Displaying publications 41 - 60 of 76 in total

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  1. Synthesis and evaluation on pH- and temperature-responsive chitosan-p(MAA-co-NIPAM) hydrogels
    Rasib SZM, Ahmad Z, Khan A, Akil HM, Othman MBH, Hamid ZAA, et al.
    Int J Biol Macromol, 2018 Mar;108:367-375.
    PMID: 29222015 DOI: 10.1016/j.ijbiomac.2017.12.021
    In this study, chitosan-poly(methacrylic acid-co-N-isopropylacrylamide) [chitosan-p(MAA-co-NIPAM)] hydrogels were synthesized by emulsion polymerization. In order to be used as a carrier for drug delivery systems, the hydrogels had to be biocompatible, biodegradable and multi-responsive. The polymerization was performed by copolymerize MAA and NIPAM with chitosan polymer to produce a chitosan-based hydrogel. Due to instability during synthesis and complexity of components to produce the hydrogel, further study at different times of reaction is important to observe the synthesis process, the effect of end product on swelling behaviour and the most important is to find the best way to control the hydrogel synthesis in order to have an optimal swelling behaviour for drug release application. Studied by using Fourier transform infra-red (FTIR) spectroscopy found that, the synthesized was successfully produced stable chitosan-based hydrogel with PNIPAM continuously covered the outer surface of hydrogel which influenced much on the stability during synthesis. The chitosan and PMAA increased the zeta potential of the hydrogel and the chitosan capable to control shrinkage above human body temperature. The chitosan-p(MAA-co-NIPAM) hydrogels also responses to pH and temperature thus improved the ability to performance as a drug carrier.
    Matched MeSH terms: Hydrogels/chemistry*
  2. Synthesis and functionalization of chitosan built hydrogel with induced hydrophilicity for extended release of sparingly soluble drugs
    Ullah F, Javed F, Othman MBH, Khan A, Gul R, Ahmad Z, et al.
    J Biomater Sci Polym Ed, 2018 03;29(4):376-396.
    PMID: 29285989 DOI: 10.1080/09205063.2017.1421347
    Addressing the functional biomaterials as next-generation therapeutics, chitosan and alginic acid were copolymerized in the form of chemically crosslinked interpenetrating networks (IPNs). The native hydrogel was functionalized via carbodiimide (EDC), catalyzed coupling of soft ligand (1,2-Ethylenediamine) and hard ligand (4-aminophenol) to replace -OH groups in alginic acid units for extended hydrogel- interfaces with the aqueous and sparingly soluble drug solutions. The chemical structure, Lower solution critical temperature (LCST ≈ 37.88 °C), particle size (Zh,app ≈ 150-200 nm), grain size (160-360 nm), surface roughness (85-250 nm), conductivity (37-74 mv) and zeta potential (16-32 mv) of native and functionalized hydrogel were investigated by using FT-IR, solid state-13C-NMR, TGA, DSC, FESEM, AFM and dynamic light scattering (DLS) measurements. The effective swelling, drug loading (47-78%) and drug release (53-86%) profiles were adjusted based on selective functionalization of hydrophobic IPNs due to electrostatic complexation and extended interactions of hydrophilic ligands with the aqueous and drug solutions. Drug release from the hydrogel matrices with diffusion coefficient n ≈ 0.7 was established by Non- Fickian diffusion mechanism. In vitro degradation trials of the hydrogel with a 20% loss of wet mass in simulated gastric fluid (SGF) and 38% loss of wet mass in simulated intestinal fluid (SIF), were investigated for 400 h through bulk erosion. Consequently, a slower rate of drug loading and release was observed for native hydrogel, due to stronger H-bonding, interlocking and entanglement within the IPNs, which was finely tuned and extended by the induced hydrophilic and functional ligands. In the light of induced hydrophilicity, such functional hydrogel could be highly attractive for extended release of sparingly soluble drugs.
