New polymeric materials for vascular surgery

The dramatic impact that vascular diseases have on human life quality and expectancy nowadays is the reason why both medical and scientific communities put great effort in discovering new and effective ways to fight vascular pathologies. Among the many different treatments, endovascular surgery is a minimally-invasive technique that makes use of X-ray fluoroscopy to obtain real-time images of the patient during interventions. In this context radiopaque biomaterials, i.e. materials able to absorb X-ray radiation, play a fundamental role as they are employed both to enhance visibility of devices during interventions and to protect medical staff and patients from X-ray radiations. Organic-inorganic hybrids are materials that combine characteristics of organic polymers with those of inorganic metal oxides. These materials can be synthesized via the sol-gel process and can be easily applied as thin coatings on different kinds of substrates. Good radiopacity of organic-inorganic hybrids has been recently reported suggesting that these materials might find applications in medical fields where X-ray absorption and visibility is required. The present PhD thesis aimed at developing and characterizing new radiopaque organic-inorganic hybrid materials that can find application in the vascular surgery field as coatings for the improvement of medical devices traceability as well as for the production of X-ray shielding objects and garments. Novel organic-inorganic hybrids based on different polyesters (poly-lactic acid and poly-ε-caprolactone) and polycarbonate (poly-trimethylene carbonate) as the polymeric phase and on titanium oxide as the inorganic phase were synthesized. Study of the phase interactions in these materials allowed to demonstrate that Class II hybrids (where covalent bonds exists between the two phases) can be obtained starting from any kind of polyester or polycarbonate, without the need of polymer pre-functionalization, thanks to the occurrence of transesterification reactions operated by inorganic molecules on ester and carbonate moieties. Polyester based hybrids were successfully coated via dip coating on different kinds of textiles. Coated textiles showed improved radiopacity with respect to the plain fabric while remaining soft to the touch. The hybrid was able to coat single fibers of the yarn rather than coating the yarn as a whole. Openings between yarns were maintained and therefore fabric breathability was preserved. Such coatings are promising for the production of light-weight garments for X-ray protection of medical staff during interventional fluoroscopy, which will help preventing pathologies that stem from chronic X-ray exposure. A means to increase the protection capacity of hybrid-coated fabrics was also investigated and implemented in this thesis. By synthesizing the hybrid in the presence of a suspension of radiopaque tantalum nanoparticles, PDMS-titania hybrid materials with tunable radiopacity were developed and were successfully applied as coatings. A solution for enhancing medical device radiopacity was also successfully investigated. High metal radiopacity was associated with good mechanical and protective properties of organic-inorganic hybrids in the form of a double-layer coating. Tantalum was employed as the constituent of the first layer deposited on sample substrates by means of a sputtering technique. The second layer was composed of a hybrid whose constituents are well-known biocompatible organic and inorganic components, such as the two polymers PCL and PDMS, and titanium oxide, respectively. The metallic layer conferred to the substrate good X-ray visibility. A correlation between radiopacity and coating thickness derived during this study allows to tailor radiopacity simply by controlling the metal layer sputtering deposition time. The applied metal deposition technique also permits easy shaping of the radiopaque layer, allowing production of radiopaque markers for medical devices that can be unambiguously identified by surgeons during implantation and in subsequent radiological investigations. Synthesized PCL-titania and PDMS-titania hybrids strongly adhered to substrates and show good biocompatibility as highlighted by cytotoxicity tests. The PDMS-titania hybrid coating was also characterized by high flexibility that allows it to stand large substrate deformations without detaching nor cracking, thus being suitable for application on flexible medical devices.

