Toxicity of nanomaterials Sharifi, Shahriar; Behzadi, Shahed; Laurent, Sophie ...
Chemical Society reviews,
2012-Mar-21, Letnik:
41, Številka:
6
Journal Article
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Nanoscience has matured significantly during the last decade as it has transitioned from bench top science to applied technology. Presently, nanomaterials are used in a wide variety of commercial ...products such as electronic components, sports equipment, sun creams and biomedical applications. There are few studies of the long-term consequences of nanoparticles on human health, but governmental agencies, including the United States National Institute for Occupational Safety and Health and Japan's Ministry of Health, have recently raised the question of whether seemingly innocuous materials such as carbon-based nanotubes should be treated with the same caution afforded known carcinogens such as asbestos. Since nanomaterials are increasing a part of everyday consumer products, manufacturing processes, and medical products, it is imperative that both workers and end-users be protected from inhalation of potentially toxic NPs. It also suggests that NPs may need to be sequestered into products so that the NPs are not released into the atmosphere during the product's life or during recycling. Further, non-inhalation routes of NP absorption, including dermal and medical injectables, must be studied in order to understand possible toxic effects. Fewer studies to date have addressed whether the body can eventually eliminate nanomaterials to prevent particle build-up in tissues or organs. This
critical review
discusses the biophysicochemical properties of various nanomaterials with emphasis on currently available toxicology data and methodologies for evaluating nanoparticle toxicity (286 references).
This review discusses the biophysicochemical properties of various nanomaterials with emphasis on currently available toxicology data and methodologies for evaluating nanoparticle toxicity.
Nanotechnology provides a flexible platform for the development of effective therapeutic nanomaterials that can interact specifically with a target in a biological system and provoke a desired ...response. Of the nanomaterials studied, iron oxide nanoparticles have emerged as one of top candidates for cancer therapy. Their intrinsic superparamagnetism enables noninvasive magnetic resonance imaging (MRI), and their biodegradability is advantageous for in vivo applications. A therapeutic superparamagnetic iron oxide nanoparticle (SPION) typically consists of three primary components: an iron oxide nanoparticle core that serves as both a carrier for therapeutics and contrast agent for MRI, a coating on the iron oxide nanoparticle that promotes favorable interactions between the SPION and the biological system, and a therapeutic payload that performs the designated function in vivo. Often, the design may include a targeting ligand that recognizes the receptors over-expressed on the exterior surface of cancer cells. The body is a highly complex system that imposes multiple physiological and cellular barriers to foreign objects. Thus, the success of a therapeutic SPION largely relies on the design of the iron oxide core to ensure its detection in MRI and the coatings that allow the nanoparticles to bypass these barriers. Strategies to bypass the physiological barriers, such as liver, kidneys, and spleen, involve tuning the overall size and surface chemistry of the SPION to maximize blood half-life and facilitate the navigation in the body. Strategies to bypass cellular barriers include the use of targeting agents to maximize uptake of the SPION by cancer cells and the employment of materials that promote desired intracellular trafficking and enable controlled drug release. The payload can be genes, proteins, chemotherapy drugs, or a combination of these molecules. Each type of therapeutic molecule requires a specific coating design to maximize the loading and to achieve effective delivery and release. In this Account, we discuss the primary design parameters in developing therapeutic SPIONs with a focus on surface coating design to overcome the barriers imposed by the body’s defense system. We provide examples of how these design parameters have been implemented to produce SPIONs for specific therapeutic applications. Although there are still challenges to be addressed, SPIONs show great promise in the successful diagnosis and treatment of the most devastating cancers. Once the critical design parameters have been optimized, these nanoparticles, combined with imaging modalities, can serve as truly multifunctional theranostic agents that not only perform a therapeutic function but also provide instant clinical feedback, allowing the physician to adjust the treatment plan.
