Locust bean gum-based silver nanocomposite hydrogel as a drug delivery system and an antibacterial agent

Effective drug release is of utmost importance in the medical field for treating various diseases, particularly cancer. Nanocomposite hydrogels remain the best materials for enhancing the bioavailability and therapeutic levels of drugs as they enable sustained, targeted, or controlled drug release. In this work, a nanocomposite hydrogel containing locust bean gum (LBG), poly(4-acryloylmorpholine) (PAcM), and silver nanoparticles (SN) has been made using an eco-friendly microwave (MW)-assisted method and characterized by various advanced techniques. The material is evaluated for its potential as a matrix material towards delivering 5-fluorouracil (5-FU), an anticancer drug in the gastrointestinal tract, and inhibiting bacterial growth. The pH-dependency of the nanocomposite materials towards swelling and drug release and its antibacterial characteristics have been compared with the neat gel in order to understand the role of SN in enhancing the performance of the materials. The results indicated both polymer materials exhibit a pH-dependent release of 5-FU with a higher release at pH 1.2, simulated gastric fluid, than at pH 7.4, simulated intestinal fluid. About 72 % of the loaded drug was released from the nanocomposite, as compared to 44 % from neat gel at pH 1.2 during the observation period of 3 h. The drug release process could be best explained by the first-order kinetic model and Fickian diffusion transport mechanism. The nanocomposite exhibited remarkable antibacterial activity against Staphylococcus aureus and Escherichia coli. The biocompatibility of the drug-loaded nanocomposite was demonstrated by a cytotoxicity study, which showed higher than 80 % viability of healthy IEC-6 cells. The results indicate the suitability of the developed nanocomposite material as a polymer matrix for sustained release of 5-FU in cancer therapy and also as an antibacterial agent to fight against bacterial infections.

Incorporating mannose-functionalized hydroxyapatite/metal-organic framework into the hyaluronic acid hydrogel film: A potential dual-targeted oral anticancer delivery system

The recent challenge in enhancing the targeted delivery of anticancer drugs to cancer cells is improving the bioavailability and therapeutic efficacy of drug delivery systems while minimizing their systemic side effects. In this study, the MIL-88(Fe) metal-organic framework was synthesized using the in situ method in the presence of hydroxyapatite nanoparticles (HAP) toward the HAP/MIL-88(Fe) (HM) nanocomposite preparation. It was then functionalized with mannose (M) as an anticancer receptor through the Steglich esterification method. Various analyses confirmed the successful synthesis of MHM. For drug release investigation, 5-Fu was loaded into the MHM, which was then coated with a hyaluronic acid (HA) hydrogel film. Characterization analyses verified the structure of the resulting HA/5-Fu-MHM hydrogel film. In vitro drug release experiments showed that the release of 5-Fu drug from HA/5-Fu-MHM could be controlled with pH, reducing its release rate in the acidic environment of the stomach while increasing it in the intestinal environment. Cytotoxicity results of the HA/5-Fu-MHM hydrogel film against HT29 cancer cells showed enhanced cytotoxicity due to the mannose and hyaluronic acid in its structure, which triggers a dual-targeted drug delivery system. The obtained results indicate that the prepared hydrogel films can be a promising bio-platform for colon cancer treatment.

Quince seed mucilage/β-cyclodextrin/Mmt-Na+-co-poly (methacrylate) based pH-sensitive polymeric carriers for controlled delivery of Capecitabine

