Stimuli-responsive nanogel composites and their application in nanomedicine

Nanogels are nanosized crosslinked polymer networks capable of absorbing large quantities of water. Specifically, smart nanogels are interesting because of their ability to respond to biomedically relevant changes like pH, temperature, etc. In the last few decades, hybrid nanogels or composites have been developed to overcome the ever increasing demand for new materials in this field. In this context, a hybrid refers to nanogels combined with different polymers and/or with nanoparticles such as plasmonic, magnetic, and carbonaceous nanoparticles, among others. Research activities are focused nowadays on using multifunctional hybrid nanogels in nanomedicine, not only as drug carriers but also as imaging and theranostic agents. In this review, we will describe nanogels, particularly in the form of composites or hybrids applied in nanomedicine

Fabrication of thermoresponsive nanogels by thermo-nanoprecipitation and in situ encapsulation of bioactives

A synthetic method for thermoresponsive, glycerol based nanogels has been developed. The nanogels were synthesized by nanoprecipitation of the orthogonally functionalized macromonomers and their gelation in water. The crosslinking points were generated by strain promoted azide–alkyne cycloaddition which enabled the in situ encapsulation of Doxorubicin HCl. The mild and surfactant free reaction conditions make these nanogels ideal candidates for biomedical applications

Stimuli-responsive nanogel composites and their application in nanomedicine

Nanogels are nanosized crosslinked polymer networks capable of absorbing large quantities of water. Specifically, smart nanogels are interesting because of their ability to respond to biomedically relevant changes like pH, temperature, etc. In the last few decades, hybrid nanogels or composites have been developed to overcome the ever increasing demand for new materials in this field. In this context, a hybrid refers to nanogels combined with different polymers and/or with nanoparticles such as plasmonic, magnetic, and carbonaceous nanoparticles, among others. Research activities are focused nowadays on using multifunctional hybrid nanogels in nanomedicine, not only as drug carriers but also as imaging and theranostic agents. In this review, we will describe nanogels, particularly in the form of composites or hybrids applied in nanomedicine

Magnetic Nanoparticle-Based Dianthin Targeting for Controlled Drug Release Using the Endosomal Escape Enhancer SO1861

Targeted tumor therapy can provide the basis for the inhibition of tumor growth. However, a number of toxin-based therapeutics lack efficacy because of insufficient endosomal escape after being internalized by endocytosis. To address this problem, the potential of glycosylated triterpenoids, such as SO1861, as endosomal escape enhancers (EEE) for superparamagnetic iron oxide nanoparticle (SPION)-based toxin therapy was investigated. Herein, two different SPION-based particle systems were synthesized, each selectively functionalized with either the targeted toxin, dianthin-epidermal growth factor (DiaEGF), or the EEE, SO1861. After applying both particle systems in vitro, an almost 2000-fold enhancement in tumor cell cytotoxicity compared to the monotherapy with SPION-DiaEGF and a 6.7-fold gain in specificity was observed. Thus, the required dose of the formulation was appreciably reduced, and the therapeutic window widened

Stimuli-responsive Nanogele für Anwendungen in der Dermatologie, in der photothermalen Therapie, sowie für die Isolation von zirkulierenden Tumorzellen