Development of Original Analytical Methods for the Determination of Drugs of Abuse in Biological Samples

Drug abuse is a major global problem which has a strong impact not only on the single individual but also on the entire society. Among the different strategies that can be used to address this issue an important role is played by identification of abusers and proper medical treatment. This kind of therapy should be carefully monitored in order to discourage improper use of the medication and to tailor the dose according to the specific needs of the patient. Hence, reliable analytical methods are needed to reveal drug intake and to support physicians in the pharmacological management of drug dependence. In the present Ph.D. thesis original analytical methods for the determination of drugs with a potential for abuse and of substances used in the pharmacological treatment of drug addiction are presented. In particular, the work has been focused on the analysis of ketamine, naloxone and long-acting opioids (buprenorphine and methadone), oxycodone, disulfiram and bupropion in human plasma and in dried blood spots. The developed methods are based on the use of high performance liquid chromatography (HPLC) coupled to various kinds of detectors (mass spectrometer, coulometric detector, diode array detector). For biological sample pre-treatment different techniques have been exploited, namely solid phase extraction and microextraction by packed sorbent. All the presented methods have been validated according to official guidelines with good results and some of these have been successfully applied to the therapeutic drug monitoring of patients under treatment for drug abuse.

Anhydrous proton conducting polymer electrolytes based on polymeric ionic liquids

Imidazolium types of ionic liquids were immobilized by tethering it to acrylate backbone. These imidazolium salt containing acrylate monomers were polymerize at 70oC by free radical polymerization to give polymers poly(AcIm-n) with n being the side chain lenght. The chemical structure of the polymer electrolytes obtained by the described synthetic routes was investigated by NMR-spectroscopy. The polymers were doped with various amounts of H3PO4 and LiN(SO2CF3)2, to obtain poly(AcIm-n) x H3PO4 and poly(AcIm-2-Li) x LiN(SO2CF3)2. The TG curves show that the polymer electrolytes are thermally stable up to about 200◦C. DSC results indicates the softening effect of the length of the spacers (n) as well as phosphoric acid. The proton conductivity of the samples increase with x and reaches to 10-2 Scm-1 at 120oC for both poly(AcIm-2)2H3PO4 and poly(AcIm-6)2H3PO4. It was observed that the lithium ion conductivity of the poly(AcIm-2-Li) x LiN(SO2CF3)2 increases with blends (x) up to certain composition and then leveled off independently from blend content. The conductivity reaches to about 10-5 S cm-1 at 30oC and 10-3 at 100oC for poly(AcIm-2-Li) x LiN(SO2CF3)2 where x is 10. The phosphate and phosphoric acid functionality in the resulting polymers, poly(AcIm-n) x H3PO4, undergoes condensation leading to the formation of cross-linked materials at elevated temperature which may improve the mechanical properties to be used as membrane materials in fuel cells. High resolution nuclear magnetic resonance (NMR) spectroscopy was used to obtain information about hydrogen bonding in solids. The low Tg enhances molecular mobility and this leads to better resolved resonances in both the backbone region and side chain region. The mobile and immobile protons can be distinguished by comparing 1H MAS and 1H-DQF NMR spectra. The interaction of the protons which may contribute to the conductivity is observed from the 2D double quantum correlation (DQC) spectra.

Design and synthesis of multipotent drugs: application to Alzheimer's disease and benign prostatic hyperplasia

The aim of this thesis was to synthesize multipotent drugs for the treatment of Alzheimer’s disease (AD) and for benign prostatic hyperplasia (BPH), two diseases that affect the elderly. AD is a neurodegenerative disorder that is characterized, among other factors, by loss of cholinergic neurons. Selective activation of M1 receptors through an allosteric site could restore the cholinergic hypofunction, improving the cognition in AD patients. We describe here the discovery and SAR of a novel series of quinone derivatives. Among them, 1 was the most interesting, being a high M1 selective positive allosteric modulator. At 100 nM, 1 triplicated the production of cAMP induced by oxotremorine. Moreover, it inhibited AChE and it displayed antioxidant properties. Site-directed mutagenesis experiments indicated that 1 acts at an allosteric site involving residue F77. Thus, 1 is a promising drug because the M1 activation may offer disease-modifying properties that could address and reduce most of AD hallmarks. BPH is an enlargement of the prostate caused by increased cellular growth. Blockade of α1-ARs is the predominant form of medical therapy for the treatment of the symptoms associated with BPH. α1-ARs are classified into three subtypes. The α1A- and α1D-AR subtypes are predominant in the prostate, while α1B-ARs regulate the blood pressure. Herein, we report the synthesis of quinazoline-derivatives obtained replacing the piperazine ring of doxazosin and prazosin with (S)- or (R)-3-aminopiperidine. The presence of a chiral center in the 3-C position of the piperidine ring allowed us to exploit the importance of stereochemistry in the binding at α1-ARs. It turned out that the S configuration at the 3-C position of the piperidine increases the affinity of the compounds at all three α1-AR subtypes, whereas the configuration at the benzodioxole ring of doxazosin derivatives is not critical for the interaction with α1-ARs.

