temperature (VPTT) to higher temperatures and exposes a more heterogeneous internal structure of the microgels with increasing cross-link density. Moreover, a change in the total energy transfer during the VPT gives evidence that the strength of hydrogen bonds is significantly affected by the cross-link density. A strong and reproducible deviation of the material density of the cross-linked microgel polymer chains toward a higher value compared to the respective linear chains has yet to be explained.

Influence of Process Variables on the Physical Properties of Gelatin/SA/HYA Composite Hydrogels

A novel composite hydrogel based on gelatin, sodium alginate (SA) and hyaluronic acid (HYA) was fabricated by freeze-drying method using 1-ethyl-(3-3-dimethylaminopropyl) carbodiimide (EDC) as a cross-linker. The effects of chemical cross-linking, including cross-linker content and cross-linking time, on the morphology, swelling ratio and compressive strength of the gelatin/SA/HYA hydrogel were investigated. The influence of pH value of the swelling medium on the swelling ratio of the gelatin/SA/HYA composite hydrogel was also studied. The results showed that the gelatin/SA/HYA composite hydrogel had a three-dimensional interconnected structure and the pore size decreased with increasing EDC concentration. The IR absorption peak intensity of the gelatin/SA/HYA hydrogel has no obvious variety with increasing EDC content. The swelling ratio of the gelatin/SA/HYA hydrogel decreased with increasing cross-linker content and cross-linking time; however, the compressive strength increased with increasing EDC content and cross-linking time. The hydrogel swelling peak reached at pH 7. Therefore, the architecture and the physical properties of the gelatin/SA/HYA composite hydrogel can be adjusted by controlling the chemical cross-linking conditions and pH value of swelling medium.

Influence of crosslinker and ionic comonomer concentration on glass transition and demixing/mixing transition of copolymers poly(N-isopropylacrylamide) and poly(sodium acrylate) hydrogels

Hydrogels based on N-isopropylacrylamide and sodium acrylate as ionic comonomer were synthesized by free radical polymerization in water using N,N′-methylenebisacrylamide as crosslinker and ammonium persulfate as initiator. The glass transition of dried copolymers poly(N-isopropylacrylamide) (PNIPA) and poly(sodium acrylate) (SA) gels and demixing/mixing transition of PNIPA-SA hydrogels swollen with increasing amounts of water were studied using conventional differential scanning calorimetry. In the crosslinked polymers, the glass transition linearly increases, and the transition range becomes broader, with increasing crosslinker content. Increasing content of ionic comonomer also produces an increase of glass transition temperature, which moves to higher temperatures with higher sodium acrylate fraction. The influence of chemical structure of PNIPA-SA hydrogels on the lower critical solution temperature (LCST) of PNIPA-SA/water mixtures during heating and cooling was quantified as function of the content of the crosslinker and the ionic comonomer, as well as water content of the hydrogel in the range from 95 to 70 wt%. At parity of water content, the LCST occurs at higher temperatures for gels containing higher amounts of sodium acrylate. Similarly, the introduction of N,N′-methylenebisacrylamide causes an increase of the LCST, which grows with increasing of crosslinking degree of the hydrogel.

Influence of a New Stiff Crosslinker on the Swelling of Poly(N-isopropyl Acrylamide-co-Sodium Acrylate) Hydrogels and Silver Nanocomposite

Hydrogels composed of N-isopropyl acrylamide and sodium acrylate were prepared using a new stiff crosslinker 1,4-diacryloyl piperazine by a room-temperature free-radical solution polymerization. The gels swelled extensively in water and the swelling increased with increase in sodium acrylate content. Compared to similar gels with N,N’-methylene bisacrylamide as crosslinker the swelling ratio was lower by 25%. Silver nanoparticles were prepared in the hydrogel matrix by in-situ chemical reduction of silver nitrate with sodium borohydride. The new crosslinker being hydrophobic with less structural flexibility controlled the diffusion of silver and borohydride ions into the gel matrix. Silver nanoparticles were formed only on the periphery of the gel as diffusion into the central matrix was hindered by the nonflexible crosslinker. The gels were responsive to temperature changes and the difference in equilibrium water content from 23 to 55°C was 4.5-fold due to strong hydrophobic interactions. The temperature dependence of equilibrium water content was studied by applying the Gibbs-Helmholtz equation and the diffusion process was found to be exothermic. The diffusion of water into the gel matrix followed a non-Fickian behavior due to polymer relaxation. The diffusion coefficient and the penetration velocity decreased with increasing crosslinker content and also with the incorporation of silver nanoparticles in the gel.

Effect of Chemical Cross-linking on Properties of Gelatin/Hyaluronic Acid Composite Hydrogels

A composite hydrogel was fabricated by introducing hyaluronic acid (HA) into gelatin (Gel) using 1-ethyl-(3-3-dimethylaminopropyl) carbodiimide (EDC) as a cross-linker. The effects of cross-linking, including cross-linker content and cross-linking time, on the morphology, swelling ratio, compressive strength and cytotoxicity in vitro of the Gel/HA hydrogel were investigated. The results showed that the pore size of the Gel/HA hydrogel decreased with increasing cross-linker content. Further, the swelling ratio of the Gel/HA hydrogel also decreased with increasing cross-linker content and cross-linking time. However, the compressive strength increased with increasing EDC content and cross-linking time. The hydrogel extracts with various contents of EDC were not toxic, due to easy removal of excess EDC by washing with dilute acid or water.

Biodegradable organic acid-crosslinked alkali-treated gelatins with anti-thrombogenic and endothelialization properties

Gelatins were crosslinked with organic acids and treated with alkali to impart to them endothelialization and anti-thrombogenic properties. These matrices were characterized by biochemical and physicochemical techniques. The amounts of residual amino groups in the matrices decreased with increasing crosslinker concentration. The matrices with the highest crosslinking densities showed excellent endothelial cell adhesion and proliferation. In addition, the adhesion of platelets and formation of fibrin networks on the matrices were suppressed with increasing crosslinker concentration. The matrices also exhibited excellent biodegradability, and the degradation rate decreased with increasing crosslinking density. All the organic acid-crosslinked alkali-treated gelatins showed excellent anti-thrombogenic and endothelialization properties, superior to those of glutaraldehyde-crosslinked alkali-treated gelatins.