Displaying publications 181 - 200 of 841 in total

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  1. Tackling membrane fouling in microalgae filtration using nylon 6,6 nanofiber membrane
    Bilad MR, Azizo AS, Wirzal MDH, Jia Jia L, Putra ZA, Nordin NAHM, et al.
    J Environ Manage, 2018 Oct 01;223:23-28.
    PMID: 29885561 DOI: 10.1016/j.jenvman.2018.06.007
    Microalgae technology, if managed properly, has promising roles in solving food-water-energy nexus. The Achilles' heel is, however, to lower the costs associated with cultivation and harvesting. As a favorable technique, application of membrane process is strongly limited by membrane fouling. This study evaluates performance of nylon 6,6 nanofiber membrane (NFM) to a conventional polyvinylidene fluoride phase inverted membrane (PVDF PIM) for filtration of Chlorella vulgaris. Results show that nylon 6,6 NFM is superhydrophilic, has higher size of pore opening (0.22 vs 0.18 μm) and higher surface pore density (23 vs 18 pores/μm2) leading to higher permeance (1018 vs 493 L/m2hbar) and better fouling resistant. Such advantages help to outperform the filterability of PVDF PIM by showing much higher steady-state permeance (286 vs 120 L/m2hbar), with comparable biomass retention. In addition, unlike for PVDF PIM, imposing longer relaxation cycles further enhances the performance of the NFM (i.e., 178 L/m2hbar for 0.5 min and 236 L/m2hbar for 5 min). Overall findings confirm the advantages of nylon 6,6 NFM over the PVDF PIM. Such advantages can help to reduce required membrane area and specific aeration demand by enabling higher flux and lowering aeration rate. Nevertheless, developments of nylon 6,6 NFM material with respect to its intrinsic properties, mechanical strength and operational conditions of the panel can still be explored to enhance its competitiveness as a promising fouling resistant membrane material for microalgae filtration.
    Matched MeSH terms: Polymers*
  2. Frequency-controlled wireless shape memory polymer microactuator for drug delivery application
    Zainal MA, Ahmad A, Mohamed Ali MS
    Biomed Microdevices, 2017 Mar;19(1):8.
    PMID: 28124762 DOI: 10.1007/s10544-017-0148-5
    This paper reports the wireless Shape-Memory-Polymer actuator operated by external radio frequency magnetic fields and its application in a drug delivery device. The actuator is driven by a frequency-sensitive wireless resonant heater which is bonded directly to the Shape-Memory-Polymer and is activated only when the field frequency is tuned to the resonant frequency of heater. The heater is fabricated using a double-sided Cu-clad Polyimide with much simpler fabrication steps compared to previously reported methods. The actuation range of 140 μm as the tip opening distance is achieved at device temperature 44 °C in 30 s using 0.05 W RF power. A repeatability test shows that the actuator's average maximum displacement is 110 μm and standard deviation of 12 μm. An experiment is conducted to demonstrate drug release with 5 μL of an acidic solution loaded in the reservoir and the device is immersed in DI water. The actuator is successfully operated in water through wireless activation. The acidic solution is released and diffused in water with an average release rate of 0.172 μL/min.
    Matched MeSH terms: Polymers*
  3. Fulltext Synthesis, Characterization, and Application of Poly(4,4'-Cyclohexylidene Bisphenol Oxalate) for Solid-Phase Extraction of DNA
    Al Balawi AN, Yusof NA, Kamaruzaman S, Mohammad F, Wasoh H, Al Abbosh KF, et al.
    Biomed Res Int, 2019;2019:7064073.
    PMID: 30868072 DOI: 10.1155/2019/7064073
    The present study has synthesized poly(4,4'-cyclohexylidene bisphenol oxalate) by the condensation of oxalyl chloride with 4,4'-cyclohexylidene bisphenol, where its efficacy was tested for the solid-phase extraction of DNA. The synthesized polymer in the form of a white powder was characterized by FTIR, TGA-DTG, SEM, and BET analysis. The study utilized solid-phase application of the resulting polymer to extract DNA. The analysis of results provided the information that the extraction efficiency is a strong dependent of polymer amount and binding buffer type. Among the three types of buffers tested, the GuHCl buffer produced the most satisfactory results in terms of yield and efficiency of extraction. Moreover, the absorbance ratio of A260/A280 in all of the samples varied from 1.682 to 1.491, thereby confirming the capability of poly(4,4'-cyclohexylidene bisphenol oxalate) to elute pure DNA. The results demonstrated an increased DNA binding capacity with respect to increased percentage of the polymer. The study has concluded that poly(bisphenol Z oxalate) can be applied as one of the potential candidates for the high efficiency extraction of DNA by means of a simple, cost-effective, and environmentally friendly approach compared to the other traditional solid-phase methods.
