Everything you always wanted to know about SDPD⋆ (⋆but were afraid to ask)

An overview of the smoothed dissipative particle dynamics (SDPD) method is presented in a format that tries to quickly answer questions that often arise among users and newcomers. It is hoped that the status of SDPD is clarified as a mesoscopic particle model and its potentials and limitations are highlighted, as compared with other methods

Nanoprobes for Tumor Theranostics

This book reports cutting-edge technology in nanoprobes or nanobiomaterials used for the accurate diagnosis and therapy of tumors, involving a multidisciplinary of chemistry, materials science, oncology, biology, and medicine

Polymeric drug delivery systems: aspects of core and shell of nanocarriers from polyesters, poly(ester amide)s or poly(2–oxazoline)s

Hydrophobe Wirkstoffe weisen häufig eine schlechten Bioverfügbarkeit und Transporteffizienz auf. Diese Nachteile können durch ein optimiertes Nanoträgersystem kompensiert werden. Hierfür sind polymerbasierte Mizellen und Nanopartikel mit einem hydrophoben Kern besonders geeignet. Die Personalisierung des jeweiligen Polymergrundgerüsts sollte jedoch unter Beachtung der kausalen Zusammenhänge erfolgen. In diesem Zusammenhang wurden in der vorliegenden Dissertation ausgewählte Kandidaten der Polyester, Polyesteramide und Poly(2-ethyl-2-oxazolin)e untersucht. Neben ihrer Synthese, wurden diese Materialien hinsichtlich ihrer Anwendung als Nanocarrier und Struktur–Eigenschafts–Beziehungen bewertet. Die konstante hydrophile-hydrophobe-Balance wurde für wohldefinierte Poly(ɛ–caprolacton)-Analoga mit unterschiedlicher Mikroarchitektur validiert. Trotz unterschiedlicher thermischer Polymereigenschaften wurden vielversprechende Nanopartikel mit gleicher Größe und ausgezeichneter Langzeitstabilität erhalten. Eine Polyesteramid-Bibliothek wurde durch die Polyaddition von acht Dicarbonsäuren und 2,2`-Bis(2-oxazoline) erzeugt. Im Anschluss wurden die geeigneten Materialien in einer Kompatibilitätsstudie mit dem hydrophoben, antientzündlichen Wirkstoff Indomethacin untersucht. Formulierbarkeit des Polymers, aber auch die Kompatibilität der Kernkomponenten in Bulk hatten beide einen signifikanten Einfluss auf die Qualität der beladenen Nanoträger. Die Einführung einer hydrophilen Stealth-Schale erfolgte im Makromonomeransatz durch Kombination der kationischen Ringöffnungspolymerization und einer kontrollierten, radikalischen Polymerisation. Resultierende Kern-Schale-Mizellen basierend auf dem hydrophoben Poly(methylmethacrylat)-Rückgrat und hydrophilien Seitenketten aus Oligo(2-ethyl-2-oxazolin) wurden in Abhängigkeit der variierenden Rückgrat-Endgruppe untersucht. Mittels intravitaler Mikroskopie wurde ein Endgruppeneinfluss auf die Leberzellspezifität in Mausstudien festgestellt

Click chemistry: an efficient toolbox for the design of chitosand-based hydrogels for biomedicine

312 p.The present thesis was focused on the development of new gel-type biomaterials form chitosan withexcellent stimuli-responsive properties using different click reactions. To this end, in the first place,chitosan was endowed with specific functionalities, after the controlled insertion of furan, maleimide,thiol or tetrazole groups in the main chain of the biopolymer, maintaining its original biocompatiblecharacter. Hereafter, hydrogels with different size and chemical structure were synthesized by means ofclick type cross-linking reactions (Diels-Alder, thiol-Michael addition or nitrile imine-mediated tetrazoleenecycloaddition). The final physico-chemical, swelling, viscoelastic and morphological properties ofthe different hydrogel systems were studied. So that the new developed biomaterials would be competentin the biomedical field, biodegradability studies under specific enzymes, controlled drug release assays,mucoadhesion experiments with mucin, antibacterial studies against Escherichia coli and Staphylococcusaureus and short-term cytotoxicity assays were conducted, depending on the intended final application.GMT :Materials Technologies Research Grou

