Soheila Kashanian

      Lead (Pb2+) is a highly toxic, non-biodegradable heavy metal that bioaccumulates in the food chain, and even very low levels of exposure pose serious risks to human health. Conventional techniques for its determination, such as atomic absorption spectroscopy and ICP-MS, are accurate but require expensive instrumentation, skilled operators, and long analysis times, which limits on-site and routine monitoring. In this work, a fluorescent "turn-off" sensor based on polymer dots (Pdots) was developed for the selective and quantitative determination of Pb2+ in aqueous media. The Pdots were prepared through a simple, one-step, and green hydrothermal route (160 °C, 4 h) using xanthan gum, a low-cost natural polysaccharide, together with o-phenylenediamine (o-PD) as the fluorophore precursor and 15-crown-5 as a capping agent and lead-recognizing ionophore. FT-IR spectroscopy confirmed the formation of new C=N, C–N, and amide linkages among the precursors, UV-Vis spectroscopy indicated the formation of an extended conjugated system, and FESEM-EDS revealed a uniform, quasi-spherical morphology with a homogeneous distribution of carbon, nitrogen, and oxygen. The Pdots exhibited a strong emission at 420 nm under excitation at 342 nm. The sensing conditions were systematically optimized, and the best response was obtained at a xanthan gum to o-PD ratio of 50:50, pH 6, a probe volume of 90 µL, and an incubation time of 3 min. The addition of Pb2+ quenched the fluorescence of the Pdots, which is attributed to the interaction of Pb2+ with the crown ether cavity and the amine and carboxyl groups on the Pdot surface. The calibration curve showed two linear ranges, 1–6.5 ppm (I0 ? I = 23.60 C + 22.02, R2 = 0.98) and 15–46.3 ppm (I0 ? I = 1.48 C + 209.92, R2 = 0.97), with a limit of detection of [LOD value] µg/L and a limit of quantification of [LOQ value] µg/L. The applicability of the sensor to a complex biological matrix was evaluated by determining Pb2+ in human serum samples using the standard addition method, with recoveries of [recovery range value] %. The results show that combining a natural biopolymer as a template and passivating agent with a crown ether as a selective ionophore provides a rapid, simple, low-cost, and environmentally friendly platform for the optical determination of lead ions, with potential for environmental monitoring and clinical analysis. Keywords: Fluorescent sensor; Polymer dots; Xanthan gum; o-Phenylenediamine; 15-Crown-5; Lead ion (Pb2+); Hydrothermal synthesis; Fluorescence quenchin

