Development of a molecularly imprinted polymer on silanized graphene oxide for the detection of 17-estradiol in wastewater.

This research article demonstrates the synthesis, characterization, and electrochemical evaluation of a molecularly imprinted polymer (MIP) on the surface of silanized graphene oxide (silanized GO), which is nanostructured and used to quantify 17-estradiol (E2) in wastewater. As characterization methods, X-ray diffraction (XRD), Raman spectroscopy, dynamic scattering light (DSL), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR) were utilized to examine the synthesized GO, silanized GO, MIP-GO composite, and non-imprinted polymer (NIP)-GO (NIP-GO) composite. FTIR results confirmed the successful synthesis of GO composites. Raman study confirmed the synthesis of monolayer silanized GO, MIP-GO composite, and NIP-GO composite. Surface morphology revealed that after polymerization, the surface of silanized GO sheet-like morphology is covered with nanoparticles. Adsorption kinetics studies revealed that adsorption follows the pseudo-second-order kinetics. Further, we studied the performance of a MIP-GO-based sensor by optimizing the effects of pH, scan rate, and incubation period. The linear calibration was achieved between the oxidation peak current and E2 concentration from 0.1 to 0.81 ppm, with a detection limit of 0.037 ppm. The selectivity of the MIP-GO composite was also checked by using other estrogens, and it was found that E2 is 3.3, 0.5, and 1.4 times more selective than equilin, estriol, and estrone, respectively. The composite was successfully applied to the wastewater samples for the detection of E2, and a good percentage of recoveries were achieved. It suggests that the reported composite can be applied to real samples. PRACTITIONER POINTS: An innovative electrochemical sensor was developed for selective detection of 17-estradiol through molecularly imprinted polymer fabricated on the surface of silanized GO (MIP-GO composite). The developed method was comprehensively validated and found to be linear in the range of 0.1 to 0.8 ppm of 17-estradiol, with 0.037 ppm of limit of detection and 0.1 ppm of limit of quantification, respectively. The developed MIP-GO-composite-based electrochemical sensor was found 3.3, 0.5, and 1.4 times more selective for 17-estradiol than equiline, estriol, and estrone, respectively. The applicability of a developed sensor was also checked on wastewater samples, and a good percent recovery was obtained.

Enhancement in photocatalytic selectivity of TiO2-based nano-catalyst through molecular imprinting technology.

Improvement in the photocatalytic selectivity is imperative for the effective and efficient utilization of catalysts. In this study, a molecularly imprinted polymer-coated iron-doped titanium dioxide (Fe-TiO2@MIP) nanocomposite was successfully synthesized by precipitation polymerization while using RB-19 as a template. The synthesized nanocomposites (Fe-TiO2@MIP and Fe-TiO2@NIP) were characterized by Fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM) with energy dispersive X-ray (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Brunauer-EMMETT-Teller (BET), and UV-visible spectrophotometry. The optimized binding experiments revealed a high imprinting factor of 5.0 for RB-19. The catalytic degradation efficiency and selectivity of Fe-TiO2@MIP enhanced to almost complete degradation of RB-19 from 70% for the parent Fe-TiO2 and 76% for Fe-TiO2@NIP. An outstanding degradation selectivity of RB-19 was achieved compared to other competitive dyes. Finally, the analysis of the non-degraded and degraded RB-19 by ESI-MS revealed the presence of different intermediates that fits well with the proposed degradation mechanism. The study opens new possibilities of selective photo-degradation of targeted contaminants that may ultimately lead to efficient use of photocatalysts.

Fabrication of 1-octane sulphonic acid modified nanoporous graphene with tuned hydrophilicity for decontamination of industrial wastewater from organic and inorganic contaminants.