In current work, quince seed mucilage and β-Cyclodextrin based pH regulated hydrogels were developed using aqueous free radical polymerization to sustain Capecitabine release patterns and to overcome its drawbacks, such as high dose frequency, short half-life, and low bioavailability. Developed networks were subjected to thermal analysis, Fourier transforms infrared spectroscopy, powder x-ray diffraction, elemental analysis, scanning electron microscopy, equilibrium swelling, and in-vitro release investigations to assess the network system's stability, complexation, morphology, and pH responsiveness. Thermally stable pH-responsive cross-linked networks were formed. Nanocomposite hydrogels were prepared by incorporating Capecitabine-containing clay into the swollen hydrogels. All the formulations exhibited equilibrium swelling ranging from 67.98 % to 92.98 % at pH 7.4. Optimum Capecitabine loading (88.17 %) was noted in the case of hydrogels, while it was 74.27 % in nanocomposite hydrogels. Excellent gel content (65.88 %-93.56 %) was noticed among developed formulations. Elemental analysis ensured the successful incorporation of Capecitabine. Nanocomposite hydrogels released 80.02 % longer than hydrogels after 30 h. NC hydrogels had higher t1/2 (10.57 h), AUC (121.52 μg.h/ml), and MRT (18.95 h) than hydrogels in oral pharmacokinetics. These findings imply that the pH-responsive carrier system may improve Capecitabine efficacy and reduce dosing frequency in cancer therapy. Toxicity profiling proved the system's safety, non-toxicity, and biocompatibility.

Photocatalytic Activity and Thermal Stability of Hybrid Metal-Polymer-Coordinated Complexes Derived from Gallic Acid and Ethylenediamine

Three new hybrid metal-polymer-coordinated complexes (MPCs) of copper(II), cobalt(II), and nickel(II) ions with an organic polymer derived from gallic acid and ethylenediamine (GAEtH) were synthesized. The structures of GAEtH and MPCs were characterized with FT-IR, ultraviolet (UV)-Vis, 1H and 13C NMR spectroscopy, and elemental and thermogravimetric analysis. The results reveal that the organic polymer GAEtH exhibits an infinite one-dimensional chain structure, while the hybrid MPCs have a double chain structure, with the two chains joined by metal ions. The thermodynamic and kinetic parameters of the thermal degradation stages were determined by the Coats Redfern method, and the photocatalytic behaviors of the MPCs were investigated through the decomposition of methyl orange dye under UV irradiation.

β-Cyclodextrin/chitosan-based (polyvinyl alcohol-co-acrylic acid) interpenetrating hydrogels for oral drug delivery

Gallic acid is an important phenolic compound with extensive applications in the food and pharmaceutical industries due to its health-promoting properties. However, due to its poor solubility and bioavailability, it is rapidly excreted from the body. Therefore, β-cyclodextrin/chitosan-based (polyvinyl alcohol-co-acrylic acid) interpenetrating controlled release hydrogels were developed to improve its dissolution and bioavailability. pH, polymer ratios, dynamic and equilibrium swelling, porosity, sol-gel, FTIR, XRD, TGA, DSC, SEM and structural parameters like an average molecular weight between crosslinks, solvent interaction parameters, and diffusion coefficient affecting release behavior were investigated. The highest swelling and release were observed at pH 7.4. Furthermore, hydrogels showed good antioxidant and antibacterial properties. Hydrogels improved the bioavailability of gallic acid in a pharmacokinetics study in rabbits. In vitro biodegradation showed that hydrogels were more stable in blank PBS than lysozyme and collagenase. Hydrogels were safe for rabbits (3500 mg/kg) without causing hematological or histopathological changes. The hydrogels showed good biocompatibility, and no adverse reactions were observed. Moreover, the developed hydrogels can be used to improve the bioavailability of various other drugs.

A pH-sensitive drug delivery using biodegradable succinoglycan/chitosan hydrogels with synergistic antibacterial activity

Since succinoglycan (SG) produced by Sinorhizobium meliloti is an anionic polysaccharide having substituents such as succinate and pyruvate groups, a polyelectrolyte composite hydrogel can be made together with chitosan (CS), a cationic polysaccharide. We fabricated polyelectrolyte SG/CS hydrogels using the semi-dissolving acidified sol-gel transfer (SD-A-SGT) method. The hydrogel showed optimized mechanical strength and thermal stability at an SG:CS weight ratio of 3:1. This optimized SG/CS hydrogel exhibited a high compressive stress of 497.67 kPa at 84.65 % strain and a high tensile strength of 9.14 kPa when stretched to 43.73 %. Additionally, this SG/CS hydrogel showed a pH-controlled drug release pattern for 5-fluorouracil (5-FU), where a change from pH 7.4 to 2.0 increased the release from 60 % to 94 %. In addition, this SG/CS hydrogel not only showed a cell viability of 97.57 %, but also showed synergistic antibacterial activity of 97.75 % and 96.76 % against S. aureus and E. coli, respectively. These results indicate the potential of this hydrogel as a biocompatible and biodegradable hydrogel material for wound healing, tissue engineering, and drug release systems.

