TY  - JOUR
AB  - Colloidal clusters of magnetic iron oxide nanocrystals (MIONs), particularly in the condensed pattern (co-CNCs), have emerged as new superstructures to improve further the performance of MIONs in applications pertaining to magnetic manipulation (drug delivery) and magnetic resonance imaging (MRI). Exploitation of the advantages they represent and their establishment in the area of nanomedicine demands a particular set of assets. The present work describes the development and evaluation of MION-based co-CNCs featuring for the first time such assets: High magnetization, as well as magnetic content and moment, high relaxivities (r2 = 400 and [Formula: see text] ) and intrinsic loss power (2.3 nH m(2) kgFe(-1)) are combined with unprecedented colloidal stability and structural integrity, stealth and drug-loading properties. The reported nanoconstructs are endowed with additional important features such as cost-effective synthesis and storage, prolonged self-life and biocompatibility. It is finally showcased with in vivo multispectral optoacoustic tomography how these properties culminate in a system suitable for targeting breast cancer and for forceful in vivo manipulation with low magnetic field gradients.
AU  - Sarigiannis, Y.*
AU  - Kolokithas-Ntoukas, A.*
AU  - Bézière, N.
AU  - Zbořil, R.*
AU  - Papadimitriou, E.*
AU  - Avgoustakis, K.*
AU  - Lamprou, M.*
AU  - Medrikova, Z.*
AU  - Rousalis, E.*
AU  - Ntziachristos, V.
AU  - Bakandritsos, A.*
C1  - 48248
C2  - 39978
CY  - Oxford
SP  - 128-139
TI  - Synthesis and evaluation of condensed magnetic nanocrystal clusters with in vivo multispectral optoacoustic tomography for tumour targeting.
JO  - Biomaterials
VL  - 91
PB  - Elsevier Sci Ltd
PY  - 2016
SN  - 0142-9612
ER  - 

TY  - JOUR
AB  - Nanosecond-duration laser pulses are exploited in a plethora of therapeutic and diagnostic applications, such as optoacoustic imaging. However, phototoxicity effects of pulsed radiation in living cells, in particular those expressing genetic reporters, are not well understood. We established a three-dimensional fluorescent protein expressing cellular model in order to reliably investigate the extent and major exposure parameters responsible for both photobleaching and phototoxicity under pulsed laser exposure, unveiling a variety of possible effects on living cells, from reversible photobleaching to cytotoxicity and cell death. Significant losses of fluorescence levels were identified when exposing the cells to illumination conditions considered safe under common standards for skin exposure in diagnostic imaging applications. Thus, the use of photolabile fluorescent proteins and their in vivo exposure parameters have to be designed carefully for all applications using pulsed nanosecond radiation. In particular, loss of signal due to bleaching may significantly alter signals in longitudinal measurements, making data quantification challenging.
AU  - Gottschalk, S.
AU  - Estrada, H.
AU  - Degtyaruk, O.
AU  - Rebling, J.
AU  - Klymenko, O.
AU  - Rosemann, M.
AU  - Razansky, D.
C1  - 46584
C2  - 37699
SP  - 38-44
TI  - Short and long-term phototoxicity in cells expressing genetic reporters under nanosecond laser exposure.
JO  - Biomaterials
VL  - 69
PY  - 2015
SN  - 0142-9612
ER  - 

