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Surface-modified nanocrystalline cellulose from oil palm empty fruit bunch for effective binding of curcumin

Foo ML, Tan CR, Lim PD, Ooi CW, Tan KW, Chew IML

Int J Biol Macromol, 2019 Oct 01;138:1064-1071.
PMID: 31301392 DOI: 10.1016/j.ijbiomac.2019.07.035

Rod-shape particles have been a good drug carrier due to the long circulatory time, tumor accumulation and high cellular uptake in body. Acid-hydrolysed nanocrystalline cellulose (NCC) from empty fruit bunch exhibited a width of 13-30nm and a length of 150-360nm in rod-shape structure. NCC holds good potential as a bio-based drug carrier owing to its biodegradability and biocompatibility. Fourier-transform infrared spectroscopy results confirmed the binding of curcumin onto the NCC modified with tannic acid (TA) and decylamine (DA). TA-DA modification rendered NCC with a higher level of hydrophobicity, as evidenced by a substantial increase in contact angle from 45° to 73°. The modified NCC had the curcumin-binding efficiency in the range of 95-99%, which is at least twofold higher than the unmodified NCC at any curcumin concentration tested. This remarkable curcumin-binding effciency was comparable to that of commercialized NCC from wood-based origin. This work suggests NCC as a superior and sustainable drug carrier, while TA-DA modification is a promising approach to alter the surface property of NCC for an efficient binding of curcumin.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
Fulltext Antifouling Properties of PES Membranes by Blending with ZnO Nanoparticles and NMP⁻Acetone Mixture as Solvent

Ahmad AL, Sugumaran J, Shoparwe NF

Membranes (Basel), 2018 Dec 14;8(4).
PMID: 30558199 DOI: 10.3390/membranes8040131

In this study, the antifouling properties of polyethersulfone (PES) membranes blended with different amounts of ZnO nanoparticles and a fixed ratio of N-methyl-2-pyrrolidone (NMP)-acetone mixture as a solvent were investigated. The properties and performance of the fabricated membranes were examined in terms of hydrophilicity, porosity, pore size, surface and cross-section image using scanning electron microscopy (SEM), surface roughness using atomic force microscopy (AFM), pure water flux, and humic acid filtration. Addition of ZnO as expected was found to improve the hydrophilicity as well as to encourage pore formation. However, the agglomeration of ZnO at a higher concentration cannot be avoided even when dissolved in a mixed solvent. The presence of highly volatile acetone contributed to the tight skin layer of the membrane which shows remarkable antifouling ability with the highest flux recovery ratio and negligible irreversible fouling. ZnO NPs in acetone/NMP mixed solvent shows an improvement in flux and rejection, but, the fouling resistance was moderate compared to the pristine membrane.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
Immobilization of bovine serum albumin on the chitosan/PVA film

Nurul Mujahidah Ahmad Khairuddin, Amalina Muhammad Afifi, Katayoon Kalantari, Nur Awanis Hashim, Shaza Eva Mohamad

Sains Malaysiana, 2018;47:1311-1318.

Chitosan/polyvinyl alcohol (Chitosan/PVA) blended film was prepared by direct blend process and solution casting methods.
In order to reduce the swelling ratio and enhance the chemical and mechanical stability, Chitosan/PVA film was crosslinked
with glutaraldehyde in order to produce Chitosan-g-PVA. Bovine serum albumin (BSA) was used as a model protein
to incorporate into the Chitosan-g-PVA. The chemical structure and morphological characteristics of films were studied
by FT-IR and scanning electron microscopy (SEM). Mechanical and physical properties of blended films such as tensile
properties in the dry and wet states, water uptake and water contact angle measurement were characterized. Blending
PVA and chitosan improved strength and flexibility of the films. Crosslinking with glutaraldehyde further improves the
tensile strength and decrease the hydrophilicity of films. BSA immobilized on the Chitosan-g-PVA film was calculated as
BSA encapsulation efficiency.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
Fulltext Pore formation in lipid membrane I: Continuous reversible trajectory from intact bilayer through hydrophobic defect to transversal pore

