Hydrogel Capsules Research Articles

Selenium: A sole treatment for erosive oral lichen planus (Randomized controlled clinical trial).

Oral lichen planus (OLP) is a chronic disease with immune-mediated pathogenesis. Selenium (Se), an antioxidant, plays a role in modulating immunity. The aim of this clinical trial was to evaluate two Se forms (novel topical hydrogel and oral capsules), solely, in treating erosive OLP based on clinical evaluation and salivary oxidative stress markers. Patients were allocated into one of three groups: group I, topical corticosteroids; group II, topical Se; and group III, systemic Se. Treatment lasted for 6weeks; patients were clinically evaluated at baseline, 6, and 12weeks. Biochemical analysis for salivary malondialdehyde (MDA) and total antioxidant capacity (TAC) levels at baseline and 6weeks was performed. There was a significant reduction in signs and symptoms in response to all treatment modalities. However, there was no significant difference among the three groups at 6weeks. At 12weeks, group II had significantly lower pain scores compared with group I. Salivary MDA levels showed a significant decrease in patients of group I and group III. TAC levels showed no significant difference in response to treatment. Selenium can be proposed as a treatment for OLP. Salivary MDA levels can be a biomarker for OLP disease severity.

Enzyme immobilization on porous chitosan hydrogel capsules formed by anionic surfactant gelation.

Sodium dodecyl sulfate (SDS)-chitosan hydrogels have been employed for adsorption of anionic dyes and metallic substances. Two mutant forms of Thermoanaerobacter ethanolicus alcohol dehydrogenase (TeSADH) were used as model enzymes to develop a novel enzyme immobilization technique employing newly formulated porous chitosan hydrogels. The enzyme immobilized on chitosan hydrogel capsules formed by 5g/l SDS gelation and subsequent treatment with 0.05M NaOH was 28-35% higher in NADPH production than that formed by 20g/l SDS gelation only under the same conditions. A 48-h asymmetric biphasic reduction of acetophenone with immobilized TeSADH enzyme at 50 °C showed 68% increase in (R)-1-phenylethanol production than the free enzyme. Compared to the free enzyme which denatured and lost its activity at 80 °C, the immobilized enzyme retained about 25% of its initial activity after 2-h incubation. In contrast to the conventional chitosan hydrogel which suffers thermal and operational stability, the newly formulated porous chitosan hydrogel capsules have excellent enzyme loading efficiency and stable at harsh temperatures. Especially, this newly developed enzyme immobilization method would be applicable for food processing.

One-step synthesis of composite hydrogel capsules to support liver organoid generation from hiPSCs.

Advances in biomaterials, especially in hydrogels, have offered great opportunities for stem cell organoid engineering with higher controllability and fidelity. Here, we propose a novel strategy for one-step synthesis of composite hydrogel capsules (CHCs) that enable engineering liver organoids from human induced pluripotent stem cells (hiPSCs) in an oil-free droplet microfluidic system. The CHCs composed of a fibrin hydrogel core and an alginate-chitosan composite shell are synthesized by an enzymatic crosslinking reaction and electrostatic complexation within stable aqueous emulsions. The proposed CHCs exhibit high uniformity with biocompatibility, stability and high-throughput properties, as well as defined compositions. Moreover, the established system enables 3D culture, differentiation and self-organized formation of liver organoids in a continuous process by encapsulating hepatocyte-like cells derived from hiPSCs. The encapsulated liver organoids consisting of hepatocyte- and cholangiocyte-like cells show favorable cell viability and growth with consistent size. Furthermore, they maintain proper liver-specific functions including urea synthesis and albumin secretion, replicating the key features of the human liver. By combining stem cell biology, defined hydrogels and the droplet microfluidic technique, the proposed system is easy-to-operate, scalable and stable to engineer stem cell organoids, which may offer a robust platform to advance organoid research and translational applications.

Polyelectrolyte hydrogel capsules as stabilizers for reconfigurable complex emulsions

Polyelectrolyte capsules stabilize biphasic oil droplets while preserving droplet reconfigurability in the presence of surfactants.