This research work is based on the fabrication of a graphene oxide-based composite (GOBC) to remove the maximum number of contaminants from different industrial effluents. The GO was first intercalated with 1-octanesulphonic acid sodium salt and subjected to microwave irradiation to produce GOBC. Fixed-bed column tests and Jar-tests were performed for removal of the most harmful endocrine disrupting compounds (EDCs) such as bisphenol A, bisphenol S, endosulphan, beta-estradiol, dyes (methylene blue and violate) and toxic metal ions such as Pb2+, Li+, Ni2+, Co2+, Cr6+, Zn2+, Cd2+, Hg2+, Cu2+, and As5+via adsorption. The prepared material was thoroughly characterized for its unique functional and structural properties. The results obtained from Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller, scanning electron microscopy, Raman spectroscopy, water contact angle and X-ray diffraction analysis confirmed the successful preparation of GOBC using the proposed intercalation/microwave method. The water contact angle results showed decreased hydrophilicity of GOBC as compared to GO as the contact angle of GOBC (77.75°) was higher than that of GO (53.98°). The effects of main column parameters such as bed height, initial analyte concentration and solution flow rate were investigated. The results revealed that shorter breakthrough time, and high adsorption capacity were obtained at high flow rates of 1 mL min-1, while longer breakthrough time and lower adsorption capacity were obtained at lower flow rates of 0.5 mL min-1. The effect of bed depth on the breakthrough curve of analyte adsorption was a steep breakthrough curve; or a shorter breakthrough time occurring at lower bed height. The adsorption data obeyed the Yoon-Nelson and Thomas models very well. The adsorption capacity for BPA, BPS, endosulphan, beta-estradiol, methylene blue and violate was found to be 307, 305, 260, 290, 230 and 195 mg g-1, respectively. The adsorption capacity of GOBC for toxic metal ions such as Pb2+, Li+, Ni2+, Co2+, Cr6+, Zn2+, Cd2+, Hg2+, Cu2+, and As5+ was found to be 156, 136, 126, 124, 118, 114, 82, 82, 72 and 72 mg g-1, respectively with excellent kinetics. The adsorption data obtained using Jar-tests revealed that GOBC obeys a Langmuir isotherm and a pseudo second order kinetics model. The analysis of industrial wastewater samples showed good removal efficiency of GOBC.

Fluorene intercalated graphene oxide based CoQ10 imprinted polymer composite as a selective platform for electrochemical sensing of CoQ10.

The new objective of sustainable analytical chemistry is to develop validated robust, swift, simple and highly sensitive analytical methods that are based on cost effective sensing technology. Therefore, in this study the electro-chemical detection of coenzyme Q10 (CoQ10) was achieved using a fluorene intercalated graphene oxide based CoQ10 imprinted polymer composite modified glassy carbon electrode (CoQ10-IGOPC/GCE). The synthesized sensing material was characterized using SEM, XRD and FT-IR to determine the morphology and functional properties. The CoQ10-IGOPC/GCE was characterized by EIS for its electrochemical properties. CoQ10 was detected selectively using Differential Pulse Voltammetry (DPV). Under ideal circumstances, a linear calibration curve with a correlation coefficient (R 2) of 0.991 was produced in the concentration range of 0.0967 to 28.7 µM. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.029 and 0.0967 µM, respectively. Furthermore, the proposed electrochemical sensor was extremely selective, accurate and thoroughly validated with RSD values less than 5%. The developed CoQ10-IGOPC/GCE based electrochemical sensor was successfully used for the detection of CoQ10 in samples of fruits, vegetables, nuts, human blood serum and pharmaceuticals. The CoQ10-IGOPC/GCE based electrochemical method showed good percent recoveries ranging from 94 to 103 percent.

Synthesis of an insulin intercalated graphene oxide nanogel composite: evaluation of its release profile and stability for oral delivery of insulin.

Diabetes mellitus (DM) is a disorder of glucose regulation produced due to insufficient availability of insulin. Generally, insulin is given to diabetes patients via subcutaneous injection which is a painful method to deliver this drug. In this work we have made an attempt to develop an oral drug delivery system that can efficiently deliver insulin to the small intestine. An insulin intercalated GO based nanogel composite (In@GO NgC) was fabricated for oral delivery of insulin. The in vitro release of insulin from In@GO NgC was studied in artificial gastric (pH 1.2) and intestinal (pH 7.5) fluids. The In@GO NgC produced better release in artificial intestinal fluid as compared to gastric fluid. The enzymatic degradation of released insulin was also examined and the results revealed that even after 6 h of incubation, the gel remained stable and the un-degraded insulin seemed to be sufficient for the physiological processes. The efficacy of In@GO NgC was also confirmed by comparing its release profile with non-intercalated GO NgC and nanogel (Ng) without GO. The prepared nanogels were thoroughly characterized using FTIR, SEM, EDS, DSC and DLS. The better release profile and enzymatic stability of In@GO NgC suggests that it can be utilized for oral drug delivery of insulin.