Akimov SA, Volynsky PE, Galimzyanov TR, Kuzmin PI, Pavlov KV, Batishchev OV

Sci Rep, 2017 09 22;7(1):12152.
PMID: 28939906 DOI: 10.1038/s41598-017-12127-7

Lipid membranes serve as effective barriers allowing cells to maintain internal composition differing from that of extracellular medium. Membrane permeation, both natural and artificial, can take place via appearance of transversal pores. The rearrangements of lipids leading to pore formation in the intact membrane are not yet understood in details. We applied continuum elasticity theory to obtain continuous trajectory of pore formation and closure, and analyzed molecular dynamics trajectories of pre-formed pore reseal. We hypothesized that a transversal pore is preceded by a hydrophobic defect: intermediate structure spanning through the membrane, the side walls of which are partially aligned by lipid tails. This prediction was confirmed by our molecular dynamics simulations. Conversion of the hydrophobic defect into the hydrophilic pore required surmounting some energy barrier. A metastable state was found for the hydrophilic pore at the radius of a few nanometers. The dependence of the energy on radius was approximately quadratic for hydrophobic defect and small hydrophilic pore, while for large radii it depended on the radius linearly. The pore energy related to its perimeter, line tension, thus depends of the pore radius. Calculated values of the line tension for large pores were in quantitative agreement with available experimental data.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
Fulltext Mechanical and Thermal Properties of Montmorillonite-Reinforced Polypropylene/Rice Husk Hybrid Nanocomposites

Majeed K, Ahmed A, Abu Bakar MS, Indra Mahlia TM, Saba N, Hassan A, et al.

Polymers (Basel), 2019 Sep 25;11(10).
PMID: 31557811 DOI: 10.3390/polym11101557

In recent years, there has been considerable interest in the use of natural fibers as potential reinforcing fillers in polymer composites despite their hydrophilicity, which limits their widespread commercial application. The present study explored the fabrication of nanocomposites by melt mixing, using an internal mixer followed by a compression molding technique, and incorporating rice husk (RH) as a renewable natural filler, montmorillonite (MMT) nanoclay as water-resistant reinforcing nanoparticles, and polypropylene-grafted maleic anhydride (PP-g-MAH) as a compatibilizing agent. To correlate the effect of MMT delamination and MMT/RH dispersion in the composites, the mechanical and thermal properties of the composites were studied. XRD analysis revealed delamination of MMT platelets due to an increase in their interlayer spacing, and SEM micrographs indicated improved dispersion of the filler(s) from the use of compatibilizers. The mechanical properties were improved by the incorporation of MMT into the PP/RH system and the reinforcing effect was remarkable as a result of the use of compatibilizing agent. Prolonged water exposure of the prepared samples decreased their tensile and flexural properties. Interestingly, the maximum decrease was observed for PP/RH composites and the minimum was for MMT-reinforced and PP-g-MAH-compatibilized PP/RH composites. DSC results revealed an increase in crystallinity with the addition of filler(s), while the melting and crystallization temperatures remained unaltered. TGA revealed that MMT addition and its delamination in the composite systems improved the thermal stability of the developed nanocomposites. Overall, we conclude that MMT nanoclay is an effective water-resistant reinforcing nanoparticle that enhances the durability, mechanical properties, and thermal stability of composites.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
Fulltext Safely Dissolvable and Healable Active Packaging Films Based on Alginate and Pectin

Makaremi M, Yousefi H, Cavallaro G, Lazzara G, Goh CBS, Lee SM, et al.