    Matched MeSH terms: Polymers/chemistry
  4. Harnessing the dual role of polysaccharides in treating gastrointestinal diseases: As therapeutics and polymers for drug delivery
    Corrie L, Gulati M, Awasthi A, Vishwas S, Kaur J, Khursheed R, et al.
    Chem Biol Interact, 2022 Dec 01;368:110238.
    PMID: 36306865 DOI: 10.1016/j.cbi.2022.110238
    Polysaccharides (PS) represent a broad class of polymer-based compounds that have been extensively researched as therapeutics and excipients for drug delivery. As pharmaceutical carriers, PS have mostly found their use as adsorbents, suspending agents, as well as cross-linking agents for various formulations such as liposomes, nanoparticles, nanoemulsions, nano lipid carriers, microspheres etc. This is due to inherent properties of PS such as porosity, steric stability and swellability, insolubility in pH. There have been emerging reports on the use of PS as therapeutic agent due to its anti-inflammatory and anti-oxidative properties for various diseases. In particular, for Crohn's disease, ulcerative colitis and inflammatory bowel disease. However, determining the dosage, treatment duration and effective technology transfer of these therapeutic moieties have not occurred. This is due to the fact that PS are still at a nascent stage of development to a full proof therapy for a particular disease. Recently, a combination of polysaccharide which act as a prebiotic and a probiotic have been used as a combination to treat various intestinal and colorectal (CRC) related diseases. This has proven to be beneficial, has shown good in vivo correlation and is well reported. The present review entails a detailed description on the role of PS used as a therapeutic agent and as a formulation pertaining to gastrointestinal diseases.
    Matched MeSH terms: Polymers*
  5. Fulltext Characterization of electrosynthesized conjugated polymer-carbon nanotube composite: optical nonlinearity and electrical property
    Bahrami A, Talib ZA, Shahriari E, Yunus WMM, Kasim A, Behzad K
    Int J Mol Sci, 2012;13(1):918-928.
    PMID: 22312294 DOI: 10.3390/ijms13010918
    The effects of multi-walled carbon nanotube (MWNT) concentration on the structural, optical and electrical properties of conjugated polymer-carbon nanotube composite are discussed. Multi-walled carbon nanotube-polypyrrole nanocomposites were synthesized by electrochemical polymerization of monomers in the presence of different amounts of MWNTs using sodium dodecylbenzensulfonate (SDBS) as surfactant at room temperature and normal pressure. Field emission scanning electron microscopy (FESEM) indicates that the polymer is wrapped around the nanotubes. Measurement of the nonlinear refractive indices (n(2)) and the nonlinear absorption (β) of the samples with different MWNT concentrations measurements were performed by a single Z-scan method using continuous wave (CW) laser beam excitation wavelength of λ = 532 nm. The results show that both nonlinear optical parameters increased with increasing the concentration of MWNTs. The third order nonlinear susceptibilities were also calculated and found to follow the same trend as n(2) and β. In addition, the conductivity of the composite film was found to increase rapidly with the increase in the MWNT concentration.
    Matched MeSH terms: Polymers/chemistry*
  6. Fulltext Investigating the in-vitro bioactivity, biodegradability and drug release behavior of the newly developed PES/HA/WS biocompatible nanocomposites as bone graft substitute
    Salimi E, Asim MH, Abidin MNZ
    Sci Rep, 2024 May 11;14(1):10798.
