Tetrabutylammonium methacrylate as a novel receptor for selective extraction of sulphonylurea drugs from biological fluids using molecular imprinting

Glibenclamide (GLIB), an oral antidiabetic medication of the sulphonylurea drugs family, was stoichiometrically imprinted using tetrabutylammonium methacrylate as the functional monomer, for the first time in molecular imprinting, and utilising the sulphonylurea affinity for carboxylate anions. Solution association between the drug and the novel functional monomer was studied by 1H-NMR titrations, whereby evidence of sulphonylurea deprotonation followed by the formation of “narcissistic” GLIB dimers was found when tested in CDCl3, while an affinity constant in excess of 105 L mol-1 was measured in DMSO-d6. Detailed analysis of GLIB binding on the subsequently prepared imprinted and non-imprinted polymers confirmed deactivation of binding sites by exchange of a proton between GLIB and methacrylate, followed by extraction of the tetrabutylammonium counterion from the polymer matrix, resulting in overall reduced binding capacities and affinities by the imprinted material under equilibrium conditions. An optimised MI-SPE protocol, which included a binding site re-activation step, was developed for the extraction of GLIB from blood serum, whereby recoveries of up to 92.4% were obtained with exceptional sample clean-up.

Chemistry and Distribution of Daughter Species in the Circumstellar Envelopes of O-Rich AGB Stars

Context. Thanks to the advent of Herschel and ALMA, new high-quality observations of molecules present in the circumstellar envelopes of asymptotic giant branch (AGB) stars are being reported that reveal large differences from the existing chemical models. New molecular data and more comprehensive models of the chemistry in circumstellar envelopes are now available.
Aims: The aims are to determine and study the important formation and destruction pathways in the envelopes of O-rich AGB stars and to provide more reliable predictions of abundances, column densities, and radial distributions for potentially detectable species with physical conditions applicable to the envelope surrounding IK Tau.
Methods: We use a large gas-phase chemical model of an AGB envelope including the effects of CO and N2 self-shielding in a spherical geometry and a newly compiled list of inner-circumstellar envelope parent species derived from detailed modeling and observations. We trace the dominant chemistry in the expanding envelope and investigate the chemistry as a probe for the physics of the AGB phase by studying variations of abundances with mass-loss rates and expansion velocities.
Results: We find a pattern of daughter molecules forming from the photodissociation products of parent species with contributions from ion-neutral abstraction and dissociative recombination. The chemistry in the outer zones differs from that in traditional PDRs in that photoionization of daughter species plays a significant role. With the proper treatment of self-shielding, the N → N2 and C+→ CO transitions are shifted outward by factors of 7 and 2, respectively, compared with earlier models. An upper limit on the abundance of CH4 as a parent species of (≲2.5 × 10-6 with respect to H2) is found for IK Tau, and several potentially observable molecules with relatively simple chemical links to other parent species are determined. The assumed stellar mass-loss rate, in particular, has an impact on the calculated abundances of cations and the peak-abundance radius of both cations and neutrals: as the mass-loss rate increases, the peak abundance of cations generally decreases and the peak-abundance radius of all species moves outwards. The effects of varying the envelope expansion velocity and cosmic-ray ionization rate are not as significant.

Ionic liquid gel materials: applications in green and sustainable chemistry

Ionic liquid gel materials offer a way to further utilise ionic liquids in technological applications. Combining the controlled and directed assembly of gels, with the diverse applications of ionic liquids, enables the design of a heady combination of functional tailored materials, leading to the development of task specific / functional ionic liquid gels. This review introduces gels and gel classification, focusing on ionic liquid gels and their potential roles in a more sustainable future. Ionic liquid gels provide the ability to build functionality at every level, the solid component, the ionic liquid, and any incorporated active functional agents. This allows materials to be custom designed for a vast assortment of applications. This diverse class of materials has the potential to yield functional materials for green and sustainable chemistry, energy, electronics, medicine, food, cosmetics, and more. The discussion of the development of ionic liquid gel materials for applications in green and sustainable chemistry centres on uses of ionic liquid gels in catalysis and energy.