Veterinary drugs in drinking water used for pharmaceutical treatments in breeding farms

Water is susceptible to be used for numerous purposes, including edible, both for humans and animals. In the food animal production, drinking water is frequently used as a way to carry out the most common pharmacological treatments. In these cases, there are many variables which could degrade drugs dissolved in this mean, even when properly arranged pharmaceutical formulations are used. In fact, although a product obtains a Marketing Authorization through appropriate laboratory studies both drug stability and solubility, on the other hand the solubility of the same drug in natural water used as a drinking water is not documented. In the present study has been evaluated the dissolution kinetics (at 0 hours and 24 hours) of products, having oxytetracycline and tylosin as active ingredient, used in drinking water samples in order to see how the different physical and chemical factors that characterize the drinking water may affect therapeutic efficacy. In fact, multiple factors, also of little relevance if individually considered, are able to adversely affect the pharmacological treatment carried out in drinking water.

Spectroscopic studies on Cyclodextrin and Metal Organic Framework based potential nanovectors for delivery of Anticancer and Antiviral drugs

The aim of this work is to contribute to the development of new multifunctional nanocarriers for improved encapsulation and delivery of anticancer and antiviral drugs. The work focused on water soluble and biocompatible oligosaccharides, the cyclodextrins (CyDs), and a new family of nanostructured, biodegradable carrier materials made of porous metal-organic frameworks (nanoMOFs). The drugs of choice were the anticancer doxorubicin (DOX), azidothymidine (AZT) and its phosphate derivatives and artemisinin (ART). DOX possesses a pharmacological drawback due to its self-aggregation tendency in water. The non covalent binding of DOX to a series of CyD derivatives, such as g-CyD, an epichlorohydrin crosslinked b-CyD polymer (pb-CyD) and a citric acid crosslinked g-CyD polymer (pg-CyD) was studied by UV visible absorption, circular dichroism and fluorescence. Multivariate global analysis of multiwavelength data from spectroscopic titrations allowed identification and characterization of the stable complexes. pg-CyD proved to be the best carrier showing both high association constants and ability to monomerize DOX. AZT is an important antiretroviral drug. The active form is AZT-triphosphate (AZT-TP), formed in metabolic paths of low efficiency. Direct administration of AZT-TP is limited by its poor stability in biological media. So the development of suitable carriers is highly important. In this context we studied the binding of some phosphorilated derivatives to nanoMOFs by spectroscopic methods. The results obtained with iron(III)-trimesate nanoMOFs allowed to prove that the binding of these drugs mainly occurs by strong iono-covalent bonds to iron(III) centers. On the basis of these and other results obtained in partner laboratories, it was possible to propose this highly versatile and “green” carrier system for delivery of phosphorylated nucleoside analogues. The interaction of DOX with nanoMOFs was also studied. Finally the binding of the antimalarial drug, artemisinin (ART) with two cyclodextrin-based carriers,the pb-CyD and a light responsive bis(b-CyD) host, was also studied.