TY  - JOUR
AB  - Multispectral optoacoustic tomography (MSOT) is a powerful modality that allows high-resolution imaging of photo-absorbers deep within tissue, beyond the classical depth and resolution limitations of conventional optical imaging. Imaging of intrinsic tissue contrast can be complemented by extrinsically administered gold nanoparticles or fluorescent molecular probes. Instead, we investigated herein generation of re-engineered clinically-used PEGylated liposomes incorporating indocyanine green (LipoICG) as a contrast strategy that combines materials already approved for clinical use, with strong photo-absorbing signal generation available today only from some metallic nanoparticles (e.g. gold nanorods). Using MSOT we confirmed LipoICG as a highly potent optoacoustic agent and resolved tissue accumulation in tumor-bearing animals over time with high-sensitivity and resolution using two tumor models of different vascularisation. We further showcase a paradigm shift in pharmacology studies and nanoparticle investigation, by enabling detailed volumetric optical imaging in vivo through the entire tumor tissue non-invasively, elucidating never before seen spatiotemporal features of optical agent distribution. These results point to LipoICG as a particle with significant advantageous characteristics over gold nanoparticles and organic dyes.
AU  - Bézière, N.
AU  - Lozano, N.*
AU  - Nunes, A.
AU  - Salichs, J.
AU  - Queirós, D.
AU  - Kostarelos, K.*
AU  - Ntziachristos, V.
C1  - 42888
C2  - 35735
SP  - 415-424
TI  - Dynamic imaging of PEGylated Indocyanine Green (ICG) liposomes within the tumor microenvironment using Multi-Spectral Optoacoustic Tomography (MSOT).
JO  - Biomaterials
VL  - 37
PY  - 2014
SN  - 0142-9612
ER  - 

TY  - JOUR
AB  - Lentiviral vectors (LV) are widely used to successfully transduce cells for research and clinical applications. Lentiviral vectors pseudotyped with the vesicular stomatitis virus glycoprotein (VSV-G) can be produced to high titers and mediate high transduction efficiencies in vitro. For clinical applications the need for optimized transduction protocols and the limited activity of retronectin as LV enhancer, results in the application of a high multiplicity of infection (MOI) to achieve effective transduction efficiencies for a number of therapeutically relevant cells, e.g. CD34(+) hematopoietic stem cells, T- and B-cells. Our study describes an optimized LV infection protocol including a non-toxic poloxamer-based adjuvant combined with antibody-retargeted lentiviral particles, improving transduction efficiency at low MOI. Cell specificity of lentiviral vectors was increased by displaying different ratios of scFv-fused VSV-G glycoproteins on the viral envelope. The system was validated with difficult to transduce human CD30(+) lymphoma cells, and EGFR(+) tumor cells. Highly efficient transduction of lymphoma cells was achieved, >50% of cells were transduced when MOI 1 was used. The scFv displaying lentiviral particles gained relative specificity for transduction of target cells. Preferential gene delivery to CD30(+) or EGFR(+) cells was increased 4-fold in mixed cell cultures by presenting scFv antibody fragments binding to respective surface markers. A combination of spinoculation, poloxamer-based chemical adjuvant, and LV displaying scFv fragments increases transduction efficiencies of hard-to-transduce suspension lymphoma cells, and promises new chances for the future development of improved clinical protocols.
AU  - Höfig, I.
AU  - Barth, S.*
AU  - Salomon, M.*
AU  - Jagusch, V.*
AU  - Atkinson, M.J.
AU  - Anastasov, N.
AU  - Thirion, C.*
C1  - 30584
C2  - 33736
CY  - Oxford
SP  - 4204-4212
TI  - Systematic improvement of lentivirus transduction protocols by antibody fragments fused to VSV-G as envelope glycoprotein.
JO  - Biomaterials
VL  - 35
IS  - 13
PB  - Elsevier Sci Ltd
PY  - 2014
SN  - 0142-9612
ER  - 

TY  - JOUR
AB  - Site specific recombinases are frequently used as gene switches in transgenic animals where recombination is induced by drug treatment or by tissue specific recombinase expression. Alternatively, lentiviral gene transfer can be utilized for the genetic modification of a wide variety of cell types, albeit systems for tight control of transcriptional activity are scarce. Here, we combined lentiviral gene transfer and the development of a tightly drug-controlled FLP recombinase for the construction of "All-in-One" inducible gene expression systems. Tight control of FLP activity was achieved through N-terminal fusion with a FKBP12-derived conditional destruction domain and a C-terminal estrogen receptor binding domain making recombination dependent on the presence of Shield-1 and 4-hydroxytamoxifen. Exploiting the capacity of FLP to mediate excision and inversion, "All-in-One" lentiviral gene switch vector systems were generated where drug-induced recombination resulted in abrogation of FLP expression and subsequent overexpression or knockdown of the prototypical tumor suppressor phosphatase and tensin homolog PTEN. "All-in-One" vectors proved their functionality in a variety of hematopoietic cell lines, and primary murine bone marrow cells. Our new vector system thus combines the ease of lentiviral gene transfer and the power of site specific recombinases for analysis of gene function.
AU  - Maetzig, T.*
AU  - Kuehle, J.*
AU  - Schwarzer, A.*
AU  - Turan, S.*
AU  - Rothe, M.*
AU  - Chaturvedi, A.*
AU  - Morgan, M.*
AU  - Ha, T.C.*
AU  - Heuser, M.*
AU  - Hammerschmidt, W.
AU  - Baum, C.*
AU  - Schambach, A.*
C1  - 30585
C2  - 33735
CY  - Oxford
SP  - 4345-4356
TI  - All-in-One inducible lentiviral vector systems based on drug controlled FLP recombinase.
JO  - Biomaterials
VL  - 35
IS  - 14
PB  - Elsevier Sci Ltd
PY  - 2014
SN  - 0142-9612
ER  - 

