Carboxyl End Research Articles

End‐group controlling aqueous solution properties in star‐shaped poly(2‐hydroxyethyl acrylate) and poly(2‐hydroxyethyl acrylate)‐b‐poly(N‐isopropylacrylamide) polymers

AbstractStar‐shaped poly(2‐hydroxyethyl acrylate) (PHEA)6 polymers were synthesized using hexafunctional chain transfer agent (CTA) trithiocarbonate type via reversible addition‐fragmentation chain transfer (RAFT) polymerization. The (PHEA)6 polymers with dodecyl chain‐end were non‐water soluble. As the molecular weight increased, the polymers could disperse in water, forming large aggregates with a DH of 1027 to 525 nm. On the contrary, the (PHEA)6 polymers with the carboxylic acid group at the chain‐end were completely soluble in water. Then, (PHEA)6 polymers were chain extended with N‐isopropylacrylamide (NIPAM) to obtain poly(2‐hydroxyethyl acrylate)‐b‐poly(N‐isopropylacrylamide) (PHEA‐b‐PNIPAM) block copolymers. The dodecyl group strongly affects the aqueous solution properties of the copolymers even with a high PNIPAM content. Copolymers with dodecyl chain‐end were insoluble or partially soluble in water, forming large aggregates (0.5 mg/ml in distilled water). The copolymers with carboxylic acid end‐group were totally water soluble. The thermo‐responsive phase behavior of the star‐shaped block copolymers was studied, and for this purpose, it was necessary to remove the RAFT group containing the dodecyl tail. The intense turbidity observed in the aqueous dispersions of the corresponding copolymers made it challenging to determine the LCST accurately. The copolymers with a carboxylic end group were evaluated as is.

Structural basis for transcription factor ZBTB7A recognition of DNA and effects of ZBTB7A somatic mutations that occur in human acute myeloid leukemia

ZBTB7A belongs to a small family of transcription factors having three members in humans (7A, 7B, and 7C). They share a BTB/POZ protein interaction domain at the amino end and a zinc-finger DNA-binding domain at the carboxyl end. They control the transcription of a wide range of genes, having varied functions in hematopoiesis, oncogenesis, and metabolism (in particular glycolysis). ZBTB7A-binding profiles at gene promoters contain a consensus G(a/c)CCC motif, followed by a CCCC sequence in some instances. Structural and mutational investigations suggest that DNA-specific contacts with the four-finger tandem array of ZBTB7A are formed sequentially, initiated from ZF1-ZF2 binding to G(a/c)CCC before spreading to ZF3-ZF4, which bind the DNA backbone and the 3' CCCC sequence, respectively. Here, we studied some mutations found in t(8;21)-positive acute myeloid leukemia patients that occur within the ZBTB7A DNA-binding domain. We determined that these mutations generally impair ZBTB7A DNA binding, with the most severe disruptions resulting from mutations in ZF1 and ZF2, and the least from a frameshift mutation in ZF3 that results in partial mislocalization. Information provided here on ZBTB7A-DNA interactions is likely applicable to ZBTB7B/C, which have overlapping functions with ZBTB7A in controlling primary metabolism.

Characterization Challenges of Self-Assembled Polymer-SPIONs Nanoparticles: Benefits of Orthogonal Methods.