   بيماري آلزايمر يك بيماري تحليل‌برنده عصبي است و اصلي‌ترين علت زوال عقل (دمانس) در سراسر جهان به شمار مي‌رود. تا به امروز درمان‌هاي موجود براي اين بيماري محدود هستند. يكي از دلايل اين محدوديت، دشواري در درك كامل علل بروز بيماري و همچنين وجود سد خوني–مغزي است، كه يك مرز نيمه‌تراوا بوده و از ورود مولكول‌هاي محلول به سيستم عصبي مركزي جلوگيري مي‌كند. بنابراين، نياز به بررسي رويكردهاي جديد براي هدف‌گيري دارو به سمت مغز وجود دارد. با وجود محدوديت‌ها و موانع يادشده، تحقيقات در زمينه? انتقال دارو از مسير بيني به مغز به توسعه? پلتفرم‌هاي اميدبخشي منجر شده است كه از پتانسيل بالايي براي بهبود قابل توجه رسانش دارو به مغز برخوردارند. اين موفقيت از طريق هدف‌گيري مسيرهاي خاص بيني، بر اساس ويژگي‌هاي مولكول دارو و سيستم دارورساني، حاصل شده و رسانش مؤثر دارو به بخش‌هاي مختلف مغز را امكان‌پذير كرده است. بررسي اين حوزه? مطالعاتي مي‌تواند به توسعه? سامانه‌هاي جديدتر و كارآمدتري بينجامد كه درمان بيماري‌هاي CNS را به‌طور چشمگيري بهبود مي‌دهند. در حال حاضر، مهاركننده‌هاي آنزيم استيل‌كولين‌استراز تأييدشده توسط سازمان غذا و داروي آمريكا براي درمان بيماري آلزايمر شامل donepezil (Dnp)، Rivastigmine (Rv) و galantamine (GLn) هستند. شواهد حاصل از مطالعات حيواني نشان مي‌دهد كه Rv در نواحي قشر مغز و هيپوكامپ، كه بيشترين تأثير را از بيماري آلزايمر مي‌پذيرند، مهاركننده? قوي‌تري نسبت به ساير AChEIs است. در سال‌هاي اخير، نانوذرات كه قادر به انتقال مولكول‌ها از سد خوني–مغزي هستند مورد توجه فراوان قرار گرفته‌اند و رويكردي اميدبخش براي رسانش هدفمند دارو به مغز محسوب مي‌شوند. در اين مطالعه، هدف بر آن است كه  نانوذرات كيتوسان اصلاح‌شده با آرژنين و سيستئين  را براي  تجويز داخل‌بيني ريواستيگمين  در درمان علامتي بيماري آلزايمر سنتز و شناسايي كنيم. نانوذرات مزاياي خاصي براي دارورساني بيني دارند؛ به دليل اندازه كوچك، نسبت سطح به حجم بالا و توانايي عبور مؤثر از لايه مخاط، اگر به‌خوبي طراحي شوند، مي‌توانند از سد مخاطي عبور كنند، از پاك شدن مخاطي جلوگيري كنند و زمان ماندگاري دارو در محل جذب را افزايش دهند، كه شانس انتقال به مغز را بالا مي‌برد. در اين زمينه،  كيتوسان  به‌عنوان پليمر پايه جذاب انتخاب شده است به دليل ويژگي‌هايي مانند زيست‌سازگاري عالي، زيست ‌تجزيه ‌پذيري، خواص مخاط ‌چسبي، سميت پايين و توانايي در باز كردن موقت اتصالات محكم بين سلول‌هاي اپيتليال. براي تقويت بيشتر چسبندگي مخاطي و نفوذپذيري، كيتوسان را به‌صورت شيميايي با  آرژنين و سيستئين  اصلاح كرديم؛ آرژنين گروه‌هاي كاتيوني اضافي فراهم مي‌كند كه تعامل الكترواستاتيكي با مخاط منفي بيني را تقويت مي‌كند، در حالي كه سيستئين گروه‌هاي تيول معرفي مي‌كند كه قادر به تشكيل پيوند دي‌سولفيدي با گليكوپروتئين‌هاي مخاط هستند و در نتيجه زمان ماندگاري و نفوذ از اپي‌تليوم بيني را بهبود مي‌بخشند. براي تأييد اتصال موفق آمينواسيدها به اسكلت كيتوسان، آزمون‌ها و تكنيك‌هاي مشخصه ‌يابي مختلف به ‌كار گرفته شدند، سپس بهينه‌سازي پارامترهاي فرمولاسيون و بررسي الگوي رهايش دارو از نانوذرات اصلاح‌شده انجام گرديد. انتظار مي‌رود اين سامانه نانوذره‌اي كيتوسان اصلاح‌شده با آرژنين و سيستئين به‌عنوان يك حامل كارآمد و زيست‌سازگار براي تجويز داخل ‌بيني ريواستيگمين عمل كند و زيست‌دسترس‌پذيري و اثربخشي درماني آن را در درمان علامتي بيماري آلزايمر بهبود دهد، و همچنين باعث  كاهش عوارض جانبي ريواستيگمين  شود، با امكان استفاده از  دوزهاي درماني پايين‌تر، هدف‌گيري بهتر به مغز و كاهش توزيع سيستميك.

Bilirubin BR a bile pigment is present in human serum in two different forms unconjugated bilirubin Bu and conjugated bilirubin BC the clinical significance of the bilirubin determination plays a major role in diagnosis prediction and treatment of hemolytic disorders in both adult and Infants. BR, a breakdown product of hemoglobin, is a remarkable marker for the diagnosis of hemolytic disorders. Low BR concentration in the blood is caused by a high risk of coronary heart disease and iron deficiency and high level leads to hyperbilirubinemia, so it’s important to find easy, inexpensive, and sensitive methods to determine a percentage of BR. There are many methods to determine BR, one of them is the “Fluorometric method” which possesses several appealing features, including low cost, easy preparation and fast response which could hold great potential for diagnostics applications. BR acts as a bichromophoric molecule. This feature accounts for the variability of BR absorption and fluorescence properties and for inter chromophore exciton energy transfer events, depending on the concentration of the molecule and its microenvironment in solution, and on the wavelength of interrogating light cost effective fluorescent Nano- sensor was developed for the early and easy detection of hyperbilirubinemia. Fluorescent copper nanoclusters due to their fast surface oxidation may cause a challenge to prepare it. However, it also has properties such as low cost. But it’s also had some properties such as, their low cost, good water solubility and wide availability of precursor become an active research area, copper nanocluster has excellent fluorescent properties that paved the way to development of new sensors complexed with chitosan as a stabilized factor of copper nanoclusters and to trace the presence of BR. The emission spectra were recorded in the wavelength range of 300 to 500 nm upon excitation at 330 nm. The present sensing strategy has appealing features, including low cost, easy preparation and fast response which could hold great potential for biological and clinical diagnostics applications. Numerous nano materials capable of emitting fluorescent light, have been developed for biosensing, bioimaging, and drug delivery for biosensing, bioimaging, and drug delivery. These include nanocluster, silica-based materials, nanoparticles, quantum dots QDs . So, the second sensor is Carbon quantum dots CQDs (typical size <10nm). That is prepared by hydrothermal carbonization and uses curcumin with citric acid and thiourea to produce these carbon quantum dots. So, such as new curcumin has limitations in clinical studies because of its stability, low water solubility, and adsorption. So, to improve the properties of curcumin and use nanostructured material carriers and to enhance Curcumin availability. This sensor is very selective to determine BR and very sensitive.  