TY  - JOUR
AB  - Nanoparticles (NP) and nanoparticulated drug delivery promise to be the breakthrough for therapy in medicine but raise concerns in terms of nanotoxicity. We present quantitative murine biokinetics assays using polyelectrolyte-multilayer-coated gold NP (AuNP, core diameter 15 and 80 nm; 198Au radio-labeled). Those were stably conjugated either with human serum albumin (alb-AuNP) or apolipoprotein E (apoE-AuNP), prior to intravenous injection. We compare the biokinetics of protein-AuNP-conjugates with citrate-stabilized AuNP (cit-AuNP). Biokinetics was complemented with histology in organs with high AuNP content using 15 nm double fluorescently-labeled alb-AuNP-conjugates. Protein conjugation massively reduced liver retention (alb-AuNP: 52%, apoE-AuNP: 72%, cit-AuNP: >95%, at 19 h and 48 h) when compared to cit-AuNP. The protein conjugates were retained in lungs (alb-AuNP (18%) and spleen (alb-AuNP (16%), apoE-AuNP (21%) at 19 h. Alb-AuNP show significantly increased fractions in lungs (factors: 60 (30 min); 111 (19 h); 235 (48 h) and brain (factors: 70 (30 min); 90 (19 h); >200 (48 h) compared to cit-AuNP (control) - or even to apoE-AuNP. The influence of protein conjugation on the biodistribution disappears for 80 nm AuNP comparing to control. Histologically, the 15 nm alb-AuNP are mainly located in the endothelium of brain, lungs, liver and kidneys after 30 min, while at 19 h they moved deeper into the parenchyma e.g. in hippocampus. Our study clearly suggests that stable conjugation of AuNP with albumin and apoE prior to intravenous administration increases specificity and efficiency of NP in diseased target-organs thus suggesting a potential role in nanomedicine and nanopharmacology.
AU  - Schäffler, M.
AU  - Sousa, F.*
AU  - Wenk, A.
AU  - Sitia, L.*
AU  - Hirn, S.
AU  - Schleh, C.
AU  - Haberl, N.
AU  - Violatto, M.*
AU  - Canovi, M.*
AU  - Andreozzi, P.*
AU  - Salmona, M.*
AU  - Bigini, P.*
AU  - Kreyling, W.G.
AU  - Krol, S.*
C1  - 30617
C2  - 33773
CY  - Oxford
SP  - 3455-3466
TI  - Blood protein coating of gold nanoparticles as potential tool for organ targeting.
JO  - Biomaterials
VL  - 35
IS  - 10
PB  - Elsevier Sci Ltd
PY  - 2014
SN  - 0142-9612
ER  - 