Polymers (Basel), 2019 Sep 29;11(10).
PMID: 31569482 DOI: 10.3390/polym11101594

Extensive usage of long-lasting petroleum based plastics for short-lived application such as packaging has raised concerns regarding their role in environmental pollution. In this research, we have developed active, healable, and safely dissolvable alginate-pectin based biocomposites that have potential applications in food packaging. The morphological study revealed the rough surface of these biocomposite films. Tensile properties indicated that the fabricated samples have mechanical properties in the range of commercially available packaging films while possessing excellent healing efficiency. Biocomposite films exhibited higher hydrophobicity properties compared to neat alginate films. Thermal analysis indicated that crosslinked biocomposite samples possess higher thermal stability in temperatures below 120 °C, while antibacterial analysis against E. coli and S. aureus revealed the antibacterial properties of the prepared samples against different bacteria. The fabricated biodegradable multi-functional biocomposite films possess various imperative properties, making them ideal for utilization as packaging material.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
Fulltext Surface Modification of Polytetrafluoroethylene Hollow Fiber Membrane for Direct Contact Membrane Distillation through Low-Density Polyethylene Solution Coating

Mohd Ramli MR, Ahmad AL, Leo CP

ACS Omega, 2021 Feb 23;6(7):4609-4618.
PMID: 33644568 DOI: 10.1021/acsomega.0c05107

Membrane distillation (MD) is an attractive technology for the separation of highly saline water used with a polytetrafluoroethylene (PTFE) hollow fiber (HF) membrane. A hydrophobic coating of low-density polyethylene (LDPE) coats the outer surface of the PTFE membrane to resolve membrane wetting as well as increase membrane permeability flux and salt rejection, a critical problem regarding the MD process. LDPE concentrations in coating solution have been studied and optimized. Consequently, the LDPE layer altered membrane morphology by forming a fine nanostructure on the membrane surface that created a hydrophobic layer, a high roughness of membrane, and a uniform LDPE network. The membrane coated with different concentrations of LDPE exhibited high water contact angles of 135.14 ± 0.24 and 138.08 ± 0.01° for membranes M-3 and M-4, respectively, compared to the pristine membrane. In addition, the liquid entry pressure values of LDPE-incorporated PTFE HF membranes (M-1 to M-5) were higher than that of the uncoated membrane (M-0) with a small decrease in the percentage of porosity. The M-3 and M-4 membranes demonstrated higher flux values of 4.12 and 3.3 L m-2 h-1 at 70 °C, respectively. On the other hand, the water permeation flux of 1.95 L m-2 h-1 for M-5 further decreased when LDPE concentration is increased.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
Fulltext Fabrication and Characterization of Novel Poly(D-lactic acid) Nanocomposite Membrane for Water Filtration Purpose

Kian LK, Jawaid M, Alamery S, Vaseashta A

Nanomaterials (Basel), 2021 Jan 20;11(2).
PMID: 33498162 DOI: 10.3390/nano11020255

The development of membrane technology from biopolymer for water filtration has received a great deal of attention from researchers and scientists, owing to the growing awareness of environmental protection. The present investigation is aimed at producing poly(D-lactic acid) (PDLA) membranes, incorporated with nanocrystalline cellulose (NCC) and cellulose nanowhisker (CNW) at different loadings of 1 wt.% (PDNC-I, PDNW-I) and 2 wt.% (PDNC-II PDNW-II). From morphological characterization, it was evident that the nanocellulose particles induced pore formation within structure of the membrane. Furthermore, the greater surface reactivity of CNW particles facilitates in enhancing the surface wettability of membranes due to increased hydrophilicity. In addition, both thermal and mechanical properties for all nanocellulose filled membranes under investigation demonstrated significant improvement, particularly for PDNW-I-based membranes, which showed improvement in both aspects. The membrane of PDNW-I presented water permeability of 41.92 L/m2h, when applied under a pressure range of 0.1-0.5 MPa. The investigation clearly demonstrates that CNWs-filled PDLA membranes fabricated for this investigation have a very high potential to be utilized for water filtration purpose in the future.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
Fulltext Carnauba Wax/Halloysite Nanotube with Improved Anti-Wetting and Permeability of Hydrophobic PVDF Membrane via DCMD