Size and zeta potential are critical physicochemical properties of nanoparticles (NPs), influencing their biological activity and safety profile. These are essential for further industrial upscale and clinical success. However, the characterization of polydisperse, non-spherical NPs is a challenge for traditional characterization techniques (ex., dynamic light scattering (DLS)). In this paper, superparamagnetic iron oxide nanoparticles (SPIONs) were coated with polyvinyl alcohol (PVAL) exhibiting different terminal groups at their surface, either hydroxyl (OH), carboxyl (COOH) or amino (NH2) end groups. Size, zeta potential and concentration were characterized by orthogonal methods, namely, batch DLS, nanoparticle tracking analysis (NTA), tunable resistive pulse sensing (TRPS), transmission electron microscopy (TEM), asymmetric flow field flow fractionation (AF4) coupled to multi-angle light scattering (MALS), UV-Visible and online DLS. Finally, coated SPIONs were incubated with albumin, and size changes were monitored by AF4-MALS-UV-DLS. NTA showed the biggest mean sizes, even though DLS PVAL-COOH SPION graphs presented aggregates in the micrometer range. TRPS detected more NPs in suspension than NTA. Finally, AF4-MALS-UV-DLS could successfully resolve the different sizes of the coated SPION suspensions. The results highlight the importance of combining techniques with different principles for NPs characterization. The advantages and limitations of each method are discussed here.

Tunable Surface Charge Enables the Electrostatic Adsorption-Controlled Release of Neuroprotective Peptides from a Hydrogel-Nanoparticle Drug Delivery System.

We exploit the electrostatic interactions between the positively charged neuroprotective peptide, pituitary adenylate cyclase-activating polypeptide (PACAP), and negatively charged poly(lactic-co-glycolic acid) (PLGA) nanoparticles to control PACAP release from the surface of nanoparticles dispersed in a hyaluronan-methylcellulose (HAMC) hydrogel composite. PACAP is a promising therapeutic for the treatment of neurological disorders, yet it has been difficult to deliver in vivo. Herein, the PACAP release rate was tuned by manipulating peptide adsorption onto the surface of blank nanoparticles by modifying either nanoparticle loading in the hydrogel or nanoparticle surface charge. This peptide-nanoparticle interaction was controlled by the pH-responsive carboxylic acid end terminal groups of PLGA. We further validated this system with the controlled release of a novel stabilized PACAP analog: Ac-[Ala15, Ala20]PACAP-propylamide, which masks its recognition to peptidases in circulation. Both wild-type and stabilized PACAP released from the vehicle increased the production of neuroprotective Interleukin-6 from cultured primary astrocytes. Using computational fluid dynamics methods, PACAP release from the composite was predicted based on experimentally derived adsorption isotherms, which exhibited similar release profiles to experimental data. This versatile adsorption-based system was used to deliver PACAP locally to the brains of stroke-injured mice over a 10 day period in vivo, highlighting its effectiveness for the controlled release of PACAP to the central nervous system.

Yeast Protein Asf1 Possesses Modulating Activity towards Protein Kinase CK2

Protein kinase CK2 plays an important role in cell survival and protects regulatory proteins from caspase-mediated degradation during apoptosis. The consensus sequence of proteins phosphorylated by CK2 contains a cluster of acidic amino acids around the phosphorylation site. The poly-acidic sequence in yeast protein Asf1 is similar to the acidic loop in CK2β, which possesses a regulatory function. We observed that the overexpression of Asf1 in yeast cells influences cell growth. Experiments performed in vitro and in vivo indicate that yeast protein Asf1 inhibits protein kinase CK2. Our data suggest that each CK2 isoform might be regulated in a different way. Deletion of the amino or carboxyl end of Asf1 reveals that the acidic cluster close to the C-terminus is responsible for the activation or inhibition of CK2 activity.

Acyl-Lipid Δ6-Desaturase May Act as a First FAD in Cyanobacteria.

