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The current treatment for periodontitis is aimed at resolving gingival inflammation, whilst complete periodontal tissue regeneration is not predictable, and it represents a therapeutic challenge. Injectable biomaterials hold tremendous potential in dental tissue regeneration. This study aimed to investigate the ability of an injectable thermosensitive β-tricalcium phosphate (β-TCP) and chitosan-based hydrogel to carry cells and promote periodontal tissue regeneration. In this study, different concentrations of β-TCP-loaded chitosan hydrogels were prepared (0%, 2%, 4%, or 6% β-TCP, 10% β-glycerol phosphate, and 1.5% chitosan). The characteristics of the hydrogels were tested using rheology, a scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), degradation, and biological analyses. The new biomaterial showed a sol–gel transformation ability at body temperature and exhibited excellent chemical and physical characteristics, whilst the existence of β-TCP enhanced the structure and the properties of the hydrogels. The SEM confirmed the three-dimensional networks of the hydrogels, and the typical rheological properties of strong gel were observed. The EDX and XRD validated the successful incorporation of β-TCP, and similar patterns between different groups were found in terms of the FTIR spectra. The stable structure of the hydrogels under 100 °C was confirmed via DSC. Biological tests such as Alamar Blue assay and Live/Dead staining confirmed the remarkable biocompatibility of the hydrogels with pre-osteoblast MC3T3-E1 and human gingival fibroblast (HGF) cells for 14 days, and the results were validated with confocal imaging. This preliminary study shows great promise for the application of the β-TCP-loaded thermosensitive chitosan hydrogels as a scaffold in periodontal bone and soft tissue repair. [ABSTRACT FROM AUTHOR]

The cross-linked microspheres were prepared and loaded with Favipiravir SARS-CoV-2 antiviral drug, by copolymerization of chitosan (CS) with a polysaccharide extracted from fresh pomegranate peels. Moreover, glutaraldehyde (Glu) has been used as a chemical cross-linker and sodium hexametaphosphate (SHMP) as a physical cross-linker. The extracted polysaccharide was analyzed, and different techniques have been used. The analyses lead to the conclusion that it is pectin. The surface morphology of the prepared microspheres was studied using a scanning electron microscope, where the size and shape factor (S) of the Glu microspheres showed high values (74.27 μm) and (0.852), respectively, meaning their surfaces tend to be rough, whereas the SHMP microspheres showed a smaller size particle (20.47 μm) and a smaller shape factor (0.748), which gives an indication that the SHMP microspheres have smooth surfaces. The swelling studies have shown that Glu microspheres have a higher degree of swelling, which means SHMP microspheres are more compact. The prepared microspheres have shown a higher loading percentage of Favipiravir antiviral drug in SHMP microspheres (37% w/w) in comparison with Glu microspheres (35% w/w), where the electrostatic interaction between the Favipiravir ions and SHMP anions helps for more loading. The microspheres prepared under different types of cross-linking have shown initial burst release of Favipiravir, followed by a step of controlled release for a certain period of time, whose period depends on the pH of the release medium. Both Glu and SHMP cross-linked microspheres have shown high controlled release times in buffered release solutions at pH = 7.4 and for shorter periods at pH = 1.3 and pH = 9.4, which may be related to the type of electrostatic interactions between drug and polymer systems and their reactions with release solution ions. [ABSTRACT FROM AUTHOR]

Nanoparticles of ZnO-Chitosan (Zn-Chit) composite were prepared using precipitation methods. Several analytical techniques, such as scanning electron microscope (SEM), transmitted electron microscope (TEM), powder X-ray diffraction (XRD), infrared spectroscopy (IR), and thermal analysis, were used to characterize the prepared composite. The activity of the modified composite was investigated for nitrite sensing and hydrogen production applications using various electrochemical techniques. A comparative study was performed for pristine ZnO and ZnO loaded on chitosan. The modified Zn-Chit has a linear range of detection 1–150 µM and a limit of detection (LOD) = 0.402 µM (response time ~3 s). The activity of the modified electrode was investigated in a real sample (milk). Furthermore, the anti-interference capability of the surface was utilized in the presence of several inorganic salts and organic additives. Additionally, Zn-Chit composite was employed as an efficient catalyst for hydrogen production in an acidic medium. Thus, the electrode showed long-term stability toward fuel production and enhanced energy security. The electrode reached a current density of 50 mA cm−2 at an overpotential equal to −0.31 and −0.2 V (vs. RHE) for GC/ZnO and GC/Zn-Chit, respectively. Electrode durability was studied for long-time constant potential chronoamperometry for 5 h. The electrodes lost 8% and 9% of the initial current for GC/ZnO and GC/Zn-Chit, respectively. [ABSTRACT FROM AUTHOR]

