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Preparação, caracterização e avaliação de novos análogos da mitoxantrona com potenciais atividades biológicasOliveira, Larissa Albuquerque de 31 July 2017 (has links)
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Previous issue date: 2017-07-31 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A síntese de derivados antraquinônicos tem sido alvo de vários grupos de pesquisas por apresentarem diversas propriedades biológicas como anticancerígenas, anti-inflamatórias, imunossupressoras, antifúngicas, etc. Neste trabalho são descritas as sínteses de derivados antraquinônicos N-alquilados e O-alquilados com estruturas análogas à da mitoxantrona que possuem diferentes cadeias carbônicas a partir dos precursores 1,4-diaminoantraquinona, 1,4diidroxiantraquinona e 1,5-diamino-4,8-diidroxiantraquinona. Duas séries de compostos foram obtidas por reação de N-alquilação da 1,4-diaminoantraquinona e duas séries por reação de O-alquilação da 1,4-diidroxiantraquinona com epicloridrina. As etapas seguintes consistiram na formação de epóxidos via reação intramolecular de éter de Williamson e abertura destes utilizando-se aminas alifáticas, cíclicas e aromáticas. Após a purificação e caracterização dos compostos através de métodos espectroscópicos disponíveis (RMN de 1H, 13C, COSY, HMQC e Infravermelho), a primeira série de derivados antraquinônicos Nalquilados foi avaliada quanto às suas propriedades antibacterianas e citotóxicas e, posteriormente, os demais compostos também foram avaliados quanto as suas atividades citotóxicas. De um modo geral, as modificações estruturais propostas neste conjunto de moléculas mostraram um aumento na atividade antibacteriana e citotóxica para derivados contendo menor cadeia carbônica lateral, resultado oposto ao esperado para estas moléculas. Além disso, os resultados para estes compostos mostraram atividade citotóxica superior à da mitoxantrona, entretanto apresentaram citotoxicidade para a célula normal testada. / The synthesis of anthraquinone derivatives have been the target of several research groups because they have several biological properties as anticancer, anti-inflammatory, immunosuppressive, antifungal, etc. In this work is described the synthesis of N-alkylated and O-alkylated anthraquinone derivatives with structures analogous to mitoxantrone bearing different carbon chains from 1,4-diaminoanthraquinone, 1,4-dihydroxyanthraquinone and 1,5diamino-4, 8-dihydroxyanthraquinone. Two series of compounds were obtained by Nalkylation reaction of 1,4-diaminoanthraquinone and two series by O-alkylation reaction of 1,4-dihydroxyanthraquinone with epichlorohydrin. The following steps consisted in the formation of epoxides via the intramolecular reaction of Williamson's ether and opening thereof using aliphatic, cyclic and aromatic amines. After purification and characterization of the compounds by available spectroscopic methods (1H, 13C NMR, COSY, HMQC and Infrared), the first series of N-alkylated anthraquinone derivatives was evaluated for their antibacterial and cytotoxic properties and, subsequently, the other compounds were also evaluated for their cytotoxic activities. In general, the structural modifications proposed in this set of molecules showed an increase in the antibacterial and cytotoxic activity for derivatives containing less lateral carbonic chain, an opposite result than expected for these molecules. In addition, the results for these compounds showed higher cytotoxic activity than mitoxantrone, however, they showed cytotoxicity for the normal cell tested.