1 Introduction ....................................................................................................14 1.1 Nanomedicine ............................................................................................................... 14 1.2 Passive and active targeting of polymer therapeutics ............................................... 16 1.3 Considerations for the design of modern nanomedicines......................................... 19 1.4 Responsive polymer materials .................................................................................... 26 1.5 Nanogel engineering approaches ................................................................................ 30 1.6 External triggers in nanomedicine ............................................................................. 35 2 Motivation and summary...............................................................................39 2.1 Motivation ..................................................................................................................... 39 2.2 Conclusion and outlook ............................................................................................... 41 2.3 Abstract......................................................................................................................... 43 2.4 Kruzzusammenfassung................................................................................................ 44 3 Publications and manuscripts........................................................................46 3.1 Engineering thermoresponsive polyether-based nanogels for temperature dependent skin penetration ............................................................................................... 46 3.2 Effects of thermoresponsivity and softness on skin penetration and cellular uptake of polyglycerol-based nanogels ....................................................... 72 3.3 Near infrared dye conjugated nanogels for combined photodynamic and photothermal therapies .......................................................................................................93 3.4 Transferrin decorated thermoresponsive nanogels as magnetic trap devices for circulating tumor cells.................................................................................. 126 4 References .....................................................................................................150 5 Appendix .......................................................................................................158 4.1 Publication and conference contributions ............................................................... 158 4.3 Curriculum vitae ........................................................................................................ 161The carfeul design and the optimization of synthetic strategies are key steps for the development of responsive nanogels (NG) that achieve the desired “smart” interaction with biological systems. In this thesis responsive nanogels were engineered through different methodologies and evaluated for their ability in biomedical applications such as for dermatology, photothermal therapy, and as capturing system for circulating tumor cells. It was found that thermoresponsive nanogels based on dendritic polyglycerol (dPG) and poly(oligoethylene glycol) (POEG) revealed an excellent biocompatible profile against human keratinocyte and fibroblast cell lines with a tolerable dose of 2 mg mL-1. The developed synthetic methodology allowed, moreover, to set the size and transition temperature of generated NGs in the range of 50 – 250 nm and 30 – 40 °C respectively. When these NGs were fluorescently labeled and applied on human skin explants a temperature dependent translocation pattern through the skin barrier and hair follicles was observed. This behavior could be attributed to the elastic nature of NGs and their structural integrity. This study demonstrated that thermoresponsive NGs reveal a great potential as smart drug carries for various hair follicle and skin related diseases. Based on the findings for the conjugation of fluorescent dyes to thermoresponsive nanogels a methodology was developed that uses ultrasound assisted precipitation polymerization. Along with the covalent incorporation of IR806, a NIR absorbing dye, into the nanogel scaffold, this methology revealed spherical shape, nanometric size (90 nm), and narrow size distribution (DLS PDI 0.16) for the generated NGs. Since IR806 is a photothermal agent that transduces NIR light into heat, NGs were evaluated for their photothermal ability against cancer cell lines. As a result selective toxicity was demonstrated when NG internalized cells were exposed to a NIR laser while excellent biocompatibility was demonstrated when cells were not exposed to a NIR laser. This study demonstrated the proof of principle that organic photothermal agents can be incorporated covalently into NGs to demonstrate reduced toxicity, improved water solubility, and excellent photothermal efficiencies. To investigate the ability of NGs for cell capturing purposes nanogels based on magnetic nanoparticles and linear polyglycerol were synthesized using strain-promoted click cross-linking chemistry. This methodology allowed moreover