The 3-(Methylthio) propyl isothiocyanate (MTPITC)-loaded inclusion complex prepared by α-cyclodextrin (α-CD) was incorporated into chitosan (CS) film to fabricate a packaging material for fresh chicken meat preservation. Scanning electron microscope images indicated homogenous dispersion of the MTPITC-α-CD in CS polymer. Fourier-transform infrared and X-ray diffraction techniques revealed that MTPITC-α-CD was incorporated into the CS film matrix by the physical interactions. The introduction of MTPITC-α-CD improved the UV-vis light-blocking ability, with a slight loss of transparency. Although the water solubility and water vapor barrier capacity were not significantly influenced by the addition of MTPITC-α-CD, the antioxidant attribute was significantly enhanced. The CS-MTPITC-α-CD film displayed obvious and sustained suppressive effects against Salmonella typhimurium, with the inhibition zone diameters of 14.7 mm at 12 h and 7.3 mm at 24 h, respectively. Moreover, the quality index analysis indicated that the CS-MTPITC-α-CD film-wrapped fresh chicken, during refrigerated storage, exhibited better preservative efficacy than the control groups, with the total viable counts of 6.5 Log CFU/g, total volatile base nitrogen of 8.4 mg/100 g, pH of 6.6, thiobarbituric acid-reactive substances of 0.2 mg/kg, and the sensory score of 5 at day 16. Collectively, these results suggest that CS-MTPITC-α-CD film is a prospective packaging candidate for delaying the quality deterioration of chicken meat. [ABSTRACT FROM AUTHOR]

In the field of bone repair, the inorganic–organic composite scaffold is a promising strategy for mimicking the compositions of the natural bone. In addition, as implants for repairing load-bearing sites, an inert permanent bone substitute composites with bioactive degradable ingredients may make full use of the composite scaffold. Herein, the porous zirconia (ZrO2) matrix was prepared via the template replication method, and the partial degradable ZrO2–chitosan particles–GelMA composite scaffolds with different chitosan/GelMA volume ratios were prepared through the vacuum infiltration method. Dynamic light scattering (DLS) and the scanning electron microscope (SEM) were adopted to observe the size of the chitosan particles and the morphologies of the composites scaffold. The mechanical properties, swelling properties, and degradation properties of the composite scaffolds were also characterized by the mechanical properties testing machine and immersion tests. The CCK-8 assay was adopted to test the biocompatibility of the composite scaffold preliminarily. The results show that chitosan particles as small as 60 nm were obtained. In addition, the ratio of chitosan/GelMA can influence the mechanical properties and the swelling and degradation behaviors of the composites scaffold. Furthermore, improved cell proliferation performance was obtained for the composite scaffolds. [ABSTRACT FROM AUTHOR]

Recently, Strontium oxide (SrO) nanoparticles (NPs) and hybrids outperformed older commercial catalysts in terms of catalytic performance. Herein, we present a microwave-assisted easy in situ solution casting approach for the manufacture of strontium oxide nanoparticles doped within a naturally occurring polymer, chitosan (CS), at varying weight percentages (2.5, 5, 10, 15, and 20 wt.% SrO/chitosan). To construct the new hybrid material as a thin film, the produced nanocomposite solutions were cast in petri dishes. The aim of the research was to synthesize these hybrid nanocomposites, characterize them, and evaluate their catalytic potential in a variety of organic processes. The strontium oxide-chitosan nanocomposites were characterized using Fourier transform infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscope (SEM) techniques. All the results confirmed the formation of chitosan–strontium oxide nanocomposite. FTIR spectrum of nanocomposite showed the presence of a characteristic peak of Sr-O bond. Furthermore, XRD revealed that SrO treatment increased the crystallinity of chitosan. The particle size was calculated using the Debye–Scherrer formula, and it was determined to be around 36 nm. The CS-SrO nanocomposite has been proven to be a highly efficient base promoter for the synthesis of 2-hydrazono [1,3,4]thiadiazole derivatives. To optimize the catalytic method, the reaction factors were investigated. The approach has various advantages, including higher reaction yields, shorter reaction durations, and milder reaction conditions, as well as the catalyst's reusability for several applications. [ABSTRACT FROM AUTHOR]