   In this work, nanocomposite hydrogels containing CsMe, PVA, ZnO-   were prepared as wound dressing.The purpose of this research is to investigate the performance of ZnO-   in the wound healing process and compare it with ZnO ontinment in the wound healing process. In vivo studies demonstrated that the group treated with hydrogel containing ZnO-   (0.5%) caused faster wound healing compare to the other group. In the group treated with ZnO ointment, The results showed that wound healing using ZnO in the form of nanoparticles is better than using ZnO ointment

  To control the corrosion rate of temporarymagnesium (alloy AZ31) implants, we used Polycaprolactone (PCL) polymer nanofibers in the presence of curcumin (Cur), which has anti-inflammatory and anti-infection properties. We produced PCL, PCL-Cur, and Sodium Alginate (SA), Polyvinyl alcohol (PVA) polymer coatings, which SA-PVA was used as an undercoat to increase adhesion, using a simple and cost-effective electrospinning technique. We used drug release, Fourier Transform Infrared (FT-IR), Scanning Electron Microscopy (SEM), and Contact Angle (CA) tests, to examine the properties of the produced fibers, and we found out that the produced fibers have continuous strands in nanoscale dimensions, and the presence of Cur had no effect on PCL fiber morphology, and only it increased fiber adhesion slightly. We used weight measurement tests, pH measurement, SEM, Polarization, and Electrochemical Impedance Spectroscopy (EIS) to evaluate the effect of different polymeric coatings on the surface of Mg metal. Finally, we found that the PCL-Cur hydrophobic polymer coating had the best function during the study period in the simulated body fluid (SBF).

  Human serum albumin nanoparticles as an effective exemestane drug delivery system to treat breast cancer: preparation and analysis

ABSTRACTBiosensors research is a rapid growing field in which tens of hundreds of papers have been published over the years; even more numerous biosensors have been developed for detection of biomolecules among them the phenolic compounds. In such, catechol which reacts with appropriate enzymatic bioreceptor like 3?-Hydroxysteroid dehydrogenase (3?-HSD). the aim in this project is to build up a novel electrochemical biosensing electrode for the determination of cholic acid by covalent immobilization of 3?-HSD on a glassy carbon electrode (GCE) modified by the mixture of carboxylated multiwall carbon nanotube (MWCNT-COOH), titanium dioxide (TiO2) in chitosan splution.   In order to achieve this aim, we examined the immobilized enzyme in electrochemical biosensor. The fabrication process of the sensing surface was characterized by Field Emission Scanning Electron Microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The electrochemical results showed that 3?-HSD was immobilized onto modified glassy carbon electrode by the covalent interaction between 3?-HSD and terminal functional groups of the MWCNT-COOH. The modified electrode showed a direct electron transfer reaction between 3?-HSD and the electrode. Under optimum conditions, the biosensor showed a linear response in the range of 7 - 43 nM. The limit of detection was calculated to be 5.9 nM with a correlation coefficient of 0.96 and the sensitivity was 900 A L mol?1 for biosensor.

  Abstract    In this study, we have focused on the fabrication and characterizations of three kinds of amino acid- modified chitosan (CS) nanoparticles structured by graft reaction with amino acid [L-alanine (Ala), L-asparagine (Asn) and L-tryptophan (Trp)]. It provides a condensed source of new insights and an improved understanding of the role of pH values of release medium on the percentage of cumulative release in advancing drug delivery. The structure of nanoparticles was elucidated by Fourier Transform Infrared Spectroscopy (FTIR) and UV-Vis spectroscopy. The shape, morphology, and mean particle size were determined by scanning electron microscopy (SEM). The nanoparticles effectively surrounded a hydrophobic model drug such as silymarin (Sly) and demonstrated different encapsulation efficiencies (EE), loading capacities (LC), and controlled drug release profiles depending on drug concentration, medium pH and type of amino acids. At pH 5, drug concentration has no effect on the LC of Sly-loaded Asn-nanoparticles while EE was increased with increasing the drug concentration, nonetheless at physiological pH (7.4), drug concentration did not affect the release rate and at high pH (9), EE was decreased with increasing drug concentration in all types of nanocarrier. The profile of cumulative release indicated that it was affected by the type of amino acids, medium pH and drug concentration. In addition, the interactions between hydrophobic moiety of nanoparticles and the hydrophobic drug have great effect on the release behavior. The affinity between the drug and the nanocarrier may contribute to the main mechanism determining drug release.