Homoeopathic Management of Allergic Rhinitis: Two Case Reports.

Allergic rhinitis is a commonly encountered condition affecting approximately 20% of the population, and exhibits symptoms either as seasonal or perennial allergic rhinitis. This study was undertaken to assess the efficacy of homoeopathic remedies in the treatment of allergic rhinitis, while also proving that totality of symptoms is important for successful treatment of the cases. The suspected cases of allergy were identified on the basis of clinical presentation. Under inclusive criteria, all of the determined cases of allergic rhinitis were selected irrespective of age, sex, socioeconomic status, religion, or occupation. The cases were recorded, keeping the individualistic and holistic concept in mind. The data were collected by questioning the patient and by physical examination. Results showed that homoeopathic remedies prescribed on the basis of totality of symptoms are efficient in treating allergic rhinitis, along with other necessary precautions taken by the patient. Homeopathic medicines work by optimizing the overactive immune system. They provide a stimulus (in a highly diluted form) to the body like that of the trigger or allergen, leading to the gradual desensitization of the immune system. Remedies used for treating allergies mainly come from the plants or substances that in their raw form are usually responsible for causing allergy-like symptoms.

Sonochemical synthesis of Co3O4 nanoparticles deposited on GO sheets and their potential application as a nanofiller in MMMs for O2/N2 separation.

In this study we report an environmentally friendly, facile and straightforward sonochemical synthetic strategy for a Co3O4/GO nanocomposite using N,N'-bis(salicylidene)ethylenediaminocobalt(ii) as a precursor and graphene oxide sheets as an immobilization support for Co3O4 nanoparticles. The synthesis was facilitated by physical and chemical effects of cavitation bubbles. The synthesized nanocomposite was thoroughly characterized for its composition and morphology using Fourier transform infrared spectroscopy (FTIR), Energy dispersive X-ray spectroscopy (EDS), Scanning electron microscopy (SEM), UV-visible, Raman and X-ray diffraction spectroscopy (XRD), etc. The results show Co3O4 nanoparticles of 10 nm (SD 3 nm) were prepared on well exfoliated sheets of GO. The applicability of the synthesized Co3O4/GO nanocomposite was optimized as a nanofiller for mixed matrix membranes (MMMs) comprised of poly(2-acrylamido-2-methyl-1-propanesulfonic acid) and polyvinyl chloride. The affinity of the prepared MMMs was evaluated for the separation of O2/N2 gases by varying the concentration of nanofiller, i.e. 0.03%, 0.04%, 0.05% and 0.075% (w/v). The results display high separation performance for O2/N2 gases with excellent permeance (N2 167 GPU and O2 432 GPU at 1 bar) and O2/N2 selectivity of 2.58, when the MMMs were loaded with 0.05% (w/v) of Co3O4/GO nanocomposite.

Preparation, characterization, and binding profile of imprinted semi-IPN cryogel composite for aluminum.

Human body is greatly exposed to aluminum due to its high abundance in the environment. This nonessential metal is a threat to the patients of chronic renal disorders, as it is easily retained in their plasma and quickly accumulates in different tissues. Thus, there is great need to remove it from the aqueous environment. In this study, Al3+ imprinted semiinterpenetrating polymer network (semi-IPN)-based cryogel composite was prepared and applied for the purification of environmental and drinking water samples from aluminum. Poly (2-hydroxyethyl methacrylate) (pHEMA) discs were produced via cryogenic treatment and imprinted semi-IPN was introduced to the 3-(trimethoxysilyl) propyl acrylatemodified macroporous cryogel discs. The adsorption properties and selectivity of the aluminum (III) imprinted semi-IPN cryogel composite were studied in detail. The imprinted semi-IPN cryogel composite showed good selectivity towards aluminum (III) ions with the imprinting factor (IF) of 76.4 in the presence of competing copper (II), nickle (II), and iron (III) ions. The maximum adsorption capacity of 271 µmol g-1 was obtained for aluminum (III) at pH 7.0 within 10 min using imprinted semi-IPN cryogel composite. The good selectivity and reusability of aluminum (III)-imprinted semi-IPN cryogel composite makes this material an eligible candidate for the purification of drinking water from aluminum (III) leaving important minerals remained in the water.

