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Identification of Microplastics and Nanoplastics and Associated Analytical Challenges
Published in Hyunjung Kim, Microplastics, 2023
Dimzon et al. (2012) and Weidner and Trimpin (2010) examined the suitability of MALDI–TOF MS to detect various polymers with different sample preparation techniques. A limitation is given by the fact that different polymers require adapted cationizing agents for their ionization. However, the technique cannot supply the size, shape, and distribution of the microplastics and nanoplastics directly at present. MALDI–TOF spectra can provide morphological information such as the size and shape of particles through imaging techniques. Rivas et al. (2016) used MALDI–TOF mass spectrometry imaging to examine modifications of polymer surfaces during degradation. Samples were placed on indium-tin-oxide glass slides, and the matrix was sublimated and deposited into the target through a special coating chamber. This technique enables the determination of spatial changes of a polymer surface.
Theranostics: A New Holistic Approach in Nanomedicine
Published in D. Sakthi Kumar, Aswathy Ravindran Girija, Bionanotechnology in Cancer, 2023
Ankit Rochani, Sreejith Raveendran
The development of nanotheranostics mostly focuses on (i) efficient synthesis strategy (for new particle designs with therapeutic potential), and (ii) high-resolution imaging technique. In terms of synthesis, self-assembly has been the primary focus of most medicinal NP synthesis; for instance, self-assembly of polymeric-drug or fluorophore-conjugated system or the polymer coating of metallic or organo-metallic NPs for developing theranostic nanoparticles (TNPs). These NPs can be seen using imaging technologies like photoacoustic imaging (PAI), fluorescence imaging, magnetic resonance imaging (MRI), electron microscopy, and mass spectrometry imaging [12]. In particular, mass spectrometry imaging for NPs is relatively new and still under development [13], whereas other techniques have been validated and used in multiple preclinical and clinical investigations. Further, some studies have also suggested that molecular theranostics is also one of the emerging technologies, wherein researchers have developed fluorescence tagged aptamers or antibodies for the targeted therapies along with diagnostic capabilities [14, 15]. This knowledge has been extensively explored for developing target-specific nanotheranostic therapies.
Pharmacokinetics, Biodistribution, and Therapeutic Applications of Recently Developed siRNA and DNA Repair Genes Recurrence
Published in Loutfy H. Madkour, Nanoparticle-Based Drug Delivery in Cancer Treatment, 2022
Swart et al. used 3H-labeled siRNA to study BD of siRNA delivered with LNPs [110]. BD of siRNA/LNPs was estimated by quantitative whole-body autoradiography (QWBA) and matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) techniques, where QWBA measured the radiolabeled siRNA and MALDI-MSI measured the cationic lipid component. Following a single IV administration, animals treated with free siRNA showed the highest radioactivity in kidney and salivary gland, and the radioactivity in different organs declined in a similar pattern (Figure 12.7a) [108]. In contrast, animals treated with siRNA/LNPs showed the highest radioactivity of siRNA in the spleen and liver, which lasted over 168 h, whereas the blood level radioactivity gradually decreased (Figure 12.7b) [110]. MALDI-MSI found similar distribution of the cationic lipid as that of siRNA radioactivity, suggesting that siRNA and lipid circulated together and co-distributed as a LNP complex (Figure 12.7c and d).
In situ characterizations for EPS-involved microprocesses in biological wastewater treatment systems
Published in Critical Reviews in Environmental Science and Technology, 2019
Peng Zhang, Bo Feng, You-Peng Chen, You-Zhi Dai, Jin-Song Guo
The microbe species, structure and components of microbial aggregates are heterogeneous, and the EPS-involved microprocesses are also in homogeneity. Chemical imaging modalities, such as mass spectrometry imaging, confocal scanning laser microscopy and Raman imaging, can map the two-dimensional and three-dimensional distributions of target substances, and can visualize the spatial function of EPS in microbial aggregates (Ding et al., 2016; Louvet et al., 2017). Furthermore, single-cell imaging can be used to visualize EPS production, EPS distribution, and analyze EPS-involved chemical and biochemical processes in the extracellular microenvironment, thus minimizing the extraneous factor disturbance and obtaining a precise result. Mass spectrometry imaging is a powerful and promised technique for mapping the distributions of the EPS and substrate with subcellular resolution (Ding et al., 2016). The development of this technique can produce insights into monitoring of the uptake of microbes to the substrate via EPS, the adhesion of EPS to a surface and quantifying the secretion of EPS under environmental stress at a single-cell scale.
Mass spectrometry imaging reveals the spatial distribution of essential lipids in Daphnia magna – potential implications for trophic ecology
Published in Inland Waters, 2023
Matthias Pilecky, Patrick Fink, Samuel K. Kämmer, Matthias Schott, Martin Zehl, Martin J. Kainz
Detailed understanding of the physiological mechanisms driving specific dietary PUFA demands requires knowledge of tissue-specific lipid composition and metabolism. To date, analyzing lipids at the tissue-specific levels on aquatic invertebrates has been hampered by their relatively small body size, which makes tissue-specific dissection difficult to perform in the quantities needed. In this study, we applied matrix-assisted laser desorption/ionization–mass spectrometry imaging (MALDI-MSI) to investigate the tissue-specific variability in lipid composition of D. magna at a small spatial scale (∼25 μm). In contrast to optical methods that provide spatial information about the absorption of electromagnetic waves with different wavelengths, MALDI-MSI displays the relative distribution of different mass to charge ratios, corresponding to the masses of ions generated from different compounds, across a sample with a spatial resolution of ∼5–50 µm (Sparvero et al. 2012, Thomas et al. 2012, Ràfols et al. 2018). This method has already been used to identify different organ-specific phospholipid species containing LC-PUFAs in terrestrial invertebrates (Bhandari et al. 2015) as well as in individual layers of the human retina (Zemski Berry et al. 2014). Because experiments in many species have shown EPA and DHA to contribute to behavioral and cognitive traits, we tested the hypothesis that lipids containing EPA are selectively retained in neuronal structures of D. magna, as shown experimentally for other larger species (Pilecky et al. 2021). Introducing this method to aquatic ecology has the potential to increase our understanding about lipid metabolism of physiologically important FAs, particularly PUFAs, within zooplankton and will further provide new insights into tissue-specific retention of essential lipids in small-sized organisms across the planktonic food web.