the surface decoration with targeting ligands. Magnetic nanogels showed cell capture efficiencies of 40 % that have to be improved in future work. Studies on the magnetic relaxations time, however, showed that the magnetic NGs obtain similar relaxivity values as commercial available contrasting agents. Hence, this study lead to the conlusion that the use of magnetic NGs is not limited to cell capturing purposes but can be extended for their use as a potential contrasting agent in MRI. This thesis shows that responsive nanogels obtain a great potential for their use in nanomedicine. Mainly their physico-chemical properties such as their size, shape, and elasticity combined with their responsiveness play a key finction on their influence to applied biological systems. Controlling these porperties can enhance the translation of responsive nanogels from bench to bedsides.Das sorgfältige Design und die Optimierung von Synthesestrategien sind Schlüsselschritte in der Entwicklung von responsiven Nanogelsystemen, mit denen eine „smarte“ Wechselwirkung mit biologischen Systemen angestrebt werden soll. In der vorliegenden Arbeit wird die Darstellung von responsiven Nanogelen und ihre biologische Evaluation für Anwendungen in der Dermatologie, in der photothermalen Therapie, sowie für die Isolation von zirkulierenden Tumorzellen beschrieben. Mittels der freien radikalischen Fällungspolymerisation wurden die thermoresponsiven Nanogele, die auf dendritischem Polyglycerin und Poly(oligoethylenglycol) basieren, synthetisiert. Diese Synthesestrategie erlaubt das Maßschneidern der Größe der Nanogele in einem Bereich zwischen 50 – 250 nm, sowie die Kontrolle über die Phasenumwandlungstemperaturen (PUT) zwischen 30 und 40 °C. Alle synthetisierten Nanogele, unabhängig von deren Größe und PUT, weisen eine überaus hohe Biokompatibilität gegenüber menschlichen Keratinozyten und Fibroblasten in vitro auf. Farbstoff-Konjugate dieser Nanogele demonstrieren zudem eine temperaturabhängige Translokation durch die äußerste Hautschicht menschlicher Haut sowie in Haarfollikeln. Diese Eigenschaft ist hauptsächlich auf die hohe Elastizität und die strukturelle Integrität der Nanogele zurückzuführen. Diese Studie zeigt das Potential thermoresponsiver Nanogele, die für den Einsatz als smarte Wirkstoffträger für Erkrankungen von Haut und Haarwurzel genutzt werden können. Basierend auf den Erkenntnissen für die Farbstoff-Konjugation an Nanogelen wurde eine weitere Synthesestrategie entwickelt, die es erlaubt den hochsensiblen Farbstoff, IR806, in das thermoresponsive Nanogelgerüst kovalent einzubinden. IR806 ist ein im nahen Infrarot (NIR) Bereich absorbierender organischer Farbstoff der die Fähigkeit besitzt absorbiertes NIR Licht in Wärme umzuwandeln. Er zeichnet sich allerdings durch schlechte Wasserlöslichkeit, hohe Toxizität und geringe photothermale Effizienz aus. Seine erfolgreiche Einbettung in das polymere Nanogelnetzwerk hat nicht nur seine Wasserlöslichkeit verbessert und seine Toxizität um das zehnfache reduziert, sondern gleichzeitig ein dual- responsives Nanogelsystem erschaffen. Diese Nanogele, die sich durch eine Größe von 90 nm mit schmalen Größenverteilungen (Polydispersitätsindex in dynamischer Lichtstreuung: 0.16), sowie hervorragenden licht- und thermoresponsiven Eigenschaften auszeichnen, sind in der Lage, nach erfolgter Internalisierung, Krebszellen in vitro durch Aussetzung von NIR Laserbestrahlung selektiv und thermisch zu zerstören. Diese Eigenschaften gepaart mit ihrer exzellenten wasserlöslich und ihre reduzierten Toxizität erweisen sich als überaus nützlich für zukünftige in vivo Anwendungen in der photothermalen Therapie. Ferner wurde eine Synthesestrategie entwickelt, die es ermöglicht Nanogele für die Isolation zirkulierender Tumorzellen einzusetzen. Die Ultraschall-unterstützte Methode ermöglicht, in einer Kupfer- freien ‚Klick‘-Reaktion, die Quervernetzung von Bycylononyn-funktionalisierten Nanopartikeln mit azid-modifiziertem linearen Polyglycerol, und die daraus resultierende Synthese von magnetischen Nanogelen. Darüber hinaus gelingt es diesem simplen Verfahren die Nanogeloberfläche mit Targeting-Liganden zu dekorieren die dann eine spezifische Bindung zu Zellrezeptoren ausüben können. Die magnetischen Nanogele zeigen eine 30 prozentige Zellerfassungseffizienz, die anhängig von der Länge des eingesetzten polymeren Abstandhalters zwischen Targeting-Ligand und Nanogel ist. Des Weiteren zeigen magnetische Relaxationsstudien, dass magnetische Nanogele eine ähnliche Relaxivität wie kommerziell erhältliche Kontrastmittel in der MRT aufweisen. Diese Erkenntnis führt zu dem Schluss, dass der Einsatz magnetischer Nanogele nicht auf Zellerfassungsuntersuchungen begrenzt ist, sondern das Potential besitzt Anwendung in der MRT zu finden. Diese vorgelegte Arbeit verdeutlicht das große Potenzial von responsiven Nanogelen für biomedizinische Anwendungen. Es sind hauptsächlich die physikalisch-chemischen Eigenschaften wie ihre Größe, Form, und Elastizität die Schlüsselfunktionen in der Interaktion mit biologischen Systemen ausüben. Eine effiziente synthetische Kontrolle über diese Eigenschaften kombiniert mit ausführlichen biologischen Evaluationen kann ihre klinische Translation vom Labor zum Patienten ermöglichen