TY  - JOUR
AB  - Airborne engineered nanoparticles undergo agglomeration, and careful distinction must be made between primary and agglomerate size of particles, when assessing their health effects. This study compares the effects on rats undergoing 15-day inhalation exposure to airborne agglomerates of gold nanoparticles (AuNPs) of similar size distribution and number concentration (1 × 10(6) particles/cm(3)), but two different primary diameters of 7 nm or 20 nm. Inhalation of agglomerates containing 7-nm AuNPs resulted in highest deposition by mass concentration in the lungs, followed by brain regions including the olfactory bulb, hippocampus, striatum, frontal cortex, entorhinal cortex, septum, cerebellum; aorta, esophagus, and kidney. Eight organs/tissues especially the brain retained greater mass concentration of Au after inhalation exposure to agglomerates of 7-nm than 20-nm AuNPs. Macrophage mediated escalation followed by fecal excretion is the major pathway of clearing inhaled AuNPs in the lungs. Microarray analyses of the hippocampus showed mostly downregulated genes, related to the cytoskeleton and neurite outgrowth. Together, results in this study indicate disintegration of nanosized agglomerates after inhalation and show impact of primary size of particles on subsequent biodistribution.
AU  - Balasubramanian, S.K.*
AU  - Poh, K.-W.*
AU  - Ong, C.-N.*
AU  - Kreyling, W.G.
AU  - Ong, W.-Y.*
AU  - Yu, L.E.*
C1  - 24398
C2  - 31540
SP  - 5439-5452
TI  - The effect of primary particle size on biodistribution of inhaled gold nano-agglomerates.
JO  - Biomaterials
VL  - 34
IS  - 22
PB  - Elsevier
PY  - 2013
SN  - 0142-9612
ER  - 

TY  - JOUR
AB  - Up to now, functionalized gold nanoparticles have been optimized as an effective intracellular in vitro delivery vehicle for siRNAs to interfere with the expression of specific genes by selective targeting, and provide protection against nucleases. Few examples however of suchlike in vivo applications have been described so far. In this study, we report the use of siRNA/RGD gold nanoparticles capable of targeting tumor cells in a lung cancer syngeneic orthotopic murine model. Therapeutic RGD-nanoparticle treatment resulted in successful targeting evident from significant c-myc oncogene down-regulation followed by tumor growth inhibition and prolonged survival of lung tumor bearing mice, possibly via αvβ3 integrin interaction. Our results suggest that RGD gold nanoparticles-mediated delivery of siRNA by intratracheal instillation in mice leads to successful suppression of tumor cell proliferation and respective tumor size reduction. These results reiterate the capability of functionalized gold nanoparticles for targeted delivery of siRNA to cancer cells towards effective silencing of the specific target oncogene. What is more, we demonstrate that the gold-nanoconjugates trigger a complex inflammatory and immune response that might promote the therapeutic effect of the RNAi to reduce tumor size with low doses of siRNA.
AU  - Conde, J.*
AU  - Tian, F.
AU  - Hernandez, Y.*
AU  - Bao, C.
AU  - Cui, D.*
AU  - Janssen, K.P.*
AU  - Ibarra, M.R.*
AU  - Baptista, P.V.*
AU  - Stöger, T.
AU  - de la Fuente, J.M.*
C1  - 26208
C2  - 32133
SP  - 7744-7753
TI  - In vivo tumor targeting via nanoparticle-mediated therapeutic siRNA coupled to inflammatory response in lung cancer mouse models.
JO  - Biomaterials
VL  - 34
IS  - 31
PB  - Elsevier Science
PY  - 2013
SN  - 0142-9612
ER  - 

TY  - JOUR
AB  - Nanoparticle-induced endothelial cell (EC) dysfunction, due to the induction of inflammation and/or the activation of the coagulation system, is associated with pulmonary and ischemic cardiovascular diseases. Although it is contigent on several mechanisms, involving formation of reactive oxygen species and inflammatory cytokines such as interleukin (IL)-6 and 8, the involvement of the coagulation system is not well understood. The results of toxicity assays using the tetrazolium reduction (MTT) and lactate dehydrogenase (LDH) release showed that silica NP-induced cytotoxicity depends on the size and the dose of applied NP. Moreover, propidium iodide (PI) stainings and caspase 3/7 assays identified increased necrosis in ECs. Exposing human umbilical vein endothelial cells (HUVECs) to SiO(2) NP with diameters of 304 nm and 310 nm led to significant increase of Weibel-Palade body (WPB) exocytosis, associated with the release of von Willebrand factor (VWF) and the formation of ultralarge fibers (ULVWF). High resolution microscopy techniques revealed that internalization and perinuclear localization of perylene-labeled NP with a size of 310 nm affect not only viability, but also cell migration and proliferation. In conclusion, our data indicate that NP-induced activation and dysfunction of ECs is reflected by release of VWF and necrotic cell death.
AU  - Bauer, A.T.*
AU  - Strozyk, E.A.
AU  - Gorzelanny, C.*
AU  - Westerhausen, C.*
AU  - Desch, A.*
AU  - Schneider, M.F.*
AU  - Schneider, S.W.*
C1  - 5638
C2  - 29437
SP  - 8385-8393
TI  - Cytotoxicity of silica nanoparticles through exocytosis of von Willebrand factor and necrotic cell death in primary human endothelial cells.
JO  - Biomaterials
VL  - 32
IS  - 33
PB  - Elsevier
PY  - 2011
SN  - 0142-9612
ER  - 