    Matched MeSH terms: Hydrogels/chemistry*
  3. Fulltext Development of a bacterial cellulose-based hydrogel cell carrier containing keratinocytes and fibroblasts for full-thickness wound healing
    Loh EYX, Mohamad N, Fauzi MB, Ng MH, Ng SF, Mohd Amin MCI
    Sci Rep, 2018 02 13;8(1):2875.
    PMID: 29440678 DOI: 10.1038/s41598-018-21174-7
    Bacterial cellulose (BC)/acrylic acid (AA) hydrogel has successfully been investigated as a wound dressing for partial-thickness burn wound. It is also a promising biomaterial cell carrier because it bears some resemblance to the natural soft tissue. This study assessed its ability to deliver human epidermal keratinocytes (EK) and dermal fibroblasts (DF) for the treatment of full-thickness skin lesions. In vitro studies demonstrated that BC/AA hydrogel had excellent cell attachment, maintained cell viability with limited migration, and allowed cell transfer. In vivo wound closure, histological, immunohistochemistry, and transmission electron microscopy evaluation revealed that hydrogel alone (HA) and hydrogel with cells (HC) accelerated wound healing compared to the untreated controls. Gross appearance and Masson's trichrome staining indicated that HC was better than HA. This study suggests the potential application of BC/AA hydrogel with dual functions, as a cell carrier and wound dressing, to promote full-thickness wound healing.
    Matched MeSH terms: Hydrogels/chemistry*
  4. Modified Dioscorea hispida starch-based hydrogels and their in-vitro cytotoxicity study on small intestine cell line (FHS-74 Int)
    Ashri A, Amalina N, Kamil A, Fazry S, Sairi MF, Nazar MF, et al.
    Int J Biol Macromol, 2018 Feb;107(Pt B):2412-2421.
    PMID: 29056465 DOI: 10.1016/j.ijbiomac.2017.10.125
    Starch-based hydrogels are promising smart materials for biomedical and pharmaceutical applications, which offer exciting perspectives in biophysical research at molecular level. This work was intended to develop, characterize and explore the properties of hydrogel from starch extracted from new source, Dioscorea hispida Dennst. Starch-mediated hydrogels were successfully synthesized via free radical polymerization method with varying concentrations of acrylic acid (AA),N,N'-methylenebisacrylamide (MBA) and sodium hydroxide (NaOH) in aqueous system. The grafting reaction between starch and AA was examined by observing the decline in intensity peak of hydrogel FTIR spectrum at 3291cm-1 and peak around 1600-1680cm-1, indicating the stretching of hydroxyl group (OH) and stretching of carbon-carbon double bond (CC) respectively. The effects of cross-linker, monomer and NaOH concentration on swelling ratio and gel content in different medium and conditions were also evaluated. The thermal stability and structural morphology of as-synthesized hydrogels were studied by thermogravimetry analysis (TGA) and scanning electron microscopy (SEM). In-vitro cytotoxicity study using small intestine cell line (FHS-74 Int) revealed that the as-formulated eco-friendly-hydrogel was free from any harmful material and safe to use for future product development.
    Matched MeSH terms: Hydrogels/chemistry*
  5. In vitro assessment of non-irritant microemulsified voriconazole hydrogel system
    Raju Y P, N H, Chowdary V H, Nair RS, Basha D J, N T
    Artif Cells Nanomed Biotechnol, 2017 Dec;45(8):1539-1547.
    PMID: 27887040 DOI: 10.1080/21691401.2016.1260579
    Research was aimed on microemulsion-based hydrogel for voriconazole. Oleic acid and isopropyl myristate as lipid phases; tween 20: tween 80 as surfactants and PEG600 as cosurfactant were selected to formulate voriconazole microemulsions. The promising microemulsions in terms of zeta potential, pH, viscosity, and drug release were selected and developed into hydrogels using carbopol 934. Resulting microemulsion-based hydrogel (MBH) of voriconazole were evaluated for in vitro diffusion and ex vivo permeation. Antifungal potentials of MBH were assessed against selected fungal strains. Optimal MBH formulations, O6 and O8 had displayed their antifungal potentials with enlarged zone of inhibition against selected fungal strains.
