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Browsing by Author "Hampel, Silke"

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Carbon nanomaterials sensitize prostate cancer cells to docetaxel and mitomycin C via induction of apoptosis and inhibition of proliferation
(Frankfurt, M. : Beilstein-Institut zur Förderung der Chemischen Wissenschaften, 2017-6-23) Erdmann, Kati; Ringel, Jessica; Hampel, Silke; Wirth, Manfred P.; Fuessel, Susanne
We have previously shown that carbon nanofibers (CNFs) and carbon nanotubes (CNTs) can sensitize prostate cancer (PCa) cells to platinum-based chemotherapeutics. In order to further verify this concept and to avoid a bias, the present study investigates the chemosensitizing potential of CNFs and CNTs to the conventional chemotherapeutics docetaxel (DTX) and mitomycin C (MMC), which have different molecular structures and mechanisms of action than platinum-based chemotherapeutics. DU-145 PCa cells were treated with DTX and MMC alone or in combination with the carbon nanomaterials. The impact of the monotreatments and the combinatory treatments on cellular function was then systematically analyzed by using different experimental approaches (viability, short-term and long-term proliferation, cell death rate). DTX and MMC alone reduced the viability of PCa cells to 94% and 68%, respectively, whereas a combined treatment with CNFs led to less than 30% remaining viable cells. Up to 17- and 7-fold higher DTX and MMC concentrations were needed in order to evoke a similar inhibition of viability as mediated by the combinatory treatments. In contrast, the dose of platinum-based chemotherapeutics could only be reduced by up to 3-fold by combination with carbon nanomaterials. Furthermore, combinatory treatments with CNFs led mostly to an additive inhibition of short- and long-term proliferation compared to the individual treatments. Also, higher cell death rates were observed in combinatory treatments than in monotreatments, e.g., a combination of MMC and CNFs more than doubled the cell death rate mediated by apoptosis. Combinations with CNTs showed a similar, but less pronounced impact on cellular functions. In summary, carbon nanomaterials in combination with DTX and MMC evoked additive to partly synergistic anti-tumor effects. CNFs and CNTs possess the ability to sensitize cancer cells to a wide range of structurally diverse chemotherapeutics and thus represent an interesting option for the development of multimodal cancer therapies. Co-administration of chemotherapeutics with carbon nanomaterials could result in a reduction of the chemotherapeutic dosage and thus limit systemic side effects.
Carbon nanotubes filled with ferromagnetic materials
(Basel : MDPI, 2010) Weissker, Uhland; Hampel, Silke; Leonhardt, Albrecht; Büchner, Bernd
Carbon nanotubes (CNT) filled with ferromagnetic metals like iron, cobalt or nickel are new and very interesting nanostructured materials with a number of unique properties. In this paper we give an overview about different chemical vapor deposition (CVD) methods for their synthesis and discuss the influence of selected growth parameters. In addition we evaluate possible growth mechanisms involved in their formation. Moreover we show their identified structural and magnetic properties. On the basis of these properties we present different application possibilities. Some selected examples reveal the high potential of these materials in the field of medicine and nanotechnology.
Carbon Nanotubes Hybrid Hydrogels for Environmental Remediation: Evaluation of Adsorption Efficiency under Electric Field
(Basel : MDPI, 2021) Cirillo, Giuseppe; Curcio, Manuela; Madeo, Lorenzo Francesco; Iemma, Francesca; De Filpo, Giovanni; Hampel, Silke; Nicoletta, Fiore Pasquale
The performance of Carbon Nanotubes hybrid hydrogels for environmental remediation was investigated using Methylene Blue (MB), Rhodamine B (RD), and Bengal Rose (BR) as model contaminating dyes. An acrylate hydrogel network with incorporated CNT was synthesized by photo-polymerization without any preliminary derivatization of CNT surface. Thermodynamics, isothermal and kinetic studies showed favorable sorption processes with the application of an external 12 V electric field found to be able to influence the amount of adsorbed dyes: stronger interactions with cationic MB molecules (qexp and q12exp of 19.72 and 33.45 mg g−1, respectively) and reduced affinity for anionic RD (qexp and q12exp of 28.93 and 13.06 mg g−1, respectively) and neutral BR (qexp and q12exp of 36.75 and 15.85 mg g−1, respectively) molecules were recorded. The influence of pH variation on dyes adsorption was finally highlighted by reusability studies, with the negligible variation of adsorption capacity after five repeated sorption cycles claiming for the suitability of the proposed systems as effective sorbent for wastewater treatment.