Click chemistry: an efficient toolbox for the design of chitosand-based hydrogels for biomedicine

312 p.The present thesis was focused on the development of new gel-type biomaterials form chitosan withexcellent stimuli-responsive properties using different click reactions. To this end, in the first place,chitosan was endowed with specific functionalities, after the controlled insertion of furan, maleimide,thiol or tetrazole groups in the main chain of the biopolymer, maintaining its original biocompatiblecharacter. Hereafter, hydrogels with different size and chemical structure were synthesized by means ofclick type cross-linking reactions (Diels-Alder, thiol-Michael addition or nitrile imine-mediated tetrazoleenecycloaddition). The final physico-chemical, swelling, viscoelastic and morphological properties ofthe different hydrogel systems were studied. So that the new developed biomaterials would be competentin the biomedical field, biodegradability studies under specific enzymes, controlled drug release assays,mucoadhesion experiments with mucin, antibacterial studies against Escherichia coli and Staphylococcusaureus and short-term cytotoxicity assays were conducted, depending on the intended final application.GMT :Materials Technologies Research Grou

Nanosistemas híbridos para la administración de agentes terapéuticos como tratamiento de enfermedades complejas

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Farmacia, Departamento de Química en Ciencias Farmacéuticas, leída el 05-07-2021The overall objective of this doctoral thesis has been the design of various nanomaterials with the aim of addressing distinct approaches to treat cancer and fibrosis, as well as overcoming some of the biological barriers that restrict nanomedicine-based therapies.These biological restrictions entail important limitations in the fight against cancer based on nanomedicines. Some of them are the sequestration of nanoparticles by the mononuclear phagocytic system, the lack of selectivity of conventional chemotherapy, which generates undesirable side-effects and disfunctions in organs or tissues, or the scarce penetration of nanoparticles within the target diseased tissue. Recent interest in the design of nanosystems that overcome these constraints is generating new tools for the effective treatment of cancer, as well as other pathologies...El objetivo general de esta tesis doctoral ha sido el diseño de varios nanomateriales con el fin de abordar distintos enfoques para tratar el cáncer y la fibrosis, así como superar algunas de las barreras biológicas que restringen las terapias basadas en el uso de nanomedicinas. Estas restricciones biológicas suponen importantes limitaciones en la lucha contra el cáncer basada en nanomedicinas. Algunas de ellas son el secuestro de las nanopartículas por el sistema fagocítico mononuclear, la falta de selectividad de la quimioterapia convencional, que genera efectos secundarios y disfunciones en órganos o tejidos, o la escasa penetración de las nanopartículas en el tejido enfermo objetivo. El reciente interés en el diseño de nanosistemas que superen estas restricciones está generando nuevas herramientas para el tratamiento eficaz del cáncer, así como también de otras patologías...Fac. de FarmaciaTRUEunpu

Cell targeted nanoparticle-based drug delivery systems for spinal cord injury regeneration