Occult Head Injury in Children Less Than 2 Years With Suspected Child Abuse in the Emergency Department.

OBJECTIVE: This study aims to determine the frequency of clinically significant findings requiring emergent neurosurgical intervention on computed tomography (CT) in neurologically intact children admitted to the hospital with suspected abuse. METHODS: This was a retrospective review of neurologically stable children (0-24 months) in whom both skeletal survey and CT head were performed for child abuse evaluation from 2000 to 2011. RESULTS: A total of 132 patients met inclusion criteria (mean age, 7.6 mo; 55% male, 52% Caucasian, and 34% African-American). Computed tomography scans demonstrated occult head injury in 5%; none required neurosurgical intervention or had any neurological deterioration. Average length of stay was 4 days, with average time to CT scan being 12.8 hours from triage, and average time to magnetic resonance imaging (MRI) scan of 70.5 hours. Five MRIs were performed, and 4 had identical results on CT scan. CONCLUSIONS: No clinically significant brain injury (requiring intervention) was seen in this cohort. These findings support delaying imaging in neurologically intact children to obtain MRI after hospital admission, thus, limiting radiation exposure.

2,3-Pyridine dicarboxylic acid functionalized gold nanoparticles: Insight into experimental conditions for Cr3+ sensing.

Selectivity of gold nanoparticles (AuNPs) depends upon surface functionality; small changes in structure or concentration bring significant changes in the behavior of AuNPs. In this study, citrate-capped AuNPs were functionalized with ortho-dicarboxylate substituted pyridine (2,3-PDCA) and detailed studies on experimental conditions were carried out to check the stability of AuNPs and response for Cr3+. Stability of PDCA-AuNPs was found sensitive to the pH, ionic strength of buffer and its type. Capping behavior of PDCA on C-AuNPs was examined by FTIR spectroscopy. Surface morphology and size of synthesized AuNPs were confirmed by AFM, XRD, and DLS techniques where particles were found 11nm in size, monodisperse and spherical in shape. Interaction of stabilized AuNPs was tested with various metal ions; where Cr3+ induced the changes in localized surface plasmon band (LSPR) of PDCA-AuNPs which leads to a color change from wine red to violet blue. The phenomenon is explained as cooperative effect of citrate and pyridine nitrogen on surface of AuNPs in contrary to meta-dicarboxylate substituted pyridine derivatives. Further, under optimized and controlled conditions Cr3+ shows linear response with decrease in absorbance at LSPR intensity of AuNPs (518nm). Moreover, to demonstrate the applicability of method, Cr3+ was determined in the presence of Cr (VI) which shows 96% recovery.

Megaporous poly(hydroxy ethylmethacrylate) based poly(glycidylmethacrylate-N-methacryloly-(L)-tryptophan) embedded composite cryogel.

One-step activation, purification, and stabilization of lipase enzyme were performed by using composite hydrophobic support at low ionic strength with increased surface area during embedding process. A novel hydrophobic poly(hydroxyethylmethacrylate) [PHEMA] based, poly(glycidyl methacrylate-N-methacryloly-(L)-tryptophan) [PGMATrp] bead embedded composite cryogel membrane having specific surface area of 195m(2)/g was used as hydrophobic matrix for adsorption of commercial Candida Rugosa lipase in a continuous system. PGMATrp embedded PHEMA cryogel membrane with 60-100 µm pore size was obtained by dispersion polymerization of GMA and MATrp to form PGMATrp beads followed by embedding of PGMATrp to HEMA via APS and TEMED redox pair. The introduction of hydrophobic MATrp monomer into bead structure aiming to increase interaction between lipase and composite membrane was estimated using nitrogen stoichiometry of elemental analysis and found to be 239 µmol/g of polymer. Hydophobicity increment due to embedding process was confirmed by measuring contact angle, it was found 42° and 48.4° for the PHEMA and PHEMA/PGMATrp composite cryogel respectively. Some parameters i.e. pH, flow-rate, protein concentration, temperature, salt type and ionic intensity were evaluated on the adsorption capacity in a continuous system. Fast protein liquid chromatography (FPLC) studies were performed for specific adsorption of lipase onto the PHEMA/PGMATrp embedded composite cryogel membrane.

