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Polymers Dec 2023Microplastic pollution is a growing public concern as these particles are ubiquitous in various environments and can fragment into smaller nanoplastics. Another...
Microplastic pollution is a growing public concern as these particles are ubiquitous in various environments and can fragment into smaller nanoplastics. Another environmental concern arises from widely used engineered nanoparticles. Despite the increasing abundance of these nano-sized pollutants and the possibility of interactions with organisms at the sub cellular level, with many risks still being unknown, there are only a few publications on this topic due to the lack of reliable techniques for nanoparticle characterization. We propose a multi-technique approach for the characterization of nanoparticles down to the 10 nm level using standard micro-Raman spectroscopy combined with standard atomic force microscopy. We successfully obtained single-particle spectra from 25 nm sized polystyrene and 9 nm sized TiO nanoparticles with corresponding mass limits of detection of 8.6 ag (attogram) and 1.6 ag, respectively, thus demonstrating the possibility of achieving an unambiguous Raman signal from a single, small nanoparticle with a resolution comparable to more complex and time-consuming technologies such as Tip-Enhanced Raman Spectroscopy and Photo-Induced Force Microscopy.
PubMed: 38139897
DOI: 10.3390/polym15244644 -
Frontiers in Cellular and Infection... 2023Periprosthetic joint infection (PJI) can be diagnosed to characterize the microorganisms constituting a biofilm, which is an essential procedure for proper treatment....
Periprosthetic joint infection (PJI) can be diagnosed to characterize the microorganisms constituting a biofilm, which is an essential procedure for proper treatment. The gold standard method for detecting and identifying the causative microorganism is culture of microorganisms from patients-derived sample.; however, this method takes a long time and has low sensitivity. To compensate for these limitations, identification methods based on real-time PCR (RT-PCR) have been widely used. However, RT-PCR also has limitations, including low sensitivity and the requirement of a standard curve for quantification. Therefore, to prevent significant proliferation of pathogenic bacteria, it is important to detect a limited number of infectious bacteria during early stages of PJI. In the present study, we developed droplet digital PCR-based detection of bacterial pathogens in PJI. And we evaluated the analytical performance of the assay using a model plasmid, based on the 16S ribosomal DNA sequence of target bacteria commonly found in PJI. We also prepared genomic DNA extracted from , , and to test whether ddPCR provides better sensitivity and quantification of the target sequences. ddPCR detected 400 attograms of target DNA, which was more than 10 times less than that detected by real-time PCR using synthesized plasmid. In addition, ddPCR detected target regions from genomic DNA of 50 femtograms for , 70 femtograms for , and 90 femtograms for . The results indicate that ddPCR has the potential to decrease the microbial detection limit and provide precise detection, signifying its effectiveness for early PJI.
Topics: Humans; Escherichia coli; Staphylococcus aureus; Plasmids; Bacteria; Arthritis, Infectious; Real-Time Polymerase Chain Reaction; DNA, Ribosomal
PubMed: 38029245
DOI: 10.3389/fcimb.2023.1301446 -
Investigative Radiology May 2024Gadolinium-based contrast agents (GBCAs) are routinely used in magnetic resonance imaging (MRI) examinations. However, there is limited knowledge about the interaction...
OBJECTIVES
Gadolinium-based contrast agents (GBCAs) are routinely used in magnetic resonance imaging (MRI) examinations. However, there is limited knowledge about the interaction with and distribution of the drug in human cells. This lack of knowledge is surprising, given that the first interaction of the drug occurs with blood cells. Moreover, recent studies reported gadolinium (Gd) deposition within organs, such as the brain. Hence, this study is aiming to determine the uptake of GBCA in blood cells of patients undergoing contrast-enhanced MRI (ce-MRI) examination.
MATERIALS AND METHODS
Human blood was exposed to either gadoterate meglumine (Gd-DOTA) or Eu-DOTA in vitro or was collected from patients undergoing ce-MRI with Gd-DOTA. Uptake of contrast agents (CAs) by blood cells was quantified by Gd measurements using single-cell inductively coupled plasma mass spectrometry (SC-ICP-MS) or, to confirm Gd-DOTA uptake, by a complementary method using Eu-DOTA by time-resolved fluorescence spectroscopy, respectively.
RESULTS
Uptake of Gd-DOTA or Eu-DOTA into white blood cells (WBCs) ex vivo was detectable by SC-ICP-MS and time-resolved fluorescence spectroscopy. The intracellular concentrations were estimated to be in the range of 1-3 μM. However, no CA uptake into erythrocytes was detected with either method. In total, 42 patients between 30 and 84 years old (24 men, 18 women) were enrolled. White blood cells' uptake of Gd was measured by SC-ICP-MS. Isolated WBCs from patients who underwent ce-MRI examination showed substantial Gd uptake; however, the studied patient group showed an inhomogeneous distribution of Gd uptake. Measurements immediately after MRI examination indicated 21-444 attogram/WBC, corresponding to an intracellular Gd concentration in the range from 0.2 to 5.5 μM.