Environmentally friendly strategy to access self-healable, reprocessable and recyclable chitin, chitosan, and sodium alginate based polysaccharide-vitrimer hybrid materials

Natural polysaccharides show enviable advantages for preparation of sustainable hybrid materials. However, in most cases, complex chemical modifications of natural polysaccharides are required, which not only causes changes of the inherent properties of polysaccharides, but also increases the manufacturing costs of the final materials. Therefore, it is highly desired to develop efficient and low-cost ways to access polysaccharides-containing hybrid materials. In this work, we report the environmentally friendly preparation of a new kind of polysaccharide-based materials, called polysaccharide-vitrimer hybrid materials, for the first time. The vitrimer synthesis and hybridization with polysaccharides can be achieved via a convenient one-pot method in absence of solvent and catalyst. In addition, time-consuming and labor-intensive physical/chemical modifications of natural polysaccharides are completely avoided. The resultant hybrid materials show good mechanical performance (tensile toughness is up to 13.7 MJ/m³), high thermal stability (T_d,max is up to 457 °C), fast self-healing ability (self-healing efficiency is up to 99 % within 20s at 80 °C) and excellent reprocessability and recyclability (at least three cycles). Especially, conductive polysaccharide-vitrimer hybrid materials could be readily prepared from the resultant materials, exhibiting novel applications as flexible sensors and electromagnetic shielding materials (the EMI SE is up to 24.93 dB).

Recent advances in SN-38 drug delivery system

DNA topoisomerase I plays a key role in lubricatingthe wheels of DNA replication or RNA transcription through breaking and reconnecting DNA single-strand. It is widely known that camptothecin and its derivatives (CPTs) have inhibitory effects on topoisomerases I, and have obtained some clinical benefits in cancer treatment. The potent cytotoxicity makes 7-ethyl-10-hydroxycamptothecin (SN-38) become a brilliant star among these derivatives. However, some undesirable physical and chemical properties of this compound, including poor solubility and stability, seriously hinder its effective delivery to tumor sites. In recent years, strategies to alleviate these defects have aroused extensive research interest. By focusing on the loading mechanism, basic nanodrug delivery systems with SN-38 loaded, like nanoparticles, liposomes and micelles, are demonstrated here. Additionally, functionalized nanodrug delivery systems of SN-38 including prodrug and active targeted nanodrug delivery systems and delivery systems designed to overcome drug resistance are also reviewed. At last, challenges for future research in formulation development and clinical translation of SN-38 drug delivery system are discussed.

Toxicity evaluation of choline ionic liquid-based nanocarriers of pharmaceutical agents for lung treatment

In vitro cytotoxicity evaluation of linear copolymer (LC) containing choline ionic liquid units and its conjugates with an antibacterial drug in anionic form, that is, p-aminosalicylate (LC_PAS), clavulanate (LC_CLV), or piperacillin (LC_PIP) was carried out. These systems were tested against normal: human bronchial epithelial cells (BEAS-2B), and cancers: adenocarcinoma human alveolar basal epithelial cells (A549), and human non-small cell lung carcinoma cell line (H1299). Cells viability, after linear copolymer LC and their conjugates addition for 72 h, was measured at concentration range of 3.125-100 μg/mL. The MTT test allowed the designation of IC₅₀ index, which was higher for BEAS-2B, and significantly lower in the case of cancer cell lines. The cytometric analyzes, that is, Annexin-V FITC apoptosis assay and cell cycle analysis as well as gene expression measurements for interleukins IL6 and IL8 were carried out, and showed pro-inflammatory activity of tested compounds toward cancer cells, while it was not observed against normal cell line.