    Matched MeSH terms: Hydrogels/chemistry*
  6. Biomolecule-Responsive Hydrogels in Medicine
    Sharifzadeh G, Hosseinkhani H
    Adv Healthc Mater, 2017 Dec;6(24).
    PMID: 29057617 DOI: 10.1002/adhm.201700801
    Recent advances and applications of biomolecule-responsive hydrogels, namely, glucose-responsive hydrogels, protein-responsive hydrogels, and nucleic-acid-responsive hydrogels are highlighted. However, achieving the ultimate purpose of using biomolecule-responsive hydrogels in preclinical and clinical areas is still at the very early stage and calls for more novel designing concepts and advance ideas. On the way toward the real/clinical application of biomolecule-responsive hydrogels, plenty of factors should be extensively studied and examined under both in vitro and in vivo conditions. For example, biocompatibility, biointegration, and toxicity of biomolecule-responsive hydrogels should be carefully evaluated. From the living body's point of view, biocompatibility is seriously depended on the interactions at the tissue/polymer interface. These interactions are influenced by physical nature, chemical structure, surface properties, and degradation of the materials. In addition, the developments of advanced hydrogels with tunable biological and mechanical properties which cause no/low side effects are of great importance.
    Matched MeSH terms: Hydrogels/chemistry*
  7. Engineered Hydrogels in Cancer Therapy and Diagnosis
    Sepantafar M, Maheronnaghsh R, Mohammadi H, Radmanesh F, Hasani-Sadrabadi MM, Ebrahimi M, et al.
    Trends Biotechnol, 2017 11;35(11):1074-1087.
    PMID: 28734545 DOI: 10.1016/j.tibtech.2017.06.015
    Over the last decade, numerous investigations have attempted to clarify the intricacies of tumor development to propose effective approaches for cancer treatment. Thanks to the unique properties of hydrogels, researchers have made significant progress in tumor model reconstruction, tumor diagnosis, and associated therapies. Notably, hydrogel-based systems can be adjusted to respond to cancer-specific hallmarks and/or external stimuli. These well-known drug reservoirs can be used as smart carriers for multiple cargos, including both naked and nanoparticle-encapsulated chemotherapeutics, genes, and radioisotopes. Recent works have attempted to specialize hydrogels for cancer research; we comprehensively review this topic for the first time, synthesizing past results and defining paths for future work.
    Matched MeSH terms: Hydrogels/chemistry
  8. Optimization, characterization, and in vitro assessment of alginate-pectin ionic cross-linked hydrogel film for wound dressing applications
    Rezvanian M, Ahmad N, Mohd Amin MC, Ng SF
    Int J Biol Macromol, 2017 Apr;97:131-140.
    PMID: 28064048 DOI: 10.1016/j.ijbiomac.2016.12.079
    Natural polymer-based hydrogel films have great potential for biomedical applications and are good candidates for wound dressings. In this study, we aimed to develop simvastatin-loaded crosslinked alginate-pectin hydrogel films by ionic crosslinking to improve the mechanical characteristics, wound fluid uptake and drug release behavior. Alginate-pectin hydrocolloid films were chemically crosslinked by immersing in different concentrations of CaCl2 (0.5-3% w/v) for 2-20min. The degree of crosslinking was influenced by both contact time and CaCl2 concentration. The optimized conditions for crosslinking were 0.5% and 1% (CaCl2) for 2min. The optimized hydrogel films were then characterized for their physical, mechanical, morphological, thermal, in vitro drug release, and cytocompatibility profiles. Crosslinking improved the mechanical profile and wound fluid uptake capacity of dressings. The hydrogel films were able to maintain their physical integrity during use, and the best results were obtained with the film in which the extent of crosslinking was low (0.5%). Thermal analysis confirmed that the crosslinking process enhanced the thermal stability of hydrogel films. Sustained, slow release of simvastatin was obtained from the crosslinked films and in vitro cytotoxicity assay demonstrated that the hydrogel films were non-toxic.