    PMID: 38734777 DOI: 10.1038/s41598-024-61586-2
    The nucleation of carbonate-containing apatite on the biomaterials surface is regarded as a significant stage in bone healing process. In this regard, composites contained hydroxyapatite (Ca10(PO4)6(OH)2, HA), wollastonite (CaSiO3, WS) and polyethersulfone (PES) were synthesized via a simple solvent casting technique. The in-vitro bioactivity of the prepared composite films with different weight ratios of HA and WS was studied by placing the samples in the simulated body fluid (SBF) for 21 days. The results indicated that the the surface of composites containing 2 wt% HA and 4 wt% WS was completely covered by a thick bone-like apatite layer, which was characterized by Grazing incidence X-ray diffraction, attenuated total reflectance-Fourier transform infrared spectrometer, field emission electron microscopy and energy dispersive X-ray analyzer (EDX). The degradation study of the samples showed that the concentration of inorganic particles could not influence the degradability of the polymeric matrix, where all samples expressed similar dexamethasone (DEX) release behavior. Moreover, the in-vitro cytotoxicity results indicated the significant cyto-compatibility of all specimens. Therefore, these findings revealed that the prepared composite films composed of PES, HA, WS and DEX could be regarded as promising bioactive candidates with low degradation rate for bone tissue engineering applications.
    Matched MeSH terms: Polymers/chemistry
  7. Fulltext Optimization of NaOH Molarity, LUSI Mud/Alkaline Activator, and Na2SiO3/NaOH Ratio to Produce Lightweight Aggregate-Based Geopolymer
    Razak RA, Abdullah MM, Hussin K, Ismail KN, Hardjito D, Yahya Z
    Int J Mol Sci, 2015 May 21;16(5):11629-47.
    PMID: 26006238 DOI: 10.3390/ijms160511629
    This paper presents the mechanical function and characterization of an artificial lightweight geopolymer aggregate (ALGA) using LUSI (Sidoarjo mud) and alkaline activator as source materials. LUSI stands for LU-Lumpur and SI-Sidoarjo, meaning mud from Sidoarjo which erupted near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia on 27 May 2006. The effect of NaOH molarity, LUSI mud/Alkaline activator (LM/AA) ratio, and Na2SiO3/NaOH ratio to the ALGA are investigated at a sintering temperature of 950 °C. The results show that the optimum NaOH molarity found in this study is 12 M due to the highest strength (lowest AIV value) of 15.79% with lower water absorption and specific gravity. The optimum LUSI mud/Alkaline activator (LM/AA) ratio of 1.7 and the Na2SiO3/NaOH ratio of 0.4 gives the highest strength with AIV value of 15.42% with specific gravity of 1.10 g/cm3 and water absorption of 4.7%. The major synthesized crystalline phases were identified as sodalite, quartz and albite. Scanning Electron Microscope (SEM) image showed more complete geopolymer matrix which contributes to highest strength of ALGA produced.
    Matched MeSH terms: Polymers/chemistry*
  8. Fulltext A Promising Polymer Blend Electrolytes Based on Chitosan: Methyl Cellulose for EDLC Application with High Specific Capacitance and Energy Density
    Aziz SB, Hamsan MH, Abdullah RM, Kadir MFZ
    Molecules, 2019 Jul 09;24(13).
    PMID: 31323966 DOI: 10.3390/molecules24132503
    In the present work, promising proton conducting solid polymer blend electrolytes (SPBEs) composed of chitosan (CS) and methylcellulose (MC) were prepared for electrochemical double-layer capacitor (EDLC) application with a high specific capacitance and energy density. The change in intensity and the broad nature of the XRD pattern of doped samples compared to pure CS:MC system evidencedthe amorphous character of the electrolyte samples. The morphology of the samples in FESEM images supported the amorphous behavior of the solid electrolyte films. The results of impedance and Bode plotindicate that the bulk resistance decreasedwith increasing salt concentration. The highest DC conductivity was found to be 2.81 × 10-3 S/cm. The electrical equivalent circuit (EEC) model was conducted for selected samples to explain the complete picture of the electrical properties.The performance of EDLC cells was examined at room temperature by electrochemical techniques, such as impedance spectroscopy, cyclic voltammetry (CV) and constant current charge-discharge techniques. It was found that the studied samples exhibit a very good performance as electrolyte for EDLC applications. Ions were found to be the dominant charge carriers in the polymer electrolyte. The ion transference number (tion) was found to be 0.84 while 0.16 for electron transference number (tel). Through investigation of linear sweep voltammetry (LSV), the CS:MC:NH4SCN system was found to be electrochemically stable up to 1.8 V. The CV plot revealed no redox peak, indicating the occurrence of charge double-layer at the surface of activated carbon electrodes. Specific capacitance (Cspe) for the fabricated EDLC was calculated using CV plot and charge-discharge analyses. It was found to be 66.3 F g-1 and 69.9 F g-1 (at thefirst cycle), respectively. Equivalent series resistance (Resr) of the EDLC was also identified, ranging from 50.0 to 150.0 Ω. Finally, energy density (Ed) was stabilized to anaverage of 8.63 Wh kg-1 from the 10th cycle to the 100th cycle. The first cycle obtained power density (Pd) of 1666.6 W kg-1 and then itdropped to 747.0 W kg-1 at the 50th cycle and continued to drop to 555.5 W kg-1 as the EDLC completed 100 cycles.