Tese de doutoramento em Engenharia de Tecidos, Medicina Regenerativa e Células EstaminaisSpinal cord injuries (SCI) afflict millions of people every year worldwide. Since no cure exists for such neurotraumatic episodes, patients thus experience highly debilitating symptoms. These comprehend partial to complete muscular weakness and sensory loss, and commonly lead to paraplegia or tetraplegia. The tremendous complexity of cellular and biochemical reactions that follow the initial trauma, along with the lack of specificity of the drugs used, are hindering the development of effective treatments for SCI. Current clinical options are thus mainly based on palliative care, and systemic high dose administration of methylprednisolone (MP), a powerful anti-inflammatory and antioxidant corticosteroid that has shown to lead to functional recovery. However, the unspecificity and deleterious side effects of MP are making some clinicians cautious towards its administration. Actually, this treatment is very controversial, therefore, new enhanced approaches are needed to repair the injured spine and provide SCI patients a better quality of life. The most recent developments in nanotechnology show great promise for tissue engineering advanced solutions. Recently, poly(amido)amine (PAMAM) dendrimer nanoparticles grafted with CMCht have been proposed as intracellular nanocarriers for stem cell osteogenic differentiation. In this thesis, it was explored the application of the developed CMCht/PAMAM dendrimer nanoparticles for neuroprotection of the injured spinal cord tissue, ultimately contributing to regeneration and repair. Firstly, functionalization of CMCht/PAMAM dendrimer nanoparticles was performed covalently binding an antibody to its structure, and then incorporating a relevant drug, such as MP. Both modifications were confirmed using spectroscopic techniques and in vitro biological evaluation was performed in primary cortical glial cultures. No cytotoxicity associated with the multifunctional CMCht/PAMAM dendrimer nanoparticles was observed. In vitro internalization studies revealed a differential uptake, when the antibody was bond to the CMCht/PAMAM dendrimer nanoparticles. Therefore, the addition of targeting moieties to the nanoparticles contributed to a modulation of the nanoparticle uptake by glial cells. In order to analyze the intracellular trafficking, as well as internalization and clearance routes, electrophysiology recordings of live astrocyte (single-cell) membrane capacitance were performed after incubation with MP-loaded CMCht/PAMAM dendrimer nanoparticles. The patch-clamp studies showed that nanoparticles do affect both endocytosis and exocytosis rates. In fact, these observations were further confirmed by confocal microscope visualization of astrocyte endocytotic and exocytotic vesicles. To our knowledge, this study clarified for the first time the endocytotic/exocytotic pathways that nanoparticles follow in primary nervous cells, demonstrating for the first time the exocytotic clearance of the nanoparticles. Following this, administration of FITC-labeled MP-loaded CMCht/PAMAM dendrimer nanoparticles in the cerebrospinal fluid (CSF) of healthy rats was performed. The distribution of the nanoparticles was widespread along several brain areas and layers, showing that once the blood-brain barrier (BBB) is overcome the nanoparticles are easily transported and retained in the brain tissue. Moreover, the drug was shown to be acting intracellularly by protein expression quantification. Subsequently, extensive investigation of the physico-chemical characteristics of the MP-loaded nanoparticles was carried out revealing its spherical 109 nm structure and zeta potential stability. Moreover, a preliminary therapeutic assessment of this system was analyzed in vitro in microglial cultures, and in vivo in an animal model of SCI. Promising results were obtained with the successful modulation of microglia proliferation, and significant locomotor improvements in the treated injured animals. Finnaly, biocompatibility and functionality studies were performed in Schwann cell pure cultures and co-cultures with dorsal root ganglia neurons, when in contact with the MP-loaded CMCht/PAMAM dendrimer nanoparticles. The presence of nanoparticles has not affected the cell morphology or typical distribution in culture. Moreover, extensive myelination was performed by Schwann cells that enveloped the axons of dorsal root ganglia neurons, showing normal viability and function. These results open new possibilities for therapeutic strategies, namely combination of Schwann cell transplantation and nanoparticle administration. From these findings, new knowledge regarding nanoparticle interaction with nervous cells was obtained, along with the potential therapeutic value. For the first time, multifunctionalization of CMCh/PAMAM dendrimer nanoparticles was successfully accomplished and proved to modulate the cell uptake rates. Moreover, the innovative use of patch-clamp electrophysiology for the quantification of vesicle formation/fusion in the cell membrane following nanoparticle incubation proved to be useful in this type of studies. The promising locomotor improvements observed in nanoparticle-treated SCI animals, along with the biocompatibility of these nanoparticles for CNS applications, bring new hopes for the development of successful