Fatty acid desaturases (FADs) play important roles in various metabolic and adaptive pathways in all living organisms. They represent a superfamily of oxygenases that introduce double bonds into the acyl chains of fatty acids (FAs). These enzymes are highly specific to the length of the carbon chain, position of double bonds formation, etc. The modes by which FADs "count" the position of the double bond formation may differ. In cyanobacteria, the first double bond is formed between 9th and 10th carbons (position Δ9), counting from the carboxylic end of an FA. Other FADs that produce polyunsaturated FAs may introduce double bonds counting from the carboxyl (Δ) or methyl (ω) terminus, or from a pre-existing double bond towards carboxyl or methyl terminus of an FA chain. Here, we expressed the desD gene for the Δ6-FAD from Synechocystis sp. PCC 6803 in Synechococcus elongatus PCC 7942 (which is capable of synthesizing only monoenoic FAs desaturated mainly at position Δ9) and observed the appearance of unusual monoenoic FAs desaturated at position Δ6, as well as Δ6,9 dienoic FAs. Exogenously added cis-10-heptadecenoic acid (17:1Δ10) was converted into cis-6,10-heptadecadienoic (17:2Δ6,10). These data demonstrate the ability of Δ6-FAD to introduce the first double bond into the unsaturated substrates and suggests that it "counts" from the carboxyl end, irrespective of the absence or presence of a previous double bond in an FA chain.

Polyhedral oligomeric silsesquioxane (POSS)-modified citric-acid coated magnetic Fe3O4 nanoparticles for anticancer drug delivery

In this work, magnetic nanoparticles coated with citric acid (Fe3O4@Cit) were synthesized via co-precipitation strategy. Then, Fe3O4@Cit was modified with octa-aminopropyl polyhedral oligomeric silsesquioxane hydrochloride salt nanoparticles (OAPOSS NPs) by amidation reaction between carboxylic acid end groups on Fe3O4@Cit and the amine groups of OAPOSS surface (Fe3O4@Cit@OAPOSS). The key point of this approach is utilizing a symmetric nanosized cagelike POSS NPs as coating material to obtain novel hybrid drug nanocarrier. The successful preparation of nanocarrier (Fe3O4@Cit@OAPOSS) was confirmed by various techniques. Drug loading and release behaviors of Fe3O4@Cit@OAPOSS were evaluated using doxorubicin (DOX), a standard anticancer model drug, in neutral and acidic conditions. Moreover, Higuchi and Korsmeyer-Peppas models were used to study the release kinetics of DOX. Obtained results confirmed the suitability of Fe3O4@Cit@OAPOSS as a potential novel nanocarrier for drug delivery.

A facile approach for grafting ion imprinted polymer onto magnetic multi-walled carbon nanotubes for selective removal and preconcentration of cadmium in food and wastewater samples prior to atomic spectrometric determination

A 3D Fe3O4@MWCNT-CdIIP was synthesized by the oxidizing surface of multi-walled carbon nanotubes with carboxylic acid end groups and its subsequent termination with an ion imprinted polymer. An artificial neural network manifests better predictability than the central composite design methodology for optimising the adsorption procedure. The adsorption capacity was 109 mg g−1 (2.5 times more than non-imprinted polymer) under optimized conditions (pH; 5.6, time; 15 min, concentration; 800 μg mL−1 temperature; 25 °C), which was in accord with Toth isotherm. Fractal-like pseudo-second-order kinetics was found reasonably fast, with 66 % adsorption in 5 min. Solid phase extraction coupled Flame atomic absorption spectrometry method provides selective recognition towards Cd(II), with limit of detection; 1.13 µg/L, limit of quantification; 3.21 µg/L after preconcentration (preconcentration factor; 50) and good robustness. The developed method was applied for Cd(II) determination in food (tea, coffee, bread, tobacco, radish, spinach), water and wastewater (>99 % removal as well). Cd(II) loaded IIP was further utilized to remove anionic dyes with >95 % removal.

Improved adsorptive purification and effective separation of acidic and lactonic sophorolipid biosurfactant

Crude Sophorolipid extract obtained from fermentation broth contains both acidic and lactonic forms of Sophorolipid with different degrees of acetylation and varying lengths of the fatty acid chains. Carboxylic end in the acidic form of the fatty acid is free, whereas in the lactonic form, it is internally esterified. Sophorolipid show different physicochemical properties with wide range of applications for each structural compound. This work represents the separation and purification strategies of acidic and lactonic Sophorolipid obtained from crude extract. Depending on structure of Sophorolipid molecule different resin were selected for screening based on % binding per ml of resin, % elution and % assay purity of the product obtained.Based on binding study, uptake kinetic, adsorption isotherm and Simchrome software results, macroporous adsorbent SEPABEADS SP 825L was selected as the choice of resin for preparative separation. Breakthrough capacity of the resin was calculated to be 37.8 and 2.801 mg/mL for lactonic and acidic SL respectively. Column study was performed to justify the previous results and 10 g of crude product was processed to obtain 4.2 and 3.9 g of acidic and lactonic SL having the assay purity of more than 90%.