Cancer nanotheranostics aims to combine imaging and therapy of cancer through use of nanotechnology. The ability to engineer nanomaterials to interact with cancer cells at the molecular level can ...significantly improve the effectiveness and specificity of therapy to cancers that are currently difficult to treat. In particular, metastatic cancers, drug‐resistant cancers, and cancer stem cells impose the greatest therapeutic challenge for targeted therapy. Targeted therapy can be achieved with appropriately designed drug delivery vehicles such as nanoparticles, adult stem cells, or T cells in immunotherapy. In this article, we first review the different types of nanotheranostic particles and their use in imaging, followed by the biological barriers they must bypass to reach the target cancer cells, including the blood, liver, kidneys, spleen, and particularly the blood‐brain barrier. We then review how nanotheranostics can be used to improve targeted delivery and treatment of cancer cells. Finally, we discuss development of nanoparticles to overcome current limitations in cancer therapy.
Cancer nanotheranostics seeks to improve cancer treatment by combining therapy with imaging through nanotechnology. Researchers are developing next‐generation nanomedicines with multiple functionalities for bypassing biological barriers and targeted delivery of therapeutics to diseased cells in order to overcome current challenges in cancer therapy.
Nanoparticles for biomedical imaging Nune, Satish K; Gunda, Padmaja; Thallapally, Praveen K ...
Expert opinion on drug delivery,
11/1/2009, 2009-Nov, 2009-11-00, 20091101, Letnik:
6, Številka:
11
Journal Article
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Background: Synthetic nanoparticles are emerging as versatile tools in biomedical applications, particularly in the area of biomedical imaging. Nanoparticles 1 - 100 nm in diameter have dimensions ...comparable to biological functional units. Diverse surface chemistries, unique magnetic properties, tunable absorption and emission properties, and recent advances in the synthesis and engineering of various nanoparticles suggest their potential as probes for early detection of diseases such as cancer. Surface functionalization has expanded further the potential of nanoparticles as probes for molecular imaging. Objective: To summarize emerging research of nanoparticles for biomedical imaging with increased selectivity and reduced nonspecific uptake with increased spatial resolution containing stabilizers conjugated with targeting ligands. Methods: This review summarizes recent technological advances in the synthesis of various nanoparticle probes, and surveys methods to improve the targeting of nanoparticles for their application in biomedical imaging. Conclusion: Structural design of nanomaterials for biomedical imaging continues to expand and diversify. Synthetic methods have aimed to control the size and surface characteristics of nanoparticles to control distribution, half-life and elimination. Although molecular imaging applications using nanoparticles are advancing into clinical applications, challenges such as storage stability and long-term toxicology should continue to be addressed.
Purpose
To investigate influence of inflammation on metabolism and pharmacokinetics (PK) of midazolam (MDZ) and construct a semi-physiologically based pharmacokinetic (PBPK) model to predict PK in ...mice with inflammatory disease.
Methods
Glucose-6-phosphate isomerase (GPI)-mediated inflammation was used as a preclinical model of arthritis in DBA/1 mice. CYP3A substrate MDZ was selected to study changes in metabolism and PK during the inflammation. The semi-PBPK model was constructed using mouse physiological parameters, liver microsome metabolism, and healthy animal PK data. In addition, serum cytokine, and liver-CYP (cytochrome P450 enzymes) mRNA levels were examined.
Results
The
in vitro
metabolite formation rate was suppressed in liver microsomes prepared from the GPI-treated mice as compared to the healthy mice. Further, clearance of MDZ was reduced during inflammation as compared to the healthy group. Finally, the semi-PBPK model was used to predict PK of MDZ after GPI-mediated inflammation. IL-6 and TNF-α levels were elevated and liver-cyp3a11 mRNA was reduced after GPI treatment.
Conclusion
The semi-PBPK model successfully predicted PK parameters of MDZ in the disease state. The model may be applied to predict PK of other drugs under disease conditions using healthy animal PK and liver microsomal data as inputs.
A human-driven decline in global burned area Andela, N.; Morton, D. C.; Giglio, L. ...
Science (American Association for the Advancement of Science),
06/2017, Letnik:
356, Številka:
6345
Journal Article
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Fire is an essential Earth system process that alters ecosystem and atmospheric composition. Here we assessed long-term fire trends using multiple satellite data sets. We found that global burned ...area declined by 24.3 ± 8.8% over the past 18 years. The estimated decrease in burned area remained robust after adjusting for precipitation variability and was largest in savannas. Agricultural expansion and intensification were primary drivers of declining fire activity. Fewer and smaller fires reduced aerosol concentrations, modified vegetation structure, and increased the magnitude of the terrestrial carbon sink. Fire models were unable to reproduce the pattern and magnitude of observed declines, suggesting that they may overestimate fire emissions in future projections. Using economic and demographic variables, we developed a conceptual model for predicting fire in human-dominated landscapes.