Carbon nanotubes hybrid hydrogels in drug delivery: A perspective review
(London : Hindawi, 2014) Cirillo, Giuseppe; Hampel, Silke; Spizzirri, Umile Gianfranco; Parisi, Ortensia Ilaria; Picci, Nevio; Iemma, Francesca
The use of biologics, polymers, silicon materials, carbon materials, and metals has been proposed for the preparation of innovative drug delivery devices. One of the most promising materials in this field are the carbon-nanotubes composites and hybrid materials coupling the advantages of polymers (biocompatibility and biodegradability) with those of carbon nanotubes (cellular uptake, stability, electromagnatic, and magnetic behavior). The applicability of polymer-carbon nanotubes composites in drug delivery, with particular attention to the controlled release by composites hydrogel, is being extensively investigated in the present review.
Chromium Trihalides CrX3 (X = Cl, Br, I): Direct Deposition of Micro- and Nanosheets on Substrates by Chemical Vapor Transport
(Weinheim : Wiley-VCH, 2019) Grönke, Martin; Buschbeck, Benjamin; Schmidt, Peer; Valldor, Martin; Oswald, Steffen; Hao, Qi; Lubk, Axel; Wolf, Daniel; Steiner, Udo; Büchner, Bernd; Hampel, Silke
The experimental observation of intrinsic ferromagnetism in single layered chromium trihalides CrX3 (X = Cl, Br, I) has gained outstanding attention recently due to their possible implementation in spintronic devices. However, the reproducible preparation of highly crystalline chromium(III) halide nanolayers without stacking faults is still an experimental challenge. As chromium trihalides consist of adjacent layers with weak interlayer coupling, the preparation of ultrathin CrX3 nanosheets directly on substrates via vapor transport proves as an advantageous synthesis technique. It is demonstrated that vapor growth of ultrathin highly crystalline CrX3 micro- and nanosheets succeeds directly on yttrium stabilized zirconia substrates in a one-step process via chemical vapor transport (CVT) in temperature gradients of 100 K (600 °C → 500 °C for CrCl3 and 650 °C → 550 °C for CrBr3 or CrI3) without a need for subsequent delamination. Due to simulation results, optimization of synthesis conditions is realized and phase pure CrX3 nanosheets with thicknesses ≤25 nm are obtained via short term CVT. The nanosheets morphology, crystallinity, and phase purity are analyzed by several techniques, including microscopy, diffraction, and spectroscopy. Furthermore, a potential subsequent delamination technique is demonstrated to give fast access to CrX3 monolayers using the example of CrCl3. © 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Curcumin and Graphene Oxide Incorporated into Alginate Hydrogels as Versatile Devices for the Local Treatment of Squamous Cell Carcinoma
(Basel : MDPI, 2022) Madeo, Lorenzo Francesco; Sarogni, Patrizia; Cirillo, Giuseppe; Vittorio, Orazio; Voliani, Valerio; Curcio, Manuela; Shai-Hee, Tyler; Büchner, Bernd; Mertig, Michael; Hampel, Silke
With the aim of preparing hybrid hydrogels suitable for use as patches for the local treatment of squamous cell carcinoma (SCC)-affected areas, curcumin (CUR) was loaded onto graphene oxide (GO) nanosheets, which were then blended into an alginate hydrogel that was crosslinked by means of calcium ions. The homogeneous incorporation of GO within the polymer network, which was confirmed through morphological investigations, improved the stability of the hybrid system compared to blank hydrogels. The weight loss in the 100–170 °C temperature range was reduced from 30% to 20%, and the degradation of alginate chains shifted to higher temperatures. Moreover, GO enhanced the stability in water media by counteracting the de-crosslinking process of the polymer network. Cell viability assays showed that the loading of CUR (2.5% and 5% by weight) was able to reduce the intrinsic toxicity of GO towards healthy cells, while higher amounts were ineffective due to the antioxidant/prooxidant paradox. Interestingly, the CUR-loaded systems were found to possess a strong cytotoxic effect in SCC cancer cells, and the sustained CUR release (~50% after 96 h) allowed long-term anticancer efficiency to be hypothesized.
