Multifunctionalized Self-supported (Nano) Membranes as Integrated Platform for Plasmonic Metamaterials

We considered the possibility to fabricate multifunctional nanocomposite membranes as a platform for plasmonic metamaterials, simultaneously incorporating pores, built-in functional groups and active nanoparticles. To this purpose we combined lamination and inclusion of nanofillers into the membrane host. For the basic material we chose macroporous crosslinked copolymers based on glycidyl methacrylate (GMA). The epoxy group present in GMA molecule is readily transformed into various functional groups that further serve as affinity enhancers, ensuring the usability of the membranes as pre-concentrators of selected agents in plasmonic sensors. To form GMA-based membranes we used a recently proposed method combining the traditional immersion precipitation with photopolymerization and crosslinking of functional monomers. Further functionalization is obtained by in-situ formation of noble metal nanoparticles directly within the GMA host. In this way membranes with simultaneous plasmonic, adsorbent and catalytic functionality are obtained. We considered the use of the our structures for plasmonic chemical sensors where separator, pre-concentrator and binding agent are integrated with the plasmonic crystal, as well as for plasmonic enhancement of photocatalytic reactions in microreactors. Our approach gives a highly tailorable element compatible with microelectromechanical systems (MEMS) technologies and readily transferable across platforms

Silver nanoparticles within functionalized hydrogels for plasmonic (bio)chemical sensors

Plasmonics is the basis for a novel generation of adsorption-based ultrasensitive (bio) chemical sensors. In nanoplasmonic sensors one utilizes nanocomposites typically in the form of thin films, comprising metal nanoparticles or ordered metal-dielectrics (plasmonic crystals). In this work we investigated thin functionalized hydrogel films with embedded silver nanoparticles. These films were prepared by copolymerizing glycidyl methacrylate with mono and multifunctional methacrylates using UV irradiation. The epoxy group in glycidyl methacrylate can then be converted by chemical means into a desired functionality to capture the targeted analyte. Silver nanoparticles were either photochemically generated in situ, or were introduced into hydrogels by chemical reduction. Differences in morphology and performance of these nanocomposites were investigated and will be discussed

Adsorption isotherms of chloroform on macroporous copolymers determined by inverse gas chromatography

The inverse gas chromatography (IGC) under finite surface coverage conditions was used for the determination of adsorption isotherms of chloroform on macroporous crosslinked poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate), PGME and copolymer modified with ethylene diamine, EDA, PGME-en. The specific surface areas of initial and modified copolymer samples calculated from IGC data are in fair agreement with those determined by the BET method from the low-temperature nitrogen adsorption isotherms.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Predictors of development of neurogenic pulmonary edema in patients with aneurysmal subarachnoid hemorrhage

