Composite Hydrogel Beads Research Articles

Amidoxime modified polymers of intrinsic microporosity/alginate composite hydrogel beads for efficient adsorption of cationic dyes from aqueous solution

Polymers of intrinsic microporosity (PIM-1) has demonstrated great potential in adsorption and separation fields. In this study, PIM-1 was structured into an applicable and efficient adsorbent using a facile way. PIM-1 was first modified by amidoxime, and then the amidoxime modified PIM-1 (AOPIM-1) was mingled into alginate (Alg) hydrogel to obtain composite hydrogel beads. The AOPIM-1/Alg composite beads were further employed for removal of malachite green (MG) from aqueous solution and the effects of doped ratio, adsorbent dosage, contact time, and initial dye concentration on the MG adsorption performance were systematically investigated. The MG adsorption capacity of pure Alg beads was substantially enhanced after incorporating AOPIM-1. Furthermore, isothermal, kinetic and thermodynamic studies were performed to explore the fundamental adsorption behavior. Both Freundlich isotherm and Langmuir isotherm models can fit the adsorption isotherm data well, and the adsorption kinetics is well described by Pseudo-second-order. The adsorption process is feasible, spontaneous and endothermic. In addition, mixed dyes adsorption measurements indicate that AOPIM-1/Alg beads are highly selective to adsorb cationic dyes from anionic/cationic mixed dyes solution. The regeneration test shows that above 90% of the adsorption capacity of the composite beads can be maintained after 10 cycles of MG adsorption/desorption. These findings point that AOPIM-1/Alg composite hydrogel beads are an efficient, up-and-coming and recyclable adsorbent for cationic dyes adsorption from aqueous solution.

PH-responsive eco-friendly chitosan modified cenosphere/alginate composite hydrogel beads as carrier for controlled release of Imidacloprid towards sustainable pest control

Efficacious pesticide formulations having prolonged activity with minimal environmental risks is imperative for sustainable agriculture. Control release formulation is a prudent approach towards efficient pesticide utilization with reduced environmental implications. This work embodies an innovative easy-to-prepare pesticide formulation using chitosan (Cht)-alginate (Alg)-cenosphere (Cn) composite hydrogel beads for the sustained release of imidacloprid (IMI) with added advantage of UV safeguarding of pesticide, direct on-field application and upscalability. The IMI@Cht-Alg-Cn beads showed high encapsulation efficiency of around 80%, owing to their hollow structure and porous crosslinked network. Around 80% release of pesticide over a period of 72 hr substantiates a slower release profile under different pH conditions mimicking different soil types. Excitingly, leaching study reveal a two fold slow pesticide loss of 12 % compared to a commercial formulation. Subsequent validations in a model plant system (Vigna unguiculata) signify on-field universal applicability of the efficacious formulation. A long-term safety assessment study involving a human skin cell line (HaCaT), a plant model (Vigna radiata), soil-dwelling bacteria (E. coli and B. subtilis) and a non-targeted aquatic model organism (Daphnia magna) advocates a safe-by-design approach of the hydrogel beads. A 100% efficacy against Aphis crassivora (cowpea aphid) over 48 hrs compared to commercial formulation and technical grade of IMI suggest its suitability for on field application. This work merits sustainable pesticide use by providing application-based proofs and qualifies as a potential pesticide formulation for sustainable pest management.

Graphene oxide‐carboxymethyl cellulose hydrogel beads for uptake and release study of doxorubicin

AbstractGraphene oxide (GO)‐based hydrogel beads were synthesized by physical crosslinking of GO with carboxymethyl cellulose (CMC) to produce a pH‐sensitive drug carrier with selective drug‐release properties. Four different GO/CMC composite hydrogel beads (GCB) were prepared with GO oxidized at 30°C and 5q0°C with varying GO loading 1 or 5 mg/ml. Physicochemical properties of the synthesized GO and its composite beads were provided in this work. A mild oxidation temperature of 50°C produce GO‐50 with satisfactory oxidation degree as shown by intensity ratio of D and G bands (ID/IG) and carbon to oxygen (C/O) ratios of 0.991 and 1.94, respectively. The highest loading capacity of doxorubicin (DOX) was 4.2494 mg/g for GCB synthesized from GO‐50 with dispersion concentration of 5 mg/ml (GCB‐50.5), corresponding to its abundant oxygen‐containing functional groups. The release profile of DOX also confirmed its strong pH‐sensitive behavior. The in vitro cytotoxicity tests on 7F2 cells by MTT assay revealed that GCBs have a higher percentage of viability than that of their GO precursors due to the incorporation of CMC into the beads. The prepared hydrogel beads thus can potentially be used as an effective and viable DOX carrier.