Facile one-pot hydrothermal synthesis of a zinc oxide/curcumin nanocomposite with enhanced toxic activity against breast cancer cells
(London : RSC Publishing, 2023) Madeo, Lorenzo Francesco; Schirmer, Christine; Cirillo, Giuseppe; Froeschke, Samuel; Hantusch, Martin; Curcio, Manuela; Nicoletta, Fiore Pasquale; Büchner, Bernd; Mertig, Michael; Hampel, Silke
Zinc oxide/Curcumin (Zn(CUR)O) nanocomposites were prepared via hydrothermal treatment of Zn(NO3)2 in the presence of hexamethylenetetramine as a stabilizing agent and CUR as a bioactive element. Three ZnO : CUR ratios were investigated, namely 57 : 43 (Zn(CUR)O-A), 60 : 40 (Zn(CUR)O-B) and 81 : 19 (Zn(CUR)O-C), as assessed by thermogravimetric analyses, with an average hydrodynamic diameter of nanoaggregates in the range of 223 to 361 nm. The interaction of CUR with ZnO via hydroxyl and ketoenol groups (as proved by X-ray photoelectron spectroscopy analyses) was found to significantly modify the key properties of ZnO nanoparticles with the obtainment of a bilobed shape (as shown by scanning electron microscopy), and influenced the growth process of the composite nanoparticles as indicated by the varying particle sizes determined by powder X-ray diffraction. The efficacy of Zn(CUR)O as anticancer agents was evaluated on MCF-7 and MDA-MB-231 cancer cells, obtaining a synergistic activity with a cell viability depending on the CUR amount within the nanocomposite. Finally, the determination of reactive oxygen species production in the presence of Zn(CUR)O was used as a preliminary evaluation of the mechanism of action of the nanocomposites.
Functionalized carbon nanotubes as transporters for antisense oligodeoxynucleotides
(Cambridge : Royal Society of Chemistry, 2014) Kaufmann, Anika; Kunhardt, David; Cirillo, Giuseppe; Hampel, Silke; Schwenzer, Bernd
The use of DNA-based therapeutics requires efficient delivery systems to transport the DNA to their place of action within the cell. To accomplish this, we investigated multiwalled carbon nanotubes (pristine MWCNT, p-MWCNT) functionalized with hydroxyl groups via 1,3-dipolar cycloaddition. In this way, we have obtained MWCNT-f-OH with improved stability in aqueous dispersions which is an advantageous property for their use in cellular environments. Afterwards, a carrier strand oligodeoxynucleotide (CS-ODN) was adsorbed to MWCNT-f-OH followed by hybridization with a therapeutic antisense oligodeoxynucleotide (AS-ODN). The amount of adsorbed CS-ODN, as well as the complementary AS-ODN and a non-complementary oligodeoxynucleotide (NS-ODN) as reference, was directly measured by radionuclide labeling of ODNs. We show that subsequent release of AS-ODNs and NS-ODNs was possible for MWCNT-f-OH above the melting temperature of AS-ODNs at 80 °C and under physiological conditions at different pH values at 37 °C. We also show a very low influence of p-MWCNT and MWCNT-f-OH on the cell viability of the bladder carcinoma (BCa) cell line EJ28 and that both MWCNT types were internalized by EJ28. Therefore, MWCNT-f-OH represents a promising carrier able to transport and release AS-ODNs inside cells.
Loss spectroscopy of molecular solids: Combining experiment and theory
(Milton Park : Taylor & Francis, 2013) Roth, Friedrich; Cudazzo, Pierluigi; Mahns, Benjamin; Gatti, Matteo; Bauer, Johannes; Hampel, Silke; Nohr, Markus; Berger, Helmuth; Knupfer, Martin; Rubio, Angel
The nature of the lowest-energy electronic excitations in prototypical molecular solids is studied here in detail by combining electron energy loss spectroscopy (EELS) experiments and state-of-the-art many-body calculations based on the Bethe–Salpeter equation. From a detailed comparison of the spectra in picene, coronene and tetracene we generally find a good agreement between theory and experiment, with an upshift of the main features of the calculated spectrum of 0.1–0.2 eV, which can be considered the error bar of the calculation. We focus on the anisotropy of the spectra, which illustrates the complexity of this class of materials, showing a high sensitivity with respect to the three-dimensional packing of the molecular units in the crystal. The differences between the measured and the calculated spectra are explained in terms of the small differences between the crystal structures of the measured samples and the structural model used in the calculations. Finally, we discuss the role played by the different electron–hole interactions in the spectra. We thus demonstrate that the combination of highly accurate experimental EELS and theoretical analysis is a powerful tool to elucidate and understand the electronic properties of molecular solids.