Synthesis of High Injection Molding Performance and Low Acetaldehyde Poly(Ethylene Terephthalate) by Eco-Friendly and Highly Active Titanium Catalyst

In this paper, ECO-friendly titanium magnesium catalyst with high activity was synthesized, and titanium based bottle polyester was synthesized on a 30,000 ton annual industrial plant. At the same time, the characterization and processing properties of titanium based and antimony based polyester were studied. Compared with commercial antimony based polyester, TMPC chips had faster SSP rate and lower AA content, easier crystallization and high catalyst activity, easy to form macromolecular chains, and the rheology of polyester melt also showed a wider processing range. However, the chain end thermal degradation reaction of titanium based bottle chips was slightly larger than that of antimony based bottle chips, and the α transition temperature in DMA test also led to the molecular chain motion of titanium bottle chips is more easily affected by temperature, which was not conducive to maintaining a better viscosity drop and AA value of bottle preform for a long time in the high-temperature injection molding process. To sum up, according to the performance test results, by using TMPC catalyst and adjusting the processing conditions to control the injection molding process of TMPC polyester, titanium bottle preform with better viscosity drop and AA content can be obtained. Finally, the bottle preform with a weight of 28.5g was prepared by using titanium TMPC bottle chips. The injection molding processing temperature was reduced by 10 °C, the viscosity drop was equivalent to that of commercial antimony bottle preform, the end carboxyl group was reduced by 54%, the color index b value was reduced by 17.3%, and the AA content was reduced by 19.8%.

Novel efficient method of chemical upcycling of waste poly(ethylene terephthalate) bottles by acidolysis with adipic acid under microwave irradiation

In this work, for the first time, the reaction of post-consumer poly(ethylene terephthalate) (PET) bottles with adipic acid (AA) under microwave (MW) irradiation without catalyst was investigated. An efficient procedure to isolate various materials was proposed, namely the excess adipic acid, terephthalic acid, and novel oligo(ethylene adipate-co-terephthalate) (OEAT) with carboxylic end groups. The structure of OEAT was confirmed by FTIR, 1H-NMR, and ESI-MS. OEAT is a mixture of oligomers, containing co-oligomers of ethylene adipate and terephthalate, and nonreacted adipic acid. An explanation of the mechanism of the reaction was proposed through a concerted six-member ring formation including an O-alkyl fission process. Adipic acid and terephthalic acid were recovered and used as basic materials. OEAT was used for curing diglycidyl ether of bisphenol-A (DGEBA) resin and applied as a coating material. This upcycling method of PET showed high atom efficiency and high isolated yield reaction.

A kinetic scission model for molecular weight evolution in bioresorbable polymers

AbstractFurther development of bioresorbable devices for use in clinical applications, where they can reduce long term risks, has been hindered by the complex degradation mechanisms that bioresorbable polymers exhibit and the difficulty this causes in designing suitable devices. Furthermore, experimental degradation studies often take years to complete, and small changes to the design of the test sample may significantly alter the degradation behavior. Motivated by existing degradation models, we present a kinetic scission model to predict how the molecular weight distribution evolves as a function of degradation time for bioresorbable polymers. Here, a refined kinetic model has been developed to capture the autocatalytic effect of carboxylic acid ends created via chain scissions, and our framework accounts for reduction in molecular weight via the cleavage of monomers from chain ends and from scissions in the middle of the polymer chain. These developments allow for a more complete representation of the molecular weight distribution during degradation. Young's modulus is estimated by approximating the changes in entropy for the molecular weight distributions following previous so‐called “entropy spring” models. The results obtained are quantitatively compared to and calibrated with existing experimental data for PLGA films. Finally, the effect of the initial carboxylic acid end on the degradation behavior is explored.