The Efficiency of P-Removal from Natural Waters with Sorbents Placed in Water Permeable Nonwovens

An important aspect of lake restoration is the reduction of phosphorus (P) concentrations in water. To achieve this effect, various methods are used, including chemical inactivation by means of the addition of different substances into the water column or sediment. Although the efficiency of chemical methods is high, there are numerous concerns related to the introduction of large amounts of atypical compounds to aquatic ecosystems, eg. the possibility of the appearance of their toxic forms, such as aluminium as a result of pH changes. The aim of the research was to evaluate the possibility of using water-permeable nonwovens as P sorbent carriers. A bag made of nonwoven is filled with the sorbing material. When placed in the water column, sorbent present in the bag reduces orthophosphate (PO43-) concentration in the water due to the water inflow into the bag. The bag is then removed from the water together with the sorbent and sorbed PO43-, which enables permanent removal of P and sorbent from the water reservoirs. Three synthetic sorbents were used in the study: SINOBENT (form: paste, composition: calcium, iron and magnesium embedded in a bentonite carrier), HYDROPHOSBIND (hydrogel capsules, biopolymer with embedded FeCl3), precipitated calcite (PCC, powder, CaCO3) and one natural sorbent: ground calcite (GCC, powder, CaCO3). Water samples for the study were taken from the eutrophic lake from the epi- and hypolimnion zone. Sorbents efficiency was tested in low (0.043 and 0.067 mg PO43-/L) and high (0.230 and 0.540 mg PO43-/L) concentrations at two temperatures (6°C and 20°C). Sorption of PO43- was tested for the sorbents placed in a bag made of permeable nonwovens. The dose of materials was 1g/L, except for HYDROPHOSBIND (5 g/L). Additional experiments were carried out with the addition of effective microorganisms to check their effect of the sorption behaviour of the tested sorbents. An unambiguous PO43- loss from the solution was observed for three materials: PCC, GCC and HYDROPHOSBIND. Given for 1g of the sorbent, the highest losses (19-79%) were found in PCC and the lowest (5-13%) in HYDROPHOSBIND treatments. For these materials, the effectiveness of PO43- removal raised with rising temperature and the initial PO43- concentration. The addition of probiotic organisms favoured the reduction of PO43- concentration, especially in the presence of PCC. The addition of SINOBENT usually resulted in an increase in PO43- concentration and pH decrease even to pH=6.45.

Multi-membrane formation in chitosan hydrogel shell by the addition of goethite nanoparticles

In this study, chitosan (an abundant natural biopolymer) was used as a polysaccharide source to synthesize multi-membrane hydrogel capsules (MHC) using a novel approach. The MHC material was formed in a single step self-assembly approach by an in-situ immobilization of goethite nanoparticles (GNP) during the chitosan-anionic surfactant complex formation reaction. The pivotal role of GNP in the formation of multi-membrane was thoroughly discussed herein. Some important factors effecting the formation and property of MHC were explored. The results of adsorption study (Co ≈ 1000 mg/L, 30 °C, and pH ≈ 7.0) demonstrated that MHC (1321 ± 35.6 mg/g) exhibited excellent adsorptive capacity for Congo red dye compared to HC (244 ± 35.6 mg/g) and GNP (91.1 ± 19.6 mg/g). Therefore, the unique characteristics of multi-membranes structures breeds an exciting prospect of application in diverse fields, especially wastewater treatment because of its excellent adsorption capacity for dye contaminants.

Effects of Diurnal Variation and Food on Gastrointestinal Transit of 111In-Labeled Hydrogel Matrix Extended-Release Tablets and 99mTc-Labeled Pellets in Humans

The aim of this research was to characterize the effect of food ingestion and circadian rhythm on the gastrointestinal transit of 2 dosage forms: a hydrogel matrix extended-release (ER) tablet and pellets with the diameter of 9 mm and 150-200 μm, respectively, in humans. Radiolabeled (111In) hydrogel matrix ER tablet and capsule containing radiolabeled (99mTc) pellets were administered with 240 mL of water under the following dosing conditions: fasted state at 8 AM or 8 PM and fed state at 8 AM or 8 PM. A high-fat and high-calorie meal was ingested in the fed state studies. The gastric emptying times and small intestinal transit times of the 2 dosage forms were monitored using gamma scintigraphy. Meal ingestion prolonged gastric emptying times for both dosage forms but had no significant impact on the small intestinal transit times of them. Administration time tended to affect gastric emptying of the ER tablet but had no significant impact on gastric emptying and small intestinal transit for both dosage forms.

