Displaying publications 1 - 20 of 256 in total

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  1. Altering substrate properties of thin film nanocomposite membrane by Al2O3 nanoparticles for engineered osmosis process
    Liew ZS, Ho YC, Lau WJ, Nordin NAHM, Lai SO, Ma J
    Environ Technol, 2024 Feb;45(6):1052-1065.
    PMID: 36250395 DOI: 10.1080/09593330.2022.2137435
    The scarcity of energy and water resources is a major challenge for humanity in the twenty-first century. Engineered osmosis (EO) technologies are extensively researched as a means of producing sustainable water and energy. This study focuses on the modification of substrate properties of thin film nanocomposite (TFN) membrane using aluminium oxide (Al2O3) nanoparticles and further evaluates the performance of resultant membranes for EO process. Different Al2O3 loading ranging from zero to 0.10 wt% was incorporated into the substrate and the results showed that the hydrophilicity of substrate was increased with contact angle reduced from 74.81° to 66.17° upon the Al2O3 incorporation. Furthermore, the addition of Al2O3 resulted in the formation of larger porous structure on the bottom part of substrate which reduced water transport resistance. Using the substrate modified by 0.02 wt% Al2O3, we could produce the TFN membrane that exhibited the highest water permeability (1.32 L/m2.h.bar, DI water as a feed solution at 15 bar), decent salt rejection (96.89%), low structural parameter (532.44 μm) and relatively good pressure withstandability (>25 bar).
    Matched MeSH terms: Permeability
  2. Fulltext Shelf-life, bioburden, water and oxygen permeability studies of laser welded SEBS/PP blended polymer
    Sundera Murthe S, Sreekantan S, Mydin RBSMN, Vasudevan M, Appaturi JN
    Sci Rep, 2023 Sep 01;13(1):14379.
    PMID: 37658068 DOI: 10.1038/s41598-023-41477-8
    The most common material used for blood bags is PVC, which requires the addition of DEHP to increase its flexibility. DEHP is known to cross the polymer barrier and move into the stored blood and, ultimately, the patient's bloodstream. In this work, an alternative prototype composed of SEBS/PP was fabricated through blow-moulding and compared with the commercially available PVC-based blood bag which was designated as the control. The blow-moulded sample layers were welded together using CO2 lasers and optimized to obtain complete sealing of the sides. The samples' performance characteristics were analyzed using water permeability, oxygen permeability, shelf-life, and bioburden tests. The SEBS/PP sample exhibited the highest oxygen permeability rate of 1486.6 cc/m2/24 h after 40 days of ageing, indicating that the sample is conducive for red blood cell (RBC) respiration. On the other hand, the SEBS/PP sample showcased a lower water permeability rate of 0.098 g/h m2 after 40 days of aging, indicating a high-water barrier property and thus preventing water loss during storage. In comparison, the oxygen and water permeability rates of PVC-DEHP were found to be distinctly lower in performance (662.7 cc/m2/24 h and 0.221 g/h m2, respectively). In addition, shelf-life analyses revealed that after 40 days of ageing, polymer samples exhibited no visual damage or degradation. The optimal parameters to obtain adequate welding of the SEBS/PP were determined to be power of 60% (18 W), speed of 70 in/sec and 500 Pulse Per Inch (PPI). Furthermore, the bioburden estimates of SEBS/PP of 115 CFU are markedly lower compared to the bioburden estimate of PVC-DEHP of 213 CFU. The SEBS/PP prototype can potentially be an effective alternative to PVC-based blood bags, particularly for high-risk patients in order to reduce the likelihood of medical issues.
    Matched MeSH terms: Permeability
  3. Strategies to improve the physicochemical properties of peptide-based drugs
    Lee MF, Poh CL
    Pharm Res, 2023 Mar;40(3):617-632.
