Use Of Fluorescent Nanoparticles Research Articles

Sustainable fluorescent dye-faujasite zeolite systems as tools for cancer bioimaging

The use of fluorescent nanoparticles for biological and medical applications has attracted great attention due to their several advantages compared to conventional fluorescent dyes. However, there is also a need for sustainable and versatile alternatives, alongside the streamlining of complex synthesis or preparations. In this work, we study the potential of the faujasite zeolite structure to encapsulate dye molecules and be applied as a bioimaging agent for cancer cells. The commercial zeolites NaY, USY, and NaX were used to encapsulate Rhodamine B (RhB) or Fluorescein (F) dyes, which present a similar tetracycle core structure. Different characterization techniques confirmed the encapsulation of the dyes and their stability. The photophysical characterization of the encapsulated RhB and F dyes was also elucidated by UV–visible and fluorescence spectroscopy. Biocompatibility was tested in different cancer cell lines and confocal laser scanning electron microscopy (CLSM) was used to track the fluorescent dye-containing zeolites. Remarkably, the dye-containing zeolite RhB@USY showed interesting multiluminescent labeling properties that make it a suitable agent for bioimaging applications. The economic feasibility of the developed fluorescent dye-zeolite probes was also examined through a detailed cost analysis, which further highlights their commercial potential.

Hypoxic-Sensitive Nano-Carriers for Anti-Neoplastic Drug Delivery: New Perspectives

Since the inception of Anti-neoplastic drug delivery in the 1950s oncologists and researchers have revolutionized the field of diagnostics and treatment with novel therapeutic modalities. Tumor hypoxia remains the first and foremost factor contributing to a resistance in anti-neoplastic drugs, ionized radiation and chemotherapy by solid tumors. The laps in vasculature in solid tumors promulgates tumor resistance by inhibiting the hypoxia inducible factor (HIF) within the tumor. It is on this basis that the selectivity of hypoxic cells are datelined. Based on clinical studies it was revealed that hypoxia does not occur in healthy human tissue; thus, paving the way for the exploitation of hypoxia as an advantage in creating novel therapeutic methods of detection and treatment for solid tumors with an added advantage of nano-science. The biological application of nano-carriers is a fast developing area of nano-science that is expected to realize new and innovative possibilities in the diagnosis and treatment of human cancers. Cancer diagnostics using nano-carriers entails the use of fluorescent nanoparticles for a multiplex of simultaneous profiling of tumor bio-markers. These fluorescent probes are also used for detection of multiple RNA matrices and genes within in-situ hybridization. It is expected that in the very near future, the application of conjugated nanoparticles in anti-neoplastic tumor detection and drug delivery will enable oncologists and scientists to pinpoint and identify cancer-related proteins on tumor surfaces, providing a new method of analysis; thus, creating personalized treatment methods for individual tumors. Nano-carriers possess an extraordinary possibility as contrast agents for cancer cell detection in vivo, and for monitoring the response to treatment of select cancers. Keywords: Nano-Medicine, Hypoxia, Solid Tumors, HIF factor. DOI: 10.7176/JHMN/102-04 Publication date: October 31 st 2022

Fluorescent nanoparticles as tools in ecology and physiology.

Fluorescent nanoparticles (FNPs) have been widely used in chemistry and medicine for decades, but their employment in biology is relatively recent. Past reviews on FNPs have focused on chemical, physical or medical uses, making the extrapolation to biological applications difficult. In biology, FNPs have largely been used for biosensing and molecular tracking. However, concerns over toxicity in early types of FNPs, such as cadmium-containing quantum dots (QDs), may have prevented wide adoption. Recent developments, especially in non-Cd-containing FNPs, have alleviated toxicity problems, facilitating the use of FNPs for addressing ecological, physiological and molecule-level processes in biological research. Standardised protocols from synthesis to application and interdisciplinary approaches are critical for establishing FNPs in the biologists' tool kit. Here, we present an introduction to FNPs, summarise their use in biological applications, and discuss technical issues such as data reliability and biocompatibility. We assess whether biological research can benefit from FNPs and suggest ways in which FNPs can be applied to answer questions in biology. We conclude that FNPs have a great potential for studying various biological processes, especially tracking, sensing and imaging in physiology and ecology.

Recent advances in the use of fluorescent nanoparticles for bioimaging.

Rapid and recent progress in fluorescence microscopic techniques has allowed for routine discovery and viewing of biological structures and processes in unprecedented spatiotemporal resolution. In these imaging techniques, fluorescent nanoparticles (NPs) play important roles in the improvement of reporting systems. A short overview of recently developed fluorescent NPs used for advanced in vivo imaging will be discussed in this mini-review. The discussion begins with the contribution of fluorescence imaging in exploring the fate of NPs in biological systems. NP applications for in vivo imaging, including cell labeling, multimodal imaging and theranostic agents, are then discussed. Finally, despite all of the advancements in bioimaging, some unsolved challenges will be briefly discussed concerning future research directions.

Fluorescent Nanoparticles for Noninvasive Stem Cell Tracking in Regenerative Medicine.

Stem cell-based therapies have emerged as promising platforms with the potential to treat serious diseases that are incurable by traditional medical approaches. To optimize the overall outcomes, it is important to understand the fate of transplanted stem cells (e.g., localization, migration, engraftment, survival, proliferation and differentiation). Fluorescent nanoparticles with good photostability and minimal perturbation of cell functions hold great promise for distinguishing transplanted stem cells from host tissues with high resolution, showing advantages over traditional histological methods. This review aims to summarize the recent advances in the use of fluorescent nanoparticles for the direct labelling of stem cells and the applications of such nanoparticles in stem cell tracking. The relevant fluorescent nanoparticles, including quantum dots, organic fluorogen-doped nanoparticles, fluorescent nanodiamonds, and upconversion nanoparticles are discussed. The advantages and limitations of the currently available fluorescent trackers are summarized, and perspectives on new research opportunities are discussed.

