Michael Riediker

Dr. Michael Riediker

orcid

Research Focus & Metrics

Academic Career Length

27Years (2000-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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15 April 2004 in American Journal of Respiratory and Critical Care Medicine
Verified
Journal Article
Closed access
MRMichael Riediker
Michael Riediker
WCWayne E. Cascio
Wayne E. Cascio
TGThomas R. Griggs
Thomas R. Griggs
MHMargaret C. Herbst
Margaret C. Herbst
PBPhilip A. Bromberg
Philip A. Bromberg
RDRobert B. Devlin
Robert B. Devlin
Exposure to fine airborne particulate matter (PM2.5) is associated with cardiovascular events and mortality in older and cardiac patients. Potential physiologic effects of in-vehicle, roadside, and ambient PM2.5 were investigated in young, healthy, nonsmoking, male North Carolina Highway Patrol troopers. Nine troopers (age 23 to 30) were monitored on 4 successive days while working a 3 P.M. to midnight shift. Each patrol car was equipped with air-quality monitors. Blood was drawn 14 hours after each shift, and ambulatory monitors recorded the electrocardiogram throughout the shift and until the next morning. Data were analyzed using mixed models. In-vehicle PM2.5 (average of 24 μg/m3) was associated with decreased lymphocytes (−11% per 10 μg/m3) and increased red blood cell indices (1% mean corpuscular volume), neutrophils (6%), C-reactive protein (32%), von Willebrand factor (12%), next-morning heart beat cycle length (6%), next-morning heart rate variability parameters, and ectopic beats throughout the recording (20%). Controlling for potential confounders had little impact on the effect estimates. The associations of these health endpoints with ambient and roadside PM2.5 were smaller and less significant. The observations in these healthy young men suggest that in-vehicle exposure to PM2.5 may cause pathophysiologic changes that involve inflammation, coagulation, and cardiac rhythm.

1 October 2011 in Journal of Aerosol Science
Verified
Journal Article
Closed access
HPHanns-R. Paur
Hanns-R. Paur
FCFlemming R. Cassee
Flemming R. Cassee
JTJustin Teeguarden
Justin Teeguarden
HFHeinz Fissan
Heinz Fissan
SDSilvia Diabate
Silvia Diabate
OSOtmar Schmid
Otmar Schmid

16 January 2015 in Journal of Nanobiotechnology
Verified
Journal Article
Open access
PDF file
PSPaul Schlinkert
Paul Schlinkert
ECEudald Casals
Eudald Casals
MBMatthew Boyles
Matthew Boyles
UTUlrike Tischler
Ulrike Tischler
EHEva Hornig
Eva Hornig
ADAlbert Duschl
Albert Duschl
Nanoparticle (NPs) functionalization has been shown to affect their cellular toxicity. To study this, differently functionalized silver (Ag) and gold (Au) NPs were synthesised, characterised and tested using lung epithelial cell systems. Monodispersed Ag and Au NPs with a size range of 7 to 10 nm were coated with either sodium citrate or chitosan resulting in surface charges from −50 mV to +70 mV. NP-induced cytotoxicity and oxidative stress were determined using A549 cells, BEAS-2B cells and primary lung epithelial cells (NHBE cells). TEER measurements and immunofluorescence staining of tight junctions were performed to test the growth characteristics of the cells. Cytotoxicity was measured by means of the CellTiter-Blue ® and the lactate dehydrogenase assay and cellular and cell-free reactive oxygen species (ROS) production was measured using the DCFH-DA assay. Different growth characteristics were shown in the three cell types used. A549 cells grew into a confluent mono-layer, BEAS-2B cells grew into a multilayer and NHBE cells did not form a confluent layer. A549 cells were least susceptible towards NPs, irrespective of the NP functionalization. Cytotoxicity in BEAS-2B cells increased when exposed to high positive charged (+65-75 mV) Au NPs. The greatest cytotoxicity was observed in NHBE cells, where both Ag and Au NPs with a charge above +40 mV induced cytotoxicity. ROS production was most prominent in A549 cells where Au NPs (+65-75 mV) induced the highest amount of ROS. In addition, cell-free ROS measurements showed a significant increase in ROS production with an increase in chitosan coating. Chitosan functionalization of NPs, with resultant high surface charges plays an important role in NP-toxicity. Au NPs, which have been shown to be inert and often non-cytotoxic, can become toxic upon coating with certain charged molecules. Notably, these effects are dependent on the core material of the particle, the cell type used for testing and the growth characteristics of these cell culture model systems.