3D-Printed Hydrogel Capsule for Transporting Particles in Flow Channel

Droplet based microfluidics is used for cell culturing, protein crystallization, drug delivery and mixture chemical reagent. It enables quick and accurate analysis with a small amount of reagent. Usually, droplets containing particles are made by T-junction using organic phase and water phase. Sometimes researchers want to replace medium, recovery and reseal particles in droplets. However it is difficult due to surface tension and difficulty to process hydrogel. It has been a problem for many years. In addition, there is a need for a capsule having a function of carrying and releasing drugs and cells to an arbitrary position. We propose 3D-printed hydrogel capsule to solve these problems. We made 3D-printed hydrogel capsule with particles entrance. The entrance is closed by bubble. N-isopropylacrylamide (NIPA) gel was selected. It was prepared for 3D-printing. NIPA gel is famous for phase transition. It swells below 32.6℃ and shrinks above that. With this principle, we can transport particle to remove rid bubble at any place. The 3D-printer we used was ACCULAS BA-30H (DMEC). Evaluate systems were made up of microscopic, syringe pump and flow channel. Flow channel was made of Polydimethylsiloxane (PDMS) using 3D-printed mold.

Crosslinked Hydrogel Capsules for Cell Encapsulation Formed Using Amino/Betaine Dual-Functional Semibatch Copolymers

Robust hydrogel capsules consisting of calcium alginate beads with shells reinforced via crosslinked amino/betaine copolymers of N-(3-aminopropyl) methacrylamide hydrochloride (APM) with 2-methacryloyloxyethyl phosphorylcholine (MPC) are described. These capsules are designed to support future use in immunoisolation of therapeutic cells for transplant purposes. The poly[APM-co-MPC] copolymers were prepared by semibatch free radical copolymerization to reduce the significant compositional drift and the resulting diffusional spread within alginate beads, observed for analogous batch copolymers. Fluorescent labeling was used to track copolymer distribution within the alginate hydrogels. Semibatch copolymers led to better shell confinement and lower cationic charge density on the capsule surface. Three reagents were used to covalently cross-link the resulting poly(amino/betaine) shells: cationic tetrakis(hydroxymethyl)phosphonium chloride (THPC), charge-neutral genipin and anionic partially hydrolyzed poly(methyl vinyl ether-alt-maleic anhydride) (PMM50). Genipin-crosslinked capsules were found to be remarkably robust in pipet aspiration tests. Selected capsules were exposed to FITC-labeled bovine serum albumin to assess the relative degree of protein adhesion, as a proxy for immune recognition; genipin crosslinked capsules were found to have very low levels of BSA binding and good mechanical robustness.

3D crateriform and honeycomb polymer capsule with nano re-entrant and screen mesh structures for the removal of Multi-component cationic dyes from water

In this study, a hybrid sodium alginate-polyvinyl alcohol-silica oxide capsule (SA-PVA-SiO2 capsule, SPSC) was fabricated via the one-step titration-gel method that directly dripped the spherical droplet of the SA, PVA and tetraethyl orthosilicate (TEOS) mixed solutions into the bath with calcium chloride (CaCl2), NaCl and oversaturated boric acid (H3BO3) cross-linking agents. The formation principle of the prepared capsule was investigated. And the adsorptive performance of the SPSC was analyzed by removing the single, binary and multi-component cationic dye solutions [i.e. Methylene Blue (MB), Malachite Green (MG) and Crystal Violet (CV)]. The results indicated that the crateriform and cellular polymer channel with nano screen mesh and re-entrant structures could help to promote the interaction between pollutants and the interface of the SPSC thereby trapping the cationic dyes in its body. In single-component dye solution, the maximal adsorption capacities of the SPSC against MB, MG and CV were respectively found to be 394.077 mg/g, 1034.047 mg/g and 1756.202 mg/g at 25 °C and pH 9. The adsorption mechanism of the cationic dyes by the SPSC was governed by electrostatic attraction and chemisorption. Though the removal capacity of the cationic dyes by the SPSC was reduced in competitive multi-component systems, the saturation adsorption amount of the CV could still maintain above 684,692 mg/g. The affinity between the SPSC and the cationic dyes was in the order of MB > MG > CV. The prepared hydrogel capsule could be used in wide range pH situations. This facile method which was used to produce free-standing spherical support adsorbent with specialized morphology might have good prospects for excessive removing cationic dyes from alkaline wastewater.