Phenol release from pNIPAM hydrogels: scaling molecular dynamics simulations with dynamical density functional theory

We employed molecular dynamic simulations (MD) and the Bennett's acceptance ratio method to compute the free energy of transfer, ΔG_trans, of phenol, methane, and 5-fluorouracil (5-FU), between bulk water and water-pNIPAM mixtures of different polymer volume fractions, ϕ_p. For this purpose, we first calculate the solvation free energies in both media to obtain ΔG_trans. Phenol and 5-FU (a medication used to treat cancer) attach to the pNIPAM surface so that they show negative values of ΔG_trans irrespective of temperature (above or below the lower critical solution temperature of pNIPAM, T_c). Conversely, methane switches the ΔG_trans sign when considering temperatures below (positive) and above (negative) T_c. In all cases, and contrasting with some theoretical predictions, ΔG_trans maintains a linear behavior with the pNIPAM concentration up to large polymer densities. We have also employed MD to compute the diffusion coefficient, D, of phenol in water-pNIPAM mixtures as a function of ϕ_p in the diluted limit. Both ΔG_trans and D as a function of ϕ_p are required inputs to obtain the release halftime of hollow pNIPAM microgels through Dynamic Density Functional Theory (DDFT). Our scaling strategy captures the experimental value of 2200 s for 50 μm radius microgels with no cavity, for ϕ_p ≃ 0.83 at 315 K.

Controlled Delivery and Photopatterning of Mechanical Properties in Polysaccharide Hydrogels Using Vanadium Coordination and Photochemistry

Incorporation of the transition metal ion V(V) into hydrogels has been used to impart photoresponsive behavior, which was used to tune materials properties during light irradiation. The photoreaction in QHE-cellulose/agarose hydrogels coordinated with vanadium was evidenced by a clear color change of yellow to blue through a green intermediate. This color change was attributed to the reduction of V(V) to V(IV) as described in our previous work. A concomitant oxidative breakdown of the polysaccharide chain was noticeable upon the reduction of V(V) with a decrease in stiffness (G') of the hydrogel material. This reduction of the metal ion and breakdown of polysaccharide chain induced irreversible changes in the microstructure of the hydrogel, enabling the controlled delivery of V(IV) and/or encapsulated cargo. Scanning electron microscopy studies showed an increase in pore sizes and guest cavity formation during irradiation. In addition to the significant drop in mechanical properties like storage and loss modulus in the gel materials, a viscosity drop in the polymer solution was observed through irradiation, indicating breakdown of the polysaccharide chain. A photomask can be used to create discrete patterns on these materials upon irradiation.

Green synthesis of bioinspired chitosan-ZnO-based polysaccharide gums hydrogels with propolis extract as novel functional natural biomaterials

A facile, green synthesis methodology to obtain zinc oxide nanoparticles using three polysaccharide gums (Acacia gum, Guar gum and Xanthan gum) of biological origin was developed. Subsequently, biosynthesized zinc oxide nanoparticles were incorporated into a sustainable chitosan hydrogel matrix functionalized with propolis extract. This study has revealed that the selected polysaccharides as chelates represents a suitable approach to synthesize ZnO nanoparticles of particular interest with controlled morphology. The formation of ZnO nanoparticles using polysaccharide gums was confirmed by FTIR, XRD, UV-Vis spectroscopy, thermal analysis, SEM, Raman and photoluminescence spectroscopies. The rheological behaviour of obtained hydrogels was evaluated. The AFM studies demonstrate that all synthesized chitosan incorporated ZnO composites hydrogels functionalized with propolis extract exhibit corrugated topographies. The present study highlights the possible incorporation of various guest molecules into hydrogel matrix due to its tuneable morphologies. The obtained hydrogel composites were cytocompatible in L929 fibroblast cell culture, in a range of concentrations between 50 and 1000 μg/mL, as assessed by MTT, LDH and Live/Dead double staining assays. By enhancing the biological properties, these novel green hydrogels show attractive superior performance in a wide concentration range to develop future in vivo suitable natural platforms as effective delivery systems of pharmacologic agents for biomedical applications.

