Silver nanoparticles nucleated in NaOH-treated halloysite: a potential antimicrobial material

Alginic acid-functionalized silver nanoparticles: A rapid monitoring tool for detecting the technology-critical element tellurium

The increasing global demand for tellurium, driven by its critical role in alloys, photovoltaic devices, and electronics, has raised concerns about its environmental pollution and neurotoxicity. In response, the potential of alginic acid (AA), a renewable, low-cost, and sustainable biopolymer, was explored for the biosynthesis of ultra-small silver nanoparticles (AgNPs) and their application in the detection of tellurium (Te(IV)). The effect of key synthesis parameters on desired physicochemical properties and yield of AgNPs was established to ensure high specificity and sensitivity towards Te(IV). The purified AgNPs with AA surface ligands were utilized to demonstrate a ratiometric absorbance sensor that exhibits excellent linearity and nanomolar-level affinity. This approach achieved a high correlation coefficient of ∼ 0.982, with a low detection limit of about 22 nM. Further investigations into the effect of pH, ionic strength, and organic molecules were conducted to elucidate detection performance and molecular understanding. The detection mechanism relies on the coordination between Te(IV) ions and the carboxylate groups of AA, which initiates aggregation-induced plasmon coupling in adjacent AgNPs. The capability of this analytical method to monitor Te(IV) in real-world water samples features its rapidity, user-friendliness, and suitability for point-of-care monitoring, making it a promising alternative to more complex techniques.

Recent Advances of Halloysite Nanotubes in Biomedical Applications

Halloysite nanotubes (HNTs) have emerged as a highly regarded choice in biomedical research due to their exceptional attributes, including superior loading capacity, customizable surface characteristics, and excellent biocompatibility. HNTs feature tubular structures comprising alumina and silica layers, endowing them with a large surface area and versatile surface chemistries that facilitate selective modifications. Moreover, their substantial pore volume and wide range of pore sizes enable efficient entrapment of diverse functional molecules. This comprehensive review highlights the broad biomedical application spectrum of HNTs, shedding light on their potential as innovative and effective therapeutic agents across various diseases. It emphasizes the necessity of optimizing drug delivery techniques, developing targeted delivery systems, rigorously evaluating biocompatibility and safety through preclinical and clinical investigations, exploring combination therapies, and advancing scientific understanding. With further advancements, HNTs hold the promise to revolutionize the pharmaceutical industry, opening new avenues for the development of transformative treatments.

Natural Nanoclay-Based Silver-Phosphomolybdic Acid Composite with a Dual Antimicrobial Effect

The problem of microbial growth on various surfaces has increased concern in society in the context of antibiotic misuse and the spreading of hospital infections. Thus, the development of new, antibiotic-free antibacterial strategies is required to combat bacteria resistant to usual antibiotic treatments. This work reports a new method for producing an antibiotic-free antibacterial halloysite-based nanocomposite with silver nanoparticles and phosphomolybdic acid as biocides, which can be used as components of smart antimicrobial coatings. The composite was characterized by using energy-dispersive X-ray fluorescence spectroscopy and transmission electron microscopy. The release of phosphomolybdic acid from the nanocomposite was studied by using UV-vis spectroscopy. It was shown that the antibiotic-free nanocomposite consisting of halloysite nanotubes decorated with silver nanoparticles loaded with phosphomolybdic acid and treated with calcium chloride possesses broad antibacterial properties, including the complete growth inhibition of Staphylococcus aureus and Pseudomonas aeruginosa bacteria at a 0.5 g × L^-1 concentration and Acinetobacter baumannii at a 0.25 g × L^-1 concentration.