Fluorescent Chemosensor for Quantitation of Multiple Atmospheric Gases

Recently, the sensing and monitoring of gases from ambient as well as industrial sources has gained a great importance in order to ensure occupational hygiene, public health, and societal welfare. The development of new technologies for visualizing and detecting gases at trace levels is imperative for various applications. There exist several established traditional methods to detect different gases. In this article, we review the latest trends in the area of fluorescence sensing of gas molecules, which is a high sensitivity technique with minimum or negligible interferences. The gas sensors fabricated with the use of fluorescent nanoparticles as detecting elements possess special feature, like high surface-to-volume ratios, ultra sensitivity, enhanced selectivity, cost effectiveness, and fast response. The inherent properties of the related systems, e.g. a large fluorescence lifetime, nanoscale particle size and a tunable zeta potential, make it possible to devise fluorescent sensors with an attractive pathway of fluorescence ‘off–on’. Several fluorimetric methods are known to detect specific gases from the atmospheric gaseous samples with satisfactory detection results. Modern fluorescent gas sensors are did not cause interference from the co-pollutants thus making the fluorimetric sensing process to be quantitative as well as specific.

Use of fluorescent nanoparticles to investigate nutrient acquisition by developing Eimeria maxima macrogametocytes.

The enteric disease coccidiosis, caused by the unicellular parasite Eimeria, is a major and reoccurring problem for the poultry industry. While the molecular machinery driving host cell invasion and oocyst wall formation has been well documented in Eimeria, relatively little is known about the host cell modifications which lead to acquisition of nutrients and parasite growth. In order to understand the mechanism(s) by which nutrients are acquired by developing intracellular gametocytes and oocysts, we have performed uptake experiments using polystyrene nanoparticles (NPs) of 40 nm and 100 nm in size, as model NPs typical of organic macromolecules. Cytochalasin D and nocodazole were used to inhibit, respectively, the polymerization of the actin and microtubules. The results indicated that NPs entered the parasite at all stages of macrogametocyte development and early oocyst maturation via an active energy dependent process. Interestingly, the smaller NPs were found throughout the parasite cytoplasm, while the larger NPs were mainly localised to the lumen of large type 1 wall forming body organelles. NP uptake was reduced after microfilament disruption and treatment with nocodazole. These observations suggest that E. maxima parasites utilize at least 2 or more uptake pathways to internalize exogenous material during the sexual stages of development.

A pH dependence study of CdTe quantum dots fluorescence quantum yields using eclipsing thermal lens spectroscopy

In this study we evaluated the absolute fluorescence quantum yield (Φ) of hydrophilic CdTe QDs in function of different pHs, modified from the alkaline to acid, by using two different chemicals compounds, the mercaptosuccinic acid (MSA-the stabilizing agent of the QDs synthesis) or hydrochloric acid (HCl). The pH control of QDs suspensions is essential for the use of fluorescent nanoparticles in biological systems. We used the eclipsing thermal lens spectroscopy technique to determine the absolute fluorescence quantum yield values. The results showed variations on the Φ values as a function of the pH, which allowed a better understanding of QDs emission characteristics, establishing parameters for their use in biomedical applications such as optical images of biological systems, immunoassays, flow cytometry, biosensors and others.

Immunospot assay based on fluorescent nanoparticles for Dengue fever detection

Dengue fever is one of the most neglected tropical diseases and of highest international public health importance, with 50 million cases worldwide every year. Early detection can decrease mortality rates from more than 20% to less than 1% and the relevant early diagnosis analyte is the viral non-structural glycoprotein, NS1. Currently, enzyme linked immunosorbent assay (ELISA) is the method of choice to detect NS1. However, this is a time consuming method, requiring 3–5h, and it is the bottleneck for routine of clinical analysis laboratory in epidemic periods, when hundreds of samples should be tested. Here we describe an easy method combining principles of fluorophore linked immunosorbent assay (FLISA) and enzyme linked immunospotting (ELISPOT). For detection, we used mouse anti-NS1 IgG labeled with fluorescent nanoparticles. The presented procedure needs only 4μL of serum samples and requires 45–60min. The detection limit, 5.2ng/mL, is comparable to ELISA tests. The comparison of 83 samples with a commercial ELISA revealed a sensitivity of 81% and specificity of 88%. The use of fluorescent nanoparticles provides a higher sensitivity than an assay using usual fluorescent dye molecules, besides avoiding bleaching effects. Based on the results, the proposed method provides fast, specific and sensitive results, and proves to be a suitable method for Dengue NS1 detection in impoverished regions or epidemic areas.

Quantum dots - characterization, preparation and usage in biological systems.

The use of fluorescent nanoparticles as probes for bioanalytical applications is a highly promising technique because fluorescence-based techniques are very sensitive. Quantum dots (QDs) seem to show the greatest promise as labels for tagging and imaging in biological systems owing to their impressive photostability, which allow long-term observations of biomolecules. The usage of QDs in practical applications has started only recently, therefore, the research on QDs is extremely important in order to provide safe and effective biosensing materials for medicine. This review reports on the recent methods for the preparation of quantum dots, their physical and chemical properties, surface modification as well as on some interesting examples of their experimental use.