    PMID: 36869247 DOI: 10.1007/s11095-023-03486-0
    Peptides are a rapid-growing class of therapeutics with unique and desirable physicochemical properties. Due to disadvantages such as low membrane permeability and susceptibility to proteolytic degradation, peptide-based drugs have limited bioavailability, a short half-life, and rapid in vivo elimination. Various strategies can be applied to improve the physicochemical properties of peptide-based drugs to overcome limitations such as limited tissue residence time, metabolic instability, and low permeability. Applied strategies including backbone modifications, side chain modifications, conjugation with polymers, modification of peptide termini, fusion to albumin, conjugation with the Fc portion of antibodies, cyclization, stapled peptides, pseudopeptides, cell-penetrating peptide conjugates, conjugation with lipids, and encapsulation in nanocarriers are discussed.
    Matched MeSH terms: Permeability
  4. Utilizing machine learning techniques to predict the blood-brain barrier permeability of compounds detected using LCQTOF-MS in Malaysian Kelulut honey
    Edros R, Feng TW, Dong RH
    SAR QSAR Environ Res, 2023;34(6):475-500.
    PMID: 37409842 DOI: 10.1080/1062936X.2023.2230868
    Current in silico modelling techniques, such as molecular dynamics, typically focus on compounds with the highest concentration from chromatographic analyses for bioactivity screening. Consequently, they reduce the need for labour-intensive in vitro studies but limit the utilization of extensive chromatographic data and molecular diversity for compound classification. Compound permeability across the blood-brain barrier (BBB) is a key concern in central nervous system (CNS) drug development, and this limitation can be addressed by applying cheminformatics with codeless machine learning (ML). Among the four models developed in this study, the Random Forest (RF) algorithm with the most robust performance in both internal and external validation was selected for model construction, with an accuracy (ACC) of 87.5% and 86.9% and area under the curve (AUC) of 0.907 and 0.726, respectively. The RF model was deployed to classify 285 compounds detected using liquid chromatography quadrupole time-of-flight mass spectrometry (LCQTOF-MS) in Kelulut honey; of which, 140 compounds were screened with 94 descriptors. Seventeen compounds were predicted to permeate the BBB, revealing their potential as drugs for treating neurodegenerative diseases. Our results highlight the importance of employing ML pattern recognition to identify compounds with neuroprotective potential from the entire pool of chromatographic data.
    Matched MeSH terms: Permeability
  5. Transformation of Hydrophilic Drug into Oil-Miscible Ionic Liquids for Transdermal Drug Delivery
    Md Moshikur R, Shimul IM, Uddin S, Wakabayashi R, Moniruzzaman M, Goto M
    ACS Appl Mater Interfaces, 2022 Dec 21;14(50):55332-55341.
    PMID: 36508194 DOI: 10.1021/acsami.2c15636
    The transdermal delivery of hydrophilic drugs remains challenging owing to their poor ability to permeate the skin; formulation with oil media is difficult without adding chemical permeation enhancers or co-solvents. Herein, we synthesized 12 oil-miscible ionic liquid (IL) drugs comprising lidocaine-, imipramine-, and levamisole (Lev)-hydrochloride with fatty acid permeation enhancers, i.e., laurate, oleate, linoleate, and stearate as counterions. A set of in vitro and in vivo studies was performed to investigate the potency and deliverability of the transdermal drug formulations. All of the synthesized compounds were freely miscible with pharmaceutically acceptable solvents/agents (i.e., ethanol, N-methyl pyrrolidone, Tween 20, and isopropyl myristate (IPM)). In vitro permeation studies revealed that the oleate-based Lev formulation had 2.6-fold higher skin permeation capability than the Lev salts and also superior ability compared with the laurate-, linoleate-, and stearate-containing samples. Upon in vivo transdermal administration to mice, the peak plasma concentration, elimination half-life, and area under the plasma concentration curve values of Lev-IL were 4.6-, 2.9-, and 5.4-fold higher, respectively, than those of the Lev salt. Furthermore, in vitro skin irritation and in vivo histological studies have demonstrated that Lev-IL has excellent biocompatibility compared with a conventional ionic liquid-based carrier. The results indicate that oil-miscible IL-based drugs provide a simple and scalable strategy for the design of effective transdermal drug delivery systems.