Magnetic Graphene Oxide Nanocarrier for Targeted Delivery of Cisplatin : A Perspective for Glioblastoma Treatment
(Basel : MDPI, 2019) Makharza, Sami A.; Cirillo, Giuseppe; Vittorio, Orazio; Valli, Emanuele; Voli, Florida; Farfalla, Annafranca; Curcio, Manuela; Iemma, Francesca; Nicoletta, Fiore Pasquale; El-Gendy, Ahmed A.; Goya, Gerardo F.; Hampel, Silke
Selective vectorization of Cisplatin (CisPt) to Glioblastoma U87 cells was exploited by the fabrication of a hybrid nanocarrier composed of magnetic γ-Fe2 O3 nanoparticles and nanographene oxide (NGO). The magnetic component, obtained by annealing magnetite Fe3 O4 and characterized by XRD measurements, was combined with NGO sheets prepared via a modified Hummer’s method. The morphological and thermogravimetric analysis proved the effective binding of γ-Fe2 O3 nanoparticles onto NGO layers. The magnetization measured under magnetic fields up to 7 Tesla at room temperature revealed superparamagnetic-like behavior with a maximum value of MS = 15 emu/g and coercivity HC ≈ 0 Oe within experimental error. The nanohybrid was found to possess high affinity towards CisPt, and a rather slow fractional release profile of 80% after 250 h. Negligible toxicity was observed for empty nanoparticles, while the retainment of CisPt anticancer activity upon loading into the carrier was observed, together with the possibility to spatially control the drug delivery at a target site. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.
Magnetic properties of individual Co2FeGa Heusler nanoparticles studied at room temperature by a highly sensitive co-resonant cantilever sensor
(London : Nature Publishing Group, 2017) Körner, Julia; Reiche, Christopher F.; Ghunaim, Rasha; Fuge, Robert; Hampel, Silke; Büchner, Bernd; Mühl, Thomas
The investigation of properties of nanoparticles is an important task to pave the way for progress and new applications in many fields of research like biotechnology, medicine and magnetic storage techniques. The study of nanoparticles with ever decreasing size is a challenge for commonly employed methods and techniques. It requires increasingly complex measurement setups, often low temperatures and a size reduction of the respective sensors to achieve the necessary sensitivity and resolution. Here, we present results on how magnetic properties of individual nanoparticles can be measured at room temperature and with a conventional scanning force microscopy setup combined with a co-resonant cantilever magnetometry approach. We investigate individual Co2FeGa Heusler nanoparticles with diameters of the order of 35 nm encapsulated in carbon nanotubes. We observed, for the first time, magnetic switching of these nanoparticles in an external magnetic field by simple laser deflection detection. Furthermore, we were able to deduce magnetic properties of these nanoparticles which are in good agreement with previous results obtained with large nanoparticle ensembles in other experiments. In order to do this, we expand the analytical description of the frequency shift signal in cantilever magnetometry to a more general formulation, taking unaligned sensor oscillation directions with respect to the magnetic field into account.
Nitrogen-Doped Carbon Nanotube/Polypropylene Composites with Negative Seebeck Coefficient
(Basel : MDPI, 2020) Krause, Beate; Konidakis, Ioannis; Arjmand, Mohammad; Sundararaj, Uttandaraman; Fuge, Robert; Liebscher, Marco; Hampel, Silke; Klaus, Maxim; Serpetzoglou, Efthymis; Stratakis, Emmanuel; Pötschke, Petra
This study describes the application of multi-walled carbon nanotubes that were nitrogen-doped during their synthesis (N-MWCNTs) in melt-mixed polypropylene (PP) composites. Different types of N-MWCNTs, synthesized using different methods, were used and compared. Four of the five MWCNT grades showed negative Seebeck coefficients (S), indicating n-type charge carrier behavior. All prepared composites (with a concentration between 2 and 7.5 wt% N-MWCNTs) also showed negative S values, which in most cases had a higher negative value than the corresponding nanotubes. The S values achieved were between 1.0 µV/K and −13.8 µV/K for the N-MWCNT buckypapers or powders and between −4.7 µV/K and −22.8 µV/K for the corresponding composites. With a higher content of N-MWCNTs, the increase in electrical conductivity led to increasing values of the power factor (PF) despite the unstable behavior of the Seebeck coefficient. The highest power factor was achieved with 4 wt% N-MWCNT, where a suitable combination of high electrical conductivity and acceptable Seebeck coefficient led to a PF value of 6.1 × 10−3 µW/(m·K2). First experiments have shown that transient absorption spectroscopy (TAS) is a useful tool to study the carrier transfer process in CNTs in composites and to correlate it with the Seebeck coefficient.