In the present study, nanocellulose was extracted from palm leaves to synthesize nanocellulose/chitosan nanocomposites for the removal of dyes from textile industrial wastewater. Nanocellulose is of interest in water purification technologies because of its high surface area and versatile surface chemistry. Following bleach, alkali, and acid treatments on palm leaves, nanocellulose is obtained as a white powder. The produced nanocellulose was investigated. The adsorption capacity of chitosan, nanocellulose, and novel synthetic nanocellulose/chitosan microbeads (CCMB) for direct blue 78 dye (DB78) removal was studied. A series of batch experiments were conducted in terms of adsorbent concentration, mixing time, pH, dye initial concentration, and nanocellulose concentration in synthetic microbeads. The CCMB was characterized by using physicochemical analysis, namely Brunauer–Emmett–Teller (BET), scanning electron microscope (SEM), zeta potential analysis, and Fourier-transform infrared spectroscopy (FTIR). It was found that the surface area of synthetic CCMB is 10.4 m2/g, with a positive net surface charge. The adsorption tests showed that the dye removal efficiency increases with an increasing adsorbent concentration. The maximum removal efficiencies were 91.5% and 88.4%, using 14 and 9 g/L of CCMB-0.25:1. The initial dye concentrations were 50 and 100 mg/L under acidic conditions (pH = 3.5) and an optimal mixing time of 120 min. The equilibrium studies for CCMB-0.25:1 showed that the equilibrium data were best fitted to Langmuir isothermal model with R2 = 0.99. These results revealed that nanocellulose/chitosan microbeads are an effective eco-adsorbent for the removal of direct blue 78 dye and provide a new platform for dye removal. [ABSTRACT FROM AUTHOR]

A biologically active agent based on a Zn-1,3,5-benzen tricarboxylic acid (Zn-BTC) framework incorporated into a chitosan (CS) biopolymer (Zn-BTC@CS) was successfully synthesized using a microwave irradiation technique. The synthesized Zn-BTC@CS was characterized using a scanning electron microscope (SEM) and the obtained data indicated a highly smooth surface morphology of the synthesized Zn-BTC and no morphological changes when the Zn-BTC covered the CS. In addition, the particle size diameter varied from 20 to 40 nm. XRD displayed a well-maintained Zn-BTC structure, and the crystal structure of Zn-BTC was not distorted by the composition of Zn-BTC and chitosan in the nanocomposite. Data from BET analysis revealed that the specific surface area of the Zn-BTC was reduced from 995.15 m2/g to 15.16 m2/g after coating with chitosan. The pore size distribution and pore volume of the Zn-BTC, Zn-BTC@CS were centered at 37.26 nm and at 22.5 nm, respectively. Zn-BTC@CS exhibited anticancer efficacy against lung and colon cancer cell lines. Zn-BTC@CS inhibited the proliferation of A549 and DLD-1 cancer cell lines in a dose-dependent manner with IC50 values of 13.2 and 19.8 µg/mL for the colon and lung cancer cell lines, respectively. Zn-BTC@CS stimulated the apoptotic process through up-regulating P53 expression and down-regulating Bcl-2 expression. Moreover, Zn-BTC@CS induced in vitro DNA fragmentation in both cancer cell lines with significantly different affinity by 66% (A549) and 20% (DLD-1) versus 52% reduction by Cisplatin. Zn-BTC@CS (IC50) exhibited anti-invasive activity and dramatically inhibited the migration of lung and colon cancer cell lines. This study provides evidence that Zn-BTC@CS targets the essential proteins involved in proliferation, metastasis, and apoptosis. Thus, Zn-BTC@CS has chemotherapeutic potential for inhibiting lung and colon cancer viability and growth. [ABSTRACT FROM AUTHOR]