    Matched MeSH terms: Permeability
  6. Differential gut microbiota and intestinal permeability between frail and healthy older adults: A systematic review
    Rashidah NH, Lim SM, Neoh CF, Majeed ABA, Tan MP, Khor HM, et al.
    Ageing Res Rev, 2022 Dec;82:101744.
    PMID: 36202312 DOI: 10.1016/j.arr.2022.101744
    This systematic review appraised previous findings on differential gut microbiota composition and intestinal permeability markers between frail and healthy older adults. A literature search was performed using PubMed, Scopus, ScienceDirect and the Cochrane Library. Relevant studies were shortlisted based on inclusion and exclusion criteria as well as assessed for risk of bias. The primary outcome was the differential composition of gut microbiota and/ or intestinal permeability markers between frail and healthy older adults. A total of 10 case-control studies and one cohort study were shortlisted. Based on consistent findings reported by more than one shortlisted study, the microbiota of frail older adults was characterised by decreased phylum Firmicutes, with Dialister, Lactobacillus and Ruminococcus being the prominent genera. Healthy controls, on the other hand, exhibited higher Eubacterium at the genera level. In terms of intestinal permeability, frail older adults were presented with increased serum zonulin, pro-inflammatory cytokines (TNF-α, HMGB-1, IL-6, IL1-ra, MIP-1β) and amino acids (aspartic acid and phosphoethanolamine) when compared to healthy controls. Altogether, frail elderlies had lower gut microbiota diversity and lower abundance of SCFA producers, which may have led to leaky guts, upregulated pro-inflammatory cytokines, frailty and sarcopenia.
    Matched MeSH terms: Permeability
  7. Fulltext MgrB Mutations and Altered Cell Permeability in Colistin Resistance in Klebsiella pneumoniae
    Yap PS, Cheng WH, Chang SK, Lim SE, Lai KS
    Cells, 2022 Sep 26;11(19).
    PMID: 36230959 DOI: 10.3390/cells11192995
    There has been a resurgence in the clinical use of polymyxin antibiotics such as colistin due to the limited treatment options for infections caused by carbapenem-resistant Enterobacterales (CRE). However, this last-resort antibiotic is currently confronted with challenges which include the emergence of chromosomal and plasmid-borne colistin resistance. Colistin resistance in Klebsiella pneumoniae is commonly caused by the mutations in the chromosomal gene mgrB. MgrB spans the inner membrane and negatively regulates PhoP phosphorylation, which is essential for bacterial outer membrane lipid biosynthesis. The present review intends to draw attention to the role of mgrB chromosomal mutations in membrane permeability in K. pneumoniae that confer colistin resistance. With growing concern regarding the global emergence of colistin resistance, deciphering physical changes of the resistant membrane mediated by mgrB inactivation may provide new insights for the discovery of novel antimicrobials that are highly effective at membrane penetration, in addition to finding out how this can help in alleviating the resistance situation.
    Matched MeSH terms: Permeability
  8. Effect of hybridization composition and glycerin content on novel corn starch/nata de coco plastic film: Thermal, mechanical, and degradation study
    Mustapha SNH, Wan JS
    Food Chem, 2022 Mar 30;373(Pt B):131440.
    PMID: 34731804 DOI: 10.1016/j.foodchem.2021.131440
    The objective of this work was to develop a plastic film from food sources with excellent thermal, mechanical, and degradability performance. Corn starch (CS)/nata de coco (NDC) were hybridized with addition of glycerin as plasticizer at different weight ratio and weight percent, respectively. Sample analysis found that the hybridization of CS with NDC improved the film forming properties, mechanical and thermal, degradation properties, as well as hydrophobicity and solubility of the film up to 0.5:0.5 wt hybrid ratio. The properties of the films were highly affected by the homogeneity of the sample during hybridization, with high NDC amount (0.3:0.7 wt CS:NDC) showing poor hydrophobicity, and mechanical and thermal properties. The glycerin content, however, did not significantly affect the hydrophobicity, water solubility, and degradability properties of CS/NDC film. Hybridization of 0.5:0.5 wt CS/NDC with 2 phr glycerin provided the optimum Young's modulus (15.67 MPa) and tensile strength (1.67 MPa) properties.