Evaluation of Antitumoral activity of bone targeted drugs/conventional chemotherapies and identification of biomarkers for the selection of patients with breast cancer for the bone targeted therapy in adjuvant setting

Bone metastases are responsible for different clinical complications defined as skeletal-related events (SREs) such as pathologic fractures, spinal cord compression, hypercalcaemia, bone marrow infiltration and severe bone pain requiring palliative radiotherapy. The general aim of these three years research period was to improve the management of patients with bone metastases through two different approaches of translational research. Firstly in vitro preclinical tests were conducted on breast cancer cells and on indirect co-colture of cancer cells and osteoclasts to evaluate bone targeted therapy singly and in combination with conventional chemotherapy. The study suggests that zoledronic acid has an antitumor activity in breast cancer cell lines. Its mechanism of action involves the decrease of RAS and RHO, as in osteoclasts. Repeated treatment enhances antitumor activity compared to non-repeated treatment. Furthermore the combination Zoledronic Acid + Cisplatin induced a high antitumoral activity in the two triple-negative lines MDA-MB-231 and BRC-230. The p21, pMAPK and m-TOR pathways were regulated by this combined treatment, particularly at lower Cisplatin doses. A co-colture system to test the activity of bone-targeted molecules on monocytes-breast conditioned by breast cancer cells was also developed. Another important criticism of the treatment of breast cancer patients, is the selection of patients who will benefit of bone targeted therapy in the adjuvant setting. A retrospective case-control study on breast cancer patients to find new predictive markers of bone metastases in the primary tumors was performed. Eight markers were evaluated and TFF1 and CXCR4 were found to discriminate between patients with relapse to bone respect to patients with no evidence of disease. In particular TFF1 was the most accurate marker reaching a sensitivity of 63% and a specificity of 79%. This marker could be a useful tool for clinicians to select patients who could benefit for bone targeted therapy in adjuvant setting.

Study of novel natural compounds as potential drugs in the treatment of acute leukemias

Introduction: Among all cancer types leukemia represents the leading cause of cancer death in man younger than 40 years. Single-target drug therapy has generally been highly ineffective in treating complex diseases such as cancer. A growing interest has been directed toward multi-target drugs able to hit multiple targets. In this context, plant products, based on their intrinsic complexity, could represent an interesting and promising approach. Aim of the research followed during my PhD was to indentify and study novel natural compounds for the treatment of acute leukemias. Two potential multi-target drugs were identified in Hemidesmus indicus and piperlongumine. Methodology/Principal Findings: A variety of cellular assays and flow cytometry were performed on different cell lines. We demonstrated that Hemidesmus modulates many components of intracellular signaling pathways involved in cell viability and proliferation and alters gene and protein expression, eventually leading to tumor cell death, mediated by a loss of mitochondrial transmembrane potential, raise of [Ca2+]i, inhibition of Mcl-1, increasing Bax/Bcl-2 ratio, and ROS formation. Moreover, we proved that the decoction causes differentiation of HL-60 and regulates angiogenesis of HUVECs in hypoxia and normoxia, by the inhibition of new vessel formation and the processes of migration/invasion. Clinically relevant observations are that its cytotoxic activity was also recorded in primary cells from acute myeloid leukemia (AML) patients. Moreover, both Hemidesmus and piperlongumine showed a selective action toward leukemic stem cell (LSC). Conclusions: Our results indicate the molecular basis of the anti-leukemic effects of Hemidesmus indicus and indentify the mitochondrial pathways, [Ca2+]i, cytodifferentiation and angiogenesis inhibition as crucial actors in its anticancer activity. The ability to selectively hit LSC showed by Hemidesmus and piperlongumine enriched the knowledge of their anti-leukemic activity. On these bases, we conclude that Hemidesmus and piperlongumine can represent a valuable strategy in the anticancer pharmacology.