Highly selective and sustainable clean-up of phosphate from aqueous phase by eco-friendly lanthanum cross-linked polyvinyl alcohol/alginate/palygorskite composite hydrogel beads

The development of feasible adsorbent for phosphate removal is of great urgency to remediate water eutrophication and maintain sustainable development of water resources. In the present work, eco-friendly lanthanum cross-linked polyvinyl alcohol/alginate/palygorskite (LPAP) composite hydrogel beads were synthetized for phosphate removal from aqueous solution. The encapsulation of palygorskite (PAL) into polymers enhanced the mechanical strength of LPAP hydrogel and selectivity towards phosphate as well. The characterization of synthesized hydrogel was conducted by SEM-EDS, BET, XRD, FT-IR and XPS, etc. Batch experiments indicated that phosphate uptake by LPAP was pH dependent with the optimal pH range of 3–6, and efficient phosphate removal (nearly 100%) was maintained in the co-existence of anions (Cl−, NO3− and SO42−). The adsorptive behavior of LPAP beads could be satisfactorily described by Freundlich isotherm model and pseudo-second-order kinetic model, with the experimental maximum phosphate uptake of ∼33.2 mg/g obtained at pH 4. Thermodynamics analysis suggested the spontaneous and endothermic character of adsorption process. More crucially, the superior reusability of LPAP beads confirmed through sorption-desorption cyclic experiments provided access for waste elimination at the minimum cost. The main phosphate removal routes were identified as electrostatic interaction, ligand exchange and Lewis acid-base interaction, and crystalline LaPO4·xH2O was formed on the surface of LPAP beads. Overall results demonstrated the applicable potential of LPAP beads as an environmental-sustainable, low-cost, anti-interfering and easily-recovered biosorbent for environmental remediation.

A core-shell structured alginate hydrogel beads with tunable thickness of carboxymethyl cellulose coating for pH responsive drug delivery

pH-responsive core-shell structured composite hydrogel beads, composed of a alginate (ALG) core coated with carboxymethyl cellulose (CMC) shell (ALG@CMC), were prepared by using in-situ gel preparation technology as a drug delivery system. An anti-inflammatory drug, indomethacin was loaded into the formed hydrogels as a model drug. The resulting gel samples were characterized by Fourier transforms infrared (FTIR) spectroscopy, thermo-gravimetric (TG) analysis, and scanning electron microscopy (SEM). The mechanical stability of all samples in phosphate buffered solution (PBS, pH 7.4) was approximately measured through oscillation experiments. Swelling and controlled drug release behaviors of ALG@CMC beads compared with ALG were studied in simulating gastric fluid of pH 1.2 or intestinal fluid of pH 7.4 at 37 °C. Oscillation experiments proved that the mechanical stability of ALG@CMC beads could be significantly improved by the CMC shell layer. The swelling and drug release behaviors revealed that the swelling and drug release rate of ALG@CMC beads were obviously slower than that of simple-ALG and both have significant pH responsiveness. The cumulative drug release from ALG, ALG@CMC-1, ALG@CMC-2 and ALG@CMC-3 was about 100%, 67%, 46% and 37% in simulated intestinal fluid of pH 7.4, respectively, while the drug release reached only about 2.0% in simulating gastric fluid of pH 1.2 within 720 min. These developed materials could potentially be employed as a pH-responsive drug delivery device in vivo.

Larvicidal composite alginate hydrogel combined with a Pickering emulsion of essential oil

Sulfonated cellulose nanocrystals (S-CNCs) can be used to encapsulate thyme white essential oil (EO) that is volatile and immiscible with water. S-CNCs form a Pickering emulsion (PE) with EOs and the micron-scale PEs are embedded in sodium alginate (SA) to form macroscale hydrogel beads. The incorporation of PEs with SA is confirmed with FTIR, XRD, SEM and confocal microscopic characterizations and the release behavior is monitored to understand the time-dependent biological activity of the EOs. The larvicidal performance of the SA-PE composite hydrogel beads is investigated with Aedes albopictus (Skuse) larvae. The larvicidal activity is higher for SA/PE hydrogel beads prepared at 0.5 % CaCl2 than 0.75 or 1.0 % CaCl2 due to their higher release rate.