TY  - JOUR
AB  - Polymeric non-viral vector systems for pulmonary application of siRNA are promising carriers, but have failed to enter clinical trials because of safety and efficiency problems. Therefore, improving their transfection efficiency, as well as their toxicological profile, is the subject of intensive research efforts. Six different poly(ethylene imine) (PEI)-based nanocarriers, with hydrophilic and hydrophobic PEG modifications, were toxicologically evaluated for pulmonary application in mice. Nanocarriers were intratracheally instilled to determine their toxicological profile, with particular focus on the inflammatory response in the lungs. Nanocarriers from both groups caused an acute inflammatory response in the lungs, albeit with different resolution kinetics and cytotoxicity. Hydrophobic modifications caused a severe inflammatory response with increased epithelial barrier permeability, accompanied by an acute antioxidant response. Hydrophilic modifications, with high PEG-grafting degrees, induced less proinflammatory effects without depleting macrophages and disrupting the epithelial/endothelial barrier in the lungs, while showing only a minor oxidative stress response. For pulmonary applications, local proinflammatory effects should be optimized by further development of nanocarriers with highly grafted PEG-PEI-based carriers or Jeffamine-modified hydrophobic PEI modifications.
AU  - Beyerle, A.
AU  - Braun, A.
AU  - Banerjee, A.*
AU  - Ercal, N.*
AU  - Eickelberg, O.
AU  - Kissel, T.H.*
AU  - Stöger, T.
C1  - 6160
C2  - 28847
SP  - 8694-8701
TI  - Inflammatory responses to pulmonary application of PEI-based siRNA nanocarriers in mice.
JO  - Biomaterials
VL  - 32
IS  - 33
PB  - Elsevier
PY  - 2011
SN  - 0142-9612
ER  - 

TY  - JOUR
AB  - Since off-target effects in non-viral siRNA delivery are quite common but not well understood, in this study various polymer-related effects observed in transfection studies were described and their mechanisms of toxicity were investigated. A variety of stably luciferase-expressing cell lines was compared concerning polymer-mediated effects after transfection with polyplexes of siRNA and poly(ethylene imine) (PEI) or poly(ethylene glycol)-grafted PEI (PEG-PEI). Cell viability, LDH release, gene expression profiles of apoptosis-related genes and promoter activation were investigated. Interestingly, PEG-PEI, which is generally better tolerated than PEI, was found to activate apoptosis in a cell line- and concentration-dependent manner. While both polymers showed sigmoidal dose-response of cell viability in L929 cells (IC(50)(PEI) = 6 μg/ml, IC(50)(PEG-PEI) = 11 μg/ml), H1299/Luc cells exhibited biphasic dose-response for PEG-PEI and stronger apoptosis at 2 μg/ml than at 20 μg/ml PEG-PEI, as shown in TUNEL assays. Gene expression profiling confirmed that H1299/Luc cells underwent apoptosis via thousand-fold activation of TNF receptor-associated factors. Additionally, it was demonstrated that NFkB-mediated CMV promoter activation in stably transfected cells can lead to increased target gene levels after transfection instead of siRNA-mediated knockdown. With these results, polymeric vectors were shown not to be inert substances. Therefore, alterations in gene expression caused by the delivery agent must be known to correctly interpret gene-silencing experiments, to understand the mechanisms of off-target effects, and most of all to further develop vectors with reduced side effects. Taking these observations into account, one established cell line was eventually identified to be suitable for RNAi experiments. As shown by these experiments, materials that have been used for many years can elicit unexpected off-target effects. Therefore, non-viral vectors must be screened for several levels of toxicity to make them promising candidates.
AU  - Merkel, O.M.*
AU  - Beyerle, A.
AU  - Beckmann, B.M.*
AU  - Zheng, M.*
AU  - Hartmann, R.K.*
AU  - Stöger, T.
AU  - Kissel, T.H.*
C1  - 3948
C2  - 28686
SP  - 2388-2398
TI  - Polymer-related off-target effects in non-viral siRNA delivery.
JO  - Biomaterials
VL  - 32
IS  - 9
PB  - Elsevier
PY  - 2011
SN  - 0142-9612
ER  - 