Charge-Converting Nanoemulsions as Promising Retinal Drug and Gene Delivery Systems.

Aim: This study aimed to develop phosphatase-responsive ζ potential converting nanocarriers utilizing polyphosphate-coated cell-penetrating peptide (CPP)-decorated nanoemulsions (NEs) as a novel gene delivery system to retinal cells. Methods: Poly-l-lysine (PLL) was first conjugated with oleylamine (OA) only at its carboxylic end to form the amphiphilic PLL–oleylamine (PLOA) conjugate. Afterward, NEs were loaded with PLOA prior to being coated with tripolyphosphate (TPP) to generate PLOA/TPP NEs. A plasmid containing a reporter gene for green fluorescent protein plasmid (pGFP) was complexed with cationic surfactants forming hydrophobic ion pairs that were loaded in the oily core of NEs. Phosphate removal, ζ potential conversion, and cytotoxicity of the system were evaluated. Cellular uptake and transfection efficiency were investigated in 661W photoreceptor-like cells via microscopic analysis, fluorescence spectroscopy, and flow cytometry. Results: Dephosphorylation of PLOA/TPP NEs triggered by alkaline phosphatase (ALP) resulted in the exposure of positive amine groups on the surface of NE droplets and a notable conversion of the ζ potential from −22.4 to +8.5 mV. Cellular uptake of PLOA/TPP NEs performed on 661W photoreceptor-like cells showed a 3-fold increase compared to control NEs. Furthermore, PLOA/TPP NEs also showed low cytotoxicity and high transfection efficacy with ∼50% of cells transfected. Conclusions: Polyphosphate-coated CPP-decorated NEs triggered by ALP could be a promising nanosystem to efficiently deliver drugs and genetic materials to photoreceptor-like cells and other retinal cells for potential treatments of retinal diseases.

Optimization of the primary purification process of extracting sphorolipid from the fermentation broth to achieve a higher yield and purity

Abstract Sophorolipid (SL) is a surface-active glycolipid biosurfactant with promising industrial applications. It is synthesised by fermentation of hydrophobic and hydrophilic substrates using selected non-pathogenic yeasts. However, its applications are limited by high production costs and ineffective product recovery in downstream purification stages. Natural sophorolipids are produced in six to nine different hydrophobic sophorosides, where the carboxyl end of the fatty acid is either free, which is known as the acidic or open form, or it can be esterified internally to produce the lactonic form. The present study deals with the screening and selection of suitable solvents for the extraction of acidic and lactonic SL from fermentation broth. The optimisation study involves exhaustive extraction with the six different immiscible solvents ethyl acetate, butyl acetate, methylene dichloride, methyl tert.-butyl ether, methyl iso-butyl ketone and methyl ethyl ketone. The partition coefficient (Kd), which is the ratio of the solute concentration in the organic layer compared to the aqueous layer, determines the performance measurement of the extraction process in terms of yield and purity of the desired solute. The factors that influence exhaustive extraction were the broth to solvent ratio and the extraction stages. The optimal extraction conditions for the highest possible yield were a broth to solvent ratio of 1:1 and a number of extraction steps of 2. Methylene dichloride showed better results in terms of yield and selectivity in the extraction of acidic and lactonic SL from the fermentation broth compared to the other solvents investigated. For lactonic SL, the highest Kd value determined was 36.6 and for acidic SL the highest Kd value was 1.14.

