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Abd-Elaal, Ali A.,Tawfik, Salah M.,Lee, Yong-Ill Elsevier 2017 Journal of molecular liquids Vol.247 No.-
<P>A cationic polyvinylpyrrolidone derivative (Cat-PVP) was prepared via Claisen-Schmidt condensation in KOH media (1.0 mM) and characterized using FT-IR and H-1 NMR spectroscopy. The prepared Cat-PVP was utilized to prepare a stable fluorescent copper coordinate Cat-PVP with outstanding properties. The Cu-Cat-PVP was successfully used to detect hydrogen sulfide ( H2S) due to the strong affinity between sulfur and copper. The quenching effect on the fluorescence intensity of the Cu-Cat-PVP probe showed very good linearity with H2S concentrations in the range of 1-40 mu M, with a detection limit as low as 0.13 mu M. The promising probe displayed high selectivity toward H2S over anions and bio-thiols and was successfully applied for detecting H2S in real samples such as human serum and water. (C) 2017 Published by Elsevier B.V.</P>
Tawfik, Salah M.,Shim, Jimin,Biechele-Speziale, Dana,Sharipov, Mirkomil,Lee, Yong-Ill Elsevier Sequoia 2018 Sensors and actuators. B Chemical Vol.257 No.-
<P><B>Abstract</B></P> <P>Novel “turn off-on” optosensors based on amphiphilic thiophene copolymers coated CdTe quantum dots (P1QDs and P2QDs) were developed for the dual detection of heparin and spermine. The emission of the P1QDs and P2QDs is found to be quenched in the presence of heparin by electron transfer mechanism through electrostatic and hydrogen bonding interactions. Upon the addition of spermine, heparin has been removed from the surface of P1QDs and P2QDs due to the strong electrostatic interactions between spermine and heparin, which showed significant fluorescence recovery of the sensors. Under optimum conditions, both P1QDs and P2QDs sensors displayed excellent limits of detection for heparin of 1.59nmolL<SUP>−1</SUP> (R<SUP>2</SUP> =0.9955) and 0.88nmolL<SUP>−1</SUP> (R<SUP>2</SUP> =0.9908) with linear ranges of 1–11μmolL<SUP>−1</SUP> and 1–10μmolL<SUP>−1</SUP>, respectively. P1QDs and P2QDs also showed remarkable limits of detection for spermine of 2.90nmolL<SUP>−1</SUP> (R<SUP>2</SUP> =0.9957) and 1.66nmolL<SUP>−1</SUP> (R<SUP>2</SUP> =0.9928) with linear ranges of 0.05–15μmolL<SUP>−1</SUP> and 1–12μmolL<SUP>−1</SUP>, respectively. The P1QDs and P2QDs sensors show a high selectivity to heparin and spermine over common interfering substances and ions. In addition, the proposed method was successfully utilized in serum samples, which could facilitate the further heparin and spermine biochemical and biomedical research.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel CdTe QDs coated with amphiphilic conjugated polythiophenes were developed. </LI> <LI> Highly fluorescent P1QDs and P2QDs (QY, 63% and 78%) were used as “turn off–on” sensors. </LI> <LI> The sensors show highly selective and sensitive responses to heparin and spermine. </LI> <LI> The sensors were successfully applied to detect heparin and spermine in human serum. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Tawfik, Salah M.,Lee, Yong-Ill Techno-Press 2021 Advances in nano research Vol.11 No.5
Natural and anthropogenic activities lead to the generation of polycyclic aromatic hydrocarbons (PAHs), persistent contaminants that adversely affect the environment and public health. However, highly sensitive, fast, and portable techniques for the detection of PAHs remain a technological challenge. The rapid analysis of urinary levels of 1-hydroxypyrene (1-HP) would enable PAH carcinogens to be measured using biomonitoring techniques. Here, we demonstrate biocompatible, easy-to-use, and portable sensors based on novel π-conjugated metal-organic frameworks (MOFs) for the detection of 1-HP. These sensors were developed by incorporating nonionic conjugated polythiophenes with a PLQY as high as 65% into lanthanide-MOFs (CP1-Eu-MOF and CP2-Eu-MOF) using an in-situ synthesis strategy. The emission of the sensors can be effectively quenched by 1-HP via hydrophobic, π-π stacking, and hydrogen bonding interactions. Significantly, the unique structure of CP2-Eu-MOF sensor displays superior performance with enhanced sensitivity (LOD ~1.02 pM) that is 1.63 times higher than that of CP1-Eu-MOF (LOD ~1.66 pM). More importantly, we successfully demonstrated the possibility of employing wax-printed paper in combination with a fast and cost-effective smartphone for rapid 1-HP detection. Moreover, portable sensory films were fabricated by incorporating CP2-Eu-MOF into a poly(vinylidene difluoride) (PVDF) matrix to produce CP2-Eu-MOF/PVDF films for the visual detection of 1-HP levels as low as 25 pM. Finally, the feasibility of successfully analyzing the levels of 1-HP in urine was verified by testing real urine samples with satisfactory recoveries of 94.1-103.5%. This method provides new pathways for the biomonitoring of polyaromatic environmental pollutants.