TY  - JOUR
AB  - Besides toxicity tests, biokinetic studies are a fundamental part of investigations to evaluate a safe and sustainable use of nanoparticles. Today, gold nanoparticles (Au NPs) are known to be a versatile tool in different areas such as science, engineering or medicine. In this study, we investigated the biokinetics after intravenous and intratracheal applications of poly(ethylene glycol) (PEG) modified Au NPs compared to plain Au NPs. Radioactive-labeled Au NPs of 5 nm inorganic core diameter were applied to rats and the NP content in tissues, organs and excretion were quantified after 1-hour and 24-hours. After intravenous injection, a prolonged blood circulation time was determined for Au NPs with 10 kDa PEG chains. Non-PEGylated Au NPs and 750 Da PEG Au NPs accumulated mostly in liver and spleen. After intratracheal application the majority of all three types of applied NPs stayed in the lungs: the total translocation towards the circulation did not differ considerably after PEGylation of the Au NPs. However, a prolonged retention time in the circulation was detected for the small fraction of translocated 10 kDa PEG Au NPs, too.
AU  - Lipka, J.
AU  - Semmler-Behnke, M.
AU  - Sperling, R.A.*
AU  - Wenk, A.
AU  - Takenaka, S.
AU  - Schleh, C.
AU  - Kissel, T.*
AU  - Parak, W.J.*
AU  - Kreyling, W.G.
C1  - 4200
C2  - 27754
SP  - 6574-6581
TI  - Biodistribution of PEG-modified gold nanoparticles following intratracheal instillation and intravenous injection.
JO  - Biomaterials
VL  - 31
IS  - 25
PB  - Elsevier
PY  - 2010
SN  - 0142-9612
ER  - 

TY  - JOUR
AB  - Plasmid DNA and viral RNA were imaged in a liquid environment by dynamic force microscopy (DFM) and fine structures of DNA with heights of 1.82+/-0.66 nm were obtained in topographical images. In simultaneously acquired phase images, DNA could be imaged with better contrast at lower imaging forces. By splitting the cantilever oscillation signal into lower and upper parts, the contribution of the adhesion between tip and sample to the topographical images was eliminated, resulting in better signal-to-noise ratio. DFM of the single stranded RNA genome of a human rhinovirus showed loops protruding from a condensed RNA core, 20-50 nm in height. The mechanical rigidity of the RNA was determined by single molecule pulling experiments. From fitting RNA stretching curves to the Worm-Like-Chain (WLC) model a persistence length of 1.0+/-0.17 nm was obtained.
AU  - Kienberger, F.*
AU  - Costa, L.T.*
AU  - Zhu, R.*
AU  - Kada, G.*
AU  - Reithmayer, M.*
AU  - Chtcheglova, L.*
AU  - Rankl, C.*
AU  - Pacheco, A.B.*
AU  - Thalhammer, S.
AU  - Pastushenko, V.*
AU  - Heckl, W.M.*
AU  - Blaas, D.*
AU  - Hinterdorfer, P.*
C1  - 2451
C2  - 24989
SP  - 2403-2411
TI  - Dynamic force microscopy imaging of plasmid DNA and viral RNA.
JO  - Biomaterials
VL  - 28
IS  - 15
PB  - Elsevier
PY  - 2007
SN  - 0142-9612
ER  -