Photocatalytic Degradation of Some Phenolic Compounds Present in Olive Mill Wastewater
(Ghaziabad : [Verlag nicht ermittelbar], 2018) Rimawi, Waleed H.; Salim, Hatim; Seder, Doaa; Ghunaim, Rasha; Hampel, Silke
The olive oil industry in Palestine is an important and widely spread one and accomplished with the release of large amounts of olive-mills wastewater. This wastewater represents a significant environmental problem due to its high phenolic content. In this work, the photocatalytic degradation of the some phenolic compounds (gallic acid, oleuropein and resorcinol) present in olive-mills wastewater using the synthesized nanoparticles of mixed SnO2-MgO catalyst and solar irradiation was performed. The nanoparticles of mixed SnO2-MgO catalyst with different ratios were prepared by sol gel method using a modified procedure. The obtained particles were characterized by SEM and XRD. The particle size was determined as 4.32 ± 0.42 nm which is much smaller than those previously prepared by standard procedures. The degradation percentage of phenolic compounds was measured by UV spectrophotometry. The effect of time, catalyst amount and phenolic compound concentration on degradation efficiency was studied. The maximum degradation was achieved using SnO2-MgO (4:1) catalyst, 2.5 mg catalyst per 5 mL solution, within the time of 60-120 min and ranged from 51 to 90 % for different concentrations of phenolic compounds.
Polyphenols delivery by polymeric materials: challenges in cancer treatment
(Abingdon : Taylor & Francis Group, 2017-2-3) Vittorio, Orazio; Curcio, Manuela; Cojoc, Monica; Goya, Gerardo F.; Hampel, Silke; Iemma, Francesca; Dubrovska, Anna; Cirillo, Giuseppe
Nanotechnology can offer different solutions for enhancing the therapeutic efficiency of polyphenols, a class of natural products widely explored for a potential applicability for the treatment of different diseases including cancer. While possessing interesting anticancer properties, polyphenols suffer from low stability and unfavorable pharmacokinetics, and thus suitable carriers are required when planning a therapeutic protocol. In the present review, an overview of the different strategies based on polymeric materials is presented, with the aim to highlight the strengths and the weaknesses of each approach and offer a platform of ideas for researchers working in the field.
Recent advances in the synthesis and biomedical applications of nanocomposite hydrogels
(Basel : MDPI, 2015) Spizzirri, Umile Gianfranco; Curcio, Manuela; Cirillo, Giuseppe; Spataro, Tania; Vittorio, Orazio; Picci, Nevio; Hampel, Silke; Iemma, Francesca; Nicoletta, Fiore Pasquale
Hydrogels sensitive to electric current are usually made of polyelectrolytes and undergo erosion, swelling, de-swelling or bending in the presence of an applied electric field. The electrical conductivity of many polymeric materials used for the fabrication of biomedical devices is not high enough to achieve an effective modulation of the functional properties, and thus, the incorporation of conducting materials (e.g., carbon nanotubes and nanographene oxide) was proposed as a valuable approach to overcome this limitation. By coupling the biological and chemical features of both natural and synthetic polymers with the favourable properties of carbon nanostructures (e.g., cellular uptake, electromagnetic and magnetic behaviour), it is possible to produce highly versatile and effective nanocomposite materials. In the present review, the recent advances in the synthesis and biomedical applications of electro-responsive nanocomposite hydrogels are discussed.