    Matched MeSH terms: Hydrogels/chemistry*
  9. Omnidirectional Shape Memory Effect via Lyophilization of PEG Hydrogels
    Chen D, Xia X, Wong TW, Bai H, Behl M, Zhao Q, et al.
    Macromol Rapid Commun, 2017 Apr;38(7).
    PMID: 28196300 DOI: 10.1002/marc.201600746
    Device applications of shape memory polymers demand diverse shape changing geometries, which are currently limited to non-omnidirectional movement. This restriction originates from traditional thermomechanical programming methods such as uniaxial, biaxial stretching, bending, or compression. A solvent-modulated programming method is reported to achieve an omnidirectional shape memory behavior. The method utilizes freeze drying of hydrogels of polyethylene glycol networks with a melting transition temperature around 50 °C in their dry state. Such a process creates temporarily fixed macroporosity, which collapses upon heating, leading to significant omnidirectional shrinkage. These shrunken materials can swell in water to form hydrogels again and the omnidirectional programming and recovery can be repeated. The fixity ratio (R f ) and recovery ratio (R r ) can be maintained at 90% and 98% respectively upon shape memory multicycling. The maximum linear recoverable strain, as limited by the maximum swelling, is ≈90%. Amongst various application potentials, one can envision the fabrication of multiphase composites by taking advantages of the omnidirectional shrinkage from a porous polymer to a denser structure.
    Matched MeSH terms: Hydrogels/chemistry*
  10. Fulltext Xeno-free culture of human pluripotent stem cells on oligopeptide-grafted hydrogels with various molecular designs
    Chen YM, Chen LH, Li MP, Li HF, Higuchi A, Kumar SS, et al.
    Sci Rep, 2017 03 23;7:45146.
    PMID: 28332572 DOI: 10.1038/srep45146
    Establishing cultures of human embryonic (ES) and induced pluripotent (iPS) stem cells in xeno-free conditions is essential for producing clinical-grade cells. Development of cell culture biomaterials for human ES and iPS cells is critical for this purpose. We designed several structures of oligopeptide-grafted poly (vinyl alcohol-co-itaconic acid) hydrogels with optimal elasticity, and prepared them in formations of single chain, single chain with joint segment, dual chain with joint segment, and branched-type chain. Oligopeptide sequences were selected from integrin- and glycosaminoglycan-binding domains of the extracellular matrix. The hydrogels grafted with vitronectin-derived oligopeptides having a joint segment or a dual chain, which has a storage modulus of 25 kPa, supported the long-term culture of human ES and iPS cells for over 10 passages. The dual chain and/or joint segment with cell adhesion molecules on the hydrogels facilitated the proliferation and pluripotency of human ES and iPS cells.
    Matched MeSH terms: Hydrogels/chemistry*
  11. Evaluation of superabsorbent linseed-polysaccharides as a novel stimuli-responsive oral sustained release drug delivery system
    Haseeb MT, Hussain MA, Bashir S, Ashraf MU, Ahmad N
    Drug Dev Ind Pharm, 2017 Mar;43(3):409-420.
    PMID: 27808567 DOI: 10.1080/03639045.2016.1257017
    CONTEXT: Advancement in technology has transformed the conventional dosage forms to intelligent drug delivery systems. Such systems are helpful for targeted and efficient drug delivery with minimum side effects. Drug release from these systems is governed and controlled by external stimuli (pH, enzymes, ions, glucose, etc.). Polymeric biomaterial having stimuli-responsive properties has opened a new area in drug delivery approach.