Biomedical Applications of polymeric micelles in the treatment of diabetes mellitus: Current success and future approaches

INTRODUCTION

Diabetes mellitus (DM) is the most common metabolic disease and multifactorial, harming patients worldwide. Extensive research has been carried out in the search for novel drug delivery systems offering reliable control of glucose levels for diabetics, aiming at efficient management of DM.

AREAS COVERED

Polymeric micelles (PMs) as smart drug delivery nanocarriers are discussed, focusing on oral drug delivery applications for the management of hyperglycemia. The most recent approaches used for the preparation of smart PMs employ molecular features of amphiphilic block copolymers (ABCs), such as stimulus sensitivity, ligand conjugation, and as a more specific example the ability to inhibit islet amyloidosis.

EXPERT OPINION

PMs provide a unique platform for self-regulated or spatiotemporal drug delivery, mimicking the working mode of pancreatic islets to maintain glucose homeostasis for prolonged periods. This unique characteristic is achieved by tailoring the functional chemistry of ABCs considering the physicochemical traits of PMs, including sensing capabilities, hydrophobicity, etc. In addition, the application of ABCs for the inhibition of conformational changes in islet amyloid polypeptide garnered attention as one of the root causes of DM. However, research in this field is limited and further studies at the clinical level are required.

Glucose-sensitive delivery of tannic acid by a photo-crosslinked chitosan hydrogel film for antibacterial and anti-inflammatory therapy

A glucose-sensitive antibacterial and anti-inflammatory hydrogel film with controlled release of tannic acid (TA) was synthesized using chitosan (CS). Specifically, the photo-crosslinked CS hydrogel was first obtained and then immersed in TA solution to generate composite hydrogel film with enhanced mechanical properties. Subsequently, N-hydroxysuccinimide/1-ethyl-3-(3-dimethylaminopropyl) carbodiimide based coupling chemistry was used to covalently crosslink glucose oxidase (GOx) to CS to obtain glucose sensitivity. The physicochemical properties, including chemical composition, enzyme-related characteristics, glucose responsiveness, and mechanical strength, were thoroughly investigated, followed by the cytotoxicity, antibacterial and anti-inflammatory tests. The results showed that the GOx immobilized on the film surface by covalent bonding gave better stability than those that were physically adsorbed. In addition, it could quickly and correspondingly modify its inner pore structure in response to the glucose stimulus and then control the loaded TA release. Meanwhile, the TA addition could enhance the film's mechanical properties. The composite hydrogel film demonstrated adequate biocompatibility and can inhibit NO, IL-6, and TNF-α production in stimulated macrophages, as well as Porphyromonas gingivalis growth, demonstrating effective antibacterial and anti-inflammatory activity.

Employing Cellulose Nanofiber-Based Hydrogels for Burn Dressing

The aim of this research was to fabricate a burn dressing in the form of hydrogel films constructed with cellulose nanofibers (CNF) that has pain-relieving properties, in addition to wound healing. In this study, the hydrogels were prepared in the form of film. For this, CNF at weight ratios of 1, 2, and 3 wt.%, 1 wt.% of hydroxyethyl cellulose (HEC), and citric acid (CA) crosslinker with 10 and 20 wt.% were used. FE-SEM analysis showed that the structure of the CNF was preserved after hydrogel preparation. Cationization of CNF by C₆H₁₄NOCl was confirmed by FTIR spectroscopy. The drug release analysis results showed a linear relationship between the amount of absorption and the concentration of the drug. The MTT test (assay protocol for cell viability and proliferation) showed the high effectiveness of cationization of CNF and confirmed the non-toxicity of the resulting hydrogels.

d-Mannitol based surfactants for cosmetic and food applications and hydrogels to produce stabilized Ag nanoparticles

A novel synthetic approach for lipid modification of mannitol for hydrogelation, cosmetic and food application.