    Matched MeSH terms: Polymers/chemistry*
  9. Fulltext Engineering of Naproxen Loaded Polymer Hybrid Enteric Microspheres for Modified Release Tablets: Development, Characterization, in silico Modelling and in vivo Evaluation
    Hameed HA, Khan S, Shahid M, Ullah R, Bari A, Ali SS, et al.
    Drug Des Devel Ther, 2020;14:27-41.
    PMID: 32021089 DOI: 10.2147/DDDT.S232111
    BACKGROUND: Naproxen (NP) is a non-steroidal anti-inflammatory drug with poor aqueous solubility and low oral bioavailability, which may lead to therapeutic failure. NP causes crucial GIT irritation, bleeding, and peptic and duodenal ulcers.

    PURPOSE OF THE STUDY: This study aimed to engineer and characterize polymer hybrid enteric microspheres using an integrated (experimental and molecular modelling) approach with further development to solid dosage form with modified drug release kinetics and improved bioavailability.

    MATERIALS AND METHODS: NP loaded polymer hybrid enteric microspheres (PHE-Ms) were fabricated by using a modified solvent evaporation technique coupled with molecular modelling (MM) approach. The PHE-Ms were characterized by particle size, distribution, morphology, crystallinity, EE, drug-polymer compatibility, and DSC. The optimized NP loaded PHE-Ms were further subjected to downstream procedures including tablet dosage form development, stability studies and comparative in vitro-in vivo evaluation.

    RESULTS: The hydrophobic polymer EUD-L100 and hydrophilic polymer HPMC-E5 delayed and modified drug release at intestinal pH while imparting retardation of NP release at gastric pH to diminish the gastric side effects. The crystallinity of the NP loaded PHE-Ms was established through DSC and P (XRD). The particle size for the developed formulations of PEH-Ms (M1-M5) was in the range from 29.06 ±7.3-74.31 ± 17.7 μm with Span index values of 0.491-0.69, respectively. The produced NP hybrid microspheres demonstrated retarded drug release at pH 1.2 and improved dissolution at pH 6.8. The in vitro drug release patterns were fitted to various release kinetic models and the best-followed model was the Higuchi model with a release exponent "n" value > 0.5. Stability studies at different storage conditions confirmed stability of the NP loaded PHE-Ms based tablets (P<0.05). The molecular modelling (MM) study resulted in adequate binding energy of co-polymer complex SLS-Eudragit-HPMC-Naproxen (-3.9 kcal/mol). In contrast to the NP (unprocessed) and marketed formulations, a significant increase in the Cmax of PHE-MT1 (44.41±4.43) was observed.

    CONCLUSION: The current study concludes that developing NP loaded PHE-Ms based tablets could effectively reduce GIT consequences with restored therapeutic effects. The modified release pattern could improve the dissolution rate and enhancement of oral bioavailability. The MM study strengthens the polymer-drug relationship in microspheres.

    Matched MeSH terms: Polymers/chemistry*
  10. Fulltext Development of Biopolymer and Conducting Polymer-Based Optical Sensors for Heavy Metal Ion Detection
    Ramdzan NSM, Fen YW, Anas NAA, Omar NAS, Saleviter S
    Molecules, 2020 May 30;25(11).