Electrospun Polymeric Scaffolds with Enhanced Biomimetic Properties for Tissue Engineering Applications

This PhD Thesis is focused on the development of fibrous polymeric scaffolds for tissue engineering applications and on the improvement of scaffold biomimetic properties. Scaffolds were fabricated by electrospinning, which allows to obtain scaffolds made of polymeric micro or nanofibers. Biomimetism was enhanced by following two approaches: (1) the use of natural biopolymers, and (2) the modification of the fibers surface chemistry. Gelatin was chosen for its bioactive properties and cellular affinity, however it lacks in mechanical properties. This problem was overcome by adding poly(lactic acid) to the scaffold through co-electrospinning and mechanical properties of the composite constructs were assessed. Gelatin effectively improves cell growth and viability and worth noting, composite scaffolds of gelatin and poly(lactic acid) were more effective than a plain gelatin scaffold. Scaffolds made of pure collagen fibers were fabricated. Modification of collagen triple helix structure in electrospun collagen fibers was studied. Mechanical properties were evaluated before and after crosslinking. The crosslinking procedure was developed and optimized by using - for the first time on electrospun collagen fibers - the crosslinking reactant 1,4-butanediol diglycidyl ether, with good results in terms of fibers stabilization. Cell culture experiments showed good results in term of cell adhesion and morphology. The fiber surface chemistry of electrospun poly(lactic acid) scaffold was modified by plasma treatment. Plasma did not affect thermal and mechanical properties of the scaffold, while it greatly increased its hydrophilicity by the introduction of carboxyl groups at the fiber surface. This fiber functionalization enhanced the fibroblast cell viability and spreading. Surface modifications by chemical reactions were conducted on electrospun scaffolds made of a polysophorolipid. The aim was to introduce a biomolecule at the fiber surface. By developing a series of chemical reactions, one oligopeptide every three repeating units of polysophorolipid was grafted at the surface of electrospun fibers.

Polymeric membranes for CO2 separation: effect of aging, humidity and facilitated transport

Polymeric membranes represent a promising technology for gas separation processes, thanks to low costs, reduced energy consumption and limited waste production. The present thesis aims at studying the transport properties of two membrane materials, suitable for CO2 purification applications. In the first part, a polyimide, Matrimid 5218, has been throughout investigated, with particular reference to the effect of thermal treatment, aging and the presence of water vapor in the gas transport process. Permeability measurements showed that thermal history affects relevantly the diffusion of gas molecules across the membrane, influencing also the stability of the separation performances. Subsequently, the effect of water on Matrimid transport properties has been characterized for a wide set of incondensable penetrants. A monotonous reduction of permeability took place at increasing the water concentration within the polymer matrix, affecting the investigated gaseous species to the same extent, despite the different thermodynamic and kinetic features. In this view, a novel empirical model, based on the Free Volume Theory, has been proposed to qualitatively describe the phenomenon. Moreover, according to the accurate representation of the experimental data, the suggested approach has been combined with a more rigorous thermodynamic tool (NELF Model), allowing an exhaustive description of water influence on the single parameters contributing to the gas permeation across the membrane. In the second part, the study has focused on the synthesis and characterization of facilitated transport membranes, able to achieving outstanding separation performances thanks to the chemical enhancement of CO2 permeability. In particular, the transport properties have been investigated for high pressure CO2 separation applications and specific solutions have been proposed to solve stability issues, frequently arising under such severe conditions. Finally, the effect of different process parameters have been investigated, aiming at the identification of the optimal conditions capable to maximize the separation performance.

Drugs down-regulating E2F-1 expression hinders cell proliferation through a p53-indipendent mechanism

E2F-1 is a transcription factor that plays a key role in cell-cycle control at G1/S check-point level by regulating the timely expression of many target genes whose products are required for S phase entry and progression. In mammalian cells, E2F-1 is negatively regulated by hypo-phosphorylated Retinoblastoma protein (pRb) whereas it is protected against degradation by its binding to Mouse Double Minute 2 protein (MDM2). In this study we experimented a drug combination in order to obtain a strong down-regulation of E2F-1 by acting on two different mechanisms of E2F-1 regulation mentioned above. This was achieved by combining drugs inhibiting the phosphorylation of pRb with drugs inactivating the MDM2 binding capability. The mechanism of action of these drugs in down-regulating E2F-1 level and activity is p53 independent. As expected, when combined, these drugs strongly inhibits E2F-1 and hinder cell proliferation in p53-/- and p53-mutated cells by blocking them in G1 phase of cell cycle, suggesting that E2F-1 down-regulation may represent a valid chemotherapeutic approach to inhibit proliferation in tumors independently of p53 status.