Spatial and temporal influences of in-stream factors on the chemistry and epilithic biomasses of upland stream metal deposits

The density and composition of stream bed metal deposits are affected by physical, chemical and biological processes. In this paper we investigate the importance of these processes and their relation to algal and non-photosynthetic detrital (NPD) biomass in a set of upland streams in Northern Ireland. Deposit density and Fe, Mn, Al and P concentrations varied with stream pH across sites but not seasonally. No effects of stream bed erosion or photoreduction were detected on deposit densities. Seasonal variation in stream water metal concentrations was correlated with rainfall. NPD biomass was a significant predictor of both spatial and seasonal variation in deposit concentrations. There were strong, non-linear, relations between NPD biomass and deposit metal concentrations, with Fe and Mn becoming relatively more important and algal biomass declining above threshold deposit/NPD densities. The results suggest that NPD biomass influences deposit density and reduces the biomass of photosynthetic autotrophs above a threshold deposit density.

Mineralogy, chemistry and biological contingents of an early-middle Miocene Antarctic paleosol and its relevance as a Martian analogue

Fossil mesofauna and bacteria recovered from a paleosol in a moraine situated adjacent to the inland ice, Antarctica, and dating to the earliest glacial event in the Antarctic Dry Valleys opens several questions. The most important relates to understanding of the mineralogy and chemistry of the weathered substrate habitat in which Coleoptera apparently thrived at some point in the Early/Middle Miocene and perhaps earlier. Here, Coleoptera remains are only located in one of six horizons in a paleosol formed in moraine deposited during the alpine glacial event (> 15 Ma). A tendency for quartz to decrease upward in the section may be a detrital effect or a product of dissolution in the early stage of profile morphogenesis when climate was presumably milder and the depositing glacier of temperate type. Discontinuous distributions of smectite, laumontite, and hexahydrite may have provided nutrients and water to mesofauna and bacteria during the early stage of biotic colonization of the profile. Because the mesofauna were members of burrowing Coleoptera species, future work should assess the degree to which the organisms occupied other sites in the Dry Valleys in the past. Whereas there is no reasonable expectations of finding Coleoptera/insect remains on Mars, the chemistry and mineralogy of the paleosol is within a life expectancy window for the presence of microorganisms, principally bacteria and fungi. Thus, parameters discussed here within this Antarctic paleosol could provide an analogue to identifying similar fossil or life-bearing weathered regolith on Mars.

Effect of poly ethylene glycol on the mechanical and thermal properties of bioactive Poly (ε–caprolactone) melt extrudates for pharmaceutical applications

This paper investigates the effects of polyethylene glycol (PEG), on the mechanical and thermal properties of nalidixic acid/ploy ε-caprolactone (NA)/PCL blends prepared by hot melt extrusion. The blends were characterized by tensile and flexural analysis, dynamic mechanical analysis, differential scanning calorimetry, thermogravimetric analysis and X-ray diffraction. Experimental data indicated that the addition of NA caused loss of the tensile strength and toughness of PCL. Thermal analysis of the PCL showed that on addition of the thermally unstable NA, thermal degradation occurred early and was autocatalytic. However, the NA did benefit from the heat shielding provided by the PCL matrix resulting in more thermally stable NA particles. Results show that loading PEG in the PCL had a detrimental effect on the tensile strength and toughness of the blends, reducing them by 20-40%. The partial miscibility of the PCL-PEG system, causes an increase in Tg. While increases in the crystallinity is attributed to the plasticisation effect of PEG and the nucleation effect of NA. The average crystal size increased by 8% upon PEG addition.

Coordination chemistry for information acquisition and processing

In the 21st century, information has become the most valuable resource that is available to modern societies. Thus, great efforts have been made to develop new information processing and storage techniques. Chemistry can offer a wide variety of computing paradigms that are closely related to the natural processes found in living organisms (e.g., in the nervous systems of animals). Moreover, these phenomena cannot be reproduced easily by solely using silicon-based technology. Other great advantages of molecular-scale systems include their simplicity and the diversity of interactions that occur among them. Thus, devices constructed using chemical entities may be programmed to deal with different information carriers (photons, electrons, ions, and molecules), possibly surpassing the capabilities of classic electronic circuits.