Preparation and application of pH-responsive composite hydrogel beads as potential delivery carrier candidates for controlled release of berberine hydrochloride.

For improving the effective concentration of berberine hydrochloride (BH) in the gastrointestinal tract, a series of pH-responsive hydrogel beads were prepared based on carboxymethylstarch-g-poly (acrylic acid)/palygorskite/starch/sodium alginate (CMS-g-PAA/PGS/ST/SA) in the present work. The developed hydrogel beads were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric analysis (TG). Effect of palygorskite (PGS) content on the swelling properties of hydrogel beads and BH cumulative release were discussed. The pH responsiveness of hydrogel beads was also investigated in different media. Results illustrated that swelling of hydrogel beads and BH cumulative release from hydrogel beads were obviously affected by PGS content. The swelling ratio and BH cumulative release of composite hydrogel beads remarkably slowed down with PGS content increasing in the range from 10 to 40 wt%. The composite hydrogel beads were pH-responsive. At pH 7.4, the swelling ratio and BH cumulative release from composite hydrogel beads were the fastest among the dissolution media of pH 1.2, pH 6.8 and pH 7.4. The BH cumulative release from hydrogel beads was related to the swelling and relaxation of composite hydrogel beads and could be fitted better by the Higuchi model. The obtained composite hydrogel beads could be potentially used for the development of BH pharmaceutical dosage forms.

Application of Photocatalytic and Adsorption Process for Residue Organic Degradation Using Doped ZnO Composites Hydrogel Beads

This research aimes to synthesize photocatalyst-sodium alginate composite hydrogel beads which apply for coupled adsorption and photocatalytic degradation of organic residue. Fe3O4, graphitic carbon nitride (g-C3N4), grapheme oxide (GO) and AgNO3 doped ZnO photocatalyst composites hydrogel beads were synthesized and characterized using Fourier-transform infrared spectroscopy (FT-IR), X-ray Diffraction (XRD), and Transmission Electron Microscopy (TEM). Photocatalytic and adsorption activity are studied by Methylene blue (MB) degradation under sunshine irradiation. The effect of different parameter as photocatalyst types and reaction time were studied upon the efficiency of organic residue degradation. The coupled photocatalytic and adsorption processes were evaluated through various kinetic models such as pseudo-first-order/ pseudo-second-order in Langmuir-Hinshelwood model model, the Elovich model and the intra particle diffusion model. Kinetics studies showed that the coupled photocatalytic and adsorption processes in photodegradation of all sample was well described by the pseudo-second-order model because R2 of all sample were close to 1 which compared with another model. For photodegradation efficiency, the best choice in this condition was g-C3N4 doped ZnO composite hydrogel bead. Photodegradation efficiency and the pseudo second order rate constant of photocatalyst ZnO+gC3N4/SA composite hydrogel bead were 83.80%(for 180 min and up to 96% for 7 hr) and 5.05×10-3 g.mg-1 min-1, respectively.

Synthesis and assessment of CTAB and NPE modified organo-montmorillonite for the fabrication of organo-montmorillonite/alginate based hydrophobic pharmaceutical controlled-release formulation

The research goal of the present study was to develop a carrier for loading and controlled -release of the hydrophobic drug with the combined use of organo-montmorillonite (OMMT) and alginate. The OMMT was synthesized through the intercalation modification of sodium montmorillonite (Na-MMT) with cationic cetyltrimethylammonium bromide (CTAB), nonionic nonylphenol polyoxyethylene ether (NPE) and the mixture of them via simple and convenient wet ball-milling method. Furthermore, the organo-montmorillonite/alginate (OMMT/Alg) composite hydrogel beads with slow and controlled release properties were constructed by using alginate as a coating material under the exogenous cross-linking of calcium ions. The physical and chemical properties of OMMT were comparatively evaluated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), thermogravimetric analyzer (TGA), BET-specific surface area measurements, and drug adsorption experiments. Experimental results showed that the presence of CTAB was able to facilitate the intercalation of CTAB/NPE into Na-MMT through the cation exchange reaction. And the cationic CTAB and nonionic NPE were adsorbed or intercalated into the MMT lamellar structure through the wet ball-milling process, which could change the hydrophilic nature of Na-MMT and improve its affinity to the hydrophobic drug molecules. In addition, the OMMT/Alg composite hydrogel beads displayed superior sustained-release properties than Na-MMT/Alg, mainly ascribed to the good affinity of OMMT to hydrophobic drug that retarded the drug diffusion. In particular, CTA/NPE-MMT/Alg with the highest loading capacity (LC) and encapsulation efficiency (EE) revealed the optimal controlled performance for the release of hydrophobic ibuprofen. The release followed the Korsmeyer–Peppas model suggested non-Fickian diffusion release mechanism. Based on the high drug loading capacity and excellent controlled drug release properties, the CTA/NPE-MMT/Alg incorporating hydrophobic drugs into hydrophilic matrices could be a highly promising material for use in hydrophobic drug delivery.