Enzyme-mediated hydrogel encapsulation of single cells for high-throughput screening and directed evolution of oxidoreductases.

Directed evolution of oxidoreductases to improve their catalytic properties is being ardently pursued in the industrial, biotechnological, and biopharma sectors. Hampering this pursuit are current enzyme screening methods that are limited in terms of throughput, cost, time, and complexity. We present a directed evolution strategy that allows for large-scale one-pot screening of glucose oxidase (GOx) enzyme libraries in well-mixed homogeneous solution. We used GOx variants displayed on the outer cell wall of yeasts to initiate a cascade reaction with horseradish peroxidase (HRP), resulting in peroxidase-mediated phenol cross-coupling and encapsulation of individual cells in well-defined fluorescent alginate hydrogel shells within ~10 min in mixed cell suspensions. Following application of denaturing stress to whole-cell GOx libraries, only cells displaying GOx variants with enhanced stability or catalytic activity were able to carry out the hydrogel encapsulation reaction. Fluorescence-activated cell sorting was then used to isolate the enhanced variants. We characterized three of the newly evolved Aspergillus niger GOx enzyme sequences and found up to ~5-fold higher specific activity, enhanced thermal stability, and differentiable glycosylation patterns. By coupling intracellular gene expression with the rapid formation of an extracellular hydrogel capsule, our system improves high-throughput screening for directed evolution of H 2 O 2 -producing enzymes many folds.

Hydrogel capsules with alfalfa as micronutrients carrier

The aim of this work was to study the properties of biocomposite based on sodium alginate and carboxymethyl cellulose with immobilized alfalfa as a material with controlled release of Cu2+ ions. Physicochemical (swelling, pHZPC) and sorption (kinetics, equilibrium) properties of the produced structures were investigated. Kinetic data were best described using a general rate law model, and the value of kinetic rate constant was 5.34 × 10−6. The sorption kinetics are also described using the Weber–Morris model, and the analysis revealed a three-step sorption. The maximum sorption capacity was determined using the Sips model and amounted to 9 mg g−1. Desorption of Cu2+ ions in soil solution (NaNO3 1 wt%) was carried out, and biocomposites released micronutrients in a slow way. The results showed that biocomposites with immobilized alfalfa are a very good material for potential applications in the agrochemical industry as a controlled released fertilizer.

Hydrogel micromotors with catalyst-containing liquid core and shell

Methacrylic anhydride-derived hydrogel microcapsules have unique properties, including reversibly tunable permeation, purification, and separation of dissolved molecular species. Endowing these dynamic encapsulant systems with autonomous motion will significantly enhance their efficiency and applicability. Here, hydrogel micromotors are realized using complex water-in-oil-in-water double emulsion drops and oil-in-water emulsion drops from glass capillary microfluidics and subsequent photopolymerization. Three hydrogel micromotor strategies are explored: microcapsules with thin shells and liquid cores with dispersed catalytic Pt nanoparticles, as well as water-cored microcapsules and homogeneous microparticles selectively coated with Ti/Pt catalytic layers. Autonomous motion of hydrogel particles and capsules is realized in hydrogen peroxide solutions, where generated oxygen microbubbles propel the dynamically responsive micromotors. The micromotors are balanced by weight, buoyancy, lateral capillary forces and show specific autonomous behaviours that significantly extend short range dynamic responses of hydrogels. Drop-based microfluidics represent a paradigm shift in the integration of multifunctional subsystems and high-throughput design of chemical micromachines in reasonable quantities towards their desired biomedical, environmental and flow/diffusion microreactor applications.