    PMID: 32486124 DOI: 10.3390/molecules25112548
    Great efforts have been devoted to the invention of environmental sensors as the amount of water pollution has increased in recent decades. Chitosan, cellulose and nanocrystalline cellulose are examples of biopolymers that have been intensively studied due to their potential applications, particularly as sensors. Furthermore, the rapid use of conducting polymer materials as a sensing layer in environmental monitoring has also been developed. Thus, the incorporation of biopolymer and conducting polymer materials with various methods has shown promising potential with sensitively and selectively toward heavy metal ions. In this feature paper, selected recent and updated investigations are reviewed on biopolymer and conducting polymer-based materials in sensors aimed at the detection of heavy metal ions by optical methods. This review intends to provide sufficient evidence of the potential of polymer-based materials as sensing layers, and future outlooks are considered in developing surface plasmon resonance as an excellent and valid sensor for heavy metal ion detection.
    Matched MeSH terms: Biopolymers/chemistry*; Polymers/chemistry
  11. Fulltext Application of supercritical antisolvent method in drug encapsulation: a review
    Kalani M, Yunus R
    Int J Nanomedicine, 2011;6:1429-42.
    PMID: 21796245 DOI: 10.2147/IJN.S19021
    The review focuses on the application of supercritical fluids as antisolvents in the pharmaceutical field and demonstrates the supercritical antisolvent method in the use of drug encapsulation. The main factors for choosing the solvent and biodegradable polymer to produce fine particles to ensure effective drug delivery are emphasized and the effect of polymer structure on drug encapsulation is illustrated. The review also demonstrates the drug release mechanism and polymeric controlled release system, and discusses the effects of the various conditions in the process, such as pressure, temperature, concentration, chemical compositions (organic solvents, drug, and biodegradable polymer), nozzle geometry, CO(2) flow rate, and the liquid phase flow rate on particle size and its distribution.
    Matched MeSH terms: Polymers/chemistry
  12. Fulltext Hydroxyethyl cellulose functionalised with maleimide groups as a new excipient with enhanced mucoadhesive properties
    Buang F, Fu M, Chatzifragkou A, Amin MCIM, Khutoryanskiy VV
    Int J Pharm, 2023 Jul 25;642:123113.
    PMID: 37301242 DOI: 10.1016/j.ijpharm.2023.123113
    Hydroxyethylcellulose (HEC) is a non-ionic water-soluble polymer with poor mucoadhesive properties. The mucoadhesive properties of hydroxyethylcellulose can be improved by modifying it through conjugation with molecules containing maleimide groups. Maleimide groups interact with the thiol groups present in cysteine domains in the mucin via Michael addition reaction under physiological conditions to form a strong mucoadhesive bond. This will prolong the residence time of a dosage form containing this modified polymer and drug on mucosal surfaces. In this study HEC was modified by reaction with 4-bromophenyl maleimide in varying molar ratios and the successful synthesis was confirmed using 1H NMR and FTIR spectroscopies. The safety of the newly synthesised polymer derivatives was assessed with in vivo planaria assays and in vitro MTT assay utilising Caco-2 cell line. The synthesized maleimide-functionalised HEC solutions were sprayed onto blank tablets to develop a model dosage form. The physical properties and mucoadhesive behavior of these tablets were evaluated using a tensile test with sheep buccal mucosa. The maleimide-functionalised HEC exhibited superior mucoadhesive properties compared to unmodified HEC.
    Matched MeSH terms: Polymers/chemistry
  13. Fulltext Bioactive polymer composite scaffolds fabricated from 3D printed negative molds enable bone formation and vascularization
    Du S, Huynh T, Lu YZ, Parker BJ, Tham SK, Thissen H, et al.
    Acta Biomater, 2024 Sep 15;186:260-274.