Novel pH-sensitive alginate hydrogel delivery system reinforced with gum tragacanth for intestinal targeting of nutraceuticals

The present study utilizes the novel combination of Gum tragacanth (GT) and sodium alginate (SA) to reinforce SA hydrogel beads. The composite hydrogel beads were encapsulated with phenolic compounds extracted from Basella sps. The rheological studies conferred increased elastic property of GT incorporated formulations. Higher swelling behavior was observed in simulated intestinal fluid (SIF) with increasing GT content in SA formulations. SA-GT composite hydrogels revealed increased encapsulation efficiency with sustained release of phenolic compounds in SIF. GT incorporated hydrogel beads exhibited increased biodegradation (up to 82% weight loss) in biodegradation media (in vitro). FTIR study found no molecular interaction between SA and GT. TGA analysis revealed that GT incorporation did not affect the thermal behavior of SA. Furthermore, SA-GT encapsulated hydrogels showed remarkable cytotoxicity against osteosarcoma cells. Thus our findings suggest SA-GT gel formulation could be used as a promising delivery system for drugs and nutraceutical compounds.

Dye Removal Using Hairy Nanocellulose: Experimental and Theoretical Investigations.

Adsorption is a common technique for the treatment of dye-contaminated wastewater. Achieving a high dye removal capacity is a common challenge with sustainable, low-cost adsorbents. Recently, a class of easily functionalized, biorenewable cellulose nanoparticles called hairy nanocellulose has been developed. Electrosterically stabilized nanocrystalline cellulose (ENCC), which can be synthesized from wood pulp through a two-step oxidation by periodate and chlorite, is a form of hairy nanocellulose with a high negative charge density, and thus has the potential for a high adsorption capacity. In this work, the adsorption of methylene blue, a cationic dye, by ENCC was shown to occur up to charge stoichiometry (1400 mg dye/g adsorbent), at which point aggregation of ENCC-dye complexes is observed. A model is developed to show that the adsorption can be described by an ion-exchange mechanism and is influenced by the presence of other ions. Equilibrium dye removal is reduced at both high ionic strengths and low pH. To facilitate handling, composite hydrogel beads of sodium alginate and ENCC (ALG-ENCC beads) are developed, and their methylene blue removal capacity is shown to maintain a high removal capacity (1250 mg/g). ALG-ENCC beads provide a facile way to employ these nanoparticles on a larger scale, providing a potential means for the removal of dyes and other contaminants at larger wastewater volumes.

Entrapment of micro-sized zeolites in porous hydrogels: Strategy to overcome drawbacks of zeolite particles and beads for adsorption of ammonium ions

We have demonstrated that the entrapment of micro-sized zeolite particles (ZPs) in porous hydrogels is a promising strategy toward overcoming several drawbacks of ZPs and zeolite beads (ZBs) for adsorption of ammonium ions. The polyvinyl alcohol (PVA)-alginate-ZPs (PAZ) composite hydrogel beads with the same size as that of ZBs were prepared by physically entrapping the ZPs. On the basis of structural characterization results, the entrapped ZPs are well distributed with minimal agglomeration in the highly permeable and porous hydrogels. Unlike the ZPs, the PAZ hydrogels had good settleability and showed no significant further agglomeration of the entrapped ZPs even under high zeolite dosage conditions. Due to still high accessible surface area of the entrapped ZPs in the hydrogel, the maximum ammonium adsorption capacities of PAZ hydrogels from Langmuir isotherm were 3.4–4.3 times higher than those of ZBs. Thus, we propose that the entrapment of ZPs in highly porous hydrogel has much less adverse effects on the adsorption capacity, compared to the binder commonly used in the synthetic ZBs. Similar to the ZPs and unlike the ZBs, the ammonium adsorption process in the PAZ hydrogels was governed by chemical ion exchange mechanism and tended to be rate-limited by boundary layer diffusion and mainly intra-particle diffusion. Owing to the above-mentioned key features toward overcoming drawbacks of both the ZPs and the ZBs, the PAZ hydrogels have great potential as promising alternative zeolite-type adsorbents for a broad range of industrial applications in water purification and wastewater treatment.