This study aims to develop chitosan-based voriconazole nanoparticles (NPs) using spray-drying technique. The effect of surfactants and polymers on the physicochemical properties, in vitro release, and permeation of NPs was investigated. The prepared NPs containing various surfactants and polymers (e.g., Tween 20 (T20), Tween 80 (T80), sodium lauryl sulfate (SLS), propylene glycol (PG), and Polyethylene glycol-4000 (PEG-4000)) were physiochemically evaluated for size, zeta potential, drug content, percent entrapment efficiency, in vitro release, and permeation across rats' skin. A Franz diffusion cell was used for evaluating the in vitro release and permeation profile. The voriconazole-loaded NPs were investigated for antifungal activity against Candida albicans (C. albicans). The prepared NPs were in the nano range (i.e., 160–500 nm) and positively charged. Images taken by a scanning electron microscope showed that all prepared NPs were spherical and smooth. The drug content of NPs ranged from 75% to 90%. Nanoparticle formulations exhibited a good in vitro release profile and transport voriconazole across the rat's skin in a slow control release manner. The NPs containing SLS, T80, and PG exhibited the best penetration and skin retention profile. In addition, the formulation exhibited a potential antifungal effect against C. albicans. It was concluded that the development of chitosan NPs has a great potential for the topical delivery of voriconazole against fungal infection. [ABSTRACT FROM AUTHOR]

Chitosan-based nanostructures have been widely applied in biomineralization and biosensors owing to its polycationic properties. The creation of chitosan nanostructures with controllable morphology is highly desirable, but has met with limited success yet. Here, we report that nanostructured chitosan tartaric sodium (CS-TA-Na) is simply synthesized in large amounts from chitosan tartaric ester (CS-TA) hydrolyzed by NaOH solution, while the CS-TA is obtained by dehydration-caused crystallization. The structures and self-assembly properties of CS-TA-Na are carefully characterized by Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (1H-NMR), X-ray diffraction (XRD), differential scanning calorimeter (DSC), transmission electron microscopy (TEM), a scanning electron microscope (SEM) and a polarizing optical microscope (POM). As a result, the acquired nanostructured CS-TA-Na, which is dispersed in an aqueous solution 20–50 nm in length and 10–15 nm in width, shows both the features of carboxyl and amino functional groups. Moreover, morphology regulation of the CS-TA-Na nanostructures can be easily achieved by adjusting the solvent evaporation temperature. When the evaporation temperature is increased from 4 °C to 60 °C, CS-TA-Na nanorods and nanosheets are obtained on the substrates, respectively. As far as we know, this is the first report on using a simple solvent evaporation method to prepare CS-TA-Na nanocrystals with controllable morphologies. [ABSTRACT FROM AUTHOR]

The interaction of copaiba oil in the polymer matrix of chitosan can produce a favorable synergistic effect and potentiate properties. Indeed, the bioactive principles present in copaiba oil have anti-inflammatory and healing action. In the present work, chitosan membranes containing different contents of copaiba oil copaíba (0.1, 0.5, 1.0 and 5.0% (v/v)) were for the first time investigated. The membranes were developed by the casting method and analyzed for their morphology, degree of intumescence, moisture content, contact angle, Scanning Electron Microscope, and X-ray diffractometry. These chitosan/copaiba oil porous membranes disclosed fluid absorption capacity, hydrophilic surface, and moisture. In addition, the results showed that chitosan membranes with the addition of 1.0% (v/v) of copaiba oil presented oil drops with larger diameters, around 123.78 μm. The highest fluid absorption indexes were observed in chitosan membranes containing 0.1 and 0.5% (v/v) of copaiba oil. In addition, the copaiba oil modified the crystalline structure of chitosan. Such characteristics are expected to favor wound treatment. However, biological studies are necessary for the safe use of chitosan/copaiba oil membrane as a biomaterial. [ABSTRACT FROM AUTHOR]