    PMID: 39089351 DOI: 10.1016/j.actbio.2024.07.038
    Scaffolds for bone defect treatment should ideally support vascularization and promote bone formation, to facilitate the translation into biomedical device applications. This study presents a novel approach utilizing 3D-printed water-dissolvable polyvinyl alcohol (PVA) sacrificial molds to engineer polymerized High Internal Phase Emulsion (polyHIPE) scaffolds with microchannels and distinct multiscale porosity. Two sacrificial mold variants (250 µm and 500 µm) were generated using fused deposition modeling, filled with HIPE, and subsequently dissolved to create polyHIPE scaffolds containing microchannels. In vitro assessments demonstrated significant enhancement in cell infiltration, proliferation, and osteogenic differentiation, underscoring the favorable impact of microchannels on cell behavior. High loading efficiency and controlled release of the osteogenic factor BMP-2 were achieved, with microchannels facilitating release of the growth factor. Evaluation in a mouse critical-size calvarial defect model revealed enhanced vascularization and bone formation in microchanneled scaffolds containing BMP-2. This study not only introduces an accessible method for creating multiscale porosity in polyHIPE scaffolds but also emphasizes its capability to enhance cellular infiltration, controlled growth factor release, and in vivo performance. The findings suggest promising applications in bone tissue engineering and regenerative medicine, and are expected to facilitate the translation of this type of biomaterial scaffold. STATEMENT OF SIGNIFICANCE: This study holds significance in the realm of biomaterial scaffold design for bone tissue engineering and regeneration. We demonstrate a novel method to introduce controlled multiscale porosity and microchannels into polyHIPE scaffolds, by utilizing 3D-printed water-dissolvable PVA molds. The strategy offers new possibilities for improving cellular infiltration, achieving controlled release of growth factors, and enhancing vascularization and bone formation outcomes. This microchannel approach not only marks a substantial stride in scaffold design but also demonstrates its tangible impact on enhancing osteogenic cell differentiation and fostering robust bone formation in vivo. The findings emphasize the potential of this methodology for bone regeneration applications, showcasing an interesting advancement in the quest for effective and innovative biomaterial scaffolds to regenerate bone defects.
    Matched MeSH terms: Polymers/chemistry
  14. Fulltext A review of the modern principles and applications of solid-phase extraction techniques in chromatographic analysis
    Badawy MEI, El-Nouby MAM, Kimani PK, Lim LW, Rabea EI
    Anal Sci, 2022 Dec;38(12):1457-1487.
    PMID: 36198988 DOI: 10.1007/s44211-022-00190-8
    Analytical processes involving sample preparation, separation, and quantifying analytes in complex mixtures are indispensable in modern-day analysis. Each step is crucial to enriching correct and informative results. Therefore, sample preparation is the critical factor that determines both the accuracy and the time consumption of a sample analysis process. Recently, several promising sample preparation approaches have been made available with environmentally friendly technologies with high performance. As a result of its many advantages, solid-phase extraction (SPE) is practiced in many different fields in addition to the traditional methods. The SPE is an alternative method to liquid-liquid extraction (LLE), which eliminates several disadvantages, including many organic solvents, a lengthy operation time and numerous steps, potential sources of error, and high costs. SPE advanced sorbent technology reorients with various functions depending on the structure of extraction sorbents, including reversed-phase, normal-phase, cation exchange, anion exchange, and mixed-mode. In addition, the commercial SPE systems are disposable. Still, with the continual developments, the restricted access materials (RAM) and molecular imprinted polymers (MIP) are fabricated to be active reusable extraction cartridges. This review will discuss all the theoretical and practical principles of the SPE techniques, focusing on packing materials, different forms, and performing factors in recent and future advances. The information about novel methodological and instrumental solutions in relation to different variants of SPE techniques, solid-phase microextraction (SPME), in-tube solid-phase microextraction (IT-SPME), and magnetic solid-phase extraction (MSPE) is presented. The integration of SPE with analytical chromatographic techniques such as LC and GC is also indicated. Furthermore, the applications of these techniques are discussed in detail along with their advantages in analyzing pharmaceuticals, biological samples, natural compounds, pesticides, and environmental pollutants, as well as foods and beverages.
    Matched MeSH terms: Polymers/chemistry
  15. Polymers from renewable materials
    Rus AZ
    Sci Prog, 2010;93(Pt 3):285-300.
    PMID: 21047019
    With the world facing depletion of its oil reserves, attention is being focused on how the plastics industry will address shortages and price increases in its crucial raw materials. One renewable resource is that of vegetable oils and fats and about a dozen crop plants make up the main vegetable oil-seed market. The main constituents of these oils are saturated and unsaturated fatty acids that are unique to the plant in which they have been developed. Moreover, technological processes can produce more well-defined and pure oils, and the fatty acid contents in the vegetable oils can be altered with modern crop development techniques. This article describes recent advances in utilising such vegetable oils in sourcing new polymeric materials. It also gives the context for the development of polymers based on renewable materials in general.
    Matched MeSH terms: Polymers*
  16. Development of 3-dimensionally printed denture base material utilizing hybrid polymer: A preliminary investigation
    Zahari NAH, Farid DAM, Alauddin MS, Said Z, Ghazali MIM, Lee HE, et al.