strategies for SCI repair.Lesões traumáticas na espinal medula afetam anualmente milhões de pessoas em todo o mundo. Atualmente não existe cura para lesões neurotraumáticas, e os pacientes vivenciam sintomas altamente debilitantes. Estes vão desde parcial a total perda de força muscular e perceção sensorial, e comummente culminam em paraplegia ou tetraplegia. A elevada complexidade de reações celulares e bioquímicas que se seguem ao trauma inicial, associada à falta de especificidade das drogas em uso, têm vindo a dificultar o desenvolvimento de terapias eficazes para o tratamento de lesões na espinal medula. Como consequência, as opções clínicas atuais centram-se maioritariamente em cuidados paliativos e na administração sistémica aguda de metilprednisolona (MP), um poderoso corticosteroide anti-inflamatório e antioxidante que demonstrou melhorias funcionais em pacientes. No entanto, a falta de especificidade e os graves efeitos secundários associados à administração sistémica de MP estão a levar alguns especialistas a administrá-la com grande precaução. De facto, a aplicação desta terapêutica é bastante controversa logo, é essencial e urgente desenvolver novas estratégias mais eficazes e seguras para regenerar a espinal medula, de forma a poder proporcionar aos pacientes uma melhor qualidade de vida. Os mais recentes desenvolvimentos na área da nanotecnologia têm mostrado grande potencial para aplicação em estratégias avançadas de engenharia de tecidos. Recentemente, nanopartículas dendriméricas de poliamidoamina (PAMAM) superficialmente modificadas com carboximetilquitosano (CMCht) foram propostas para transporte intracelular de fármacos. Nesta tese, a aplicação destas nanopartículas dendriméricas de CMCht/PAMAM é explorada para neuroprotecção da espinal medula após lesão, tendo como objetivo permitir a regeneração do tecido. Primeiramente procedeu-se à funcionalização das nanopartículas dendriméricas CMCht/PAMAM através da ligação covalente de um anticorpo à sua estrutura, e subsequente incorporação do corticosteroide MP. Ambas as modificações foram confirmadas por análise espectroscópica, e de seguida efetuou-se uma avaliação biológica in vitro em culturas primárias de células da glia. Não foi observado qualquer efeito citotóxico relacionado com a presença das nanopartículas multifuncionais nas culturas e a presença do anticorpo na sua estrutura originou uma alteração do perfil de internalização das mesmas nas culturas de glia. Confirmou-se, assim, que a adição de agentes de direcionamento à estrutura das nanopartículas CMCht/PAMAM contribui para a alteração da distribuição da internalização celular. Com a finalidade de analisar a distribuição intracelular das nanopartículas, assim como as vias de internalização e remoção, efetuaram-se análises eletrofisiológicas para medir a capacitância de membrana de astrócitos viáveis após incubação com nanopartículas com MP. Os estudos de patch-clamp demonstraram que as nanopartículas afetam as taxas de endocitose e exocitose destas células. Estas observações foram também confirmadas por observação por microscopia confocal e quantificação de fluorescência. Este estudo clarifica pela primeira vez as vias que estas nanopartículas seguem em células nervosas, nomeadamente endocitose e exocitose. Seguidamente, administrou-se nanopartículas com MP e marcadas com o fluorocromo FITC no líquido cefalorraquidiano de ratos saudáveis e verificou-se uma distribuição ampla ao longo de várias regiões e camadas do cérebro, provando que uma vez ultrapassada a barreira hematoencefálica as nanopartículas facilmente são transportadas no tecido nervoso. Posteriormente, procedeu-se à caracterização físico-química das nanopartículas incorporadas com MP e efetuou-se uma avaliação preliminar do potencial terapêutico deste sistema em culturas de microglia e in vivo num modelo animal de lesão de espinal medula. A modulação da proliferação de microglias in vitro, assim como as melhorias locomotoras registadas nos animais lesionados tratados com nanopartículas são resultados bastante encorajadores. Finalmente, os estudos de biocompatibilidade e funcionalidade em células de Schwann expostas a nanopartículas incorporadas com MP não indicaram qualquer anomalia na morfologia celular ou na típica distribuição destas células em cultura. Quando em co-cultura com neurónios de gânglios espinais, as células de Schwann mielinizaram de forma extensa os axónios destas células, comprovando a sua normal viabilidade e funcionalidade. Destes resultados, obteve-se novo conhecimento acerca da interação de nanopartículas dendriméricas CMCht/PAMAM multifuncionalizadas com células nervosas, assim como do seu potencial valor terapêutico em lesões de espinal medula. Efetuou-se com sucesso uma funcionalização que conduziu à alteração do perfil de internalização celular. O uso inovador de eletrofisiologia patch-clamp para quantificar a formação/fusão de vesículas na membrana celular após incubação com nanopartículas demostrou ter extrema utilidade neste tipo de estudos. Os resultados obtidos revelando melhorias locomotoras em animais lesionados e tratados com nanopartículas com metilprednisolona, associados à biocompatibilidade destas nanopartículas para aplicações do foro neurológico, traz renovada esperança na busca de melhores estratégias para tratar de forma eficaz as consequências de lesões na espinal medula