Salah M. Tawfik,Mirkomil Sharipov,Buithehuy,Zayakhuu Gerelkhuu,Dana Biechele-Speziale,이용일 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.57 No.-
Naturally modified nonionic alginate-based polymers were synthesized to act as functionalizing agentsfor upconversion nanoparticles (UCNPs). The synthesized polymer-UCNPs hybrid nanoparticles showhigh stability, excellent biocompatibility and enhanced luminescence intensity for NIR imaging. Additionally, our results show that due to the large cavities of the materials and amphiphilic polymershell, these nonionic alginate-functionalized UCNPs were able to load the anticancer drug doxorubicin(DOX) with the exceptional efficiency as well as release it in a highly controlled and selectivepH-responsive manner via folate receptor-mediated endocytosis. Targeting using this multifunctionpolymer significantly improved the capability of DOX-loaded UCNPs to inhibit the growth of KB cancercells than free DOX. These biocompatible nonionic alginate-functionalized UCNPs hold substantialpotential as effective anticancer drug-delivery carriers and NIR imaging agents.
Tawfik, Salah M.,Sharipov, Mirkomil,Huy, Bui The,Gerelkhuu, Zayakhuu,Biechele-Speziale, Dana,Lee, Yong-Ill Elsevier 2018 Journal of industrial and engineering chemistry Vol.57 No.-
<P><B>Abstract</B></P> <P>Naturally modified nonionic alginate-based polymers were synthesized to act as functionalizing agents for upconversion nanoparticles (UCNPs). The synthesized polymer-UCNPs hybrid nanoparticles show high stability, excellent biocompatibility and enhanced luminescence intensity for NIR imaging. Additionally, our results show that due to the large cavities of the materials and amphiphilic polymer shell, these nonionic alginate-functionalized UCNPs were able to load the anticancer drug doxorubicin (DOX) with the exceptional efficiency as well as release it in a highly controlled and selective pH-responsive manner via folate receptor-mediated endocytosis. Targeting using this multifunction polymer significantly improved the capability of DOX-loaded UCNPs to inhibit the growth of KB cancer cells than free DOX. These biocompatible nonionic alginate-functionalized UCNPs hold substantial potential as effective anticancer drug-delivery carriers and NIR imaging agents.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Novel biocompatible amphiphilic alginates for functionalizing UCNPs are developed. </LI> <LI> The functionalized-UCNPs possess high stability and less cytotoxicity. </LI> <LI> Functionalized-UCNPs enhanced bioimaging and specific in targeting KB cancer cells. </LI> <LI> Novel UCNP is potentially capable of pH responsive targeted DOX to cancer cell. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
AHMED SALAH MAHMOUD TAWFIK,Mohamed F. Zaky,Tahany G.M. Mohammad,Hanaa A.E. Attia 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.29 No.-
Fungi have long been identified as causal agents of plant diseases. The development of plant antifungalactivity was attempted by synthesis of a new type of anionic and nonionic surfactant. The surfaceproperties were studied, including critical micelle concentration (CMC), effectiveness (pcmc), maximumsurface excess (Gmax), and minimum surface area (Amin). Free energy of micellization and adsorption wascalculated (DG8mic and DG8ads). The antifungal activity of the prepared surfactants was verified in vitro bythe poisoned food technique against eight phytopathogenic fungi: Colletotrichum dematium, Drechslerahawaiiensis, Fusarium oxysporum, Fusarium solani, Humicola fuscoatra, Pestalotia laurocerasi, Phoma spp.,and Phytophthra. The results reported that the percentage inhibition of mycelial growth increases withincreasing concentrations of the surfactant for all fungal species used. These results indicated that thesurfactant inhibited the mycelial growth of all fungal species in a dose-dependent manner. Blendsurfactants have a potential antifungal effect for the control of some phytopathogenic fungi.
Shim Jimin,Tawfik Salah M.,Thangadurai Daniel T.,Lee Yong‐Ill 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.7
The ability to detect pathogenic microbes in water and food samples is of prominent interest, but it remains a great challenge. Herein, we report a simple fluorescence sensor based on amphiphilic conjugated polythiophene (ACPT) for the detection of gram-negative pathogenic bacteria, Escherichia coli, in pH 7.0. The ACPT sensor was synthesized by the oxidative polymerization of water-soluble thiophene monomers in an aqueous solution. The ACPT sensor undergoes the fluorescence “turn on” response at 432 nm upon the addition of E. coli. The ionic complex, which is generated by electrostatic interaction during the short incubation time of 15 min, resulting in the enhancement of the fluorescence intensity of ACPT. The application of ACPT enables the detection of E. coli pathogens in tap water and milk samples with good recoveries of 96.94–100.83% and 93.27–116.75%, respectively, and excellent reproducibility (n = 3, relative standard deviation [RSD] = 1.78%). The current findings pave the way for the promising application of a novel ACPT system that could be used in food safety and environmental monitoring.
Nabel A. Negma,Salah M. Tawfik,Ali A. Abd-Elaal 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1
Here in, the new gemini anionic surfactants with different alkyl chain length were synthesized (C8A,C12A, C16A and C18A). The chemical structure of the synthesized surfactants was confirmed using infraredspectroscopy (IR) and proton nuclear magnetic resonance spectroscopy (1H NMR). Silvernanoparticles colloidal solution of 20–25 nm diameters was prepared using trisodium citrate asreducing agent. The nanostructure of the synthesized surfactant with silver nanoparticles withdiameters ranging from 6.3 to 23.2 nm was prepared and characterized using ultra violetspectrophotometer (UV), transmission electron microscope (TEM), dynamic light scattering (DLS)and energy dispersive X-ray (EDX). The results declare formation and stabilization of silver nanoparticleusing synthesized anionic surfactants. Antimicrobial activity of the synthesized anionic surfactants andtheir nanostructure with silver nanoparticles were evaluated against pathogenic bacteria and fungi. Theantimicrobial activity showed the enhancement in the antimicrobial activity of the synthesized geminianionic surfactants in the nanostructures form.