Barium ion cross-linked alginate-carboxymethyl cellulose composites for controlled release of anticancer drug methotrexate

In the present study, sodium alginate (NaAlg)/sodium carboxymethyl cellulose (NaCMC) composite hydrogel beads were prepared by cross-linking with barium chloride solution. The degree of swelling and the release profile of methotrexate (MTX) from the beads were investigated under phosphate buffer saline (PBS) condition (pH = 7.4 at 37 °C). Since the water solubility of MTX is low, the drug was dissolved in the green solvent DMSO and added to the polymer solution. The existence of DMSO (10% v/v) significantly affected the morphology, swelling, and release profiles of the beads. Scanning electron microscopy (SEM) and Fourier transformed infrared spectroscopy (FTIR) analysis were performed to characterize the Ba-Alg/CMC composites. The results showed that almost the total amount of MTX release (98.1 ± 2.64%) was completed in 5 h. Moreover, synthesized Cu(II) (MXT-Cu) and Zn(II) (MXT-Zn) metal complexes of MTX were loaded to Ba-Alg/CMC beads and subjected to drug release studies. Entrapment efficiency (EE%) and release behaviors of the metal complexes of MTX were compared to MTX. The mostly used drug release kinetic models which are first order, Higuchi and Hixson-Crowell were applied to release data.

Preparation and characterization of alginate-kelp biochar composite hydrogel bead for dye removal.

The alginate-kelp biochar composite hydrogel bead (Alg-KBC) was successfully developed via physical crosslinking with Ca2+. The composite material was characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), inductively coupled plasma optical emission spectrometry (ICP-OES), and elemental analyzer. The Alg-KBC showed high removal capacity for crystal violet (CV), from aqueous solution (33.8% more than that of the pristine alginate bead). The adsorption isotherm data were fitted to the nonlinear forms of the Langmuir, Freundlich, and Redlich-Peterson isotherm models. Also, the adsorption kinetics data were analyzed with the nonlinear forms of the pseudo-first-order, pseudo-second-order, and intra-particle diffusion models. Both chemisorption and physisorption with an indispensable role of external mass transfer and stagewise pore diffusion were essential in the adsorption process. Thus, by impregnating biochar powder in alginate, a bio-platform, a composite hydrogel bead which has higher affinity for cationic dye in aqueous medium and also eliminates the onerous task of separating biochar powder from the adsorbate solution, was obtained. Hence, the Alg-KBC can be considered for efficient dye removal in the wastewater treatment process.

Alginate/k-carrageenan and alginate/gelatin composite hydrogel beads for controlled drug release of curcumin

Alginate/k-carrageenan and alginate/gelatin composite hydrogel beads for controlled drug release of curcumin

Fabrication of magnetic bentonite/carboxymethyl chitosan/sodium alginate hydrogel beads for Cu (II) adsorption

In this work, composite hydrogel beads based on magnetic bentonite/carboxymethyl chitosan/sodium alginate (Mag-Ben/CCS/Alg) were fabricated and their ability to adsorb copper ions in water was studied. The structure and properties of the composite were characterized via SEM, FTIR, XPS, TGA, VSM, and Zeta potential tests. The effects of the adsorbent dosage, adsorption time, pH, temperature, and initial concentration of Cu(II) on the adsorption results were studied. The results showed that Mag-Ben/CCS/Alg reached equilibrium after 90 min of adsorption, the removal rate of Cu(II) was 92.62 ± 0.39%, and the maximum adsorption capacity was 56.79 mg/g (30 °C). The removal rate of Cu(II) by Mag-Ben/CCS/Alg still remained above 80% after recycling four times. The adsorption process of Cu(II) by Mag-Ben/CCS/Alg occurred in accordance with the quasi-second-order kinetic model and Langmuir adsorption isotherm. The adsorption process was spontaneous and endothermic.