Core-shell molecularly imprinted polymer-based solid-phase microextraction fiber for ultra trace analysis of endosulfan I and II in real aqueous matrix through gas chromatography-micro electron capture detector.

In this study, core-shell molecularly imprinted polymer selective for endosulfan I and II was prepared by copolymerization of Fe3O4@SiO2-methacrylamide composites and N,N'-methylene-bis-acrylamide. The synthesized polymer was thoroughly characterized by FT-IR, TGA, and SEM. The adsorption properties of the MIP and NIP were demonstrated by equilibrium rebinding experiments, pseudo-second-order kinetic model, LF-isotherm and Scatchard analysis. The competitive recognition studies were performed with endosulfan I and II and structurally similar compounds: aldrin, dieldrin and heptachlor. The imprinting factors (IF) of endosulfan I and II were found to be 10.1 and 9.1, respectively, which were much higher than the imprinting factors (IF) of other cyclodienes. The imprinted polymer was then coated on stainless steel wire to develop an easy and simple laboratory made solid phase microextraction device for selective extraction of endosulfan I and II from water samples of environmental importance. Also the main parameters influencing coating of fiber and microextraction procedure were investigated and optimized using Plackett-Burman and Central Composite designs. The developed method was thoroughly validated for its linearity, selectivity, precision and accuracy. The developed MISPME method's linearity ranged from 7 to 5×10(3)ngl(-1) (R(2)=0.999) and from 10 to 5×10(3)ngl(-1) (R(2)=0.999) for endosulfan I and II, respectively. The limits of detection for endosulfan I and II were found to be 2ngl(-1) and 3ngl(-1), respectively. However, the limits of quantification for endosulfan I and II were 7ngl(-1) and 10ngl(-1), respectively.

Molecular imprinted magnetic nanoparticles for controlled delivery of mitomycin C.

Controlled drug delivery system is a technique which has considerable recent potential in the fields of pharmacy and medicine. Mitomycin C is commonly used drug in the treatment of superficial bladder and breast cancers. In the present study, mitomycin C-imprinted magnetic poly(hydroxyethyl methacrylate)-based nanoparticles (MIMNs) were prepared using surfactant free emulsion polymerization for controlled delivery of mitomycin C. The MIMNs were characterized by fourier transform infrared spectroscopy, scanning electron microscopy, atomic force microscopy, electron spin resonance, and elemental analysis. The average particle diameter of MIMNs was about 200 nm.

Preparation and characterization of molecularly imprinted polymer for di(2-ethylhexyl) phthalate: application to sample clean-up prior to gas chromatographic determination.

The molecularly imprinted polymer (MIP) selective for di(2-ethylhexyl) phthalate (DEHP) an environmental endocrine disruptor was prepared by suspension polymerization using methacrylamide as functional monomer and N,N'-methylene-bis-acrylamide as cross-linker. The imprinted polymer was employed for solid-phase extraction of DEHP from water samples of environmental importance and characterized by FT-IR and SEM. The adsorption properties of the imprinted polymer were demonstrated by equilibrium rebinding experiments, Pseudo-second-order kinetic model, Sips isotherm and Scatchard analysis. The reusability of MIP was checked for at least six repeated batch adsorption cycles and the results showed almost no deterioration in the adsorption capacity. The competitive recognition studies were performed with DEHP and structurally similar compounds; dimethyl phthalate (DMP), diethyl phthalate (DEP), and dibutyl phthalate (DBP). The imprinting factor (IF) of DEHP was found to be 12.86 which was much higher than the imprinting factors (IF) of other phthalates. A method constituted by molecularly imprinted solid-phase extraction (MISPE) with GC-FID was developed for DEHP analysis in water samples under very simple conditions. Sample loading and desorption conditions were also optimized. The MISPE method's linearity ranged from 0.035 to 3.0 µg ml⁻¹ with r² = 0.9998. Intra-assay, interassay precision and accuracy ranged from 0.0168% to 1.017%, 1.130% to 4.799% and 94.98% to 99.35%, respectively. The LOD and LOQ were found to be 0.011 and 0.035 µg ml⁻¹, respectively. Synthesized MIP was employed in MISPE for cleaning up the spiked river water samples prior to gas chromatographic analysis. The river samples were found to contain DEHP in the range of 1.4 × 10⁻³ to 0.349 µg ml⁻¹.