AbdulKadir WAFW, Ahmad AL, Boon Seng O

Membranes (Basel), 2021 Mar 23;11(3).
PMID: 33807017 DOI: 10.3390/membranes11030228

The hydrophobic membranes have been widely explored to meet the membrane characteristics for the membrane distillation (MD) process. Inorganic metal oxide nanoparticles have been used to improve the membrane hydrophobicity, but limited studies have used nano clay particles. This study introduces halloysite nanotube (HNT) as an alternative material to synthesis a hydrophobic poly(vinylidene fluoride) (PVDF)-HNT membrane. The PVDF membranes were fabricated using functionalized HNTs (e.g., carnauba wax and 1H,1H,2H,2H-perfluorooctyl-trichlorosilane (FOTS)). The results were determined by Fourier transform infrared-attenuated total reflection, scanning electron microscope, goniometer and porometer to determine the desired hydrophobic membrane for direct contact membrane distillation (DCMD). The addition of FOTS-HNT (fs-HNT) and carnauba wax-HNT (fw-HNT) in the PVDF membrane enhanced the water contact angle (CA) to 127° and 137°, respectively. The presence of fw-HNT in the PVDF membrane exhibited higher liquid entry pressure (LEP) (2.64 bar) compared to fs-HNT in the membrane matrix (1.44 bar). The PVDF/fw-HNT membrane (Pfw-HNT) obtained the highest flux of 7.24 L/m2h with 99.9% salt removal. A stable permeability in the Pfw-HNT membrane was obtained throughout 16 h of DCMD. The incorporation of fw-HNT in the PVDF membrane had improved the anti-wetting properties and the membrane performance with the anti-fouling effect.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
Design of oral intestinal-specific alginate-vitexin nanoparticulate system to modulate blood glucose level of diabetic rats

Shaedi N, Naharudin I, Choo CY, Wong TW

Carbohydr Polym, 2021 Feb 15;254:117312.
PMID: 33357875 DOI: 10.1016/j.carbpol.2020.117312

Vitexin of Ficus deltoidea exhibits intestinal α-glucosidase inhibitory and blood glucose lowering effects. This study designs oral intestinal-specific alginate nanoparticulate system of vitexin. Nanospray-dried alginate, alginate/stearic acid and alginate-C18 conjugate nanoparticles were prepared. Stearic acid was adopted to hydrophobize the matrix and minimize premature vitexin release in stomach, whereas C-18 conjugate as immobilized fatty acid to sustain hydrophobic effect and drug release. Nanoparticles were compacted with polyethylene glycol (PEG 3000, 10,000 and 20,000). The physicochemical, drug release, in vivo blood glucose lowering and intestinal vitexin content of nanoparticles and compact were determined. Hydrophobization of alginate nanoparticles promoted premature vitexin release. Compaction of nanoparticles with PEG minimized vitexin release in the stomach, with stearic acid loaded nanoparticles exhibiting a higher vitexin release in the intestine. The introduction of stearic acid reduced vitexin-alginate interaction, conferred alginate-stearic acid mismatch, and dispersive stearic acid-induced particle breakdown with intestinal vitexin release. Use of PEG 10,000 in compaction brought about PEG-nanoparticles interaction that negated initial vitexin release. The PEG dissolution in intestinal phase subsequently enabled particle breakdown and vitexin release. The PEG compacted nanoparticles exhibited oral intestinal-specific vitexin release, with positive blood glucose lowering and enhanced intestinal vitexin content in vivo.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
Fulltext Chemical and Thermo-Mechanical Properties of Waterborne Polyurethane Dispersion Derived from Jatropha Oil

Saalah S, Abdullah LC, Aung MM, Salleh MZ, Awang Biak DR, Basri M, et al.