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Encapsulation and delivery of mitoxantrone using zirconium-based metal–organic frameworks (MOFs) and their cytotoxic potential in breast cancer cellsSinghal, M., Riches-Suman, Kirsten, Pors, Klaus, Addicoat, M.A., Ruiz, Amalia, Nayak, Sanjit, Elies, Jacobo 22 February 2024 (has links)
Yes / Mitoxantrone (MTX) is a drug employed in breast cancer treatment, but its application is largely limited due to side effects. A controlled delivery approach can potentially reduce the side effects. In this study, two zirconium (Zr)-based MOFs, UiO-66 and UiO-66-NH2, were studied for a more controlled delivery of MTX with a 40% and 21% loading capacity, respectively. Characterisation via powder X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectrometry, scanning electron microscopy, and dynamic light scattering confirmed the integrity of structure post-MTX loading. UV–vis spectrophotometry revealed distinctive release profiles, with UiO-66-MTX exhibiting a 25% cumulative release after 96 h in water and 120 h in PBS +10% FBS. UiO-66-NH2-MTX displayed a more sustained release, reaching 62% in water and 47% in PBS +10% FBS after 168 h. The interaction between MTX and the MOFs was also proposed based on computational modelling, suggesting a stronger interaction of UiO-66NH2 and MTX, and an optimised interaction of MTX in the tetrahedral and octahedral pores of the MOFs. The study also reports the release profile of the drug and antiproliferative activity against a panel of breast cancer cell lines (MDA-MB-231, MDA-MB-468, and MCF7) and a normal breast epithelial cell line (MCF10A). MTX-encapsulated MOFs were thoroughly characterised, and their biological activity was assessed in vitro. MTT cell viability assay indicated a higher IC50 value for MTX-loaded MOFs compared to free MTX in physiological conditions, albeit with a slower release profile. These findings suggest the potential of these MTX-loaded MOFs as an alternative avenue for formulation to mitigate side effects. / A.R. would like to thank The Royal Society (RGS\R1\221399) and the MRC Confidence in Concept grant (RM0039); MAA is grateful for HPC resources via membership of the UK’s HEC Materials Chemistry Consortium, which is funded by EPSRC (EP/X035859), this work used the UK Materials and Molecular Modelling Hub, which is partially funded by EPSRC (EP/T022213).
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The nuclear export of DNA topoisomerase iialpha in hematological myeloma cell lines as a function of drug sensitivity : clinical implications and a theoretical approach for overcoming the observed drug resistance /Engel, Roxane. January 2005 (has links)
Thesis (Ph.D.)--University of South Florida, 2005. / Includes vita. Includes bibliographical references (leaves 221-265).
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Planejamento, síntese e avaliação imunossupressora e anti-inflamatória de derivados antraquinônicosCorrêa, Taís Arthur 31 January 2014 (has links)
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Previous issue date: 2014-01-31 / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / As antraquinonas constituem uma importante classe de compostos orgânicos, devido a sua ocorrência na natureza e por serem versáteis na preparação de novos compostos bioativos. Tal fato pode ser confirmado pelo grande número de moléculas sintetizadas a cada ano pertencentes a essa classe, dando destaque aos compostos com atividade antitumoral, antiinflamatória e imunossupressora. Neste trabalho são descritas as sínteses de aminas, amidas, éteres e amino-álcoois a partir das antraquinonas 1,4-diaminoantraquinona, 1,4-diidroxiantraquinona e 1,5-diamino-4,8-diidroxiantraquinona, usando a mitoxantrona como composto protótipo. Duas séries foram obtidas por reação de O-alquilação da 1,4-diidroxiantraquinona com posterior substituição do grupo abandonador presente no grupo alquila ou mesmo dos grupos O-alquila ligados ao anel antraquinônico por diferentes aminas ou amino-álcoois. Uma terceira série de compostos foi obtida através da preparação de dois intermediários reativos “leucoquinizarim” e sua posterior condensação com diferentes amino-álcoois. As quarta e quinta séries tratam da síntese de diferentes compostos a