    J Prosthet Dent, 2024 Dec;132(6):1329.e1-1329.e6.
    PMID: 39147631 DOI: 10.1016/j.prosdent.2024.07.017
    STATEMENT OF PROBLEM: Current 3-dimensionally (3D) printed denture bases have inadequate strength and durability for long-term use, and milled denture bases generate excessive waste. Addressing these limitations is crucial to advancing prosthetic dentistry, ensuring improved patient outcomes and promoting environmental responsibility.

    PURPOSE: The purpose of this in vitro study was to incorporate microparticles into a commercially available 3D printed denture base resin and compare its mechanical and biological properties with the conventional polymethyl methacrylate (PMMA) denture base material.

    MATERIAL AND METHODS: Microparticles were collected from milled zirconia blanks and were blended with a 3D printing denture base resin (NextDent Denture 3D+). The optimal zirconia microparticle content (2%) for blending and printed was determined by using a liquid-crystal display (LCD) 3D printer. The printed specimens were then postrinsed and postpolymerized based on the manufacturer's instructions. Mechanical and biological characterization were carried out in terms of flexural strength, fracture toughness, and fungal adhesion. One-way ANOVA was carried out to analyze the results statistically.

    RESULTS: The incorporation of microparticles in the 3D printed denture demonstrated higher mechanical strength (104.77 ±7.60 MPa) compared with conventional heat-polymerized denture base resin (75.15 ±24.41 MPa) (P

    Matched MeSH terms: Polymers/chemistry
  17. Water as Dual-Function Plasticizer and Cosolvent in Gel Electrolytes for Dye-Sensitized Solar Cells
    Goh ZL, Farhana NK, Kamarulazam F, Pershaanaa M, Bashir S, Ramesh K, et al.
    Macromol Rapid Commun, 2025 Jan;46(2):e2400481.
    PMID: 39405501 DOI: 10.1002/marc.202400481
    This study presents a novel approach to developing eco-friendly dye-sensitized solar cells (DSSCs) using natural and renewable materials for gel polymer electrolytes (GPEs), reducing reliance on unsustainable solvents. Water is added to polar aprotic solvents, specifically ethylene carbonate/propylene carbonate (EC/PC), across various mass fractions (0:100 to 100:0). An amphiphilic hydroxypropyl cellulose (HPC) natural polymer is employed to formulate GPEs within this water-EC/PC cosolvent system, achieving successful gelation up to 50:50 mass fractions. Incorporating water reduced the gel strength and viscosity of the GPEs. Water acted as a plasticizer, enhancing the polymer chains mobility, and creating a more flexible and permeable structure. This increased ion diffusion coefficients and ion mobility, resulting in a maximum ionic conductivity of 18.17 mS cm-1. The highest efficiency achieved in DSSCs using these GPEs is 5.81%, with elevated short-circuit current density and reduced recombination losses. However, some compositions experienced syneresis, affecting their stability. The GPE with a 40:60 mass fraction exhibited superior long-term stability because it is free from syneresis, though it achieved a lower efficiency (4.83%), making it the best-performing sample. This work demonstrates the feasibility and benefits of using gel polymer electrolytes in an aqueous system, improving DSSC efficiency and sustainability.
    Matched MeSH terms: Polymers/chemistry
  18. Aptamer-Mediated Polymeric Vehicles for Enhanced Cell-Targeted Drug Delivery
    Tan KX, Danquah MK, Sidhu A, Yon LS, Ongkudon CM
    Curr Drug Targets, 2018 02 08;19(3):248-258.
    PMID: 27321771 DOI: 10.2174/1389450117666160617120926
    BACKGROUND: The search for smart delivery systems for enhanced pre-clinical and clinical pharmaceutical delivery and cell targeting continues to be a major biomedical research endeavor owing to differences in the physicochemical characteristics and physiological effects of drug molecules, and this affects the delivery mechanisms to elicit maximum therapeutic effects. Targeted drug delivery is a smart evolution essential to address major challenges associated with conventional drug delivery systems. These challenges mostly result in poor pharmacokinetics due to the inability of the active pharmaceutical ingredients to specifically act on malignant cells thus, causing poor therapeutic index and toxicity to surrounding normal cells. Aptamers are oligonucleotides with engineered affinities to bind specifically to their cognate targets. Aptamers have gained significant interests as effective targeting elements for enhanced therapeutic delivery as they can be generated to specifically bind to wide range of targets including proteins, peptides, ions, cells and tissues. Notwithstanding, effective delivery of aptamers as therapeutic vehicles is challenged by cell membrane electrostatic repulsion, endonuclease degradation, low pH cleavage, and binding conformation stability.