Application or function of citric acid in drug delivery platforms

Nontoxic materials with natural origin are promising materials in the designing and preparation of the new drug delivery systems (DDSs). Today's, citric acid (CA) has attracted a great deal of attention because of its special features; green nature, biocompatibility, low price, biodegradability, and commercially available property. So, CA has been employed in the preparation of the various platforms to induce a suitable property on their structure. Recently, several research groups investigated the CA-based platforms in different forms like tablets, dendrimers, hyperbranched polymers, (co)polymer, hydrogels, and nanoparticles as efficient DDSs. By considering an increasing amount of published articles in this field, for the first time, in this review, an overview of the published works regarding CA applications in the design of various DDSs is presented with a detailed and insightful discussion.

Formulation, In Vitro Evaluation, and Toxicity Studies of A. vulgaris-co-AAm Carrier for Vildagliptin

This study investigated the use of Artemisia vulgaris L. seed mucilage as a new excipient for sustained delivery of Vildagliptin. Copolymeric carrier of A. vulgaris seed mucilage-co-AAm was devised by using acrylamide (AAm) as a monomer, methylene-bis-acrylamide (MBA) as a crosslinker, and potassium persulfate (KPS) as an initiator through free radical polymerization. Different formulations of A. vulgaris-co-AAm were devised by varying contents of polymer, monomer, crosslinking agent, initiator, and reaction temperature. Copolymeric structures were characterized through XRD analysis, Fourier transform infrared (FTIR) spectroscopy, TGA and DSC analysis, and scanning electron microscopy. Porosity, gel fraction, and Vildagliptin loading capacity of copolymers were also established. Swelling and in vitro drug release studies were conducted. XRD evaluation showed the alteration of the crystalline structure of Vildagliptin into an amorphous form. FTIR analysis confirmed the successful grafting of AAm to A. vulgaris seed mucilage backbone. Porosity was increased with increasing polymer concentration and reaction temperature while it was decreased with an increasing amount of AAm, MBA, and KPS. Gel content was decreased with increasing polymer concentration and reaction temperature while it was increased with an increasing amount of AAm, MBA, and KPS. Acute oral toxicity of copolymeric network was done in animal models to evaluate the safety. Copolymers showed the same swelling behavior at all pH 1.2, 4.5, 6.8, and 7.4. Vildagliptin release from copolymer showed a cumulative trend by increasing polymer content and reaction temperature, while a declining trend was observed with increasing contents of monomer, crosslinking agent, and initiator. Sustained release of Vildagliptin was observed from copolymers and release followed the Korsmeyer-Peppas model. From the acute oral toxicity studies, it is evident that newly synthesized copolymeric carriers are potentially safe for eyes, skin, and vital organs.

Recent advances in composite hydrogels prepared solely from polysaccharides

The proliferating demand for sustainable, biodegradable, and biologically safe materials has triggered the development of polysaccharide-based hydrogels. The translation of research on single polysaccharide-based hydrogels into their desired clinical or industrial application is minimal. This is attributable to their lack of mechanical strength, inadequate stability, and constrained the possibility of their modulation to obtain the desired property. Polysaccharide-based composite hydrogels (PCHs) have proven their mantle to counteract this issue while expanding the horizons for their applications. PCHs can be fabricated by physical and/or chemical interlinking techniques, which entails the association of macromolecular chain linkages. The resulting composites can impart remarkably higher stability and elevate the suitability and efficiency of the system. Owing to these advantages, the research on PCHs has been gaining momentum. They are emerging as a lucrative alternative for the conventional molecules used for the fabrication of such materials. The review would initially focus on providing a detailed outlook for the various physical/chemical techniques involved in the preparation of PCHs. Subsequently, the characterization techniques used to understand the structural and chemical behavior of PCHs would be discussed. The article would also elaborate on the various fields of application and the possible areas for future research of PCHs.