    Matched MeSH terms: Permeability
  9. Advanced nanocellulose-based gas barrier materials: Present status and prospects
    Wu Y, Liang Y, Mei C, Cai L, Nadda A, Le QV, et al.
    Chemosphere, 2022 Jan;286(Pt 3):131891.
    PMID: 34416587 DOI: 10.1016/j.chemosphere.2021.131891
    Nanocellulose based gas barrier materials have become an increasingly important subject, since it is a widespread environmentally friendly natural polymer. Previous studies have shown that super-high gas barrier can be achieved with pure and hierarchical nanocellulose films fabricated through simple suspension or layer-by-layer technique either by itself or incorporating with other polymers or nanoparticles. Improved gas barrier properties were observed for nanocellulose-reinforced composites, where nanocellulose partially impermeable nanoparticles decreased gas permeability effectively. However, for nanocellulose-based materials, the higher gas barrier performance is jeopardized by water absorption and shape deformation under high humidity conditions which is a challenge for maintaining properties in material applications. Thus, numerous investigations have been done to solve the problem of water absorption in nanocellulose-based materials. In this literature review, gas barrier properties of pure, layer-by-layer and composite nanocellulose films are investigated. The possible theoretical gas barrier mechanisms are described, and the prospects for nanocellulose-based materials are discussed.
    Matched MeSH terms: Permeability
  10. Fulltext Physical and functional properties of fish gelatin-based film incorporated with mangrove extracts
    Nurdiani R, Ma'rifah RDA, Busyro IK, Jaziri AA, Prihanto AA, Firdaus M, et al.
    PeerJ, 2022;10:e13062.
    PMID: 35411257 DOI: 10.7717/peerj.13062
    BACKGROUND: The fishery processing industry produces a remarkable number of by-products daily. Fish skin accounts for one of the significant wastes produced. Fish skin, however, can be subjected to extraction to yield gelatine and used as the primary raw material for edible film production. To increase the functionality of edible films, bioactive compounds can be incorporated into packaging. Mangroves produce potential bioactive compounds that are suitable as additional agents for active packaging. This study aimed to create a fish gelatine-based edible film enriched with mangrove extracts and to observe its mechanical and biological properties.

    METHODS: Two mangrove species (Bruguiera gymnorhiza and Sonneratia alba) with four extract concentrations (control, 0.05%, 0.15%, 0.25%, and 0.35%) were used to enrich edible films. The elongation, water vapour transmission, thickness, tensile strength, moisture content, antioxidant and antibacterial properties of the resulting packaging were analysed.

    RESULTS: The results showed that the mangrove species and extract concentration significantly affected (p 

    Matched MeSH terms: Permeability
  11. Development of mushroom polysaccharide and probiotics based solid self-nanoemulsifying drug delivery system loaded with curcumin and quercetin to improve their dissolution rate and permeability: State of the art
    Khursheed R, Singh SK, Wadhwa S, Gulati M, Kapoor B, Jain SK, et al.
    Int J Biol Macromol, 2021 Oct 31;189:744-757.
    PMID: 34464640 DOI: 10.1016/j.ijbiomac.2021.08.170
    The role of mushroom polysaccharides and probiotics as pharmaceutical excipients for development of nanocarriers has never been explored. In the present study an attempt has been made to explore Ganoderma lucidum extract powder (GLEP) containing polysaccharides and probiotics to convert liquid self nanoemulsifying drug delivery system (SNEDDS) into solid free flowing powder. Two lipophilic drugs, curcumin and quercetin were used in this study due to their dissolution rate limited oral bioavailability and poor permeability. These were loaded into liquid SNEDDS by dissolving them into isotropic mixture of Labrafill M1944CS, Capmul MCM, Tween-80 and Transcutol P. The liquid SNEDDS were solidified using probiotics and mushroom polysaccharides as carriers and Aerosil-200 as coating agent. The solidification was carried out using spray drying process. The process and formulation variables for spray drying process of liquid SNEDDS were optimized using Box Behnken Design to attain required powder properties. The release of both drugs from the optimized spray dried (SD) formulation was found to be more than 90%, whereas, it was less than 20% for unprocessed drugs. The results of DSC, PXRD and SEM, showed that the developed L-SNEDDS preconcentrate was successfully loaded onto the porous surface of probiotics, mushroom polysaccharides and Aerosil-200.