    OBJECTIVE: Potential of a polysaccharide (rhamnogalacturonan)-based hydrogel from Linseeds (Linum usitatissimum L.) was investigated as an intelligent drug delivery material.

    MATERIALS AND METHODS: Different concentrations of Linseed hydrogel (LSH) were used to prepare caffeine and diacerein tablets and further investigated for pH and salt solution-responsive swelling, pH-dependent drug release, and release kinetics. Morphology of tablets was observed using SEM.

    RESULTS: LSH tablets exhibited dynamic swelling-deswelling behavior with tendency to swell at pH 7.4 and in deionized water while deswell at pH 1.2, in normal saline and ethanol. Consequently, pH controlled release of the drugs was observed from tablets with lower release (<10%) at pH 1.2 and higher release at pH 6.8 and 7.4. SEM showed elongated channels in swollen then freeze-dried tablets.

    DISCUSSION: The drug release was greatly influenced by the amount of LSH in the tablets. Drug release from LSH tablets was governed by the non-Fickian diffusion.

    CONCLUSIONS: These finding indicates that LSH holds potential to be developed as sustained release material for tablet.

    Matched MeSH terms: Hydrogels/chemistry
  12. Formulation and in vitro and in vivo evaluation of a new osteoprotegerin-chitosan gel for bone tissue regeneration
    Jayash SN, Hashim NM, Misran M, Baharuddin NA
    J Biomed Mater Res A, 2017 02;105(2):398-407.
    PMID: 27684563 DOI: 10.1002/jbm.a.35919
    The osteoprotegerin (OPG) system plays a critical role in bone remodelling by regulating osteoclast formation and activity. The study aimed to determine the physicochemical properties and biocompatibility of a newly formulated OPG-chitosan gel. The OPG-chitosan gel was formulated using human OPG protein and water-soluble chitosan. The physicochemical properties were determined using Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Gel morphology was determined using scanning electron microscopy (SEM) and then it was subjected to a protein release assay and biodegradability test. An in vitro cytotoxicity test on normal human periodontal ligament (NHPL) fibroblasts and normal human (NH) osteoblasts was carried out using the AlamarBlue assay. In vivo evaluation in a rabbit model involved creating critical-sized defects in calvarial bone, filling with the OPG-chitosan gel and sacrificing at 12 weeks. In vitro results demonstrated that the 25 kDa OPG-chitosan gel had the highest rate of protein release and achieved 90% degradation in 28 days. At 12 weeks, the defects filled with 25 kDa OPG-chitosan gel showed significant (p 
    Matched MeSH terms: Hydrogels/chemistry
  13. Nanoencapsulation, an efficient and promising approach to maximize wound healing efficacy of curcumin: A review of new trends and state-of-the-art
    Hussain Z, Thu HE, Ng SF, Khan S, Katas H
    Colloids Surf B Biointerfaces, 2017 Feb 01;150:223-241.
    PMID: 27918967 DOI: 10.1016/j.colsurfb.2016.11.036
    Wound healing is a multifarious and vibrant process of replacing devitalized and damaged cellular structures, leading to restoration of the skin's barrier function, re-establishment of tissue integrity, and maintenance of the internal homeostasis. Curcumin (CUR) and its analogs have gained widespread recognition due to their remarkable anti-inflammatory, anti-infective, anticancer, immunomodulatory, antioxidant, and wound healing activities. However, their pharmaceutical significance is limited due to inherent hydrophobic nature, poor water solubility, low bioavailability, chemical instability, rapid metabolism and short half-life. Owing to their pharmaceutical limitations, newer strategies have been attempted in recent years aiming to mitigate problems related to the effective delivery of curcumanoids and to improve their wound healing potential. These advanced strategies include nanovesicles, polymeric micelles, conventional liposomes and hyalurosomes, nanocomposite hydrogels, electrospun nanofibers, nanohybrid scaffolds, nanoconjugates, nanostructured lipid carriers (NLCs), nanoemulsion, nanodispersion, and polymeric nanoparticles (NPs). The superior wound healing activities achieved after nanoencapsulation of the CUR are attributed to its target-specific delivery, longer retention at the target site, avoiding premature degradation of the encapsulated cargo and the therapeutic superiority of the advanced delivery systems over the conventional delivery. We have critically reviewed the literature and summarize the convincing evidence which explore the pharmaceutical significance and therapeutic feasibility of the advanced delivery systems in improving wound healing activities of the CUR and its analogs.