Effect of water chemistry on the physiology and toxicity assessment in Daphnia

Todos os sistemas aquáticos estão potencialmente expostos a alterações nos parâmetros da água em consequência de fenómenos ambientais tais como deposição ácida, lixiviação de iões dos solos e alterações climáticas. Dado que os parâmetros químicos da água estão geralmente correlacionados, é pertinente estudar os seus efeitos combinados para o biota aquático. Assim, o principal objetivo desta tese é avaliar a importância ecológica da variação simultânea dos principais parâmetros fisico-químicos da água nos parâmetros de história de vida dos crustáceos tanto na ausência como na presença de metais. Foram estudados os seguintes parâmetros: dureza (0.5 - 3.5 mM), alcalinidade (0.3 - 2.3 mM), pH (5.7 - 9.0) e temperatura (13 - 30ºC). A Daphnia magna foi usada como espécie modelo representando os crustáceos aquáticos. A variação simultânea da dureza e alcalinidade afetou significativamente o crescimento, reprodução e crescimento populacional de Daphnia; no entanto, os efeitos da dureza excederam os efeitos da alcalinidade. Pareceu haver interação entre a dureza e alcalinidade na reprodução dos dafnídeos, o que sugere que os efeitos da variação da dureza para Daphnia e provavelmente outros crustáceos poderão depender do nível de alcalinidade. O pH e dureza da água exerceram efeitos combinados para Daphnia, sendo os efeitos do pH mais pronunciados do que os efeitos da dureza. A diminuição do pH reduziu a sobrevivência, crescimento, reprodução, taxa de ingestão e crescimento populacional dos dafnídeos. No entanto, os efeitos do pH baixo foram mais adversos a baixa dureza, o que sugere uma interação entre estes parâmetros. Assim, a diminuição do pH em lagos de água mole pode ser um estressor determinante para os crustáceos sensíveis à acidez, ameaçando a sua sobrevivência e, consequentemente, afetando a estrutura das cadeias alimentares aquáticas. A temperatura e a química da água (dureza e alcalinidade) interagiram entre si nos parâmetros de história de vida de Daphnia; no entanto, os efeitos da temperatura excederam os efeitos da química da água. De um modo geral, temperaturas extremas reduziram o crescimento, reprodução e, consequentemente, o crescimento populacional de Daphnia. Os efeitos do aumento da temperatura foram mais adversos a baixa dureza e alcalinidade, aumentando a preocupação com os efeitos ecológicos do aquecimento global em águas moles. A dureza e alcalinidade da água também desempenharam um papel importante na toxicidade aguda e subletal (inibição da ingestão) dos metais para Daphnia. A diminuição da dureza aumentou a toxicidade aguda do zinco. Por outro lado, a diminuição da alcalinidade aumentou a toxicidade aguda e subletal do cobre, mas reduziu a toxicidade subletal do zinco, tornando evidente o importante papel da alcalinidade na toxicidade subletal dos metais para Daphnia. Globalmente, os parâmetros fisico-químicos da água parecem interagir entre si, afetando os parâmetros de história de vida e o crescimento populacional de Daphnia e também afetam a toxicidade dos metais. Em particular, a baixa dureza agrava os efeitos adversos da diminuição do pH, aumento da temperatura e toxicidade dos metais, o que aumenta a preocupação com os efeitos ecológicos da sua variação simultânea sobre os crustáceos e, portanto, sobre as cadeias alimentares aquáticas.