partir da 1,4-diaminoantraquinona como monoamidas, diamidas e amino-álcoois, via condensação empregando reagentes de acoplamento, cloreto de acila e abertura de epóxido, respectivamente. Após a purificação e caracterização dos compostos através de métodos espectroscópicos usuais (RMN de 1H e de 13C, infravermelho e massas) suas propriedades citotóxicas, antiinflamatória e imunossupressora foram avaliadas in vitro e as substâncias mais ativas estão sendo avaliadas quanto a sua atividade frente à modulação da resposta imune in vivo no modelo de encefalomielite autoimune experimental (EAE). Em geral, as modificações estruturais propostas neste conjunto de moléculas apresentaram uma diminuição no processo inflamatório através da diminuição na produção de NO, que é uma melhoria quando comparado com a mitoxantrona, além de apresentarem inibição de mediadores inflamatórios (TNF-α e IL-1β), sugerindo um caráter imunossupressor. / Anthraquinone is an important class of organic compounds due to their common occurrence in nature, as well as being versatile in the preparation of novel bioactive compounds. This can be confirmed by the large number of molecules synthesized each year containing this group, emphasizing compounds with immunosuppressive, antitumor and anti-inflammatory activity. This work describes the synthesis of amines, amides, ethers and amino alcohols derived from anthraquinones such as 1,4-diaminoanthraquinone, 1,4-dihydroxianthraquinone and 1-5-dihydroxi-4,8-diaminoanthraquinone using mitoxantrone as a prototype compound. Two series were obtained by O-alkylation reaction of 1,4-dihydroxianthraquinona with subsequent replacement of the leaving group or the same group attached to the alkyl-anthraquinone ring with different amino alcohols or amines. A third series of compounds was obtained by preparing two reactive intermediate "leucoquinizarim" and subsequent condensation to various amino-alcohols. The fourth and fifth series reports the synthesis of different compounds from the 1,4-diaminoanthraquinones as monoamides, diamides and amino alcohols, via condensation with coupling reagents, acyl chloride and epoxide opening, respectively. After purification and characterization of the compounds though the usual spectroscopic methods (1H and 13C NMR, Infrared and mass spectra) their immunosuppressive, anti-inflammatory and cytotoxic properties were evaluated in vitro and the most active substances are being evaluated and check the action in the modulation of the in vivo immune response of experimental autoimmune encephalomyelitis (EAE). In general, structural modifications proposed in this set of molecules showed a decrease in inflammation by reducing the production of NO, which is an improvement compared to the mitoxantrone, besides presenting inhibition of inflammatory mediators (TNF-α and IL-1β), suggesting an immunosuppressive character.
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Desenvolvimento de nanopartículas lipídicas para o carreamento conjunto do gene para PTEN e mitoxantrona em células de câncer de mama e de próstata / Development of lipidic nanoparticles for PTEN gene and mitoxantrone delivery in breast and prostate cancer cellsRadaic, Allan, 1986- 21 August 2018 (has links)
Orientadores: Eneida de Paula, Marcelo Bispo de Jesus / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-21T18:01:25Z (GMT). No. of bitstreams: 1
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Previous issue date: 2012 / Resumo: O câncer é a doença genética responsável pelo maior número de mortes em países desenvolvidos e a segunda maior causa mortis em países em desenvolvimento. Uma das principais formas de tratamento do câncer é a quimioterapia, que se utiliza de fármacos para induzir a morte em células cancerígenas, impedindo, assim, seu crescimento anormal. Para ultrapassar desvantagens das tratamentos atuais, novas terapias vêm sendo desenvolvidas. Dentre elas, a terapia gênica e o uso de sistemas de liberação de fármacos foram as abordagens escolhidas em nossa pesquisa. Carreadores Lipídicos Nanoestruturados (CLN) e Nanopartículas Lipídicas Sólidas (NLS) são alternativas interessantes para viabilizar tais terapias, por conseguirem entregar material genético de forma efetiva e segura de genes, fármacos e proteínas