    Matched MeSH terms: Hydrogels/chemistry
  14. Nanoreinforced Hydrogels for Tissue Engineering: Biomaterials that are Compatible with Load-Bearing and Electroactive Tissues
    Mehrali M, Thakur A, Pennisi CP, Talebian S, Arpanaei A, Nikkhah M, et al.
    Adv Mater, 2017 Feb;29(8).
    PMID: 27966826 DOI: 10.1002/adma.201603612
    Given their highly porous nature and excellent water retention, hydrogel-based biomaterials can mimic critical properties of the native cellular environment. However, their potential to emulate the electromechanical milieu of native tissues or conform well with the curved topology of human organs needs to be further explored to address a broad range of physiological demands of the body. In this regard, the incorporation of nanomaterials within hydrogels has shown great promise, as a simple one-step approach, to generate multifunctional scaffolds with previously unattainable biological, mechanical, and electrical properties. Here, recent advances in the fabrication and application of nanocomposite hydrogels in tissue engineering applications are described, with specific attention toward skeletal and electroactive tissues, such as cardiac, nerve, bone, cartilage, and skeletal muscle. Additionally, some potential uses of nanoreinforced hydrogels within the emerging disciplines of cyborganics, bionics, and soft biorobotics are highlighted.
    Matched MeSH terms: Hydrogels/chemistry*
  15. Novel Fish Oil-based Bigel System for Controlled Drug Delivery and its Influence on Immunomodulatory Activity of Imiquimod Against Skin Cancer
    Rehman K, Zulfakar MH
    Pharm Res, 2017 01;34(1):36-48.
    PMID: 27620176 DOI: 10.1007/s11095-016-2036-8
    PURPOSE: To characterize bigel system as a topical drug delivery vehicle and to establish the immunomodulatory role of imiquimod-fish oil combination against skin cancer and inflammation resulting from chemical carcinogenesis.

    METHODS: Imiquimod-loaded fish oil bigel colloidal system was prepared using a blend of carbopol hydrogel and fish oil oleogel. Bigels were first characterized for their mechanical properties and compared to conventional gel systems. Ex vivo permeation studies were performed on murine skin to analyze the ability of the bigels to transport drug across skin and to predict the release mechanism via mathematical modelling. Furthermore, to analyze pharmacological effectiveness in skin cancer and controlling imiquimod-induced inflammatory side effects, imiquimod-fish oil combination was tested in vitro on epidermoid carcinoma cells and in vivo in Swiss albino mice cancer model.

    RESULTS: Imiquimod-loaded fish oil bigels exhibited higher drug availability inside the skin as compared to individual imiquimod hydrogel and oleogel controls through quasi-Fickian diffusion mechanism. Imiquimod-fish oil combination in bigel enhanced the antitumor effects and significantly reduced serum pro-inflammatory cytokine levels such as tumor necrosis factor-alpha and interleukin-6, and reducing tumor progression via inhibition of vascular endothelial growth factor. Imiquimod-fish oil combination also resulted in increased expression of interleukin-10, an anti-inflammatory cytokine, which could also aid anti-tumor activity against skin cancer.

    CONCLUSION: Imiquimod administration through a bigel vehicle along with fish oil could be beneficial for controlling imiquimod-induced inflammatory side effects and in the treatment of skin cancer.