Curricular training report: pharmaceutical industry & spin-off company

O presente relatório expõe as atividades desenvolvidas durante o estágio curricular, frequentado na Bluepharma - Indústria Farmacêutica S.A. e na TREAT U, Lda. uma Spin-off da Universidade de Coimbra, no âmbito do Mestrado em Biomedicina Farmacêutica da Universidade de Aveiro. Esta foi uma experiência de 6 meses que teve duas componentes, uma multidisciplinar e outra monodisciplinar, as quais me permitiram desenvolver os conhecimentos e aptidões adquiridas ao longo do curso de mestrado e de as aplicar ao mundo real. Para além do desenvolvimento de competências profissionais, esta experiência possibilitou também a aquisição e desenvolvimento de várias aptidões, quer a nível pessoal como social. Nos primeiros dois meses desta minha experiência adquiri um conhecimento essencialmente teórico em várias áreas da indústria farmacêutica (financeira, desenvolvimento de negócio, assuntos regulamentares, investigação e desenvolvimento de medicamentos, garantia da qualidade, etc.) através da minha passagem pela Bluepharma. De seguida, na minha experiência de quatro meses na TREAT U, foi-me dada a oportunidade de realizar de forma mais independente, as funções inerentes ao cargo de assistente da gerência, com especial enfoque para atividades de gestão de projeto (incluindo assuntos regulamentares), tais como, apoio na preparação do plano de desenvolvimento não clínico e na preparação do pedido de aconselhamento científico. Este relatório começa assim por descrever os objectivos do estágio e uma breve descrição das instituições que me acolheram para a sua realização. De seguida, os conhecimentos adquiridos na vertente multidisciplinar do estágio e depois as atividades desenvolvidas no âmbito monodisciplinar. Por fim, apresenta uma análise das dificuldades e desafios encontrados bem como os esforços realizados para os ultrapassar.

Effects of active pharmaceutical ingredients in mussel mytilus galloprovincialis

More than 3000 types of active pharmaceutical ingredients (APIs) are applied in Human and veterinary medicine practice. These compounds are considered an emergent class of environmental contaminants with the ability to cause damage and unexpected effects to aquatic organisms, namely in species of high commercial value. APIs are ubiquitous in the environment being frequently detected in influents and effluents of waste water treatment plants (WWTPs), surface waters and more distressingly in the public tap water in concentrations ranging from ng to μg.L-1. Considering these premises, the present thesis focused on APIs detection in the Arade river water, the impact of summer period in APIs’ concentration alterations applying the passive sampler device, POCIS (polar organic compound integrative sampler), as well as, the assessment of the effects caused by non-steroidal anti-inflammatory drugs (NSAID) ibuprofen (IBU) and diclofenac (DCF) and antidepressant selective serotonin reuptake inhibitor (SSRI) fluoxetine as single and mixture exposures along with a classical contaminant copper (Cu) on a non-target species, mussel Mytilus galloprovincialis. For this purpose, a multibiomarker approach was applied namely including biomarkers of oxidative stress (antioxidant enzymes activities of superoxide dismutase – SOD, catalase – CAT, glutathione reductase – GR and Phase II glutathione-S-transferase), damage - lipid peroxidation (LPO), neurotoxic effects (through the activity of acetylcholinesterase enzyme - AChE) and endocrine disruption (through vitellogenin-like proteins measurement applying the indirect method of alkali-labile phosphate - ALP) after exposure of mussel species’ to selected APIs at environmental relevant concentrations. The main results highlighted the occurrence of 19 APIs in the river Arade from several distinct therapeutic classes. Stimulant caffeine, antiasthmatic theophylline, NSAID ibuprofen and analgesic paracetamol presented the highest concentrations. Summer impact was inconclusive due to each API transient concentration in each month. The multibiomarker results revealed distinct responses towards each selected API (as single exposure or as mixtures) that were tissue and time dependent. Several multistressor interactions were proposed for each biomarker. The results also revealed APIs potential to induce oxidative stress, LPO, neurotoxicity and endocrine disruption even at extremely low concentrations on a species extremely vulnerable to APIs presence highlighting the urgency on the development of methodologies able to prevent its entrance in the aquatic environment.

