Author
John J. Schlager
Other affiliations: Wright-Patterson Air Force Base, United States Department of the Army, Cancer Research UK ...read more
Bio: John J. Schlager is an academic researcher from Air Force Research Laboratory. The author has contributed to research in topics: Silver nanoparticle & Nanotoxicology. The author has an hindex of 41, co-authored 74 publications receiving 13262 citations. Previous affiliations of John J. Schlager include Wright-Patterson Air Force Base & United States Department of the Army.
Papers published on a yearly basis
Papers
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TL;DR: The microscopic studies demonstrated that nanoparticle-exposed cells at higher doses became abnormal in size, displaying cellular shrinkage, and an acquisition of an irregular shape, which suggested that cytotoxicity of Ag (15, 100 nm) in liver cells is likely to be mediated through oxidative stress.
1,949 citations
TL;DR: A size-dependent toxicity was produced by silver nanoparticles, and one predominant mechanism of toxicity was found to be largely mediated through oxidative stress.
Abstract: The rapid advancement of nanotechnology has created a vast array of engineered nanomaterials (ENMs) which have unique physical (size, shape, crystallinity, surface charge) and chemical (surface coating, elemental composition and solubility) attributes. These physicochemical properties of ENMs can produce chemical conditions to induce a pro-oxidant environment in the cells, causing an imbalanced cellular energy system dependent on redox potential and thereby leading to adverse biological consequences, ranging from the initiation of inflammatory pathways through to cell death. The present study was designed to evaluate size-dependent cellular interactions of known biologically active silver nanoparticles (NPs, Ag-15nm, Ag-30nm, and Ag-55nm). Alveolar macrophages provide the first defense and were studied for their potential role in initiating oxidative stress. Cell exposure produced morphologically abnormal sizes and adherence characteristics with significant NP uptake at high doses after 24 h. Toxicity eva...
1,640 citations
TL;DR: The suitability of a mouse spermatogonial stem cell line as a model to assess nanotoxicity in the male germline in vitro is assessed and it is suggested that this cell line provides a valuable model with which to assess the cytotoxicity of nanoparticles in the germ line in vitro.
1,196 citations
TL;DR: It is demonstrated that many metal and metal oxide nanomaterials agglomerate in solution and that depending upon the solution particleagglomeration is either agitated or mitigated.
967 citations
TL;DR: It is found that the ability of biguanides to inhibit mTORC1 activation and signaling is, instead, dependent on the Rag GTPases.
769 citations
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TL;DR: Probing the various interfaces of nanoparticle/biological interfaces allows the development of predictive relationships between structure and activity that are determined by nanomaterial properties such as size, shape, surface chemistry, roughness and surface coatings.
Abstract: Rapid growth in nanotechnology is increasing the likelihood of engineered nanomaterials coming into contact with humans and the environment. Nanoparticles interacting with proteins, membranes, cells, DNA and organelles establish a series of nanoparticle/biological interfaces that depend on colloidal forces as well as dynamic biophysicochemical interactions. These interactions lead to the formation of protein coronas, particle wrapping, intracellular uptake and biocatalytic processes that could have biocompatible or bioadverse outcomes. For their part, the biomolecules may induce phase transformations, free energy releases, restructuring and dissolution at the nanomaterial surface. Probing these various interfaces allows the development of predictive relationships between structure and activity that are determined by nanomaterial properties such as size, shape, surface chemistry, roughness and surface coatings. This knowledge is important from the perspective of safe use of nanomaterials.
6,075 citations
TL;DR: Silver nanoparticles have emerged up with diverse medical applications ranging from silver based dressings, silver coated medicinal devices, such as nanogels, nanolotions, etc, due to its capability of modulating metals into their nanosize.
5,014 citations
TL;DR: Recent advances in understanding of mTOR function, regulation, and importance in mammalian physiology are reviewed and how the mTOR signaling network contributes to human disease is highlighted.
4,719 citations
TL;DR: A possible mechanism of toxicity is proposed which involves disruption of the mitochondrial respiratory chain by Ag-np leading to production of ROS and interruption of ATP synthesis, which in turn cause DNA damage.
Abstract: Silver nanoparticles (Ag-np) are being used increasingly in wound dressings, catheters, and various household products due to their antimicrobial activity. The toxicity of starch-coated silver nanoparticles was studied using normal human lung fibroblast cells (IMR-90) and human glioblastoma cells (U251). The toxicity was evaluated using changes in cell morphology, cell viability, metabolic activity, and oxidative stress. Ag-np reduced ATP content of the cell caused damage to mitochondria and increased production of reactive oxygen species (ROS) in a dose-dependent manner. DNA damage, as measured by single cell gel electrophoresis (SCGE) and cytokinesis blocked micronucleus assay (CBMN), was also dose-dependent and more prominent in the cancer cells. The nanoparticle treatment caused cell cycle arrest in G2/M phase possibly due to repair of damaged DNA. Annexin-V propidium iodide (PI) staining showed no massive apoptosis or necrosis. The transmission electron microscopic (TEM) analysis indicated the presen...
3,261 citations
TL;DR: The rationales for these studies, the current progress in studies of the interactions of nanomaterials with biological systems, and a perspective on the long-term implications of these findings are provided.
Abstract: An understanding of the interactions between nanoparticles and biological systems is of significant interest. Studies aimed at correlating the properties of nanomaterials such as size, shape, chemical functionality, surface charge, and composition with biomolecular signaling, biological kinetics, transportation, and toxicity in both cell culture and animal experiments are under way. These fundamental studies will provide a foundation for engineering the next generation of nanoscale devices. Here, we provide rationales for these studies, review the current progress in studies of the interactions of nanomaterials with biological systems, and provide a perspective on the long-term implications of these findings.
2,969 citations