CONCLUSIONS
This study confirms the ex vivo uptake of GBCA by WBCs and provides the first evidence that GBCA is indeed taken up by WBCs in vivo by patients undergoing ce-MRI examination. However, the observed Gd uptake in WBCs does not follow a log-normal distribution commonly observed in the fields of environmental studies, biology, and medicine. Whether cellular uptake of GBCA is linked to the observed deposition of Gd remains unclear. Therefore, studying the interaction between GBCA and human cells may clarify crucial questions about the effects of Gd on patients after MRI examinations.
Topics: Male; Animals; Humans; Female; Adult; Middle Aged; Aged; Aged, 80 and over; Contrast Media; Gadolinium; Gadolinium DTPA; Models, Animal; Organometallic Compounds; Erythrocytes; Brain; Magnetic Resonance Imaging; Heterocyclic Compounds
PubMed: 37824716
DOI: 10.1097/RLI.0000000000001029 -
Analytical Chemistry Oct 2023Owing to the exceedingly small mass involved, complete elemental characterization of single nanoparticles demands a highly precise control of signal background and noise...
Owing to the exceedingly small mass involved, complete elemental characterization of single nanoparticles demands a highly precise control of signal background and noise sources. LIBS has demonstrated remarkable merits for this task, providing a unique tool for the multielemental analysis of particles on the attogram-picogram mass scale. Despite this outstanding sensitivity, the air plasma acting as a heat source for particle dissociation and excitation is a meddling agent, often limiting the acquisition of an accurate sample signature. Although thermal effects associated with ultrashort laser pulses are known to be reduced when compared to the widely used nanosecond pulse duration regime, attempts to improve nanoinspection performance using ultrafast excitation have remained largely unexplored. Herein, picosecond laser pulses are used as a plasma excitation source for the elemental characterization of single nanoparticles isolated within optical traps in air at atmospheric pressure. Results for picosecond excitation of copper particles lead to a mass detection limit of 27 attogram, equivalent to single particles 18 nm in diameter. Temporally and wavelength-resolved plasma imaging reveals unique traits in the mechanism of atomic excitation in the picosecond regime, leading to a deeper understanding of the interactions occurring in single nanoparticle spectroscopy.
PubMed: 37729543
DOI: 10.1021/acs.analchem.3c01376 -
IScience Feb 2023The inherent properties of 2D materials-light mass, high out-of-plane flexibility, and large surface area-promise great potential for precise and accurate nanomechanical...
The inherent properties of 2D materials-light mass, high out-of-plane flexibility, and large surface area-promise great potential for precise and accurate nanomechanical mass sensing, but their application is often hampered by surface contamination. Here we demonstrate a tri-layer graphene nanomechanical resonant mass sensor with sub-attogram resolution at room temperature, fabricated by a bottom-up process. We found that Joule-heating is effective in cleaning the graphene membrane surface, which results in a large improvement in the stability of the resonance frequency. We characterized the sensor by depositing Cr metal using a stencil mask and found a mass-resolution that is sufficient to weigh very small particles, like large proteins and protein complexes, with potential applications in the fields of nanobiology and medicine.
PubMed: 36718371
DOI: 10.1016/j.isci.2023.105958 -
Communications Biology Oct 2022The analysis of trace amounts of proteins based on immunoassays and other methods is essential for the early diagnosis of various diseases such as cancer, dementia, and...
The analysis of trace amounts of proteins based on immunoassays and other methods is essential for the early diagnosis of various diseases such as cancer, dementia, and microbial infections. Here, we propose a light-induced acceleration of antigen-antibody reaction of attogram-level proteins at the solid-liquid interface by tuning the laser irradiation area comparable to the microscale confinement geometry for enhancing the collisional probability of target molecules and probe particles with optical force and fluidic pressure. This principle was applied to achieve a 10-fold higher sensitivity and ultrafast specific detection in comparison with conventional protein detection methods (a few hours) by omitting any pretreatment procedures; 47-750 ag of target proteins were detected in 300 nL of sample after 3 minutes of laser irradiation. Our findings can promote the development of proteomics and innovative platforms for high-throughput bio-analyses under the control of a variety of biochemical reactions.
Topics: Antigen-Antibody Reactions; Early Detection of Cancer; Immunoassay; Proteins
PubMed: 36203087
DOI: 10.1038/s42003-022-03946-0 -
Microsystems & Nanoengineering 2022The use of nanoparticles has been growing in various industrial fields, and concerns about their effects on health and the environment have been increasing. Hence,...
The use of nanoparticles has been growing in various industrial fields, and concerns about their effects on health and the environment have been increasing. Hence, characterization techniques for nanoparticles are essential. Here, we present a silicon dioxide microfabricated suspended microchannel resonator (SMR) to measure the mass and concentration of nanoparticles in a liquid as they flow. We measured the mass detection limits of the device using laser Doppler vibrometry. This limit reached a minimum of 377 ag that correspond to a 34 nm diameter gold nanoparticle or a 243 nm diameter polystyrene particle, when sampled every 30 ms. We compared the fundamental limits of the measured data with an ideal noiseless measurement of the SMR. Finally, we measured the buoyant mass of gold nanoparticles in real-time as they flowed through the SMR.