Synthesis and Evaluation of AlgNa-g-Poly(QCL-co-HEMA) Hydrogels as Platform for Chondrocyte Proliferation and Controlled Release of Betamethasone

Hydrogels obtained from combining different polymers are an interesting strategy for developing controlled release system platforms and tissue engineering scaffolds. In this study, the applicability of sodium alginate-g-(QCL-co-HEMA) hydrogels for these biomedical applications was evaluated. Hydrogels were synthesized by free-radical polymerization using a different concentration of the components. The hydrogels were characterized by Fourier transform-infrared spectroscopy, scanning electron microscopy, and a swelling degree. Betamethasone release as well as the in vitro cytocompatibility with chondrocytes and fibroblast cells were also evaluated. Scanning electron microscopy confirmed the porous surface morphology of the hydrogels in all cases. The swelling percent was determined at a different pH and was observed to be pH-sensitive. The controlled release behavior of betamethasone from the matrices was investigated in PBS media (pH = 7.4) and the drug was released in a controlled manner for up to 8 h. Human chondrocytes and fibroblasts were cultured on the hydrogels. The MTS assay showed that almost all hydrogels are cytocompatibles and an increase of proliferation in both cell types after one week of incubation was observed by the Live/Dead^® assay. These results demonstrate that these hydrogels are attractive materials for pharmaceutical and biomedical applications due to their characteristics, their release kinetics, and biocompatibility.

Fucoidan- and carrageenan-based biosynthetic poly(vinyl alcohol) hydrogels for controlled permeation

Since the permeation of the inflammatory cytokines into hydrogel scaffolds has been shown to cause dysfunction of encapsulated cells, appropriate design strategies to circumvent this are essential. In the present work, it was hypothesized that highly crosslinked PVA-fucoidan and PVA-carrageenan hydrogels can control permeation of the trefoil-shaped inflammatory cytokine IL-1β while allowing the permeation of the globular protein albumin. PVA, fucoidan, and carrageenans were functionalized with methacrylate groups and the functionalized polymers were co-crosslinked by UV photopolymerization. The resultant hydrogels were characterized physicochemically and the release of fucoidan and carrageenans was quantified by developing a colorimetric assay, which was validated by XPS analysis. The permeability characteristics of the hydrogels were evaluated using bovine serum albumin (BSA), IgG, and IL-1β. The results demonstrated an increase in hydrogel swelling through the incorporation of the polysaccharides with minimal overall mass loss. The release studies showed hydrogel stability, where the formulations exhibited ~43% retention of fucoidan and ~60-80% retention of carrageenans consistently up to 7 days. The permeation data revealed very low permeation of IgG and IL-1β through the hydrogels, with <1% permeation after 24 h, while allowing >6% permeation of BSA. These data indicate that such hydrogels can be used as the basis for cytokine-protective implantable devices for clinical applications.

Carbon Dot Cross-Linked Gelatin Nanocomposite Hydrogel for pH-Sensing and pH-Responsive Drug Delivery

Delivery of therapeutics to the intestinal region bypassing the harsh acidic environment of the stomach has long been a research focus. On the other hand, monitoring a system's pH during drug delivery is a crucial diagnosis factor as the activity and release rate of many therapeutics depend on it. This study answered both of these issues by fabricating a novel nanocomposite hydrogel for intestinal drug delivery and near-neutral pH sensing at the same time. Gelatin nanocomposites (GNCs) with varying concentrations of carbon dots (CDs) were fabricated through simple solvent casting methods. Here, CDs served a dual role and simultaneously acted as a cross-linker and chromophore, which reduced the usage of toxic cross-linkers. The proposed GNC hydrogel sample acted as an excellent pH sensor in the near-neutral pH range and could be useful for quantitative pH measurement. A model antibacterial drug (cefadroxil) was used for the in vitro drug release study at gastric pH (1.2) and intestinal pH (7.4) conditions. A moderate and sustained drug release profile was noticed at pH 7.4 in comparison to the acidic medium over a 24 h study. The drug release profile revealed that the pH of the release medium and the percentage of CDs cross-linking influenced the drug release rate. Release data were compared with different empirical equations for the evaluation of drug release kinetics and found good agreement with the Higuchi model. The antibacterial activity of cefadroxil was assessed by the broth microdilution method and found to be retained and not hindered by the drug entrapment procedure. The cell viability assay showed that all of the hydrogel samples, including the drug-loaded GNC hydrogel, offered acceptable cytocompatibility and nontoxicity. All of these observations illustrated that GNC hydrogel could act as an ideal pH-monitoring and oral drug delivery system in near-neutral pH at the same time.