Polymers (Basel), 2021 Mar 05;13(5).
PMID: 33807622 DOI: 10.3390/polym13050795

Nowadays, there is a significant trend away from solvent-based polyurethane systems towards waterborne polyurethane dispersions due to government regulations requiring manufacturers to lower total volatile organic compounds, as well as consumer preference for more environmentally friendly products. In this work, a renewable vegetable oil-based polyol derived from jatropha oil was polymerized with isophorone diisocyanate and dimethylol propionic acid to produce anionic waterborne polyurethane dispersion. Free standing films with up to 62 wt.% bio-based content were successfully produced after evaporation of water from the jatropha oil-based waterborne polyurethane (JPU) dispersion, which indicated good film formation. The chemical and thermo-mechanical properties of the JPU films were characterized. By increasing the OH numbers of polyol from 161 mgKOH/g to 217 mgKOH/g, the crosslinking density of the JPU was significantly increased, which lead to a better storage modulus and improved hydrophobicity. Overall, JPU produced from polyol having OH number of 217 mgKOH/g appears to be a promising product for application as a binder for wood and decorative coatings.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
Fulltext Development of Polyvinylidene Fluoride Membrane via Assembly of Tannic Acid and Polyvinylpyrrolidone for Filtration of Oil/Water Emulsion

Nawi NIM, Ong Amat S, Bilad MR, Nordin NAHM, Shamsuddin N, Prayogi S, et al.

Polymers (Basel), 2021 Mar 22;13(6).
PMID: 33810126 DOI: 10.3390/polym13060976

Wastewater containing oil/water emulsion has a serious ecological impact and threatens human health. The impact worsens as its volume increases. Oil/water emulsion needs to be treated before it is discharged or reused again for processing. A membrane-based process is considered attractive in effectively treating oil/water emulsion, but progress has been dampened by the membrane fouling issue. The objective of this study is to develop polyvinylidene fluoride (PVDF) membranes customized for oil/water emulsion separation by incorporating assembly of tannic acid (TA) and polyvinylpyrrolidone (PVP) in the polymer matrix. The results show that the assembly of TA/PVP complexation was achieved as observed from the change in colour during the phase inversion and as also proven from the characterization analyses. Incorporation of the TA/PVP assembly leads to enhanced surface hydrophilicity by lowering the contact angle from 82° to 47°. In situ assembly of the TA/PVP complex also leads to enhanced clean water permeability by a factor of four as a result of enhanced mean flow pore size from 0.2 to 0.9 µm. Owing to enhanced surface chemistry and structural advantages, the optimum hydrophilic PVDF/TA/PVP membrane poses permeability of 540.18 L/(m2 h bar) for oil/water emulsion filtration, three times higher than the pristine PVDF membrane used as the reference.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
Fulltext Interfacial Compatibility Evaluation on the Fiber Treatment in the Typha Fiber Reinforced Epoxy Composites and Their Effect on the Chemical and Mechanical Properties

Rizal S, Ikramullah, Gopakumar DA, Thalib S, Huzni S, Abdul Khalil HPS

Polymers (Basel), 2018 Nov 28;10(12).
PMID: 30961241 DOI: 10.3390/polym10121316

Natural fiber composites have been widely used for various applications such as automotive components, aircraft components and sports equipment. Among the natural fibers Typha spp have gained considerable attention to replace synthetic fibers due to their unique nature. The untreated and alkali-treated fibers treated in different durations were dried under the sun for 4 h prior to the fabrication of Typha fiber reinforced epoxy composites. The chemical structure and crystallinity index of composites were examined via FT-IR and XRD respectively. The tensile, flexural and impact tests were conducted to investigate the effect of the alkali treated Typha fibers on the epoxy composite. From the microscopy analysis, it was observed that the fracture mechanism of the composite was due to the fiber and matrix debonding, fiber pull out from the matrix, and fiber damage. The tensile, flexural and impact strength of the Typha fiber reinforced epoxy composite were increased after 5% alkaline immersion compared to untreated Typha fiber composite. From these results, it can be concluded that the alkali treatment on Typha fiber could improve the interfacial compatibility between epoxy resin and Typha fiber, which resulted in the better mechanical properties and made the composite more hydrophobic. So far there is no comprehensive report about Typha fiber reinforcing epoxy composite, investigating the effect of the alkali treatment duration on the interfacial compatibility, and their effect on chemical and mechanical of Typha fiber reinforced composite, which plays a vital role to provide the overall mechanical performance to the composite.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
Casein nanomicelle as an emerging biomaterial-A comprehensive review