    Matched MeSH terms: Permeability
  12. Fulltext Thermodynamic stability, in-vitro permeability, and in-silico molecular modeling of the optimal Elaeis guineensis leaves extract water-in-oil nanoemulsion
    Romes NB, Abdul Wahab R, Abdul Hamid M, Oyewusi HA, Huda N, Kobun R
    Sci Rep, 2021 10 21;11(1):20851.
    PMID: 34675286 DOI: 10.1038/s41598-021-00409-0
    Nanoemulsion is a delivery system used to enhance bioavailability of plant-based compounds across the stratum corneum. Elaeis guineensis leaves are rich source of polyphenolic antioxidants, viz. gallic acid and catechin. The optimal E. guineensis leaves extract water-in-oil nanoemulsion was stable against coalescence, but it was under significant influence of Ostwald ripening over 90 days at 25 °C. The in-vitro permeability revealed a controlled and sustained release of the total phenolic compounds (TPC) of EgLE with a cumulative amount of 1935.0 ± 45.7 µgcm-2 after 8 h. The steady-state flux and permeation coefficient values were 241.9 ± 5.7 µgcm-2 h-1 and 1.15 ± 0.03 cm.h-1, respectively. The kinetic release mechanism for TPC of EgLE was best described by the Korsmeyer-Peppas model due to the highest linearity of R2 = 0.9961, indicating super case II transport mechanism. The in-silico molecular modelling predicted that the aquaporin-3 protein in the stratum corneum bonded preferably to catechin over gallic acid through hydrogen bonds due to the lowest binding energies of - 57.514 kcal/mol and - 8.553 kcal/mol, respectively. Thus, the in-silico study further verified that catechin could improve skin hydration. Therefore, the optimal nanoemulsion could be used topically as moisturizer to enhance skin hydration based on the in-silico prediction.
    Matched MeSH terms: Permeability
  13. Insulin Transdermal Delivery System for Diabetes Treatment Using a Biocompatible Ionic Liquid-Based Microemulsion
    Islam MR, Uddin S, Chowdhury MR, Wakabayashi R, Moniruzzaman M, Goto M
    ACS Appl Mater Interfaces, 2021 Sep 15;13(36):42461-42472.
    PMID: 34460218 DOI: 10.1021/acsami.1c11533
    Since injection administration for diabetes is invasive, it is important to develop an effective transdermal method for insulin. However, transdermal delivery remains challenging owing to the strong barrier function of the stratum corneum (SC) of the skin. Here, we developed ionic liquid (IL)-in-oil microemulsion formulations (MEFs) for transdermal insulin delivery using choline-fatty acids ([Chl][FAs])-comprising three different FAs (C18:0, C18:1, and C18:2)-as biocompatible surface-active ILs (SAILs). The MEFs were successfully developed using [Chl][FAs] as surfactants, sorbitan monolaurate (Span-20) as a cosurfactant, choline propionate IL as an internal polar phase, and isopropyl myristate as a continuous oil phase. Ternary phase behavior, dynamic light scattering, and transmission electron microscopy studies revealed that MEFs were thermodynamically stable with nanoparticle size. The MEFs significantly enhanced the transdermal permeation of insulin via the intercellular route by compromising the tight lamellar structure of SC lipids through a fluidity-enhancing mechanism. In vivo transdermal administration of low insulin doses (50 IU/kg) to diabetic mice showed that MEFs reduced blood glucose levels (BGLs) significantly compared with a commercial surfactant-based formulation by increasing the bioavailability of insulin in the systemic circulation and sustained the insulin level for a much longer period (half-life > 24 h) than subcutaneous injection (half-life 1.32 h). When [Chl][C18:2] SAIL-based MEF was transdermally administered, it reduced the BGL by 56% of its initial value. The MEFs were biocompatible and nontoxic (cell viability > 90%). They remained stable at room temperature for 3 months and their biological activity was retained for 4 months at 4 °C. We believe SAIL-based MEFs will alter current approaches to insulin therapy and may be a potential transdermal nanocarrier for protein and peptide delivery.