Analysis of Foot and Mouth Disease Virus Polyprotein for Multi Peptides Vaccine Design: An In silico Strategy

Foot-and-mouth disease virus (FMDV) is small RNA virus from Picornaviridae family; genus Aphthovirus. FMDV causes maximum levels of infectivity in cattle and harmful socioeconomic effects. The present report attempted to design vaccine candidate from the polyprotein of FMDV to stimulate protective immune response. The IEDB server was used to predict B and T cells epitopes that were linked via GPGPG and YAA linkers, respectively. Mycobacterium tuberculosis 50S ribosomal protein was exploited as an adjuvant and a six histidine-tag sequence was linked to the carboxyl end of the vaccine for purification and identification. The predicted vaccine comprised 313aa and was antigenic and not allergic. Moreover, the vaccine was acidic and showed stability and hydrophilicity. Vaccine secondary and tertiary structures were predicted. The tertiary structure was refined to ameliorate the quality of the global and local structures of the vaccine. Vaccine model validation was performed and the final quality score of the structural model was computed. The validated model was used for molecular docking with bovine (N*01801-BoLA-A11) allele. Docking process in terms of binding free energy score was significant. Vaccine solubility was investigated based on the protein of E. coli and the stability was based on the disulfide bonding to lessen the entropic and mobile points in vaccine. Lastly, the in silico cloning ensured the proper cloning and best translation of the DNA of vaccine in molecular vectors.

Highly Ordered Supramolecular Assembled Networks Tailored by Bioinspired H-Bonding Confinement for Recyclable Ion-Transport Materials

Highly Ordered Supramolecular Assembled Networks Tailored by Bioinspired H-Bonding Confinement for Recyclable Ion-Transport Materials

Liddle syndrome misdiagnosed as primary aldosteronism is caused by inaccurate aldosterone-rennin detection while a novel SCNN1G mutation is discovered

Purpose Through describing the confusing misdiagnosis process of Liddle syndrome, we try to reveal the importance of accurate aldosterone-renin detection and a genetic test for Liddle syndrome. Methods We found a family of hypertension and hypokalaemia with the proband of a 21-year-old female who had been misdiagnosed as primary aldosteronism (PA). She presented with high aldosterone and low renin levels. Aldosterone is not suppressed in the saline infusion test and captopril challenge test. However, treatment with a standard dose of spironolactone has no blood pressure improvement effect. A heterozygous variant of SCNN1G was found with whole exome sequencing and Liddle syndrome is indicated. Treatment with amiloride was effective. We rechecked aldosterone-renin levels with two different aldosterone and renin test kits. Clinical features and the mutant gene SCNN1G of each family member were determined by the Sanger method. Results The two kits had nearly opposite results. Among those Liddle syndrome patients confirmed by a genetic test, for Test kit A all ARR were screened positive while for test kit B negative. It seems Test kit B is consistent with the diagnosis while test kit A misleads the diagnosis. A novel SCNN1G mutation, c.1729 C > T, was found in this family, which introduce a premature stop codon in the γ subunit in the epithelial Na+ channel (ENaC) and resulted in a deletion of 72 amino acids at the carboxyl end. Conclusion inaccurate ARR detection might misdiagnose Liddle syndrome. A Gene test is an important method for the diagnosis of Liddle syndrome. A novel SCNN1G missense mutation, c.1729 C > T, is found in a Chinese family.

The Deubiquitinase USP29 Promotes SARS-CoV-2 Virulence by Preventing Proteasome Degradation of ORF9b.

ABSTRACTUbiquitin signaling is essential for immunity to restrict pathogen proliferation. Due to its enormous impact on human health and the global economy, intensive efforts have been invested in studying severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its interactions with hosts. However, the role of the ubiquitin network in pathogenicity has not yet been explored. Here, we found that ORF9b of SARS-CoV-2 is ubiquitinated on Lys-4 and Lys-40 by unknown E3 ubiquitin ligases and is degraded by the ubiquitin proteasomal system. Importantly, we identified USP29 as a host factor that prevents ORF9b ubiquitination and subsequent degradation. USP29 interacts with the carboxyl end of ORF9b and removes ubiquitin chains from the protein, thereby inhibiting type I interferon (IFN) induction and NF-κB activation. We also found that ORF9b stabilization by USP29 enhanced the virulence of VSV-eGFP and transcription and replication-competent SARS-CoV-2 virus-like-particles (trVLP). Moreover, we observed that the mRNA level of USP29 in SARS-CoV-2 patients was higher than that in healthy people. Our findings provide important evidence indicating that targeting USP29 may effectively combat SARS-CoV-2 infection.