Rehan F, Ahemad N, Gupta M

Colloids Surf B Biointerfaces, 2019 Jul 01;179:280-292.
PMID: 30981063 DOI: 10.1016/j.colsurfb.2019.03.051

Casein nanomicelles, a major fraction of milk protein, are emerging as a novel drug delivery system owing to their various structural and functional properties. Casein is further divided into α-, β- and κ-casein, and to date various models have been proposed to describe casein structure, but still no definite structure presenting a detailed assembly of the casein micelle has been found. Thus far, the submicellar model and Horne and Holt model are the most accepted models. This article presents a detailed review of casein micelles and their fractions, and the physicochemical properties that account for their numerous applications in nutraceutics, pharmaceutics and cosmetics. Due to their nanosize and self-assembling nature, casein nanomicelles are considered as excellent delivery carriers to provide better bioavailability and stability of various compounds such as vitamins, oils, polyphenols, fattyacids and minerals. Their amphiphilic nature also provides a great opportunity to deliver hydrophobic bioactives in various drug delivery systems such as nanoparticles, nanomicelles, nanogels and nanoemulsions to improve drug binding and targeting.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
Gold interdigitated triple-microelectrodes for label-free prognosticative aptasensing of prostate cancer biomarker in serum

Ibau C, Md Arshad MK, Gopinath SCB, Nuzaihan M N M, M Fathil MF, Estrela P

Biosens Bioelectron, 2019 Jul 01;136:118-127.
PMID: 31054519 DOI: 10.1016/j.bios.2019.04.048

A simple, single-masked gold interdigitated triple-microelectrodes biosensor is presented by taking the advantage of an effective self-assembled monolayer (SAM) using an amino-silanization technique for the early detection of a prostate cancer's biomarker, the prostate-specific antigen (PSA). Unlike most interdigitated electrode biosensors, biorecognition happens in between the interdigitated electrodes, which enhances the sensitivity and limit of detection of the sensor. Using the Faradaic mode electrochemical impedance spectroscopy (EIS) technique to quantify the PSA antigen, the developed sensing platform demonstrates a logarithmic detection of PSA ranging from 0.5 ng/ml to 5000 ng/ml, an estimated LOD down to 0.51 ng/ml in the serum, and a good sensor's reproducibility. The sensor's detection range covers the clinical threshold value at 4 ng/ml and the crucial diagnosis 'grey zone' of 4-10 ng/ml of PSA in serum for an accurate cancer diagnosis. The selectivity test revealed an excellent discrimination of other competing proteins, with a recorded detection signals at 5 ng/ml PSA as high as 7-fold increase versus the human serum albumin (HSA) and 8-fold increase versus the human glandular kallikrein 2 (hK2). The stability test showed an acceptable stability of the aptasensor recorded at six (6) days before the detection signal started degrading below 10% of the peak detection value. The developed sensing scheme is proven to exhibit a great potential as a portable prostate cancer biosensor, also as a universal platform for bio-molecular sensing with the versatility to implement nanoparticles and other surface chemistry for various applications.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
Exploring the combination characteristics of lumefantrine, an antimalarial drug and human serum albumin through spectroscopic and molecular docking studies

Musa KA, Ridzwan NFW, Mohamad SB, Tayyab S

J Biomol Struct Dyn, 2021 Feb;39(2):691-702.
PMID: 31913089 DOI: 10.1080/07391102.2020.1713215