Preparation, characterization and antitumor activity of a cationic starch-derivative membrane embedded with a β-cyclodextrin/curcumin inclusion complex

A membrane of cationic starch-derivative/poly(vinyl alcohol) was prepared and utilized as a support to immobilize a β-cyclodextrin/curcumin inclusion complex. The resulting material (denote as β-CD/CUR-MBN) was characterized in detail by different techniques. In vitro experiments revealed that β-CD/CUR-MBN enables the controlling of the curcumin release process, which is guided by the relaxation of the polymer matrix. Moreover, cytotoxic assays were performed to investigate the effect of β-CD/CUR-MBN on two cancer cell lines (melanoma and glioblastoma). The results showed that the polymeric membrane exerts higher cytotoxicity against these cells than free curcumin. Also, β-CD/CUR-MBN exerted a prolonged cytotoxic effect (up to 96 h), even using a low concentration (50 μg mL^-1), indicating that the curcumin in the polymeric membrane showed increased bioavailability under the tested condition. β-CD/CUR-MBN was non-cytotoxic against normal cells suggesting a specific action of this material against target cancer cells. The results reported here allow ranks β-CD/CUR-MBN as a promising biomaterial to act as a local drug delivery system to treat cancer.

Salecan polysaccharide-based hydrogels and their applications: a review

This review systematically summarizes for the first time the recent progress on hydrogels containing salecan polysaccharides.

Polysaccharide-based cationic hydrogels for dye adsorption

With advances in soft material design and engineering, naturally resourced polysaccharides have frequently been used to construct hydrogels because of their unique properties such as renewability, biodegradability and biocompatibility. In this work, we use a water-soluble microbial polysaccharide, salecan as a trapped natural polymer, poly(acrylamide-co-diallyldimethylammonium chloride) (PAD) as a functional matrix to prepare salecan/PAD hydrogels through a facile one-pot method. We employed a variety of spectroscopic techniques to probe the physicochemical properties of the designed hydrogels. The results demonstrated that salecan not only tuned the polarity of the PAD hydrogels, but also endowed them with adjustable water content. Subsequently, the adsorption performance of these hydrogels to methyl orange (MO) dye was investigated in detail. It was found that the salecan/PAD had the ability to remove MO from the surrounding aqueous solutions. In addition, adsorption kinetic data were nicely described by pseudo-second-order model and the adsorption isotherm data fitted well with the Freundlich equation. Having tailorable physicochemical properties coupled with the ability to uptake dye, these salecan-incorporated hydrogels could be promising platform for wastewater treatment and removal of heavy metal ions.

Bacterial cellulose-poly(acrylic acid-co-N,N′-methylene-bis-acrylamide) interpenetrated networks for the controlled release of fertilizers

In this study, composite hydrogels with interpenetrated polymer networks (IPNs), based on bacterial cellulose (BC) and poly(acrylic acid-co-N,N′-methylene-bis-acrylamide) (PAA), were synthesized by radical polymerization and characterized herein for the first time. Liquid fertilizer (LF) formulations, containing potassium, phosphorus, ammonium oxides and micronutrients, were encapsulated directly into the IPNs of the composite hydrogels during synthesis. Thermal analyses and scanning electron microscopy of control and composite xerogels highlighted the formation of IPNs between BC and PAA. Swelling determinations confirmed the influence of the crosslinker and of the liquid fertilizer concentration upon the density of the IPNs. Further rheology studies and release profiles indicated how the presence of BC and the increase of the crosslinking density of IPNs improved the mechanical strength and the release profile of LF for the innovative composite BC-PAA hydrogels. Results regarding the fertilizer release indicated that the presence of the BC led to a more controlled liberation of the fertilizer proving that this new formulation is potentially viable for application in agricultural practices.

In this study, composite hydrogels with interpenetrated polymer networks (IPNs), based on bacterial cellulose (BC) and poly(acrylic acid-co-N,N′-methylene-bis-acrylamide) (PAA) were synthesized by radical polymerization.