Release of Bioactive Molecules from Graphene Oxide-Alginate Hybrid Hydrogels: Effect of Crosslinking Method
(Basel : MDPI, 2023) Madeo, Lorenzo Francesco; Curcio, Manuela; Iemma, Francesca; Nicoletta, Fiore Pasquale; Hampel, Silke; Cirillo, Giuseppe
To investigate the influence of crosslinking methods on the releasing performance of hybrid hydrogels, we synthesized two systems consisting of Graphene oxide (GO) as a functional element and alginate as polymer counterpart by means of ionic gelation (physical method, 𝐻𝑃𝐴−𝐺𝑂) and radical polymerization (chemical method, 𝐻𝐶𝐴−𝐺𝑂). Formulations were optimized to maximize the GO content (2.0 and 1.15% for 𝐻𝑃𝐴−𝐺𝑂 and 𝐻𝐶𝐴−𝐺𝑂, respectively) and Curcumin (CUR) was loaded as a model drug at 2.5, 5.0, and 7.5% (by weight). The physico-chemical characterization confirmed the homogeneous incorporation of GO within the polymer network and the enhanced thermal stability of hybrid vs. blank hydrogels. The determination of swelling profiles showed a higher swelling degree for 𝐻𝐶𝐴−𝐺𝑂 and a marked pH responsivity due to the COOH functionalities. Moreover, the application of external voltages modified the water affinity of 𝐻𝐶𝐴−𝐺𝑂, while they accelerated the degradation of 𝐻𝑃𝐴−𝐺𝑂 due to the disruption of the crosslinking points and the partial dissolution of alginate. The evaluation of release profiles, extensively analysed by the application of semi-empirical mathematical models, showed a sustained release from hybrid hydrogels, and the possibility to modulate the releasing amount and rate by electro-stimulation of 𝐻𝐶𝐴−𝐺𝑂.
Removal of toxic hexavalent chromium via graphene oxide nanoparticles: study of kinetics, isotherms, and thermodynamics
(London : RSC Publishing, 2024) Khdoor, Zohor; Makharza, Sami; Qurie, Mohannad; Fohely, Firas; Abu Taha, Abdallah; Hampel, Silke
In this study, graphene oxide (GO) was prepared by the Hummers' method from graphite material. The adsorption potential of GO-200 nm for the removal of Cr(vi) ions was investigated. Fourier transform infrared (FTIR) spectroscopy was used to analyze Cr(vi) before and after adsorption. The adsorption isotherm was fitted by the Langmuir model and the maximum adsorption capacity of the GO was 41.27 mg g−1 at 25 °C. Thermodynamic parameters (ΔG°), (ΔH°), and (ΔS°) were calculated and exhibited as +2.63 kJ mol−1 K−1, +4.30 kJ mol−1 K−1, and +5.56 kJ mol−1 K−1 at 30 mg L−1 of Cr(vi) solution, respectively.
Surface defects reduce Carbon Nanotube toxicity in vitro
(Amsterdam [u.a.] : Elsevier Science, 2019) Requardt, Hendrik; Braun, Armin; Steinberg, Pablo; Hampel, Silke; Hansen, Tanja
The cytotoxicity of two different types of Multi-walled Carbon Nanotubes (MWCNTs)in A549 lung epithelial cells and HepG2 hepatocytes was investigated. One MWCNT still contained iron that was used as a catalyst during production, while the other one had all iron removed in a post-production heat treatment resulting in significantly fewer surface defects. The WST-8 assay was applied to test cell viability. To check the integrity of the cell membrane, we performed the lactate dehydrogenases assay (LDH)and measured the cellular production of reactive oxygen species (ROS). Finally, to examine cell proliferation, we conducted a cell cycle analysis. The results showed a dose- and time-dependent decrease in cell viability for both MWCNTs in both cell types. Moreover, a dose- and time-dependent increase in LDH leakage was detected, thereby indicating a decreased membrane integrity. The production of ROS was significantly increased in the case of the heat-treated MWCNTs. The heat-treated MWCNTs showed significantly stronger adverse effects when compared to the non-treated MWCNTs. Additionally, the heat-treated MWCNTs induced a dose-dependent cell cycle arrest in A549 cells. Both MWCNTs induced a significant cytotoxicity, whereby the heat treatment, leading to a decrease in surface defects, further increased the indicated adverse effects. © 2019 The Authors
Systematic evaluation of oligodeoxynucleotide binding and hybridization to modified multi-walled carbon nanotubes