Uvod: Neurogeni edem pluća (NEP) je klinički sindrom koji se karakteriše akutnim početkom edema pluća posle značajnog insulta centralnog nervnog sistema (CNS). Posledica je oslobađanje kateholamina u krv neposredno posle rupture aneurizme. Cilj ove studije je ispitivanje veze između EKG promena, vrednosti kardiospecifičnih enzima i biomarkera inflamacije na prijemu i drugog dana od prijema i pojave neurogenog edema pluća (NEP) kod pacijenata sa aneurizmatskom SAH. Materijal i metode: Ukupno 262 pacijenata sa aneurizmatskom SAH (162 žene je prospektivno uključeno u studiju. Kliničke karakteristike, elektrokardiografske (EKG) promene i vrednosti serumskih kardiospecifičnih i inflamatornih biomarkera je određeno na prijemu, a EKG promene i vrednosti biomarkera i 2 dana nakon prijema i na dan nastanka NEP-a kod pacijenata koji su razvili NEP. Sve vrednosti biohumoralnih parametara su takođe i dihotomizovane na povišene i normalne. Svi pacijenti su podeljenji u dve grupe, na one koji su razvili NEP i koji nisu. Podaci su analizirani radi određivanja značajnosti razlike karakteristika kod pacijenata sa NEP-om i bez i određivanja prediktora razvoja NEP-a. Da bismo isključili uticaj terapije na pojavu NEP-a, izdvojili smo pacijente primljene unutar 24 sata od nastanka SAH, podelili ih u grupu sa NEP-om i bez i analizirali podatke radi određivanja potencijalno različitih prediktora nastanka NEP-a. Rezultati: 19 pacijenata (7.25%) je razvilo NEP. Pacijenti koji će razviti NEP su imali teži oblik SAH. Bilo je značajno više pacijenata ženskog pola, sa anamnezom hipertenzije (HTA). Srčano oštećenje je bilo teže kod pacijenata sa NEP-om, što je predstavljeno značajno višim prosečnim vrednostima kardiospecifičnih enzima (p=0.000), izuzev srčanog troponina I (cTnI) koji je bio značajno niži (p=0.000). Nezavisni prediktori nastanka NEP-a kod pacijenata sa aneurizmatskom SAH su povišeni cTnI (OR 4.980, 95% CI 1.27-19.49, p=0.021) i leukociti (OR 22.195, 95% CI 3.99-123.50, p=0.000) kao i ženski pol (OR 5.253, 95% CI 1.14-24.16, p=0.033), Hant i Hesov gradus ≥3 (OR 12.593, 95% CI 1.27-124.79, p=0.030) i postojanje HTA (OR 3.922, 95% CI 1.07- 14.39, p=0.039). Kod pacijenata primljenih unutar 24 sata od nastanka SAH, prediktori NEP-a su postojanje hidrocefalusa (OR 8.075, 95% CI 1.55-42.06, p=0.013), povišen cTnI (OR 16.182, 95% CI 2.46-106.21, p=0.004) i više vrednosti broja leukocita (OR 1.418, 95% CI 1.12-1.79, P=0.004). Zaključak: Značajno više vrednosti kardiospecifičnih enzima su nađene kod pacijenata sa SAHom koja se komplikovala pojavom NEP-a. Povišene vrednosti kardiospecifičnih enzima imaju aktivnu ulogu u predviđanju nastanka NEP-a, mada i broj leukocita može biti uključen u mogućnost predviđanja NEP-a.Background: Neurogenic pulmonary edema (NPE) is a clinical syndrome characterized by the acute onset of pulmonary edema after a significant central nervous system (CNS) insult. It’s a consequence of releasing of catecholamines into blood immediately after aneurysmal rupture. The purpose of this project is to investigate the connection between cardiac biomarkers values on admission and occurrence of NPE in patients with aneurysmal subarachnoid hemorrhage. Methods: 262 SAH patients (162 females) are prospectively included in the study. Clinical characteristics, electrocardiographic (ECG) changes, serum cardiac and inflammatory biomarkers were determined on admission, 2 days after admission and also on the day of development of NPE. The values of the biohumoral parameters were also dichotomized on elevated and normal. All of the patients were separated into two groups, which developed NPE and not. Data were analyzed in order to determine the significance of difference between parameters of the groups and to predict the development of NPE. With intention to exclude the influence of SAH therapy on occurrence of NPE, we excluded the patients admitted into the hospital within 24 hours of SAH onset and analyzed the data to determine the potentially different predictors of NPE. Results: 19 patients (7.25%) developed NPE. Patients who will develop NPE sustained more severe SAH. There were significantly more women with history of hypertension (HTA). Cardiac damage was more severe in these patients as represented by significantly higher mean of all examined cardiac biomarkers (p=0.000), except cardiac troponin I (cTnI) which was significantly lower (p=0.000). Multivariate regression analysis revealed that elevated cTnI (OR 4.980, 95% CI 1.27-19.49, p=0.021) and white blood cells count (WBC) (OR 22.195, 95% CI 3.99-123.50, p=0.000) as well as being female (OR 5.253, 95% CI 1.14-24.16, p=0.033), Hunt and Hess of ≥3 (OR 12.593, 95% CI 1.27-124.79, p=0.030), and presence of HTA (OR 3.922, 95% CI 1.07-14.39, p=0.039) are also predictors of NPE. For the patients admitted within 24 hours of the SAH onset, predictors of NPE are presence of hydrocephalus (OR 8.075, 95% CI 1.55-42.06, p=0.013), elevated cTnI (OR 16.182, 95% CI 2.46-106.21, p=0.004) and higher WBC count (OR 1.418, 95% CI 1.12-1.79, P=0.004). Conclusions: Significantly higher values of cardiac biomarkers were observed in SAH patients complicated by NPE. Elevated values of cardiac biomarkers play appear to play an active role in prediction of NPE, although white blood cells count may be involved in prediction of NPE

Immobilization of biocatalysts for enzymatic polymerizations:Possibilities, advantages, applications

Biotechnology also holds tremendous opportunities for realizing functional polymeric materials. Biocatalytic pathways to polymeric materials are an emerging research area with not only enormous scientific and technological promise, but also a tremendous impact on environmental issues. Many of the enzymatic polymerizations reported proceed in organic solvents. However, enzymes mostly show none of their profound characteristics in organic solvents and can easily denature under industrial conditions. Therefore, natural enzymes seldom have the features adequate to be used as industrial catalysts in organic synthesis. The productivity of enzymatic processes is often low due to substrate and/or product inhibition. An important route to improving enzyme performance in non-natural environments is to immobilize them. In this review we will first summarize some of the most prominent examples of enzymatic polymerizations and will subsequently review the most important immobilization routes that are used for the immobilization of biocatalysts relevant to the field of enzymatic polymerizations. (C) 2011 Elsevier Ltd. All rights reserved