    Matched MeSH terms: Hydrogels/chemistry
  16. Lateral Flow Assay Based on Paper-Hydrogel Hybrid Material for Sensitive Point-of-Care Detection of Dengue Virus
    Choi JR, Yong KW, Tang R, Gong Y, Wen T, Yang H, et al.
    Adv Healthc Mater, 2017 Jan;6(1).
    PMID: 27860384 DOI: 10.1002/adhm.201600920
    Paper-based devices have been broadly used for the point-of-care detection of dengue viral nucleic acids due to their simplicity, cost-effectiveness, and readily observable colorimetric readout. However, their moderate sensitivity and functionality have limited their applications. Despite the above-mentioned advantages, paper substrates are lacking in their ability to control fluid flow, in contrast to the flow control enabled by polymer substrates (e.g., agarose) with readily tunable pore size and porosity. Herein, taking the benefits from both materials, the authors propose a strategy to create a hybrid substrate by incorporating agarose into the test strip to achieve flow control for optimal biomolecule interactions. As compared to the unmodified test strip, this strategy allows sensitive detection of targets with an approximately tenfold signal improvement. Additionally, the authors showcase the potential of functionality improvement by creating multiple test zones for semi-quantification of targets, suggesting that the number of visible test zones is directly proportional to the target concentration. The authors further demonstrate the potential of their proposed strategy for clinical assessment by applying it to their prototype sample-to-result test strip to sensitively and semi-quantitatively detect dengue viral RNA from the clinical blood samples. This proposed strategy holds significant promise for detecting various targets for diverse future applications.
    Matched MeSH terms: Hydrogels/chemistry*
  17. Fulltext Highly porous regenerated cellulose hydrogel and aerogel prepared from hydrothermal synthesized cellulose carbamate
    Gan S, Zakaria S, Chia CH, Chen RS, Ellis AV, Kaco H
    PLoS One, 2017;12(3):e0173743.
    PMID: 28296977 DOI: 10.1371/journal.pone.0173743
    Here, a stable derivative of cellulose, called cellulose carbamate (CC), was produced from Kenaf (Hibiscus cannabinus) core pulp (KCP) and urea with the aid of a hydrothermal method. Further investigation was carried out for the amount of nitrogen yielded in CC as different urea concentrations were applied to react with cellulose. The effect of nitrogen concentration of CC on its solubility in a urea-alkaline system was also studied. Regenerated cellulose products (hydrogels and aerogels) were fabricated through the rapid dissolution of CC in a urea-alkaline system. The morphology of the regenerated cellulose products was viewed under Field emission scanning electron microscope (FESEM). The transformation of allomorphs in regenerated cellulose products was examined by X-ray diffraction (XRD). The transparency of regenerated cellulose products was determined by Ultraviolet-visible (UV-Vis) spectrophotometer. The degree of swelling (DS) of regenerated cellulose products was also evaluated. This investigation provides a simple and efficient procedure of CC determination which is useful in producing regenerated CC products.
    Matched MeSH terms: Hydrogels/chemistry*
  18. Fulltext pH responsive N-succinyl chitosan/Poly (acrylamide-co-acrylic acid) hydrogels and in vitro release of 5-fluorouracil
    Bashir S, Teo YY, Naeem S, Ramesh S, Ramesh K
    PLoS One, 2017;12(7):e0179250.