em células alvo. Portanto, esta dissertação teve por objetivos i) desenvolver e aperfeiçoar um novo método de produção de CLN e NLS: a extrusão de microemulsão e ii) produzir nanopartículas capazes de carrear genes (gene codificante para PTEN) e fármacos (mitoxantrona) concomitantemente em células de câncer. Os resultados demonstram que a extrusão de microemulsão é um método factível para a produção de tais partículas, sendo que 15 passagens pela membrana de 100 nm, 5 ºC acima da temperatura de fusão dos lipídios sólidos são os melhores parâmetros para otimização deste processo. As nanopartículas lipídicas produzidas apresentaram diâmetro médio em torno de 140 nm e foram estáveis por, pelo menos, 180 dias estocadas a 4 ºC. Além disso, CLN e NLS mostraram-se semelhantes quanto ao tamanho, potencial Zeta e polidispersão (PDI). Apesar de não apresentarem diferenças quanto a transição de fase, as nanopartículas lipídicas apresentaram uma ultraestrutura monolítica bastante distinta dos lipossomas, o que garantiu uma alta eficiência de encapsulamento para o fármaco mitoxantrona: de 81% em CLN e 64 % em NLS. Finalmente, o carreamento concomitante do fármaco mitoxantrona e do gene da PTEN diminuiu a viabilidade celular em linhagens de câncer de mama (MCF-7) e de próstata (PC3), de maneira mais eficiente que formulações lipossomais / Abstract: Cancer is the genetic disease responsible for major death causes in developed countries and it is the second leading cause of death in developing countries. One of the main forms of cancer treatment is chemotherapy, which uses drugs to induce death in neoplastic cells, thereby preventing their overgrowth. To overcome disadvantages of current treatments, new therapies have been developed. Among them, gene therapy and the use of drug delivery systems were the approaches used in our research. Nanostructured Lipid Carriers (NLC) and Solid Lipid Nanoparticles (SLN) are suitable carriers for such therapies since they can effectively and safely deliver genetic material, drugs and proteins in target cells. Therefore, this work was aimed i) to develop and optimize a new method of production of NLC and SLN: the microemulsion extrusion and ii) to produce nanoparticles capable of co-delivery genes (the coding gene for PTEN) and drugs (mitoxantrone) into cancer cells. The results demonstrate that microemulsion extrusion is a reliable method for the production of such particles, being 15 passages through 100 nm membrane, at 5 °C above the solid lipid melting temperature, are the best parameters for process optimization. The lipid nanoparticles showed average diameter of 140 nm and they were stable up to 180 days of storage at 4 °C. Moreover, NLC and SLN showed similar size, Zeta potential and polydispersity (PDI). While calorimetry did not reveal great differences among the formulations tested, transmission electron microscopy revealed a monolithic structure for lipid nanoparticles distinct from lipossomes, which allowed NLC and SLN to encapsulate 81 and 64 %, respectively, of mitoxantrone. Finally, concomitant entrapment of mitoxantrone and PTEN gene in lipid nanoparticles led to a decrease in the cell viability of breast (MCF-7) and prostate (PC3) cancer cells, more efficiently than liposomal formulations / Mestrado / Bioquimica / Mestre em Biologia Funcional e Molecular
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Engineering PSMA-targeted nanoparticles co-encapsulating mitoxantrone and indocyanine green for precise combinatory therapy in prostate cancerKhalid, Hafiza J., Khan, Sobia, Hussain, Danyaal, Obinyima, Amarachi, Pina, Clara, Walker, Harriet R., Fox, Stuart, Elies, Jacobo, Ruiz, Amalia 31 October 2024 (has links)