    OBJECTIVE: The application of molecularly engineered biodegradable and biocompatible polymeric particles with tunable features such as surface area and chemistry, particulate size distribution and toxicity creates opportunities to develop smart aptamer-mediated delivery systems for controlled drug release.

    RESULTS: This article discusses opportunities for particulate aptamer-drug formulations to advance current drug delivery modalities by navigating active ingredients through cellular and biomolecular traffic to target sites for sustained and controlled release at effective therapeutic dosages while minimizing systemic cytotoxic effects.

    CONCLUSION: A proposal for a novel drug-polymer-aptamer-polymer (DPAP) design of aptamer-drug formulation with stage-wise delivery mechanism is presented to illustrate the potential efficacy of aptamer- polymer cargos for enhanced cell targeting and drug delivery.

    Matched MeSH terms: Polymers/administration & dosage; Polymers/chemical synthesis*; Polymers/chemistry
  19. Fulltext PFO-DBT:MEH-PPV:PC₇₁BM ternary blend assisted platform as a photodetector
    Zafar Q, Ahmad Z, Sulaiman K
    Sensors (Basel), 2015;15(1):965-78.
    PMID: 25574936 DOI: 10.3390/s150100965
    We present a ternary blend-based bulk heterojunction ITO/PEDOT:PSS/PFO-DBT: MEH-PPV:PC71BM/LiF/Al photodetector. Enhanced optical absorption range of the active film has been achieved by blending two donor components viz. poly[2,7-(9,9-di-octyl-fluorene)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole] (PFO-DBT) and poly(2-methoxy-5(2'-ethylhexyloxy) phenylenevinylene (MEH-PPV) along with an acceptor component, i.e., (6,6)-phenyl-C71 hexnoic acid methyl ester. The dependency of the generation rate of free charge carriers in the organic photodetector (OPD) on varied incident optical power density was investigated as a function of different reverse biasing voltages. The photocurrent showed significant enhancement as the intensity of light impinging on active area of OPD is increased. The ratio of Ilight to Idark of fabricated device at -3 V was ~3.5 × 10(4). The dynamic behaviour of the OPD under on/off switching irradiation revealed that sensor exhibits quick response and recovery time of ∼800 ms and 500 ms, respectively. Besides reliability and repeatability in the photoresponse characteristics, the cost-effective and eco-friendly fabrication is the added benefit of the fabricated OPD.
    Matched MeSH terms: Polymers
  20. Molecularly imprinted polymers as optical sensing receptors: correlation between analytical signals and binding isotherms
    Ng SM, Narayanaswamy R
    Anal Chim Acta, 2011 Oct 10;703(2):226-33.
    PMID: 21889638 DOI: 10.1016/j.aca.2011.07.032
    Despite the increasing number of usage of molecularly imprinted polymers (MIPs) in optical sensor application, the correlation between the analytical signals and the binding isotherms has yet to be fully understood. This work investigates the relationship between the signals generated from MIPs sensors to its respective binding affinity variables generated using binding isotherm models. Two different systems based on the imprinting of metal ion and organic compound have been selected for the study, which employed reflectance and fluorescence sensing schemes, respectively. Batch binding analysis using the standard binding isotherm models was employed to evaluate the affinity of the binding sites. Evaluation using the discrete bi-Langmuir isotherm model found both the MIPs studied have generally two classes of binding sites that was of low and high affinities, while the continuous Freundlich isotherm model has successfully generated a distribution of affinities within the investigated analytical window. When the MIPs were incorporated as sensing receptors, the changes in the analytical signal due to different analyte concentrations were found to have direct correlation with the binding isotherm variables. Further data analyses based on this observation have generated robust models representing the analytical performance of the optical sensors. The best constructed model describing the sensing trend for each of the sensor has been tested and demonstrated to give accurate prediction of concentration for a series of spiked analytes.
    Matched MeSH terms: Polymers
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