Functional Nanogels in Biomedical Applications

This review addresses current and future perspectives of nanogel technology for nanomedicine. The synthetic methodologies and material properties of nanogels prepared by chemical meanings are discussed in detail, and examples that illustrate the different methodologies are presented. Applications in the fields of drug and gene delivery, smart imaging modalities, responsive materials, and multivalency as a therapeutic approach highlight the enormous potential of the functional nanogels as novel polymeric platforms for biomedicine.Fil: Asadian Birjand, Mazdak. Freie Universität Berlin; AlemaniaFil: Sousa Herves, Ana. Freie Universität Berlin; AlemaniaFil: Steinhilber, Dirk. Freie Universität Berlin; AlemaniaFil: Cuggino, Julio César. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; ArgentinaFil: Calderon, Marcelo. Freie Universität Berlin; Alemani

Transferrin Decorated Thermoresponsive Nanogels as Magnetic Trap Devices for Circulating Tumor Cells

A rational design of magnetic capturing nanodevices, based on a specifi c interaction withcirculating tumor cells (CTCs), can advance the capturing effi ciency and initiate the developmentof modern smart nanoformulations for rapid isolation and detection of these CTCsfrom the bloodstream. Therefore, the development and evaluation of magnetic nanogels(MNGs) based on magnetic nanoparticles and linear thermoresponsive polyglycerol forthe capturing of CTCs with overexpressed transferrin (Tf + )receptors has been presented in this study. The MNGs aresynthesized using a strain-promoted ?click? approachwhich has allowed the in situ surface decoration withTf?polyethylene glycol (PEG) ligands of three different PEGchain lengths as targeting ligands. An optimal value ofaround 30% of cells captures is achieved with a linker ofeight ethylene glycol units. This study shows the potentialof MNGs for the capture of CTCs and the necessity of precisecontrol over the linkage of the targeting moiety to thecapturing device.Fil: Asadian Birjand, Mazdak. Universität zu Berlin; AlemaniaFil: Biglione, Catalina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Bergueiro, Julian. Universität zu Berlin; AlemaniaFil: Cappelletti, Ariel Leonardo. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Rahane, Chinmay. Maeers Maharashtra Institute Of Pharmacy; IndiaFil: Chate, Govind. Maeers Maharashtra Institute Of Pharmacy; IndiaFil: Khandare, Jayant. Maeers Maharashtra Institute Of Pharmacy; IndiaFil: Klemke, Bastian. Helmholtz-zentrum Berlin Für Materialien Und Energie Gm; AlemaniaFil: Strumia, Miriam Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Calderon, Marcelo. Freie Universität Berlin; Alemani

Optimizing Circulating Tumor Cells’ Capture Efficiency of Magnetic Nanogels by Transferrin Decoration

Magnetic nanogels (MNGs) are designed to have all the required features for their use as highly efficient trapping materials in the challenging task of selectively capturing circulating tumor cells (CTCs) from the bloodstream. Advantageously, the discrimination of CTCs from hematological cells, which is a key factor in the capturing process, can be optimized by finely tuning the polymers used to link the targeting moiety to the MNG. We describe herein the relationship between the capturing efficiency of CTCs with overexpressed transferrin receptors and the different strategies on the polymer used as linker to decorate these MNGs with transferrin (Tf). Heterobifunctional polyethylene glycol (PEG) linkers with different molecular weights were coupled to Tf in different ratios. Optimal values over 80% CTC capture efficiency were obtained when 3 PEG linkers with a length of 8 ethylene glycol (EG) units were used, which reveals the important role of the linker in the design of a CTC-sorting system