Comparative assessment of the fate and toxicity of chemically and biologically synthesized silver nanoparticles to juvenile clams

Nanoparticles (NPs) can be produced via physical, chemical, or biological approaches. Yet, the impact of the synthesis approaches on the environmental fate and effects of NPs is poorly understood. Here, we synthesized AgNPs through chemical and biological approaches (cit-AgNPs and bio-AgNPs), characterized their properties, and toxicities relative to commercially available Ag nanopowder (np-AgNPs) to the clam Mercenaria mercenaria. The chemical synthesis is based on the reduction of ionic silver using sodium borohydride as a reducing agent and trisodium citrate as a capping agent. The biological synthesis is based on the reduction of ionic silver using biomolecules extracted from an atoxigenic strain of a filamentous fungus Aspergillus parasiticus. The properties of AgNPs were determined using UV-vis, dynamic light scattering, laser Doppler electrophoresis, (single particle)-inductively coupled plasma-mass spectroscopy, transmission electron microscopy, and asymmetric flow-field flow fractionation. Both chemical and biological synthesis approaches generated spherical AgNPs. The chemical synthesis produced AgNPs with narrower size distributions than those generated through biological synthesis. The polydispersity of bio-AgNPs decreased with increases in cell free extract (CFE):Ag ratios. The magnitude of the zeta potential of the cit-AgNPs was higher than those of bio-AgNPs. All AgNPs formed aggregates in the test media i.e., natural seawater. Based on the same total Ag concentrations, all AgNPs were less toxic than AgNO₃. The toxicity of AgNPs toward the juvenile clam, Mercenaria mercenaria, decreased following the order np-AgNPs > cit-AgNPs > bio-AgNPs. Expressed as a function of dissolved Ag concentrations, the toxicity of Ag decreased following the order cit-AgNPs > bio-AgNPs > AgNO₃ ~ np-AgNPs. Therefore, the toxicity of AgNP suspensions can be attributed to a combined effect of dissolved and particulate Ag forms. These results indicate that AgNP synthesis methods determine their environmental and biological behaviors and should be considered for a more comprehensive environmental risk assessment of AgNPs.

Bioremoval of PVP-coated silver nanoparticles using Aspergillus niger: the role of exopolysaccharides

Extensive use of engineered nanoparticles has led to their eventual release in the environment. The present work aims to study the removal of Polyvinylpyrrolidone-coated silver nanoparticles (PVP-Ag-NPs) using Aspergillus niger and depict the role of exopolysaccharides in the removal process. Our results show that the majority of PVP-Ag-NPs were attached to fungal pellets. About 74% and 88% of the PVP-Ag-NPs were removed when incubated with A. niger pellets and exopolysaccharide-induced A. niger pellets, respectively. Ionized Ag decreased by 553 and 1290-fold under the same conditions as compared to stock PVP-Ag-NP. PVP-Ag-PVP resulted in an increase in reactive oxygen species (ROS) in 24 h. Results show an increase in PVP-Ag-NPs size from 28.4 to 115.9 nm for A. niger pellets and 160.3 nm after removal by stress-induced A. niger pellets and further increased to 650.1 nm for in vitro EPS removal. The obtained findings show that EPS can be used for nanoparticle removal, by increasing the net size of nanoparticles in aqueous media. This will, in turn, facilitate its removal through conventional filtration techniques commonly used at wastewater treatment plants.

Synthesis, characterization, and biomedical applications (antibacterial, antibiofilm, anticancer and effects on hospital-acquired pneumonia infection) of copper titanium oxide nanostructures

Hospital-acquired pneumonia (HAP) is the second most common cause of nosocomial infections and is responsible for 15% of nosocomial infections, with a high mortality rate, which has led to increased concern and significant costs in healthcare settings. The most significant agents of HAP are Pseudomonas aeruginosa and Klebsiella pneumoniae, which create a biofilm that results in a resistant infection. We aimed to study the synthesis of Cu2Ti2O5 nanoparticles, their effects on the growth and biofilms of Pseudomonas aeruginosa and Klebsiella pneumoniae isolated from respiratory infections, and their anticancer effects. In this study, for the first time, the Pechini method was used to synthesize Cu2Ti2O5 nanostructures. The effects of nanoparticles on the growth and biofilms of Pseudomonas aeruginosa and Klebsiella pneumoniae were evaluated using a microdilution broth and the microtiter plate method, and the cytotoxic effect of the nanoparticles on the A549 cell line was also assessed by MTT. The characteristics of the nanoparticles were confirmed through XRD, FTIR, SEM, and TEM techniques. Cu2Ti2O5 showed a minimum inhibitory effect in concentrations of 156.25 to 625 μg mL-1 for ten isolates of K. pneumoniae and 625 to 1250 μg mL-1 for ten isolates of P. aeruginosa and at sub-MIC concentrations as well. It reduced the biofilms of K. pneumoniae and P. aeruginosa strains by 75% and 44.4%. The nanoparticles killed 50% of A549 cancer cells in 48 h at concentrations of 30 to 40 μg mL-1 and in 24 h at concentrations of 200 to 250 μg mL-1. The findings of this study show the antibacterial, anti-biofilm, and anti-cancer effects of Cu2Ti2O5 nanoparticles. Therefore, these nanoparticles can be considered potential antimicrobial candidates; however, these effects should be confirmed with more bacterial isolates.