Natural polymers have attracted a lot of interest in researchers of late as they are environmentally friendly, biocompatible, and possess excellent characters. Membranes forming natural polymers have provided a whole new dimension to the separation technology. In this work, chitosan-gelatin blend membranes were fabricated using chitosan as the base and varying the amount of gelatin. Transport, mechanical, and surface characteristics of the fabricated membranes were examined in detail by means of the characterizing techniques such as Fourier transform infrared spectroscopy, differential scanning colorimetry, wide angle X-ray diffraction, scanning electron microscope, and thermogravimetric analysis. In order to analyze the water affinity of the developed blend chitosan-gelatin membranes, the percentage degree of swelling was examined. Out of the fabricated membranes, the membrane loaded with 15 mass% of gelatin exhibited the better pervaporation performance with a pervaporation separation index value of 266 at 30 °C for the solution containing 10% in terms of the mass of water, which is the highest among the contemporary membranes. All the fabricated membranes were stable during the pervaporation experiments, and permeation flux of water for the fabricated membranes was dominant in the overall total permeation flux, signifying that the developed membranes could be chosen for efficient separation of water–isopropanol mixture on a larger scale. [ABSTRACT FROM AUTHOR]

Chitosan/starch-based composites were prepared by thermomechanical processing as an alternative to the traditional solution method, with the aim of fabricating environmentally friendly materials on a larger scale. Different contents and types of lignin and poly(vinyl alcohol), PVA were incorporated into chitosan/starch compositions to improve their mechanical properties. It was demonstrated that the presence of both lignin and PVA increases the values of tensile strength and elongation at break of the composites. Moreover, it was observed that by the selection of a type of lignin and PVA, it was possible to tailor the internal microstructure of the samples. As observed in scanning electron microscope (SEM) micrographs, the introduction of lignin and PVA resulted in the formation of a smooth surface and homogeneous samples. [ABSTRACT FROM AUTHOR]

Heavy metal ions have a toxic and negative influences on the environment and human health even at low concentrations and need to be removed from wastewater. Chitosan and graphene oxide are suitable nano plate adsorbents with high adsorption potential because of their π-π interaction, and they are available functional groups that interact with other elements. In this study, graphene oxide was coated with silica to enhance the hydrophilicity of the adsorbent. Subsequently, the adsorbent was functionalised by various amounts of chitosan to improve the Pb(II) removal. The adsorbent was analysed using transmission electron microscopy (TEM), Raman, Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and mapping analysis techniques. An investigation of the influences of the initial concentration of Pb(II), pH and contact time were included to obtain the optimum amount of adsorption. The range of the initial Pb(II) concentration studied was from 10 to 120 mg/L. The pH factor ranged from 3 to 8 with contact time from 0 to 140 min. Freundlich, Temkin and Langmuir isotherm models were fit to the results, and a pseudo-second-order kinetic model was found to provide a good fit as well. The maximum Pb(II) removal capacity achieved was 256.41 (+/− 4%) mg/g based on Langmuir isotherms. [ABSTRACT FROM AUTHOR]

In this study, three-dimensional (3D) biopolymeric scaffolds made from collagen, silk fibroin and chitosan were successfully prepared by the freeze drying method. Dialdehyde starch (DAS) was used as a cross-linking agent for the materials. The properties of the materials were studied using density and porosity measurements, scanning electron microscope (SEM) imaging, swelling and moisture content measurements. Additionally, cytocompatibility of the materials in contact with MG-63 osteoblast-like cells was tested by live/dead staining and resazurin reduction assay on days 1, 3 and 7. It was found that new 3D materials made from collagen/silk fibroin/chitosan binary or ternary mixtures are hydrophilic with a high swelling ability (swelling rate in the range of 1680–1900%). Cross-linking of such biopolymeric materials with DAS increased swelling rate up to about 2100%, reduced porosity from 96–97% to 91–93%, and also decreased density and moisture content of the materials. Interestingly, presence of DAS did not influence the microstructure of the scaffolds as compared to non-cross-linked samples as shown by SEM. All the tested samples were found to be cytocompatible and supported adhesion and growth of MG-63 cells as shown by live–dead staining and metabolic activity test. [ABSTRACT FROM AUTHOR]

The combined effects of nano titanium dioxide (TiO2-N) and clove oil (CO) on the physico-chemical, biological and structural properties of chitosan (CH)/starch (ST) films were investigated by using a solvent casting method. Results indicated that the incorporation of TiO2-N could improve the compactness of the film, increase the tensile strength (TS) and antioxidant activity, and decrease the water vapour permeability (WVP). As may be expected, the incorporation of CO into the film matrix decreased TS but increased the hydrophobicity as well as water vapour barrier antimicrobial and antioxidant properties. Fourier-transform infrared spectroscopy (FTIR) data supported intermolecular interactions between TiO2-N, CO and the film matrix. Use of a scanning electron microscope (SEM) showed that TiO2-N and CO were well dispersed and emulsified in the film network. Thermogravimetric (TG) and derivative thermogravimetric (DTG) curves demonstrated that TiO2-N and CO were well embedded in the film matrix, hence this blend film system could provide new formulation options for food packaging materials in the future. [ABSTRACT FROM AUTHOR]