Binding of lumefantrine (LUM), an antimalarial drug to human serum albumin (HSA), the main carrier protein in human blood circulation was investigated using fluorescence quenching titration, UV-vis absorption and circular dichroism (CD) spectroscopy as well as molecular docking. LUM-induced quenching of the protein (HSA) fluorescence was characterized as static quenching, as revealed by the decrease in the value of the Stern-Volmer quenching constant, K
sv
with increasing temperature, thus suggesting LUM-HSA complex formation. This was also confirmed from the UV-vis absorption spectral results. Values of the association constant, Ka for LUM-HSA interaction were found to be within the range, 7.27-5.01 × 104 M-1 at three different temperatures, i.e. 288 K, 298 K and 308 K, which indicated moderate binding affinity between LUM and HSA. The LUM-HSA complex was stabilized by hydrophobic interactions, H-bonds, as well as van der Waals forces, as predicted from the thermodynamic data (ΔS = +50.34 J mol-1 K-1 and ΔH = -12.3 kJ mol-1) of the binding reaction. Far-UV and near-UV CD spectral results demonstrated smaller changes in both secondary and tertiary structures of HSA upon LUM binding, while three-dimensional fluorescence spectra suggested alterations in the microenvironment around protein fluorophores (Trp and Tyr). LUM binding to HSA offered stability to the protein against thermal stress. Competitive drug displacement results designated Sudlow's Site I, located in subdomain IIA of HSA as the preferred binding site of LUM on HSA, which was well supported by molecular docking analysis.Communicated by Ramaswamy H. Sarma.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
Fulltext Functional Hydrophilic Membrane for Oil-Water Separation Based on Modified Bio-Based Chitosan-Gelatin

Zakuwan SZ, Ahmad I, Abu Tahrim N, Mohamed F

Polymers (Basel), 2021 Apr 06;13(7).
PMID: 33917600 DOI: 10.3390/polym13071176

In this study, we fabricated a modified biomaterial based on chitosan and gelatin, which is an intrinsic hydrophilic membrane for oil-water separation to clean water contamination by oil. Modification of the membrane with a non-toxic natural crosslinker, genipin, significantly enhanced the stability of the biopolymer membrane in a water-based medium towards an eco-friendly environment. The effects of various compositions of genipin-crosslinked chitosan-gelatin membrane on the rheological properties, thermal stability, and morphological structure of the membrane were investigated using a dynamic rotational rheometer, thermogravimetry analysis, and chemical composition by attenuated total reflectance spectroscopy (ATR). Modified chitosan-gelatin membrane showed completely miscible blends, as determined by field-emission scanning electron microscopy, differential scanning calorimetry, and ATR. Morphological results showed membrane with establish microstructure to further experiment as filtration product. The membranes were successfully tested for their oil-water separation efficiencies. The membrane proved to be selective and effective in separating water from an oil-water mixture. The optimum results achieved a stable microporous structure of the membrane (microfiltration) and a separation efficiency of above 98%. The membrane showed a high permeation flux, generated as high as 698 and 420 L m-2 h-1 for cooking and crude oils, respectively. Owing to its outstanding recyclability and anti-fouling performance, the membrane can be washed away easily, ensuring the reusability of the prepared membrane.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
Fulltext QSAR Studies on Neuraminidase Inhibitors as Anti-influenza Agents

Veerasamy R, Rajak H

Turk J Pharm Sci, 2021 04 20;18(2):151-156.
PMID: 33900700 DOI: 10.4274/tjps.galenos.2020.45556