    Matched MeSH terms: Permeability
  14. The effects of Naja sumatrana venom cytotoxin, sumaCTX on alteration of the secretome in MCF-7 breast cancer cells following membrane permeabilization
    Hiu JJ, Yap MKK
    Int J Biol Macromol, 2021 Aug 01;184:776-786.
    PMID: 34174307 DOI: 10.1016/j.ijbiomac.2021.06.145
    Naja sumatrana venom cytotoxin (sumaCTX) is a basic protein which belongs to three-finger toxin family. It has been shown to induce caspase-dependent, mitochondrial-mediated apoptosis in MCF-7 cells at lower concentrations. This study aimed to investigate the alteration of secretome in MCF-7 cells following membrane permeabilization by high concentrations of sumaCTX, using label-free quantitative (LFQ) approach. The degree of membrane permeabilization of sumaCTX was determined by lactate dehydrogenase (LDH) assay and calcein-propidium iodide (PI) assays. LDH and calcein-PI assays revealed time-dependent membrane permeabilization within a narrow concentration range. However, as toxin concentrations increased, prolonged exposure of MCF-7 cells to sumaCTX did not promote the progression of membrane permeabilization. The secretome analyses showed that membrane permeabilization was an event preceding the release of intracellular proteins. Bioinformatics analyses of the LFQ secretome revealed the presence of 105 significantly distinguished proteins involved in metabolism, structural supports, inflammatory responses, and necroptosis in MCF-7 cells treated with 29.8 μg/mL of sumaCTX. Necroptosis was presumably an initial stress response in MCF-7 cells when exposed to high sumaCTX concentration. Collectively, sumaCTX-induced the loss of membrane integrity in a concentration-dependent manner, whereby the cell death pattern of MCF-7 cells transformed from apoptosis to necroptosis with increasing toxin concentrations.
    Matched MeSH terms: Cell Membrane Permeability/drug effects
  15. Short- and long-term probiotic effects of Enterococcus hirae isolated from fermented vegetable wastes on the growth, immune responses, and disease resistance of hybrid catfish (Clarias gariepinus × Clarias macrocephalus)
    Hamid NH, Daud HM, Kayansamruaj P, Hassim HA, Mohd Yusoff MS, Abu Bakar SN, et al.
    Fish Shellfish Immunol, 2021 Jul;114:1-19.
    PMID: 33872754 DOI: 10.1016/j.fsi.2021.04.012
    This study evaluated the short- and long-term effects of dietary supplementation with Enterococcus hirae strain UPM02 on the growth performance, immunity, and disease resistance of hybrid catfish (Clarias gariepinus × Clarias macrocephalus) against Aeromonas hydrophila infection. In the long-term trial, fingerling fish were fed diets containing 0 (control), 2 × 105, or 2 × 107 CFU/g E. hirae UPM02 for 120 days. Administration of E. hirae UPM02 had significant effects on the specific growth rate (SGR), feed utilization efficiency, body indices (P 
    Matched MeSH terms: Permeability
  16. Sustainable mixed matrix membranes containing porphyrin and polysulfone polymer for acid gas separations
    Saqib S, Rafiq S, Muhammad N, Khan AL, Mukhtar A, Ullah S, et al.
    J Hazard Mater, 2021 06 05;411:125155.