PubMed: 36051745
DOI: 10.1038/s41378-022-00425-8 -
Frontiers in Molecular Biosciences 2022Thrips cause considerable economic losses to a wide range of food, feed, and forest crops. They also transmit several plant viruses. Being cryptic, it is often difficult...
Thrips cause considerable economic losses to a wide range of food, feed, and forest crops. They also transmit several plant viruses. Being cryptic, it is often difficult to distinguish thrips species in crops and large consignments by conventional methods. Melon thrips ( Karny, Thysanoptera: Thripidae) is an invasive insect pest of vegetables, legumes, and ornamentals besides being vector to several viruses. It poses a threat to domestic and international plant biosecurity and can invade and establish in new areas. Here, we report a polymerase spiral reaction (PSR)-based isothermal assay for rapid, sensitive, specific, low-cost, and on-site detection of . To the best of our knowledge, this is the first application of PSR in the identification of any insect species. A primer pair designed based on 3'-polymorphism of mtCOIII region can specifically identify without any cross-reactivity with predominant thrips species. The assay uses crude lysate of a single thrips saving time and reagents involved in nucleic acid extraction. The presence of is visualized by the appearance of bright fluorescence under ultraviolet light or a change in reaction color thus avoiding gel electrophoresis steps. The entire process can be completed in 70 min on-site using only an ordinary water bath. The assay is sensitive to detecting as little as 50 attograms of template. The assay was validated with known thrips specimens and found to be efficient in diagnosing under natural conditions. The described method will be useful for non-expert personnel to detect an early infestation, accidental introduction to a new area, restrict the spread of diseases and formulate appropriate management strategies.
PubMed: 35586189
DOI: 10.3389/fmolb.2022.853339 -
Frontiers in Immunology 2021Engineered gold nanoparticles (AuNPs) find application in several fields related to human activities (, food and cosmetic industry or water purification) including...
Engineered gold nanoparticles (AuNPs) find application in several fields related to human activities (, food and cosmetic industry or water purification) including medicine, where they are employed for diagnosis, drug delivery and cancer therapy. As for any material/reagent for human use, the safety of AuNPs needs accurate evaluation. AuNPs are prone to contamination by bacterial endotoxin (lipopolysaccharide, LPS), a potent elicitor of inflammatory responses in mammals. It is therefore important, when assessing AuNP immunosafety and immune-related effects, to discriminate between inflammatory effects intrinsic to the NPs from those caused by an undeliberate and undetected LPS contamination. Detection of LPS contamination in AuNP preparations poses different problems when using the current LPS detection assays, given the general interference of NPs, similar to other particulate agents, with the assay reagents and endpoints. This leads to time-consuming search for optimal assay conditions for every NP batch, with unpredictable results, and to the use in parallel of different assays, each with its weaknesses and unpredictability. Thus, the development of highly sensitive, quantitative and accurate assays able to detect of LPS on AuNPs is very important, in view of their medical applications. Surface-enhanced Raman spectroscopy (SERS) is a label-free, sensitive, chemical-specific, nondestructive and fast technique that can be used to directly obtain molecular fingerprint information and a quantitative analysis of LPS adsorbed on AuNPs. Within this study, we describe the use of SERS for the label-free identification and quantitative evaluation - down to few attograms - of the LPS adsorbed on the surface of 50 nm AuNPs. We thus propose SERS as an efficient tool to detect LPS on the AuNP surface, and as the basis for the development of a new sensitive and specific LPS-detection sensor based on the use of AuNPs and SERS.
Topics: Biosensing Techniques; Gold; Humans; Lipopolysaccharides; Metal Nanoparticles; Spectrum Analysis, Raman; Surface Properties
PubMed: 34691081
DOI: 10.3389/fimmu.2021.758410 -
Science Advances Oct 2021Actinium-based therapies could revolutionize cancer medicine but remain tantalizing due to the difficulties in studying and limited knowledge of Ac chemistry. Current...
Actinium-based therapies could revolutionize cancer medicine but remain tantalizing due to the difficulties in studying and limited knowledge of Ac chemistry. Current efforts focus on small synthetic chelators, limiting radioisotope complexation and purification efficiencies. Here, we demonstrate a straightforward strategy to purify medically relevant radiometals, actinium(III) and yttrium(III), and probe their chemistry, using the recently discovered protein, lanmodulin. The stoichiometry, solution behavior, and formation constant of the Ac-lanmodulin complex and its Y/Y/La analogs were experimentally determined, representing the first actinium-protein and strongest actinide(III)-protein complex (sub-picomolar ) to be characterized. Lanmodulin’s unparalleled properties enable the facile purification recovery of radiometals, even in the presence of >10 equivalents of competing ions and at ultratrace levels: down to 2 femtograms Y and 40 attograms Ac. The lanmodulin-based approach charts a new course to study elusive isotopes and develop versatile chelating platforms for medical radiometals, both for high-value separations and potential in vivo applications.
PubMed: 34669462
DOI: 10.1126/sciadv.abk0273