Magnetically-guided hydrogel capsule motors produced via ultrasound assisted hydrodynamic electrospray ionization jetting

Hydrogel capsules are a potential candidate for drug delivery and an interesting alternative to polyelectrolyte multilayer capsules which are under investigation since 20 years. Recently introduced polyelectrolyte complex capsules produced by spraying are non-biodegradable and not biocompatible, which limits their practical application, while biodegradable alginate capsules require complex coaxial electrospray ionization jetting. In this work, biodegradable alginate capsules cross-linked by calcium are successfully produced by hydrodynamic electrospray ionization jetting with the assistance of low frequency ultrasound. The size and shape of most capsules show significant differences with respect to different spraying distance, spraying mode, electrode shape and spraying concentration. Capsules in the shape of vase, mushrooms and spheres were successfully produced. Average capsule size can be adjusted from 10 μm to 2 mm. These capsules are used to encapsulate a model drug. Encapsulated paramagnetic particles enable defined directional motion under the propulsion of a rotating magnetic field, while model drugs can be released by ultrasound.

Onion-structure bionic hydrogel capsules based on chitosan for regulating doxorubicin release

Inspired by the multilayer structure of onion, herein, a novel strategy to prepare bionic multilayer hydrogel capsules for inhibiting burst release of doxorubicin (DOX) is reported. The bionic multilayer hydrogel capsules are prepared by the ionotropic crosslinking method. Compared with monolayer hydrogel capsules, the multilayer hydrogel capsules can largely homogenize the distribution of DOX and suppress the concentration gradient of DOX between the outermost hydrogel layer and external environment and the dense cuticular membranes of capsules can restrict the migration and diffusion of DOX. As a result, a significant inhibition of the burst release of DOX can be achieved. Moreover, the bionic multilayer hydrogel capsules demonstrate pH sensitivity and good biocompatibility to human epidermal keratinocyte (HaCaT) cells. This work opens up a new horizon in the burst release of biomaterial-based hydrogels for drug delivery system.

Genetically Encoded Stimuli-Responsive Cytoprotective Hydrogel Capsules for Single Cells Provide Novel Genotype–Phenotype Linkage

Modification of cell surfaces with synthetic polymers is a promising approach for regulating cellular behavior. Here, we describe a genetically controlled strategy for selectively encapsulating sin...

Development of gelatin-coated ι-carrageenan hydrogel capsules by electric field-aided extrusion. Impact of phenolic compounds on their performance

The aim of this work was to develop edible encapsulation structures based on gelatin-coated ι-carrageenan hydrogel beads, and to study the impact of incorporating different phenolic compounds within them in their microstructure, physic-chemical properties and release performance. The developed capsules were produced in aqueous solutions and mild conditions (i.e. suitable for food applications and sensitive bioactive compounds) by electric field-aided extrusion of ι-carrageenan solutions onto a gelatin bath containing calcium chloride, and exhibited shape-memory behaviour upon re-hydration in water after freeze-drying. The impact of loading them with gallic acid, catechin, chlorogenic acid and tannic acid was evaluated, and the results showed that only tannic acid could be efficiently incorporated within the hydrogel structures, while it limited the binding of the gelatin coating and altered the structure and thermal properties of the capsules. Reducing the concentration of tannic acid minimised its impact on the structure of the beads without negatively affecting its release, which was found to be however affected by the capsule size. The potential of these structures for the encapsulation of hydrophobic compounds was also anticipated.

Encapsulation and Ultrasound-Triggered Release of G-Quadruplex DNA in Multilayer Hydrogel Microcapsules.