Optimization of the preparation of novel polymer/clay nanocomposites

Recent advances in material technologies have resulted in the preparation of novel polymer/clay composites with improved thermal, mechanical, optoelectronic/ magnetic properties and increased biodegradability [1]. In this study, six samples of poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) (PGME) nanocomposites with organically-modified montmorillonite clay Cloisite 30B® (C30B), were prepared via suspension copolymerization. In order to obtain nanocomposites with fine spherical beads of regular shape and satisfying thermal stability the optimization of the synthesis conditions was performed. Firstly, the influence of the poly(N-vinyl pyrrolidone) (PVP) quantity in the aqueous phase was varied (1, 3 and 5 wt.%) at a constant stirring rate of 250 rpm and constant clay content C30B (10 wt.%). In the second phase of the optimization of the preparation, samples with a constant composition of the composite reaction mixture (5 wt.% PVP and 10 wt.% C30B) at a stirring rate of 250, 325 and 400 rpm, were prepared. According to the obtained results, it was concluded that the optimal conditions for preparation of these composites are 5 wt.% of PVP and 400 rpm. The prepared nanocomposites were characterized with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) in air. The structure of the prepared nanocomposites was confirmed with FTIR spectroscopy. According to the obtained SEM microphotographs the fine spherical beads, with desired size and homogeneous morphology, were prepared. Furthermore, SEM analysis was also showed that clay nanoparticles are homogeneously dispersed both inside surface and cross-section area. The incorporation of C30B clay increased the thermal stability of the prepared polymer/clay nanocomposites in comparison to the pure PGME copolymer

Study of copper adsorption on aminofunctionalized macroporous poly(gma-co-egdma)

Macroporous crosslinked copolymer of glycidyl methacrylate and ethylene glycoldimethacrylate (PGME) was synthesized by suspension copolymerisation and modified by ring-opening reaction of epoxy groups with ethylene diamine, diethylene triamine and triethylene tetramine. The uptake of copper ions by amino-functionalized macroporous PGME from aqueous solutions was investigated in batch experiments. The equilibrium data fitted well with the Langmuir model.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Optimization of the preparation of novel polymer/clay nanocomposites

Recent advances in material technologies have resulted in the preparation of novel polymer/clay composites with improved thermal, mechanical, optoelectronic/ magnetic properties and increased biodegradability [1]. In this study, six samples of poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) (PGME) nanocomposites with organically-modified montmorillonite clay Cloisite 30B® (C30B), were prepared via suspension copolymerization. In order to obtain nanocomposites with fine spherical beads of regular shape and satisfying thermal stability the optimization of the synthesis conditions was performed. Firstly, the influence of the poly(N-vinyl pyrrolidone) (PVP) quantity in the aqueous phase was varied (1, 3 and 5 wt.%) at a constant stirring rate of 250 rpm and constant clay content C30B (10 wt.%). In the second phase of the optimization of the preparation, samples with a constant composition of the composite reaction mixture (5 wt.% PVP and 10 wt.% C30B) at a stirring rate of 250, 325 and 400 rpm, were prepared. According to the obtained results, it was concluded that the optimal conditions for preparation of these composites are 5 wt.% of PVP and 400 rpm. The prepared nanocomposites were characterized with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) in air. The structure of the prepared nanocomposites was confirmed with FTIR spectroscopy. According to the obtained SEM microphotographs the fine spherical beads, with desired size and homogeneous morphology, were prepared. Furthermore, SEM analysis was also showed that clay nanoparticles are homogeneously dispersed both inside surface and cross-section area. The incorporation of C30B clay increased the thermal stability of the prepared polymer/clay nanocomposites in comparison to the pure PGME copolymer

Design of an amino-functionalized chelating macroporous copolymer poly(GMA-co-EGDMA) for the sorption of Cu(II) ions

Polymer-based, highly porous nanocomposites with functionalized ligands attached to the core structure are extremely efficient in the detection, removal and recovery of metals through the process of sorption. Quantum-chemical models could be helpful for sorption process analyses. The sorption of Cu(II) ions by amino-functionalized chelating macroporous copolymers poly(GMA-co-EGDMA)-amine and sorption selectivity of the subject copolymers, ethylenediamine (en), diethylenetriamine (dien) and triethylenetetramine (trien), were successfully modelled by quantum chemical calculations. Considering the crystal structures from CSD and experimental conditions during the formation of metal complexes, the most frequent mononuclear complexes are those with the tetradentate teta ligand, while binuclear complexes are formed when the metal ion is in large excess. Although the en-copolymer was the most effective functionalized one, higher maximum sorption capacities (Qmax) were observed for the dien- and trien-copolymers, due to their abilities to form binuclear complexes. The enthalpy term has the greatest contribution to the total Gibbs energy change of reaction for the formation of mononuclear Cu(II) complexes (ΔGaq), while the solvation energy of the reaction has the greatest contribution in the formation of binuclear complexes. The results of the study indicate that small amines with the ability to form binuclear complex are the best choice for functionalization of the considered copolymer

Kinetics of heavy metal sorption on macroporous vinylpyridine based copolymer

Sorption of copper, nickel and cobalt on macroporous crosslinked copolymer of 4- vinylpyridine and ethylene glycol dimethacrylate, PVPE, was studied. The kinetics models (pseudo-first and pseudo-second order equations) were applied to the data obtained from batch sorption experiments at room temperature. The sorption of heavy metals was found to proceed according to pseudo-second order kinetics.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200