Yes / Prostate cancer is the 2nd most common cancer in men worldwide. Chemotherapeutic treatment of prostate cancer with mitoxantrone (MTX) has limited efficacy due to severe side effects in which cardiotoxicity and myelosuppression are the two major causes of its dose-limiting toxicity. This study aimed to obtain a poly (lactic-co-glycolic acid) (PLGA) nanoparticle that can precisely deliver MTX to the prostate cancer cells overexpressing the Prostate-specific membrane antigen (PSMA) receptor-sparing healthy tissues and co-loading Indocyanine green (ICG) as a fluorescent photothermal/photodynamic agent for precise combinatory therapy in prostate cancer. The biocompatible polymer PLGA was covalently modified with the peptide of sequence (WQPDTAHHWATL) to actively target the PSMA receptor. Factors like the peptide-to-polymer ratio or the peptide's orientation during the polymer's chemical modification were investigated to enhance the active targeting of the nanoparticles (NPs). NPs were characterised using dynamic light scattering, scanning electron microscopy, and UV–vis spectroscopy to determine their morphological and colloidal properties and optimal MTX and ICG encapsulation efficiency. Quantitative FACS analysis of LNCaP and PC-3 cells incubated with Nile Red-labelled non-targeted PLGA or PLGA-PSMA targeted NPs was assessed to identify the best formulation that bound selectively to PSMA. The orientation of the peptide conjugated to the polymer, which has the C-terminal end of the peptide sequence accessible for interaction with the cell receptor, maximises the targeting capacity of the system. Photothermal experiments using 808 nm near-infrared laser irradiation were conducted, and cytotoxicity was assessed using the resazurin viability assay. Remarkably, our results confirmed the safety and efficacy of a targeted and activatable therapy using polymeric NPs functionalised with the peptide and co-loaded with MTX and ICG. This pioneer nanosystem opens new perspectives for exploring advanced targeted delivery in prostate cancer. It offers a straightforward methodology for functionalising drug delivery systems with bioactive peptides that can be applied to different types of cancer. / Royal Society Research Grant (RGS\R1\221399); MRC Confidence in Concept grant (RM0039); University of Bradford. This work was partially supported by a grant to I.H. (PID2021-122216OB-I00) funded by the Spanish Ministry of Economy, Industry and Competitiveness at the European Regional Development Fund
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Application of Mixture Design Response Surface Methodology for Combination Chemotherapy in PC-3 Human Prostate Cancer CellsOblad, Richard Vernon 01 April 2018 (has links)
Combining chemotherapeutics to treat malignant tumors has been shown to be effectivein preventing drug resistance, tumor recurrence, and reducing tumor size. We modeledcombination drug therapy in PC-3 human prostate cancer cells using mixture design responsesurface methodology (MDRSM), a statistical technique designed to optimize compositions thatwe applied in a novel manner to design combinations of chemotherapeutics. Conventionalchemotherapeutics (mitoxantrone, cabazitaxel, and docetaxel) and natural bioactive compounds(resveratrol, piperlongumine, and flavopiridol) were used in twelve different combinationscontaining three drugs at varying concentrations. Cell viability and cell cycle data werecollected and used to plot response surfaces in MDRSM that identified the most effectiveconcentrations of each drug in combination. MDRSM allows for extrapolation of data fromthree or more compounds in variable ratio combinations, unlike the Chou-Talalay method.MDRSM combinations were compared with combination index data from the Chou-Talalaymethod and were found to coincide. We propose MDRSM as an effective tool in devisingcombination treatments that can improve treatment effectiveness, and increase treatmentpersonalization because MDRSM measures effectiveness rather than synergism, potentiation orantagonism.
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ABC-Transporter-Gen-Polymorphismen sind potentielle pharmakogenetische Marker der Ansprechrate auf Mitoxantron in der Behandlung der Multiplen Sklerose / ABC-transporter gene polymorphisms are potential pharmacogenetic markers for mitoxantrone response in multiple sclerosisCotte, Steffi 20 February 2012 (has links)
No description available.
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Therapie der experimentellen autoimmunen Enzephalomyelitis mit Mitoxantron - Vergleichende Analyse von C57BL/6J- mit Abcg2-knock-out-Mäusen / Therapeutic effect of mitoxantrone in experimental autoimmune encephalomyelitis - Comparative analysis of the effect on C57BL/6J- and abcg2-knock-out-miceHuber, Bastian 12 March 2012 (has links)
No description available.