    PMID: 33858108 DOI: 10.1016/j.jhazmat.2021.125155
    The synergetic effect of nitrogen-rich and CO2-philic filler and polymer in mixed matrix-based membranes (MMMs) can separate CO2 competently. The introduction of well-defined nanostructured porous fillers of pores close to the kinetic diameter of the gas molecule and polymer matrix compatibility is a challenge in improving the gas transportation characteristics of MMMs. This study deals with the preparation of porphyrin filler and the polysulfone (PSf) polymer MMMs. The fillers demonstrated uniform distribution, uniformity, and successful bond formation. MMMs demonstrated high thermal stability with a glass transition temperature in the range of 480-610 °C. The porphyrin filler exhibited microporous nature with the presence of π-π bonds and Lewis's basic functionalities between filler-polymer resulted in a highly CO2-philic structure. The pure and mixed gas permeabilities and selectivity were successfully improved and surpass the Robeson's upper bound curve's tradeoff. Additionally, the temperature influence on CO2 permeability revealed lower activation energies at higher temperatures leading to the gas transport facilitation. This can be granted consistency and long-term durability in polymer chains. These results highlight the unique properties of porphyrin fillers in CO2 separation mixed matrix membranes and offer new knowledge to increase comprehension of PSf performance under various contents or environments.
    Matched MeSH terms: Permeability
  17. Fluid-structure interaction (FSI) modeling of bone marrow through trabecular bone structure under compression
    Rabiatul AAR, Fatihhi SJ, Md Saad AP, Zakaria Z, Harun MN, Kadir MRA, et al.
    Biomech Model Mechanobiol, 2021 Jun;20(3):957-968.
    PMID: 33547975 DOI: 10.1007/s10237-021-01423-x
    The present study has sought to investigate the fluid characteristic and mechanical properties of trabecular bone using fluid-structure interaction (FSI) approach under different trabecular bone orientations. This method imposed on trabecular bone structure at both longitudinal and transverse orientations to identify effects on shear stress, permeability, stiffness and stress regarded to the trabeculae. Sixteen FSI models were performed on different range trabecular cubes of 27 mm3 with eight models developed for each longitudinal and transverse direction. Results show that there was a moderate correlation between permeability and porosity, and surface area in the longitudinal and transverse orientations. For the longitudinal orientation, the permeability values varied between 3.66 × 10-8 and 1.9 × 10-7 and the sheer stress values varied between 0.05 and 1.8 Pa, whilst for the transverse orientation, the permeability values varied between 5.95 × 10-10 and 1.78 × 10-8 and the shear stress values varied between 0.04 and 3.1 Pa. Here, transverse orientation limits the fluid flow from passing through the trabeculae due to high shear stress disturbance generated within the trabecular bone region. Compared to physiological loading direction (longitudinal orientation), permeability is higher within the range known to trigger a response in bone cells. Additionally, shear stresses also increase with bone surface area. This study suggests the shear stress within bone marrow in real trabecular architecture could provide the mechanical signal to marrow cells that leads to bone anabolism and can depend on trabecular orientation.
    Matched MeSH terms: Permeability
  18. Fulltext Fabrication and Characterization of Chitosan-Tamarind Seed Polysaccharide Composite Film for Transdermal Delivery of Protein/Peptide
    Malviya R, Tyagi A, Fuloria S, Subramaniyan V, Sathasivam K, Sundram S, et al.
    Polymers (Basel), 2021 May 10;13(9).
    PMID: 34068768 DOI: 10.3390/polym13091531
    Transdermal drug delivery is used to deliver a drug by eliminating the first-pass metabolism, which increases the bioavailability of the drug. The present study aims to formulate the chitosan-tamarind seed polysaccharide composite films and evaluate for the delivery of protein/peptide molecules. Nine formulations were prepared and evaluated by using different parameters, such as physical appearance, folding endurance, thickness of film, surface pH, weight variation, drug content, surface morphology, percentage moisture intake and uptake, drug release kinetics, and drug permeability. The film weight variance was observed between 0.34 ± 0.002 to 0.47 ± 0.003 g. The drug level of the prepared films was found to be between 96 ± 1.21 and 98 ± 1.33μg. Their intake of moisture ranged between 2.83 ± 0.002 and 3.76 ± 0.001 (%). The moisture absorption of the films ranged from 5.33 ± 0.22 to 10.02 ± 0.61 (%). SEM images revealed a smooth film surface, while minor cracks were found in the film after permeation tests. During the first 4 days, drug release was between 13.75 ± 1.64% and 22.54 ± 1.34% and from day 5 to day 6, it was between 72.67 ± 2.13% and 78.33 ± 3.13%. Drug permeation during the first 4 days was 15.78 ± 1.23 %. Drug permeation (%) during the first 4 days was between 15.78 ± 1.23 and 22.49 ± 1.29 and from day 5 to day 6, it was between 71.49 ± 3.21 and 77.93 ± 3.20.