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Compared to conventional treatments, gene therapy offers a variety of advantages for cancer treatment including high potency and specificity, low off-target toxicity, and delivery of ...multiple genes that concurrently target cancer tumorigenesis, recurrence, and drug resistance. In the past decades, gene therapy has undergone remarkable progress, and is now poised to become a first line therapy for cancer. Among various gene delivery systems, nanoparticles have attracted much attention because of their desirable characteristics including low toxicity profiles, well-controlled and high gene delivery efficiency, and multi-functionalities. This review provides an overview on gene therapeutics and gene delivery technologies, and highlight recent advances, challenges and insights into the design and the utility of nanoparticles in gene therapy for cancer treatment.
Rising atmospheric CO₂ will make Earth warmer, and many studies have inferred that this warming will cause droughts to become more widespread and severe. However, rising atmospheric CO₂ also modifies ...stomatal conductance and plant water use, processes that are often are overlooked in impact analysis. We find that plant physiological responses to CO₂ reduce predictions of future drought stress, and that this reduction is captured by using plant-centric rather than atmosphere-centric metrics from Earth system models (ESMs). The atmosphere-centric Palmer Drought Severity Index predicts future increases in drought stress for more than 70% of global land area. This area drops to 37% with the use of precipitation minus evapotranspiration (P-E), a measure that represents the water flux available to downstream ecosystems and humans. The two metrics yield consistent estimates of increasing stress in regions where precipitation decreases are more robust (southern North America, northeastern South America, and southern Europe). The metrics produce diverging estimates elsewhere, with P-E predicting decreasing stress across temperate Asia and central Africa. The differing sensitivity of drought metrics to radiative and physiological aspects of increasing CO₂ partly explains the divergent estimates of future drought reported in recent studies. Further, use of ESM output in offline models may double-count plant feedbacks on relative humidity and other surface variables, leading to overestimates of future stress. The use of drought metrics that account for the response of plant transpiration to changing CO₂, including direct use of P-E and soil moisture from ESMs, is needed to reduce uncertainties in future assessment.
Smartphone Spectrometers McGonigle, Andrew J S; Wilkes, Thomas C; Pering, Tom D ...
Sensors (Basel, Switzerland),
01/2018, Letnik:
18, Številka:
1
Journal Article
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Smartphones are playing an increasing role in the sciences, owing to the ubiquitous proliferation of these devices, their relatively low cost, increasing processing power and their suitability for ...integrated data acquisition and processing in a 'lab in a phone' capacity. There is furthermore the potential to deploy these units as nodes within Internet of Things architectures, enabling massive networked data capture. Hitherto, considerable attention has been focused on imaging applications of these devices. However, within just the last few years, another possibility has emerged: to use smartphones as a means of capturing spectra, mostly by coupling various classes of fore-optics to these units with data capture achieved using the smartphone camera. These highly novel approaches have the potential to become widely adopted across a broad range of scientific e.g., biomedical, chemical and agricultural application areas. In this review, we detail the exciting recent development of smartphone spectrometer hardware, in addition to covering applications to which these units have been deployed, hitherto. The paper also points forward to the potentially highly influential impacts that such units could have on the sciences in the coming decades.
Magnetite nanoparticles for medical MR imaging Stephen, Zachary R.; Kievit, Forrest M.; Zhang, Miqin
Materials today (Kidlington, England),
07/2011, Letnik:
14, Številka:
7-8
Journal Article
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Nanotechnology has given scientists new tools for the development of advanced materials for the detection and diagnosis of disease. In particular, superparamagnetic iron oxide nanoparticles (SPIONs) ...have been extensively investigated as novel magnetic resonance imaging (MRI) contrast agents due to a combination of favorable superparamagnetic properties, biodegradability, and surface properties. This review discusses the basics of MR imaging, the origin of SPION's unique magnetic properties, recent developments in MRI acquisition methods for detection of SPIONs, synthesis and post-synthesis processes that improve SPION's imaging characteristics, and the outlook of the translational potential of SPIONs.
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