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Ανάπτυξη νέας τεχνικής επιφανειακής ενίσχυσης της σκέδασης Raman (SERS) για ποσοτικές μετρήσεις ενεργών ουσιών σε πολύ μικρές συγκεντρώσειςΜανίκας, Αναστάσιος 09 May 2012 (has links)
Η φασματοσκοπία Raman θεωρείται αξιόπιστη μέθοδος χαρακτηρισμού της μοριακής δομής της ύλης. Τελευταία δε καταβάλλεται μεγάλη προσπάθεια να αναδειχθεί και ως μη επεμβατική τεχνική ανίχνευσης ουσιών φαρμακευτικού και βιολογικού ενδιαφέροντος. Επειδή όμως το φαινόμενο Raman είναι ασθενές και τα όρια ανίχνευσης των ουσιών αυτών ιδιαίτερα χαμηλά, η συμβατική φασματοσκοπία Raman ανταποκρίνεται με μεγάλη δυσκολία στις απαιτήσεις μιας μη επεμβατικής τεχνικής. Τα τελευταία χρόνια με την ανακάλυψη της επιφανειακής ενίσχυσης της σκέδασης Raman (Surface Enhanced Raman Scattering) και την ανάπτυξη της ομώνυμης τεχνικής SERS αυξήθηκε η πιθανότητα του φαινομένου κατά τάξεις μεγέθους. Στο πλαίσιο αυτό, έχουν αναφερθεί και μελέτες SERS με ανίχνευση σκέδασης Raman ακόμη και από ένα μόνο μόριο (single molecule detection). Προϋπόθεση όμως ανάπτυξης φαινομένου SERS είναι η γειτνίαση της εξεταζόμενης ουσίας με νανοσωματίδια αργύρου (Ag) ή χρυσού (Au). Τα νανοσωματίδια αυτά χρησιμοποιούνται κυρίως είτε υπό μορφή κολλοειδών διαλυμάτων είτε υπό την μορφή νανοδομημένων επιφανειών. Μια επιπλέον παράμετρος που πρέπει να συνυπολογισθεί ώστε η μέθοδος αυτή να χαρακτηριστεί αναλυτική είναι η δυνατότητα πραγματοποίησης με SERS ποσοτικών μετρήσεων.
Στην παρούσα εργασία ως “υπόστρωμα” εμφάνισης του φαινομένου SERS χρησιμοποιήθηκαν κολλοειδή διαλύματα Au και Ag (~2 mL), στα οποία προστίθεντο 25-100 μL διαλύματος της προς ανίχνευσης ουσίας. Η χρησιμοποίηση της γεωμετρίας σκέδασης 90ο, της πλέον ενδεδειγμένης για λήψη φασμάτων Raman από υγρά και κολλοειδή διαλύματα νανομετρικής κλίμακας (10-100 nm), έδωσε τη δυνατότητα ανίχνευσης συγκεντρώσεων ουσιών-στόχων ακόμη και της τάξης των fg/mL. Επιπλέον, η χρησιμοποίηση μιας κυψελίδας με συνεχή ταλάντωση σε κάθετη ως προς το επίπεδο σκέδασης διεύθυνση (oscillating or shaking cell), επέτρεψε την πραγματοποίηση ποσοτικών μετρήσεων SERS σε συγκεντρώσεις της τάξης των (sub)-ng & (sub)-pg/mL. Η διάταξη αυτή φωταψίας δείγματος και συλλογής σκεδαζόμενης ακτινοβολίας εφαρμόστηκε σε αντικαρκινικά φάρμακα (Novantrone® & Doxorubicin), αντιβιοτικό (Ciproxin®) και βάσεις του DNA. Στην περίπτωση του αντιβιοτικού με ενεργή ουσία το Ciprofloxacin ελήφθησαν ποσοτικά αποτελέσματα σε διαλύματα τεχνητών δακρύων της τάξης των ng/mL, κάτω από την συνολική κλίμακα της μέσης ανασταλτικής πυκνότητας (minimum inhibitory concentration range) του φαρμάκου. Στόχος και φιλοδοξία είναι η τεχνική αυτή να αναδειχθεί ως μια ταχεία μη επεμβατική αναλυτική μέθοδος μέτρησης φαρμακευτικών ή/και βιολογικών ουσιών σε σωματικά υγρά (π.χ. σίελος, δάκρυα, …), για την μελέτη της φαρμακοκινητικής, την έγκαιρη διάγνωση ασθενειών καθώς και τη μελέτη ελεγχόμενης αποδέσμευσης ενεργών ουσιών από πολυμερικές μήτρες σε πολύ μικρές συγκεντρώσεις.