Ultralow Wear Self-Mated PTFE Composites

Remarkably low wear rates were observed in PTFE–PEEK and polytetrafluoroethylene (PTFE)-alpha-alumina composites when evaluated in a “self-mated” configuration, where a polymer pin is slid against a polymer countersample of the same composition. Each composite was tested in a controlled humidity environment on a linearly reciprocating tribometer on two different countersamples: a polymer countersample (self-mated) and a stainless steel countersample for comparison. For all the self-mated PTFE–PEEK composites [polyether ether ketone (PEEK) wt % 10, 20, 30, 40, and 50], the average friction coefficient was reduced, and the steady-state and total specific wear rates were improved when compared to testing against stainless steel. Self-mated PTFE–PEEK (wt % 10–40) achieved ultralow wear rates on the order of 10–9 mm3/Nm and friction coefficients of 0.08–0.14. When compared with samples slid against stainless steel, IR spectroscopy of the sliding surface showed that the self-mated PTFE–PEEK composites accumulate more PEEK at the sliding interface and more expression of a tribochemical carboxylate species, which have been linked with ultralow wear PTFE materials. The PTFE composites slid on steel rely on the formation of transfer films for ultralow wear performance. This is achieved by unidirectional increasing surface energy gradients from the polymer pin to the steel substrate, which dominate the transport and wear of PTFE composites slid on steel. However, the self-mated ultralow wear PTFE-based composites rely only on the formation and stability of tribofilms that consist of tribochemically altered PTFE with new carboxylate end groups as well as accumulated filler (i.e., PEEK or alumina). These films have self-regulating, minimal differences in surface energy. The close match of these low-energy surfaces contributes to low friction and ultralow wear. The self-mated PEEK-filled PTFE outperforms the alumina-filled PTFE primarily because of the ease at which PEEK accumulates at the surface. Additionally, the reinforcement and anchoring of the surface is better for a polymer blend than a particle-reinforced composite.

Nano drug (AgNPs capped with hydroxychloroquine): Synthesis, characterization, anti-covid-19 and healing the wound infected with S. aureus

Almost existing anti-viral drugs are only organic molecules that are able to circumvent the system the virus works with, which leaves it facing the immune system of our bodies and then kills it. Unfortunately, this type of pharmacological fight did not succeed in a way to overcome this virus, so it became necessary to think outside the box, to find a drug that would kill the virus or alter its protein structure. This research aims to prepare silver nanoparticle (AgNPs) by the green method depending on the reaction of the silver nitrate (safe for humans) with the phoenix dactylifera extract (safe for humans) and then coated with the hydroxychloroquine (HQ, known antiviral drug). This substance will fight the virus with different mechanisms (i) silver will carry the drug to cells easily, and then (ii) nano silver will perform a physical inhibition of the virus and thus reduce its susceptibility to binding to host cells. In addition, (iii) silver nanoparticle is much smaller than the size of the virus which qualifies it to cross into the virus and change the structure of RNA. Furthermore, (iv) it is possible for silver to interact with the amino and carboxylic ends in the virus proteins. The results of TCID50 shows that the prepared nano drug is able to reduce the viability of covid-19 to about 22% using 400 mg/ml of AgNPs/HQ. The resulted nanodrug was also used for healing the wound infected with S. aureus and the histological results revealed that all of the disease symptoms improved, with the epidermal layer multiplying quickly and the infected wounds healing quickly.