    PMID: 28678803 DOI: 10.1371/journal.pone.0179250
    There has been significant progress in the last few decades in addressing the biomedical applications of polymer hydrogels. Particularly, stimuli responsive hydrogels have been inspected as elegant drug delivery systems capable to deliver at the appropriate site of action within the specific time. The present work describes the synthesis of pH responsive semi-interpenetrating network (semi-IPN) hydrogels of N-succinyl-chitosan (NSC) via Schiff base mechanism using glutaraldehyde as a crosslinking agent and Poly (acrylamide-co-acrylic acid)(Poly (AAm-co-AA)) was embedded within the N-succinyl chitosan network. The physico-chemical interactions were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and field emission scanning electron microscope (FESEM). The synthesized hydrogels constitute porous structure. The swelling ability was analyzed in physiological mediums of pH 7.4 and pH 1.2 at 37°C. Swelling properties of formulations with various amounts of NSC/ Poly (AAm-co-AA) and crosslinking agent at pH 7.4 and pH 1.2 were investigated. Hydrogels showed higher swelling ratios at pH 7.4 while lower at pH 1.2. Swelling kinetics and diffusion parameters were also determined. Drug loading, encapsulation efficiency, and in vitro release of 5-fluorouracil (5-FU) from the synthesized hydrogels were observed. In vitro release profile revealed the significant influence of pH, amount of NSC, Poly (AAm-co-AA), and crosslinking agent on the release of 5-FU. Accordingly, rapid and large release of drug was observed at pH 7.4 than at pH 1.2. The maximum encapsulation efficiency and release of 5-FU from SP2 were found to be 72.45% and 85.99%, respectively. Kinetics of drug release suggested controlled release mechanism of 5-FU is according to trend of non-Fickian. From the above results, it can be concluded that the synthesized hydrogels have capability to adapt their potential exploitation as targeted oral drug delivery carriers.
    Matched MeSH terms: Hydrogels/chemistry*
  19. Characterisation and in vitro antimicrobial activity of biosynthetic silver-loaded bacterial cellulose hydrogels
    Gupta A, Low WL, Radecka I, Britland ST, Mohd Amin MC, Martin C
    J Microencapsul, 2016 Dec;33(8):725-734.
    PMID: 27781557 DOI: 10.1080/02652048.2016.1253796
    Wounds that remain in the inflammatory phase for a prolonged period of time are likely to be colonised and infected by a range of commensal and pathogenic microorganisms. Treatment associated with these types of wounds mainly focuses on controlling infection and providing an optimum environment capable of facilitating re-epithelialisation, thus promoting wound healing. Hydrogels have attracted vast interest as moist wound-responsive dressing materials. In the current study, biosynthetic bacterial cellulose hydrogels synthesised by Gluconacetobacter xylinus and subsequently loaded with silver were characterised and investigated for their antimicrobial activity against two representative wound infecting pathogens, namely S. aureus and P. aeruginosa. Silver nitrate and silver zeolite provided the source of silver and loading parameters were optimised based on experimental findings. The results indicate that both AgNO3 and AgZ loaded biosynthetic hydrogels possess antimicrobial activity (p 
    Matched MeSH terms: Hydrogels/chemistry
  20. Functional properties of chitosan built nanohydrogel with enhanced glucose-sensitivity
    Ullah F, Othman MB, Javed F, Ahmad Z, Akil HM, Rasib SZ
    Int J Biol Macromol, 2016 Feb;83:376-84.
    PMID: 26597568 DOI: 10.1016/j.ijbiomac.2015.11.040
    A new approach to design multifunctional chitosan based nanohydrogel with enhanced glucose sensitivity, stability, drug loading and release profile are reported. Two approaches were followed for functionalization of chitosan based nanohydrogel with 3-APBA via EDC and 3-APTES. The effective functionalization, structure and morphology of Chitosan based IPN respectively were confirmed by FTIR, SEM and AFM. At physiological conditions, the glucose-induced volume phase transition and release profile of the model drug Alizarin Red with 1,2-diol structure (comparative to insulin as a drug as well as a dye for bio separation) were studied at various glucose concentrations, pH and ionic strengths. The results suggested a new concept for diabetes treatment and diols sensitivity in view of their potential hi-tech applications in self-regulated on-off response to the treatment (drug delivery and bio separation concurrently).
    Matched MeSH terms: Hydrogels/chemistry*
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