Επιπλέον, έγινε προσπάθεια μελέτης/ανίχνευσης μορίων Ε18 primary rat cortical cells με την χρήση του SERS σε συνθήκες προσομοίωσης ηλεκτροχημικού εμφυτεύματος. Για τον λόγο αυτό σχεδιάστηκε και αναπτύχθηκε ένας μικρο-επωαστής (micro-incubator) που επιτρέπει αφ’ ενός μεν τη συντήρηση των κυττάρων σε περιβάλλον κατάλληλο για τη μελέτη τους (layer of Neurobasal-culture medium with a 95% air & 5% CO2 gas flow at 37oC), αφ’ ετέρου δε την προσαρμογή του σε χώρο υποδοχής δείγματος ενός φασματοφωτόμετρου μικρο-Raman για τη λήψη φασματοηλεκτροχημικών μετρήσεων Raman/SERS. Το κύριο σημείο ενδιαφέροντος στο οποίο εστιάσαμε στην παρούσα εργασία αναφέρεται στην διερεύνηση ανίχνευσης βασικών/θεμελιωδών μορίων των κυττάρων στo θρεπτικό υγρό του πειράματος για την ταχεία εκτίμηση ενδεχόμενης αποδέσμευσης DNA που θα αντικατόπτριζε την κατάσταση των κυττάρων. / Laser Raman spectroscopy plays an increasing important role in polymer science, biophysics/biochemistry and life science. Based on vibrational transitions, it has long been regarded as a valuable non destructive tool for the identification of chemical and biological samples as well as the elucidation of molecular structure, surface processes and interface reactions. Spontaneous Raman scattering is however an inherently weak process characterized by extremely small cross sections. Even so, the Raman signal can be highly enhanced when the analyte is placed on or near either to nano-rough noble-metal substrates or to nano-structured colloidal clusters of noble metals. This nano-enhanced scattering process is known as Surface Enhanced Raman Scattering, SERS. With SERS, extremely small amounts of substances can be detected; even single molecule detection has been reported. This constitutes a challenge of applying SERS to extremely low concentration measurements.
Nevertheless, the quantitative evaluation by means of SERS was proved difficult, due largely to lack of nano-sized noble metal structures with analytically suitable stability and reproducibility. The commonly used SERS substrates are nanostructured colloids or roughened surfaces of mainly silver and gold undergoing visible or NIR excitation. A note is made of the fact that the Raman scattering geometry that is actually largely used is the backscattering geometry. For solids this is better achieved via a microscope objective, while for liquids via a macro lens. However, the best scattering geometry for Raman light collection from liquids and nanostructured colloids is the right angle scattering; that is, the scattered light is collected at 90o from the excitation light. Having all above in mind, in order to perform quantitative SERS measurements we have designed and developed an oscillating cell making use of the right angle Raman scattering geometry. Originally, the development of the oscillating or “shaking” cell allows large sample sectional surface monitoring, better mixing and homogeneity giving rise to SERS signal reproducibility. In addition, the application of the advantageous for nanocolloidal solutions right angle Raman scattering collection geometry enables SERS measurements at extremely low concentrations.
We demonstrated the use this new surface enhanced Raman scattering excitation/collection configuration to monitor the level of the antitumor drugs mitoxantrone and doxorubicin as well as the antibiotic ciprofloxacin at very low concentrations performing fast SERS & SERRS measurements. We have also quantified the concentration of the active agents in aqueous solutions as well as in artificial tears by a partial least-squares (PLS) chemo metric regression algorithm. All above reveal the potential of this technique in the monitoring of the controlled release of active agents from polymeric matrices as well as in the quantitative analysis of drugs in corporal fluids. The only need is to add in a test tube containing 0.5 mL of a nanocolloidal noble metal solution3 about 25-100 μL of a sampling fluid.
Finally, in an attempt to detect “living” cells by SERS, to identify DNA components released in a cell culture medium as a “touch mark” of cell death and to perform even single molecule detection, a home-made micro-incubator was designed to allow Raman measurements of neuron cells under the microscope. Commercial micro incubators feature higher optical path between coverslips than the required (<1-1,5 cm) for typical micro-Raman systems even bearing long working distance objectives. It was at that sense a prerequisite to design, construct and optimize a micro-incubator to fit a conventional micro-Raman configuration. The designed micro-incubator meets well-defined stable conditions (temperature, culture solution and atmosphere).
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