On the influence of polymeric nanofibers in laminated composite materials. Studio dell'influenza di nanofibre polimeriche in materiali compositi laminati

During the last years an increased interest about the reinforcement of laminated composites by means of polymeric nanofibers has been growth. During this master-degree-thesis work, unidirectional and plane-textile composites have been interleaved with Nylon 6.6, PCL and mixed (Nylon 6.6+PCL) nanofibrous mats and the DCB (mode I interlaminar fracture toughness), ENF (mode II interlaminar fracture toughness and DMA (damping capability) tests have been performed. Regarding the interlaminar fracture toughness, marked increases have been recorded; while further investigation about damping capability is requested.

Nicht-wässrige Emulsionen zur Erzeugung neuer Nanopartikel

In der eingereichten Arbeit wurde die Nutzung von nicht-wässrigen Emulsionen, bestehend aus zwei organischen, aprotischen Lösungsmitteln, zur Erzeugung verschiedener polymerer Nanopartikel beschrieben. Diese Zweiphasenmischungen und die Verwendung maßgeschneiderter Emulgatoren bestehend aus Poly(isopren-block-methylmethacrylat) ermöglichten den Zugang zu einer Vielzahl an Reaktionen und Prozessen, welche in wässrigen Emulsionen bisher nicht oder nur schwer möglich waren. Die Generierung von Partikeln auf Basis katalytischer Polymerisationen erfolgte unter Verwendung der Ringöffnenden Metathese-Polymerisation (ROMP), der Acyclischen Dien-Metathese-Polymerisation (ADMET), der Cyclopolymerisation von α,ω-Diinen und der Ni-katalysierten Polymerisation von Isocyaniden. Mittels ROMP konnten stabile Dispersionen erzeugt werden, welche Partikel mit verschiedensten Molekulargewichten, Größen und Morphologien enthielten. Diese Eigenschaften konnten durch die Wahl des Monomers, die Katalysatorkonzentration oder den Emulgatortyp beeinflusst werden. Des Weiteren wurden Partikel mit komplexen Morphologien wie Kern-Schale-Strukturen synthetisiert. Dazu erfolgte die Generierung von Partikeln aus Poly(urethan) oder Poly(norbornenderivaten), welche in situ und ohne intermediäre Aufarbeitung mit einer Schale aus Poly(methacrylat) versehen wurden. Der Nachweis dieser Strukturen gelang mittels verschiedener Schwermetall-Markierungsverfahren in der Transmissionselektronenmikroskopie. Schlussendlich erfolgte die Herstellung von hochvernetzten und molekular geprägten Poly(acrylsäure)-Partikeln. Hierbei wurden unterschiedliche pharmakologische Wirkstoffe und Farbstoffe in die Partikel eingebracht, um deren Migrationsverhalten und Wiederanbindung an die Partikel zu untersuchen. Weiterhin wurden die Partikel erfolgreich in Zellaufnahmeexperimenten eingesetzt.