Recent advances in targeting cancer stem cells by using nanomaterials

Cancer stem cells (CSCs) are a special group of cells that start, regenerate, and maintain the growth of tumors. Cancer stem cells (CSCs) contribute to the dissemination of tumors, their recurrence following treatment, and the mechanisms by which cancers develop resistance to therapies. CSCs reside in a unique microenvironment influenced by a variety of factors from their immediate surroundings. These factors include low oxygen levels, too much new blood vessel growth, a shift in how cells use energy from breathing oxygen to breaking down glucose, and an increase in certain markers and signals related to stem cells that help remove drugs from the body. Antibodies and special molecules that focus on the unique features keeping the environment stable are used to deliver cancer treatments to CSCs. As a result, nanoparticles are extremely effective in delivering drugs that combat cancer directly to cancer stem cells. Right now, stem cell nanotechnology is a new and interesting area of study. Some experiments on how stem cells interact with tiny structures or materials have shown good results. The importance of tiny structures and materials in creating treatments using stem cells for diseases and injuries has been clearly understood. The way nanomaterials are built and their characteristics influence how stem cells grow and change. This area of study is a new and exciting field where material science meets medicine. This review talks about the biology of CSCs and new ways to create nanoparticles (NPs) that can deliver cancer drugs specifically to these CSCs. This review talks about the creation of different types of tiny particles, including synthetic and natural polymer particles, lipid particles, inorganic particles, protein particles that can assemble themselves, combined antibody-drug particles, and small bubbles called nanovesicles, all aimed at targeting cancer stem cells. This paper talks about recent progress and opinions on using nanotechnology in stem cell research and therapy. It also covers how nanoparticles can help track, control, and improve the retention of stem cells.

Transforming Medicine with Nanobiotechnology: Nanocarriers and Their Biomedical Applications

Nanobiotechnology, at the intersection of nanotechnology and biology, represents a burgeoning field poised to revolutionize medicine through the use of advanced nanocarriers. These nanocarriers, endowed with distinctive physiobiological attributes, are instrumental in diverse therapeutic domains including drug delivery for microbial infections, cancer treatment, tissue engineering, immunotherapy, and gene therapy. Despite the transformative potential, several challenges hinder their efficacy, such as limited drug capacity, suboptimal targeting, and poor solubility. This review delves into the latest advancements in nanocarrier technologies, examining their properties, associated limitations, and the innovative solutions developed to address these issues. It highlights promising nanocarrier systems like nanocomposites, micelles, hydrogels, microneedles, and artificial cells that employ advanced conjugation techniques, sustained and stimulus-responsive release mechanisms, and enhanced solubility. By exploring these novel structures and their contributions to overcoming existing barriers, the article emphasizes the vital role of interdisciplinary research in advancing nanobiotechnology. This field offers unparalleled opportunities for precise and effective therapeutic delivery, underscoring its potential to reshape healthcare through personalized, targeted treatments and improved drug performance.

Comparative Assessment of the Impacts of Wildland-Urban Interface Fire Ash on Growth of the Diatom Thalassiosira weissflogii

