Quantifying the binding between proteins and open chromatin-like DNA sequences with gold nanorods

Gold Nanoparticle-based "Mix and Measure" Fluorimetric Assays to Quantify Antibody Titer

Monoclonal antibodies (mAbs) for treatment of human diseases are typically human or humanized Immunoglobulin G (IgG) produced in mammalian cell lines. A rapid, less tedious, and high throughput method to quantify mAbs is in demand to accelerate mAb production efficiency. To quantify mAb titer, we developed gold nanoparticle (AuNPs)-based "mix and measure" fluorimetric assays by exploiting AuNPs' fluorescence quenching ability. The AuNPs are functionalized by an Fc binding protein, i. e. protein G, which binds human IgG and fluorescently labeled rat IgG (Alexa Fluor 488-rat IgG) with differential affinity. The assays can be in competition or displacement format. The competitive binding of human IgG drug and the labelled rat IgG to protein G-coated AuNP lead to varied fluorescent intensity that is proportional to the amount of human IgG analte; or the displacement of the labelled rat IgG from protein G-coated AuNP by human IgG can lead to fluorescent recovery that is also proportionally related to human IgG concentration. The assays can quantify therapeutic mAbs in the range of 10-1,000 mg/L, demonstrated for Herceptin, Avastin, and Humira in cell culture media. The assays have fast turn over time (within 15 min). They can be performed in microplates and are suitable for high throughput "on-line" or "at-line" measurement in mAbs production lines.

Transforming lanthanide and actinide chemistry with nanoparticles

Lanthanides and actinides are used in a wide variety of applications, from energy production to life sciences. To address toxicity issues due to the chemical, and often radiological, properties of these elements, methods to quantify and recover them from industrial waste are necessary. When used in biomedicine, lanthanides and actinides are incorporated in compounds that show promising therapeutic and/or bioimaging properties, but lack robust strategies to target cancer and other pathologies. Furthermore, current decorporation protocols to respond to accidental actinide exposure rely on intravenous injections of soluble chelating agents, which are inefficient for treatment of inhaled radionuclides trapped in lungs. In recent years, nanoparticles have emerged as powerful tools in both industry and clinical settings. Because some inorganic nanoparticles are sensitive to external stimuli, such as light and magnetic fields, they can be used as building blocks for sensitive bioassays and separation techniques. In addition, nanoparticles can be functionalized with multiple ligands and act as carriers for selective delivery of therapeutic and contrast agents. This review summarizes and discusses recent progress on the use of nanoparticles in lanthanide and actinide chemistry. We examine different types of nanoparticles based on composition, functionalization, and properties, and we critically analyze their performance in a comparative mode. Our focus is two-pronged, including the nanoparticles free of lanthanides and actinides that are used for the detection, separation, or decorporation of f-block elements, as well as the nanoparticles that enhance the inherent properties of lanthanides and actinides for therapeutics, imaging and catalysis.

Sensors, Biosensors, and Analytical Technologies for Aquaculture Water Quality

In aquaculture industry, fish, shellfish, and aquatic plants are cultivated in fresh, salt, or brackish waters. The increasing demand of aquatic products has stimulated the rapid growth of aquaculture industries. How to effectively monitor and control water quality is one of the key concerns for aquaculture industry to ensure high productivity and high quality. There are four major categories of water quality concerns that affect aquaculture cultivations, namely, (1) physical parameters, e.g., pH, temperature, dissolved oxygen, and salinity, (2) organic contaminants, (3) biochemical hazards, e.g., cyanotoxins, and (4) biological contaminants, i.e., pathogens. While the physical parameters are affected by climate changes, the latter three are considered as environmental factors. In this review, we provide a comprehensive summary of sensors, biosensors, and analytical technologies available for monitoring aquaculture water quality. They include low-cost commercial sensors and sensor network setups for physical parameters. They also include chromatography, mass spectrometry, biochemistry, and molecular methods (e.g., immunoassays and polymerase chain reaction assays), culture-based method, and biophysical technologies (e.g., biosensors and nanosensors) for environmental contamination factors. According to the different levels of sophistication of various analytical techniques and the information they can provide (either fine fingerprint, highly accurate quantification, semiquantification, qualitative detection, or fast screening), we will comment on how they may be used as complementary tools, as well as their potential and gaps toward current demand of real-time, online, and/or onsite detection.