Nucleic acid therapeutics have the potential to be the most effective disease treatment strategy due to their intrinsic precision and selectivity for coding highly specific biological processes. However, freely administered nucleic acids of any type are quickly destroyed or rendered inert by a host of defense mechanisms in the body. In this work, we address the challenge of using nucleic acids as drugs by preparing stimuli responsive poly(methacrylic acid)/poly(N-vinylpyrrolidone) (PMAA/PVPON)n multilayer hydrogel capsules loaded with ~7 kDa G-quadruplex DNA. The capsules are shown to release their DNA cargo on demand in response to both enzymatic and ultrasound (US)-triggered degradation. The unique structure adopted by the G-quadruplex is essential to its biological function and we show that the controlled release from the microcapsules preserves the basket conformation of the oligonucleotide used in our studies. We also show that the (PMAA/PVPON) multilayer hydrogel capsules can encapsulate and release ~450 kDa double stranded DNA. The encapsulation and release approaches for both oligonucleotides in multilayer hydrogel microcapsules developed here can be applied to create methodologies for new therapeutic strategies involving the controlled delivery of sensitive biomolecules. Our study provides a promising methodology for the design of effective carriers for DNA vaccines and medicines for a wide range of immunotherapies, cancer therapy and/or tissue regeneration therapies in the future.

A green approach towards functional hydrogel particles from synthetic polymers via spherical capsule mini-reactors

In the present study, we firstly reported a green approach to prepare synthetic polymer-based particle adsorbents in aqueous solution. A novel spherical hydrogel capsule (SHC) was prepared through a facile method by partial ionic-crosslinking of carboxylated chitosan (CCS). Then, 2-acrylamido-2-methyl-propanesulfonic acid (AMPS) and acrylic acid (AA) were chosen as monomers to prepare P(AMPS-co-AA) hydrogel particles by using the SHCs as sacrificial mini-reactors. Different feed monomer molar ratios of core/shell structured CCS/P(AMPS-co-AA) hydrogel particles were synthesized through free radical polymerization. After removing the shells of the core/shell particles, the obtained P(AMPS-co-AA) particles were further used as adsorbents. The maximum adsorption capacities to the metallic ions of Ni2+, Cd2+, Cu2+, and Ag+ were 171.6, 220.5, 366.0, and 668.4 mg/g, respectively. In addition, the adsorption amount towards methylene blue (MB) reached as high as 2970 mg/g, and the removal ratio to MB by the particle columns was over 92%. Furthermore, the particles showed excellent reusability. Thus, we provide a green and economical methodology for the preparation of tunable synthetic polymer-based hydrogel particles in aqueous solution that can be used as recyclable adsorbents for water remediation.

Multilayer Hydrogel Capsules of Interpenetrated Network for Encapsulation of Small Molecules.

We report on a facile capsule-based platform for efficient encapsulation of a broad spectrum of hydrophilic compounds with molecular weight less than 1000 g mol-1. The encapsulated compounds extend from low-molecular-weight anionic Alexa Fluor 532 dye and cationic anticancer drug doxorubicin (DOX) to fluorescein isothiocyanate-dextrans with Mw ranging from 4000 to 40 000 g mol-1. The pH-sensitive hydrogel capsules with an interpenetrated network shell are synthesized by layer-by-layer assembly of poly(methacrylic acid) (PMAA, Mw = 150 000 g mol-1) and poly( N-vinylpyrrolidone) (PVPON, Mw = 1 300 000 g mol-1) on 5 μm silica microparticles followed by chemical cross-linking of the PMAA multilayers. Following core dissolution, the result is a hollow microcapsule with PVPON interpenetrated in the PMAA network. The capsules exhibit a reversible change in the diameter with a swelling ratio of 1.5 upon pH variation from 7.5 to 5.5. Capsules cross-linked for 4 h display high permeability toward molecules with molecular weight under 1000 g mol-1 at pH = 7.5 but exclude dextran molecules with Mw ≥ 40 000 g mol-1. Encapsulation of small molecules was achieved at pH = 7.5 followed by sealing the capsule wall with 40 000 g mol-1 dextran at pH = 5.5. This approach results in negatively charged molecules such as Alexa Fluor being entrapped within the capsule cavity, whereas positively charged molecules such as DOX are encapsulated within the negatively charged capsule shell. Considering the simple postloading approach, the ability to entrap both anionic and cationic small molecules, and the pH-responsiveness of the interpenetrated network in the physiologically relevant range, these capsules offer a versatile method for controlled delivery of multiple hydrophilic compounds.