By Bruce B. Weiner Ph.D. Introduction: Zeta potential is a useful property to know for colloids, nanoparticles, and proteins. It is a substitute for the otherwise hard to measure surface charge. The zeta potential is not equal to the surface potential but rather it is the electrostatic potential difference between a rotationally averaged point at the […]
Summary The purpose of this guide is to demonstrate the proper method for preparing a zeta potential validation sample used for checking the performance of the NanoBrook ZetaPlus, ZetaPALS, 90PlusPALS, and Omni instrumentation. The BI-ZR5 validation material is a dark blue, inorganic powder that is insoluble in water. It has a mean particle size of […]
Brookhaven Instruments Corporation has been pioneering advancements in particle characterization instrumentation for 40 years. To celebrate this milestone we spoke to one of Brookhaven’s founders, Dr. Bruce Weiner, about the company’s inception and earlier years. Can you name a few scientists that have inspired you in your life or career? “Let’s start with Prof. Carl […]
In the previous entry in this series of papers on particle size and size distribution, the main features of the differential and cumulative size distribution functions were defined and discussed using continuous distributions. Continuous distributions can be measured approximately in fractionation experiments† where, for example, data is taken every second as fractionated slices of the […]
Particle size distribution data can be presented numerically (tabular format) or graphically. When presented graphically, there are two types: differential and cumulative. They are related. If one differentiates the cumulative distribution curve, the differential distribution is obtained. If one integrates the differential distribution curve, the cumulative distribution is obtained. Differential Distribution The differential distribution shows […]
What is Static Light Scattering? Static light scattering (SLS) is a technique that leverages high precision photon counting to measure size, molecular weight, and other structural parameters. Common samples include synthetic polymers, nanoparticles, biomolecules, and other macromolecules. SLS makes extensive use of extrapolation, typically with respect to scattering angle, concentration, or in the case of […]
In order for DLS data to be relatable to a physically meaningful parameter, frequently size, it is necessary to know a number of other parameters describing either the solvent, measurement conditions, or the configuration of a given hardware system. Brookhaven fully supports export of raw data, specially DLS autocorrelation functions, for fitting using more advanced algorithms. […]
Summary Liposomes are a common system used to encapsulate and deliver bioactive cargo molecules. In contrast to simple emulsions (oil-in-water or water-in-oil), these lipid vesicles are composed of well-defined bilayer structures and have aqueous interiors. These bilayers encircle the molecule of interest, often proteins or oligonucleotides such as DNA or RNA. These vesicle structures are inherently […]
Summary An industrial carbon black sample was used for the purpose of demonstrating the efficacy of the Brookhaven Instruments DCP. Due to the intrinsically differential nature of the results, it is possible to identify the existence of multiple species even from raw, uncorrected results. The basis of this technique is sedimentation, meaning that larger particles […]