In order to improve the bioactivity of chitosan, we synthesized a novel series of chitosan derivatives: firstly, chitosan was reacted with methylclhlorofonmate obtaining N-methoxyformylated chitosan (1), which was then converted into N-pyridylurea chitosan derivatives (2a-2c) by amine-ester exchange reaction. In addition, N-pyridylurea chitosan derivatives were conducted by reacting with iodomethane to obtain quaternized N-pyridylurea chitosan derivatives (3a-3c). The structural characteristics of as-prepared chitosan derivatives were confirmed by fourier transform infrared (FT-IR), 1H nuclear magnetic resonance (1H NMR), elemental analysis, and scanning electron microscope (SEM). Meanwhile, the antioxidant activity of the chitosan derivatives was assessed in vitro. As shown in this paper, the antioxidant activity decreased in the order: c > b > a. Moreover, after the quaternization with iodomethane, quaternized N-pyridylurea chitosan derivatives immediately exhibited enhanced antioxidant capacity compared with N-pyridylurea chitosan derivatives. For example, in 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, the scavenging activities of 3a-3c were 91.75%, 93.63%, and 97.63% while 2a-2c were 42.32%, 42.97%, and 43.07% at 0.4 mg/mL. L929 cells were also adopted for cytotoxicity test of chitosan and synthesized derivatives by CCK-8 assay and all samples showed decreased cytotoxicity. These results suggested that the novel pyridylurea-functionalized chitosan derivatives could be an ideal biomaterial. [ABSTRACT FROM AUTHOR]

This work provides a simple method for the preparation of thermoplastic chitosan using the most common dilute inorganic and organic acids in aqueous solutions, namely hydrochloric acid (HCl) and acetic acid (HAc). The melting plasticization behavior of chitosan under different concentrations and types of acid solution was investigated. By means of infrared spectra (IR), scanning electron microscope (SEM), X-ray diffraction (XRD), and other characterization methods, as well as a mechanical property test, it was found that as the acid solution concentration increased, the protonation effect was stronger and the plasticization performance showed a better trend. The structure and performance of the modified chitosan were optimal when the concentration of HCl was around 8 wt %. In addition, it was found that HCl had a better effect on the plasticization of chitosan than HAc, which was because the protonation ability of HCl was stronger than that of HAc. Unlike the casting method, the structure and properties of chitosan sheets prepared by thermoplastic processing were directly affected by protonation, however not by the interaction of anionic-cationic electrostatic attractions between the –NH3+ groups of chitosan chains and the carboxyl groups of acetic acids or the chloridoid groups of hydrochloric acid. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) printing holds great potential for preparing sophisticated scaffolds for tissue engineering. As a result of the shear thinning properties of an alginate solution, it is often used as 3D printing ink. However, it is difficult to prepare scaffolds with complexity structure and high fidelity, because the alginate solution has a low viscosity and alginate hydrogels prepared with Ca2+ crosslinking are mechanically weak. In this work, chitosan powders were dispersed and swelled in an alginate solution, which could effectively improve the viscosity of an alginate solution by 1.5–4 times. With the increase of chitosan content, the shape fidelity of the 3D printed alginate–chitosan polyion complex (AlCh PIC) hydrogels were improved. Scanning electron microscope (SEM) photographs showed that the lateral pore structure of 3D printed hydrogels was becoming more obvious. As a result of the increased reaction ion pairs in comparison to the alginate hydrogels that were prepared with Ca2+ crosslinking, AlCh PIC hydrogels were mechanically strong, and the compression stress of hydrogels at a 90% strain could achieve 1.4 MPa without breaking. In addition, human adipose derived stem cells (hASCs) adhered to the 3D printed AlCh PIC hydrogels and proliferated with time, which indicated that the obtained hydrogels were biocompatible and could potentially be used as scaffolds for tissue engineering. [ABSTRACT FROM AUTHOR]