Fires at the wildland-urban interface (WUI) result in the release of ash into the atmosphere that can be transported for long distances and deposited on land and in oceans. Wildfire ash has the potential to increase phytoplankton biomass in the open ocean by providing both major nutrients and trace metals. However, fires that originate at the WUI contain potentially toxic concentrations of metals such as Ti, Cr, Cu, Pb, and Zn, especially in coastal oceans close to WUI fires, where ash deposition rates are high. Here, we investigated the impact of fire ash from different sources originating from vegetation, structures, and vehicles on growth of the diatom Thalassiosira weissflogii (T. weissflogii). The diatom was exposed to ash suspensions containing equimolar concentrations of 10 and 50 µM Fe. The concentration of potentially toxic metals (e.g., Ti, Cu, and Zn) in the exposure suspensions decreased following the order vehicle ash suspension > structural ash suspension > vegetation ash suspension. Growth rates (GR) of T. weissflogii were between 0.44 d-1 and 0.52 d-1 in the controls, and varied with ash types, following the order vegetation (GR = 0.40 d-1 to 0.48 d-1) > vehicle (GR = 0.06 d-1 to 0.46 d-1) > structure (GR = 0.02 d-1 to 0.31 d-1) ash. Two ash samples (A 131 and A136) completely inhibited the growth of T. weissflogii, possibly due to high Ti, Cu, and Zn concentrations in the form of (nano)particles. Overall, this study showed that structural and vehicle ash, with high concentrations of potentially toxic metals, significantly suppress the growth of T. weissflogii, whereas vegetation ash with high concentrations of Fe and Mn but low concentrations of potentially toxic metals had no significant beneficial or suppressive effect. High concentrations of the metals Ti, Cu, and Zn in the form of nano(particles) in structural and vehicle ash are possible sources of toxicity to diatom growth. This study provides valuable insights into the potential impacts of WUI fires on aquatic ecosystems and can inform management strategies aimed at reducing these impacts.

Exploring TGF-β Signaling in Cancer Progression: Prospects and Therapeutic Strategies

Cancer persists as a ubiquitous global challenge despite the remarkable advances. It is caused by uncontrolled cell growth and metastasis. The Transforming Growth Factor-beta (TGF-β) signaling pathway is considered a primary regulator of various normal physiological processes in the human body. Recently, factors determining the nature of TGF-β response have received attention, specifically its signaling pathway which can be an attractive therapeutic target for various cancer treatments. The TGF-β receptor is activated by its ligands and undergoes transduction of signals via canonical (SMAD dependent) or non-canonical (SMAD independent) signaling pathways regulating several cellular functions. Furthermore, the cross talk of the TGF-β signaling pathway cross with other signaling pathways has shown the controlled regulation of cellular functions. This review highlights the cross talk between various major signaling pathways and TGF-β. These signaling pathways include Wnt, NF-κB, PI3K/Akt, and Hedgehog (Hh). TGF-β signaling pathway has a dual role at different stages. It can suppress tumor formation at early stages and promote progression at advanced stages. This complex behaviour of TGF-β has made it a promising target for therapeutic interventions. Moreover, many strategies have been designed to control TGF-β signaling pathways at different levels, inhibiting tumor-promoting while enhancing tumor-suppressive effects, each with unique molecular mechanisms and clinical implications. This review also discusses various therapeutic inhibitors including ligand traps, small molecule inhibitors (SMIs), monoclonal antibodies (mAbs), and antisense oligonucleotides which target specific components of TGF-β signaling pathway to inhibit TGF-β signaling and are studied in both preclinical and clinical trials for different types of cancer. The review also highlights the prospect of TGF-β signaling in normal physiology and in the case of dysregulation, TGF-β inhibitors, and different therapeutic effects in cancer therapy along with the perspective of combinational therapies to treat cancer.

Nanotechnology for Healthcare: Plant-Derived Nanoparticles in Disease Treatment and Regenerative Medicine

Nanotechnology has revolutionised biomedical research, offering innovative healthcare solutions. Plant-based nanotechnology is emerging as a sustainable alternative, minimising environmental impacts and enhancing therapeutic effectiveness. This paper explores the potential of plant-derived nanoparticles (PNPs) in medicine, highlighting their biocompatibility, multifunctionality, and eco-friendliness. PNPs, synthesised through green methods, have demonstrated promising applications in drug delivery, cancer therapy, antimicrobial treatments, and tissue regeneration. Their unique properties, such as a high surface area and bioactive components, enable improved drug delivery, targeting, and controlled release, reducing side effects and enhancing treatment efficacy. Additionally, plant-derived compounds' inherent antimicrobial and antioxidant properties, retained within platinum nanoparticles (PNPs), present innovative opportunities for combating antimicrobial resistance and promoting wound healing. Despite their potential, challenges remain in standardising PNP synthesis, ensuring consistency, and scaling up production for industrial applications. This review emphasises the need for further research on PNP toxicity, biocompatibility, and regulatory frameworks to fully harness their capabilities in clinical and commercial applications. Plant-based nanotechnology represents a promising, greener alternative for advancing healthcare solutions, aligning with global sustainability goals.