(London : Biomed Central, 2017) Kaufmann, Anika; Hampel, Silke; Rieger, Christiane; Kunhardt, David; Schendel, Darja; Füssel, Susanne; Schwenzer, Bernd; Erdmann, Kati
Background: In addition to conventional chemotherapeutics, nucleic acid-based therapeutics like antisense oligodeoxynucleotides (AS-ODN) represent a novel approach for the treatment of bladder cancer (BCa). An efficient delivery of AS-ODN to the urothelium and then into cancer cells might be achieved by the local application of multi-walled carbon nanotubes (MWCNT). In the present study, pristine MWCNT and MWCNT functionalized with hydrophilic moieties were synthesized and then investigated regarding their physicochemical characteristics, dispersibility, biocompatibility, cellular uptake and mucoadhesive properties. Finally, their binding capacity for AS-ODN via hybridization to carrier strand oligodeoxynucleotides (CS-ODN), which were either non-covalently adsorbed or covalently bound to the different MWCNT types, was evaluated. Results: Pristine MWCNT were successfully functionalized with hydrophilic moieties (MWCNT-OH, -COOH, -NH2, -SH), which led to an improved dispersibility and an enhanced dispersion stability. A viability assay revealed that MWCNT-OH, MWCNT-NH2 and MWCNT-SH were most biocompatible. All MWCNT were internalized by BCa cells, whereupon the highest uptake was observed for MWCNT-OH with 40% of the cells showing an engulfment. Furthermore, all types of MWCNT could adhere to the urothelium of explanted mouse bladders, but the amount of the covered urothelial area was with 2-7% rather low. As indicated by fluorescence measurements, it was possible to attach CS-ODN by adsorption and covalent binding to functionalized MWCNT. Adsorption of CS-ODN to pristine MWCNT, MWCNT-COOH and MWCNT-NH2 as well as covalent coupling to MWCNT-NH2 and MWCNT-SH resulted in the best binding capacity and stability. Subsequently, therapeutic AS-ODN could be hybridized to and reversibly released from the CS-ODN coupled via both strategies to the functionalized MWCNT. The release of AS-ODN at experimental conditions (80 °C, buffer) was most effective from CS-ODN adsorbed to MWCNT-OH and MWCNT-NH2 as well as from CS-ODN covalently attached to MWCNT-COOH, MWCNT-NH2 and MWCNT-SH. Furthermore, we could exemplarily demonstrate that AS-ODN could be released following hybridization to CS-ODN adsorbed to MWCNT-OH at physiological settings (37 °C, urine). Conclusions: In conclusion, functionalized MWCNT might be used as nanotransporters in antisense therapy for the local treatment of BCa.
ZnO–Graphene Oxide Nanocomposite for Paclitaxel Delivery and Enhanced Toxicity in Breast Cancer Cells
(Basel : MDPI, 2024) Madeo, Lorenzo Francesco; Schirmer, Christine; Cirillo, Giuseppe; Asha, Ayah Nader; Ghunaim, Rasha; Froeschke, Samuel; Wolf, Daniel; Curcio, Manuela; Tucci, Paola; Iemma, Francesca; Büchner, Bernd; Hampel, Silke; Mertig, Michael
A ZnO-Graphene oxide nanocomposite (Z-G) was prepared in order to exploit the biomedical features of each component in a single anticancer material. This was achieved by means of an environmentally friendly synthesis, taking place at a low temperature and without the involvement of toxic reagents. The product was physicochemically characterized. The ZnO-to-GO ratio was determined through thermogravimetric analysis, while scanning electron microscopy and transmission electron microscopy were used to provide insight into the morphology of the nanocomposite. Using energy-dispersive X-ray spectroscopy, it was possible to confirm that the graphene flakes were homogeneously coated with ZnO. The crystallite size of the ZnO nanoparticles in the new composite was determined using X-ray powder diffraction. The capacity of Z-G to enhance the toxicity of the anticancer drug Paclitaxel towards breast cancer cells was assessed via a cell viability study, showing the remarkable anticancer activity of the obtained system. Such results support the potential use of Z-G as an anticancer agent in combination with a common chemotherapeutic like Paclitaxel, leading to new chemotherapeutic formulations.

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