11 March 2013 in Nanomedicine
Verified
Journal Article
Closed access
CSCatherine A Schütz
Catherine A Schütz
LJLucienne Juillerat-Jeanneret
Lucienne Juillerat-Jeanneret
HMHeinz Mueller
Heinz Mueller
Iseult LynchIseult Lynch
Iseult Lynch
MRMichael Riediker
Michael Riediker
This article reviews nanoparticulate-chemotherapeutic systems that have been developed for human therapy, considering the components of the nanoparticles, the therapeutic agents associated with the nanoparticles and the clinical indications these therapeutic nanoparticles have been developed for. In this evaluation we have put into perspective the types of nanomaterials and their therapeutic indications. We have reviewed the nanoparticulate-chemotherapeutic systems that have been published, approved and marketed and that are currently in clinical use. We have also analyzed the nanoparticulate-chemotherapeutic systems that are in clinical trials and under preclinical development.

16 March 2012 in Ecotoxicology
Verified
Journal Article
Open access
PDF file
RHRichard D. Handy
Richard D. Handy
NBNico van Den Brink
Nico van Den Brink
MCMark Chappell
Mark Chappell
MMMartin Mühling
Martin Mühling
RBRenata Behra
Renata Behra
MRMichael Riediker
Michael Riediker
This review paper reports the consensus of a technical workshop hosted by the European network, NanoImpactNet (NIN). The workshop aimed to review the collective experience of working at the bench with manufactured nanomaterials (MNMs), and to recommend modifications to existing experimental methods and OECD protocols. Current procedures for cleaning glassware are appropriate for most MNMs, although interference with electrodes may occur. Maintaining exposure is more difficult with MNMs compared to conventional chemicals. A metal salt control is recommended for experiments with metallic MNMs that may release free metal ions. Dispersing agents should be avoided, but if they must be used, then natural or synthetic dispersing agents are possible, and dispersion controls essential. Time constraints and technology gaps indicate that full characterisation of test mediaduringecotoxicity tests is currently not practical. Details of electron microscopy, dark-field microscopy, a range of spectroscopic methods (EDX, XRD, XANES, EXAFS), light scattering techniques (DLS, SLS) and chromatography are discussed. The development of user-friendly software to predict particle behaviour in test media according to DLVO theory is in progress, and simple optical methods are available to estimate the settling behaviour of suspensionsduringexperiments. However, for soil matrices such simple approaches may not be applicable. Alternatively, a Critical Body Residue approach may be taken in which body concentrations in organisms are related to effects, and toxicity thresholds derived. For microbial assays, the cell wall is a formidable barrier to MNMs and end points that rely on the test substance penetrating the cell may be insensitive. Instead assays based on the cell envelope should be developed for MNMs. In algal growth tests, the abiotic factors that promote particle aggregation in the media (e.g. ionic strength) are also important in providing nutrients, and manipulation of the media to control the dispersion may also inhibit growth. Controls to quantify shading effects, and precise details of lighting regimes, shaking or mixing should be reported in algal tests. Photosynthesis may be more sensitive than traditional growth end points for algae and plants. Tests with invertebrates should consider non-chemical toxicity from particle adherence to the organisms. The use of semi-static exposure methods with fish can reduce the logistical issues of waste water disposal and facilitate aspects of animal husbandry relevant to MMNs. There are concerns that the existing bioaccumulation tests are conceptually flawed for MNMs and that new test(s) are required. In vitro testing strategies, as exemplified by genotoxicity assays, can be modified for MNMs, but the risk of false negatives in some assays is highlighted. In conclusion, most protocols will require some modifications and recommendations are made to aid the researcher at the bench.

19 November 2013 in Journal of Nanoparticle Research
Verified
Journal Article
Open access
PDF file
PHPatrick Hole
Patrick Hole
KSKatherine Sillence
Katherine Sillence
CHClaire Hannell
Claire Hannell
CMCiaran Maguire
Ciaran Maguire
MRMatthias Roesslein
Matthias Roesslein
PWPeter Wick
Peter Wick
One of the key challenges in the field of nanoparticle (NP) analysis is in producing reliable and reproducible characterisation data for nanomaterials. This study looks at the reproducibility using a relatively new, but rapidly adopted, technique, Nanoparticle Tracking Analysis (NTA) on a range of particle sizes and materials in several different media. It describes the protocol development and presents both the data and analysis of results obtained from 12 laboratories, mostly based in Europe, who are primarily QualityNano members. QualityNano is an EU FP7 funded Research Infrastructure that integrates 28 European analytical and experimental facilities in nanotechnology, medicine and natural sciences with the goal of developing and implementing best practice and quality in all aspects of nanosafety assessment. This study looks at both the development of the protocol and how this leads to highly reproducible results amongst participants. In this study, the parameter being measured is the modal particle size.