Light-sensitive polymeric nanoparticles based on photo-cleavable chromophores

Der Fokus dieser Arbeit liegt in dem Design, der Synthese und der Charakterisierung neuartiger photosensitiver Mikrogele und Nanopartikel als potentielle Materialien für Beladungs- und Freisetzungsanwendungen. Zur Realisierung dieses Konzepts wurden verschiedene Ansätze untersucht.Es wurden neuartige niedermolekulare lichtspaltbare Vernetzermoleküle auf der Basis von o-Nitrobenzylderivaten synthetisiert, charakterisiert und zur Herstellung von photosensitiven PMMA und PHEMA Mikrogelen verwendet. Diese sind unter Bestrahlung in organischen Lösungsmitteln quellbar und zersetzbar. Durch die Einführung anionischer MAA Gruppen in solche PHEMA Mikrogele wurde dieses Konzept auf doppelt stimuliresponsive p(HEMA-co-MAA) Mikrogele erweitert. Hierbei wurde ein pH-abhängiges Quellbarkeitsprofil mit der lichtinduzierten Netzwerkspaltung in wässrigen Medien kombiniert. Diese duale Sensitivität zu zwei zueinander orthogonalen Reizen stellt ein vielversprechendes Konzept zur Kombination einer pH-abhängigen Beladung mit einer lichtinduzierten Freisetzung von funktionellen Substanzen dar. Desweiteren wurden PAAm Mikrogele entwickelt, welche sowohl eine Sensitivität gegenüber Enzymen als auch Licht aufweisen. Dieses Verhalten wurde durch die Verwendung von (meth-)acrylatfunktionalisierten Dextranen als polymere Vernetzungsmoleküle erreicht. Das entsprechende stimuliresponsive Profil basiert auf der enzymatischen Zersetzbarkeit der Polysaccharid-Hauptkette und der Anbindung der polymerisierbaren Vinyleinheiten an diese über photospaltbare Gruppen. Die gute Wasserlöslichkeit der Vernetzermoleküle stellt einen vielversprechenden Ansatz zur Beladung solcher Mikrogele mit funktionellen hydrophilen Substanzen bereits während der Partikelsynthese dar. Ein weiteres Konzept zur Beladung von Mikrogelen basiert auf der Verwendung von photolabilen Wirkstoff-Mikrogel Konjugaten. In einem ersten Schritt zur Realisierung solch eines Ansatzes wurde ein neuartiges Monomer entwickelt. Hierbei wurde Doxorubicin über eine lichtspaltbare Gruppe an eine polymerisierbare Methacrylatgruppe angebunden. Für die Freisetzung hydrophober Substanzen in wässrigen Medien wurden polymere Photolack-Nanopartikel entwickelt, welche sich unter Bestrahlung in Wasser zersetzen. Die lichtinduzierte Änderung der Hydrophobizität des Polymers ermöglichte die Freisetzung von Nilrot durch das Auflösen der partikulären Struktur. Ein interessanter Ansatz zur Verhinderung einer unkontrollierten Freisetzung funktioneller Substanzen aus Mikrogelen ist die Einführung einer stimuliresponsiven Schale. In diesem Kontext wurden Untersuchungen zur Bildung von nicht-stimulisensitiven Schalen um vorgefertigte Mikrogelkerne und zur Synthese von Hydrogelkernen in vorgefertigten polymeren Schalen (Nanokapseln) durchgeführt.

The impact of intraclonal heterogeneity on the outcomes of Multiple Myeloma patients treated with new drugs

Understanding the biology of Multiple Myeloma (MM) is of primary importance in the struggle to achieve a cure for this yet incurable neoplasm. A better knowledge of the mechanism underlying the development of MM can guide us in the development of new treatment strategies. Studies both on solid and haematological tumours have shown that cancer comprises a collection of related but subtly different clones, a feature that has been termed “intra-clonal heterogeneity”. This intra-clonal heterogeneity is likely, from a “Darwinian” natural selection perspective, to be the essential substrate for cancer evolution, disease progression and relapse. In this context the critical mechanism for tumour progression is competition between individual clones (and cancer stem cells) for the same microenvironmental “niche”, combined with the process of adaptation and natural selection. The Darwinian behavioural characteristics of cancer stem cells are applicable to MM. The knowledge that intra-clonal heterogeneity is an important feature of tumours’ biology has changed our way to addressing cancer, now considered as a composite mixture of clones and not as a linear evolving disease. In this variable therapeutic landscape it is important for clinicians and researchers to consider the impact that evolutionary biology and intra-clonal heterogeneity have on the treatment of myeloma and the emergence of treatment resistance. It is clear that if we want to effectively cure myeloma it is of primarily importance to understand disease biology and evolution. Only by doing so will we be able to effectively use all of the new tools we have at our disposal to cure myeloma and to use treatment in the most effective way possible. The aim of the present research project was to investigate at different levels the presence of intra-clonal heterogeneity in MM patients, and to evaluate the impact of treatment on clonal evolution and on patients’ outcomes.