Valorização de resíduos carbonosos de gasificação como precursores de materiais para adsorção de poluentes em fase aquosa

Tese de doutoramento, Energia e Ambiente (Energia e Desenvolvimento Sustentável), Universidade de Lisboa, Faculdade de Ciências, 2014

Medicinal chemistry approaches to malaria drug discovery

Tese de doutoramento, Farmácia (Química Farmacêutica e Terapêutica), Universidade de Lisboa, Faculdade de Farmácia, 2016

High field chemistry with scanning probes

Fabricating Ge and Si integrated structures with nanoscale accuracy is a challenging pursuit essential for novel advances in electronics and photonics. While several scanning probe-based techniques have been proposed, no current technique offers control of nanostructure size, shape, placement, and chemical composition. To this end, atomic force microscope direct write uses a high electric field (> 109 V m-1) to create nanoscale features as fast as 1 cm s-1 by reacting a liquid precursor with a biased AFM tip. In this work, I present the first results on fabricating inorganic nanostructures via AFM direct write. Using diphenylgermane (DPG) and diphenylsilane (DPS), carbon-free germanium and silicon nanostructures (SIMS, x-ray PEEM) are fabricated. For this chemistry, I propose a model that involves electron capture and precursor fragmentation under the high electric field. To verify this model, experimental data and simulations are presented. High field chemistry for DPG and DPS has also been demonstrated for both sequential deposition and the creation of nanoscale heterostuctures, in addition to microscale deposition using a flexible stamp approach. This high field chemistry approach to the deposition of organometallic precursors could offer a low-cost, high throughput alternative for future optical, electronic, and photovoltaic applications.

Enzymatic grafting: A novel approach to develop multifunctional materials of interest

Today more than 99% of plastics are petroleum-based because of the availability and cost of the raw material. The durability of disposed plastics contributes to the environmental problems as waste and their persistence in the environment causes deleterious effects on the ecosystem. Environmental pollution awareness and the demand for green technology have drawn considerable attention of both academia and industry into biodegradable polymers. In this regard green chemistry technology has the potential to provide solution to this issue. Enzymatic grafting has recently been the focus of green chemistry technologies due to the growing environmental concerns, legal restrictions, and increasing availability of scientific knowledge. Over the last several years, research covering various applications of robust enzymes like laccases and lipases has been increased rapidly, particularly in the field of polymer science, to graft multi-functional materials of interest. In principle, enzyme-assisted grafting may modify/impart a variety of functionalities to the grafted composites which individual materials fail to demonstrate on their own. The modified polymers through grafting have a bright future and their development is practically boundless. In the present study series of graft composites with poly(3-hydroxybutyrate) (P(3HB) as side chain and cellulose as a backbone polymer were successfully synthesised by introducing enzymatic grafting technique where laccase and lipase were used as model catalysts [1-3]. Subsequently, the resulting composites were removed from the casting surface under ambient environment and characterised by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) in detail. Moreover, the thermo-mechanical behaviours of the grafted composites were investigated by differential scanning calorimetry (DSC) and dynamic mechanical analyser (DMA) measurements, respectively. In addition, hydrophobic and hydrophilic characteristics of the grafted polymers were studied through drop contour analysis using water contact angle (WCA). In comparison to the individual counterparts improvement was observed in the thermo- mechanical properties of the composites to varied extent. The tensile strength, elongation at break, and Young’s modulus values of the composites reached their highest levels in comparison to the films prepared with pure P(3HB) only which was too fragile to measure any of the above said characteristics. Interestingly, untreated P(3HB) was hydrophobic in nature and after lipase treatment P(3HB) and P(3HB)-EC-based graft composite attained higher level of hydrophilicity. This is a desired characteristic that enhances the biocompatibility of the materials for proper cell adhesion and proliferation therefore suggesting potential candidates for tissue engineering/bio-medical type applications [3]. The present research will be a first step in the biopolymer modification. To date no report has been found in literature explaining the laccase/lipase assisted grafting of P(3HB) [1-3]. The newly grafted composites exhibit unique functionalities with wider range of potential applications in bio-plastics, pharmaceutical, and cosmetics industries, tissue engineering, and biosensors. [1] H.M.N. Iqbal, G. Kyazze, T. Tron and T. Keshavarz, Cellulose 21, 3613-3621 (2014). [2] H.M.N. Iqbal, G. Kyazze, T. Tron and T. Keshavarz, Carbohydrate Polymers 113, 131-137 (2014). [3] H.M.N. Iqbal, G. Kyazze, T. Tron and T. Keshavarz, Polymer Chemistry In-Press, DOI: 10.1039/C4PY0 0857J (2014).