    Matched MeSH terms: Permeability
  19. Delayed Linker Addition (DLA) Synthesis for Hybrid SOD ZIFs with Unsubstituted Imidazolate Linkers for Propylene/Propane and n-Butane/i-Butane Separations
    Hillman F, Hamid MRA, Krokidas P, Moncho S, Brothers EN, Economou IG, et al.
    Angew Chem Int Ed Engl, 2021 Apr 26;60(18):10103-10111.
    PMID: 33620755 DOI: 10.1002/anie.202015635
    We present a novel synthesis strategy termed delayed linker addition (DLA) to synthesize hybrid zeolitic-imidazolate frameworks containing unsubstituted imidazolate linkers (Im) with SOD topology (hereafter termed Im/ZIF-8). Im linker incorporation can create larger voids and apertures, which are important properties for gas storage and separation. To date, there have been only a handful of reports of Im linkers incorporated into ZIF-8 frameworks, typically requiring arduous and complicated post synthesis approaches. DLA, as reported here, is a simple one-step synthesis strategy allowing high incorporation of Im linker into the ZIF-8 framework while still retaining its SOD topology. We fabricated mixed-matrix membranes (MMMs) with 6FDA-DAM polymer and Im/ZIF-8 obtained via DLA as a filler. The Im/ZIF-8-containing MMMs showed excellent performance for both propylene/propane and n-butane/i-butane separation, displaying permeability and ideal selectivity well above the polymer upper bound. Moreover, highly detailed molecular simulations shed light to the aperture size and flexibility response of Im/ZIF-8 and its improved diffusivity as compared to ZIF-8.
    Matched MeSH terms: Permeability
  20. Fulltext Antimicrobial activity and mode of action of terpene linalyl anthranilate against carbapenemase-producing Klebsiella pneumoniae
    Yang SK, Yusoff K, Ajat M, Yap WS, Lim SE, Lai KS
    J Pharm Anal, 2021 Apr;11(2):210-219.
    PMID: 34012697 DOI: 10.1016/j.jpha.2020.05.014
    Mining of plant-derived antimicrobials is the major focus at current to counter antibiotic resistance. This study was conducted to characterize the antimicrobial activity and mode of action of linalyl anthranilate (LNA) against carbapenemase-producing Klebsiella pneumoniae (KPC-KP). LNA alone exhibited bactericidal activity at 2.5% (V/V), and in combination with meropenem (MPM) at 1.25% (V/V). Comparative proteomic analysis showed a significant reduction in the number of cytoplasmic and membrane proteins, indicating membrane damage in LNA-treated KPC-KP cells. Up-regulation of oxidative stress regulator proteins and down-regulation of oxidative stress-sensitive proteins indicated oxidative stress. Zeta potential measurement and outer membrane permeability assay revealed that LNA increases both bacterial surface charge and membrane permeability. Ethidium bromide influx/efflux assay showed increased uptake of ethidium bromide in LNA-treated cells, inferring membrane damage. Furthermore, intracellular leakage of nucleic acid and proteins was detected upon LNA treatment. Scanning and transmission electron microscopies again revealed the breakage of bacterial membrane and loss of intracellular materials. LNA was found to induce oxidative stress by generating reactive oxygen species (ROS) that initiate lipid peroxidation and damage the bacterial membrane. In conclusion, LNA generates ROS, initiates lipid peroxidation, and damages the bacterial membrane, resulting in intracellular leakage and eventually killing the KPC-KP cells.
    Matched MeSH terms: Permeability
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