Objectives: The present study aimed to establish significant and validated quantitative structure-activity relationship (QSAR) models for neuraminidase inhibitors and correlate their physicochemical, steric, and electrostatic properties with their anti-influenza activity.
Materials and Methods: We have developed and validated 2D and 3D QSAR models by using multiple linear regression, partial least square regression, and k-nearest neighbor-molecular field analysis methods.
Results: 2D QSAR models had q2: 0.950 and pred_r2: 0.877 and 3D QSAR models had q2: 0.899 and pred_r2: 0.957. These results showed that the models werere predictive.
Conclusion: Parameters such as hydrogen count and hydrophilicity were involved in 2D QSAR models. The 3D QSAR study revealed that steric and hydrophobic descriptors were negatively contributed to neuraminidase inhibitory activity. The results of this study could be used as platform for design of better anti-influenza drugs.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
Role of Wettability on the Adsorption of an Anionic Surfactant on Sandstone Cores

Amirmoshiri M, Zhang L, Puerto MC, Tewari RD, Bahrim RZBK, Farajzadeh R, et al.

Langmuir, 2020 Sep 01.
PMID: 32870010 DOI: 10.1021/acs.langmuir.0c01521

We investigate the dynamic adsorption of anionic surfactant C14 - 16 alpha olefin sulfonate on Berea sandstone cores with different surface wettability and redox states under high temperature that represents reservoir conditions. Surfactant adsorption levels are determined by analyzing the effluent history data with a dynamic adsorption model assuming Langmuir isotherm. A variety of analyses, including surface chemistry, ionic composition, and chromatography, is performed. It is found that the surfactant breakthrough in the neutral-wet core is delayed more compared to that in the water-wet core because the deposited crude oil components on the rock surface increase the surfactant adsorption via hydrophobic interactions. As the surfactant adsorption is satisfied, the crude oil components are solubilized by surfactant micelles and some of the adsorbed surfactants are released from the rock surface. The released surfactant dissolves in the flowing surfactant solution, thereby resulting in an overshoot of the produced surfactant concentration with respect to the injection value. Furthermore, under water-wet conditions, changing the surface redox potential from an oxidized to a reduced state decreases the surfactant adsorption level by 40%. We find that the decrease in surfactant adsorption is caused not only by removing the iron oxide but also by changing the calcium concentration after the core restoration process (calcite dissolution and ion exchange as a result of using EDTA). Findings from this study suggest that laboratory surfactant adsorption tests need to be conducted by considering the wettability and redox state of the rock surface while recognizing how core restoration methods could significantly alter the ionic composition during surfactant flooding.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions
Fulltext Preparation and Characterization of Polyphenylsulfone (PPSU) Membranes for Biogas Upgrading

Kujawski W, Li G, Van der Bruggen B, Pedišius N, Tonkonogij J, Tonkonogovas A, et al.

Materials (Basel), 2020 Jun 25;13(12).
PMID: 32630434 DOI: 10.3390/ma13122847

Asymmetric polyphenylsulfone (PPSU) membranes were fabricated by a non-solvent induced phase inversion method. Glycerin and silica nanoparticles were added into the polymer solution to investigate their effects on the material properties and gas separation performance of prepared membranes. The morphology and structure of PPSU membranes were analyzed by scanning electron microscopy (SEM), the surface roughness of the selective layer was analyzed by atomic force microscopy (AFM), and the surface free energy was calculated based on the contact angle measurements by using various solvents. The gas separation performance of PPSU membranes was estimated by measuring the permeability of CO2 and CH4. The addition of glycerin as a nonsolvent into the polymer solution changed the cross-section structure from finger-like structure into sponge-like structure due to the delayed liquid-liquid demixing process, which was confirmed by SEM analysis. The incorporation of silica nanoparticles into PPSU membranes slightly increased the hydrophilicity, which was confirmed by water contact angle results. PPSU membrane fabricated from the polymer solution containing 10 wt.% glycerin showed the best CO2/CH4 selectivity of 3.86 and the CO2 permeability of 1044.01 Barrer. Mixed matrix PPSU membrane containing 0.1 wt.% silica nanoparticles showed the CO2/CH4 selectivity of 3.16 and the CO2 permeability of 1202.77 Barrer.

Matched MeSH terms: Hydrophobic and Hydrophilic Interactions

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