Alginate Composite Hydrogel Bead with Multilayer Flake Structure for Dye Adsorptions

Alginate Composite Hydrogel Bead with Multilayer Flake Structure for Dye Adsorptions

Response surface methodology for optimization of methylene blue adsorption onto carboxymethyl cellulose-based hydrogel beads: adsorption kinetics, isotherm, thermodynamics and reusability studies.

Environment-friendly composite hydrogel beads based on carboxymethyl cellulose (CMC), alginate (Alg) and graphene oxide (GO) were synthesized by an ionotropic gelation technique and studied as an efficient adsorbent for methylene blue (MB). The chemical structure and surface morphology of the prepared hydrogel beads were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential thermal analysis (DTA) and point of zero charge (pHpzc). A hybrid response surface methodology integrated Box–Behnken design (RSM-BBD) was successfully developed to model, simulate, and optimize the biosorption process. The synergistic effects between three critical independent variables including adsorbent dose (0.3–0.7 g), pH of the MB solution (6.5–9.5) and initial MB concentration (15–45 mg L−1) on the MB adsorption capacity (mg g−1) and removal efficiency (%) were statistically studied and optimized. The performance of the RSM-BBD method was found to be very impressive and efficient. Results proved that the adsorption process follows a polynomial quadratic model since high regression parameters were obtained (R2-value = 99.8% and adjusted R2-value = 99.3%). Analysis of variance (ANOVA) further confirms the validity of the suggested model. The optimal conditions for 96.22 ± 2.96% MB removal were predicted to be 0.6 g of CMC-Alg/GO hydrogel beads, MB concentration of 15 mg L−1 and pH of 9.5 within 120 min. The adsorption equilibrium is better described by the Freundlich isotherm, indicating that physisorption is the rate controlling mechanism. The MB adsorption process was thermodynamically spontaneous and endothermic. A reusability study revealed that the prepared adsorbent is readily reusable. The adsorbent still maintains its ability to adsorb MB for up to four cycles. Results reported in this study demonstrated that CMC-Alg/GO hydrogel beads are an effective, promising and recyclable adsorbent for the removal of MB from aqueous solutions.

Generating cellulose-agar composite hydrogels for uptake-release kinetic studies of selenate and selenomethionine

Cellulose-agar (CAB) composite hydrogel beads were generated for the uptake-release kinetics studies of Se(VI) and selenomethionine (SeMt) from water medium. The objective of this work is to analyze the surface structure, gel properties, thermal stability and chemical functionalities responsible for the adsorption of Se(VI) and SeMt. We propose here a possible mechanism for the adsorptions. Adsorption isotherms are in good agreement with the Freundlich model, yielding a high adsorption capacity for the CAB composite. Maximum adsorption capacity of Se(VI) and SeMt were found to be 7.083 mg g−1 and 34.639 mg g−1 respectively. The mean free energy of adsorption (E*) value was found to be 0.0423 kJ mol−1 and 0.329 kJ mol−1 of Se(VI) and SeMt respectively. 1 M HCl and 0.1 M HCl were able to desorb Se(VI) and SeMt respectively from CAB. The adsorption of Se(VI) was significantly reduced if As(III), Cr(III) and Hg(II) were present as complementary ions in the medium. Similar studies with pristine cellulose beads (CB) yielded insignificant uptake properties.

Characterization, release, and antioxidant activity of curcumin-loaded sodium alginate/ZnO hydrogel beads

In this study, we fabricated a series of novel sodium alginate/ZnO hydrogel beads to optimize the release profile of curcumin (Cur) and to avoid the burst release associated with pure hydrogels, which were used to mitigate the weaknesses of Cur, such as rapid physiological clearance and sensitivity to ultraviolet (UV) light and alkaline solutions. The results show that the composite hydrogel beads exhibit good pH sensitivity and controlled-release capacity, which could prolong the residence time of Cur in the gastrointestinal tract. After exposure to UV irradiation for 6 h, the 1,1-Diphenyl-2-picrylhydrazyl (DPPH) scavenging capacity of Cur-loaded hydrogel beads was decreased by only 13.70%, whereas that of pure Cur decreased by 62.04% under the same conditions; therefore, the encapsulated Cur showed a higher antioxidant activity. The composite hydrogel beads protected the Cur from light degradation and can therefore prolong the antioxidant activity of Cur. These results are beneficial for the design of delivery systems to entrap and control the release of unstable drugs.