Protein characterization using the Zetasizer Nano

More information:
	Protein characterization overview
	Measuring absolute molecular weight
	What is the Hydrodynamic radius
Case studies :
	Crystal screening
	Protein melting point
	Protein formulation stability

See how the Zetasizer Nano Simplifies Protein Characterization

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Zetasizer Nano for proteins

Zetasizer Nano for Protein Characterization

The new Zetasizer Nano series is ideal for protein characterization. The user friendly software includes customizable protein specific reports, a solvent builder library, and protein utilities to assist with the interpretation of data.

The new technology incorporated in these systems delivers unequalled sensitivity and versatility.

Protein size – NIBS/DLS technology enables measurements of protein molecules down to 0.3nm hydrodynamic radius (equivalent to less than 1 kDa).
Highest sensitivity - 0.1 mg/ml Lysozyme, for larger molecules even lower concentrations can be detected.
Low sample volume - only 12µl sample volume are required and hence only small amounts of protein, and the sample can be recovered.
Precision temperature control – Peltier elements provide software controlled temperature range from 2ºC to 90ºC for accurate temperature scans.
Absolute molecular weight - An avalanche-photodiode detector and fiber detection optics give the sensitivity and stability required for absolute molecular weight measurement.

The Zetasizer Nano S provides a powerful, easy to use protein characterization tool for every laboratory. All systems are compatible with the MPT-2 autotitrator to enable trend measurements and sample preparation to be automated.

Option	Advantage*	Availability
MPT-2 Titrator for Titration vs. pH and charge.	Automation, trend measurements	Available on all models.
Zeta potential & estimated charge	Effective protein surface charge, disposable zeta cells	Available on Zetasizer Nano ZS and ZS90.
532nm 50mW green laser	Measurements of red-sensitive molecules	Available on all models. Note: this option replaces the standard 633nm He-Ne red laser.
21 CFR part 11	FDA compliant access security and audit trails	Available for all models via software key.

* Sample dependent


	Presentations and application notes:

	On demand presentation on automated protein characterization The Zetasizer Nano may be used for automated isoelectric point and charge titration, size versus pH, size versus time, temperature ramps and melting points.


	Publication: Automated protein characterization. Protein interactions are strongly influenced by electrostatics. While hydrogen bonding and London forces are key to position and orientation. The zeta potential at the slipping plane dictates the electrostatic interaction strength, rather than the surface charge density or surface potential. The zeta potential of bovine serum albumin (BSA), in 100mM NaCl at 1 mg/mL is shown for different pH values. Automatic pH titration from pH 11 to pH 2 is demonstrated with the MPT-2 titration system. The isoelectric point obtained from the zeta potential (pI = 5.1) is consistent with literature values. Dynamic light scattering mirrors a low zeta potential with an increased z-average hydrodynamic size at this pH. (published in ABL, December 2004).


	Application note on Automated size and intensity trend measurements. The ability to automate particle size and scattering intensity trend measurements can be a major advantage in many applications. Processes such as aggregation, sedimentation, solubilization and changes in molecular conformation can be followed by monitoring changes in the size and the scattering of the sample. The Zetasizer Nano range allows automated measurements of particle size and scattering intensity as a function of temperature or time. This application note discusses the trend measurement options with examples.


	Application note: Characterization of protein-polyelectrolyte complexes. The interactions governing protein-polyelectrolyte complexation are important in protein purification, enzyme immobilization, immunosensing and bioactive sensors. This application note shows the interaction of bovine serum albumin (BSA) with a custom synthesized anionic copolymer. At high pH the negative charge on the protein inhibits complexation. With decreasing pH the binding is seen as a decreasing intensity signal from the free, unbound BSA.


	Application note: Measurement of sub-nanometer size particles using dynamic light scattering (DLS). In principle, any small ‘particle’ can be measured using DLS - if sufficient light is detected and the particles are diffusing freely. For sub-nanometer particles, however, the level of scattered light, even at high concentrations is usually so small that only the most sensitive experimental setup can detect them. In this application note cholesterol (MW 387Da) in butanone, is prepared at 20 mg/mL. The hydrodynamic radius is found to be 0.3nm, or 3 Angstroms. This value agrees with expectations for this molecular weight range.


	Application note: Characterization of mixed micelles. Ionic-non-ionic surfactant systems, or detergents have found a wide range of applications from oil recovery to enhanced solubility to cosmetics. Surfactants form micelles in which the ionic/non-ionic head group is exposed and the hydrophobic tail is buried. Co-micellization takes place in mixed systems. Micelle size is an important parameter which correlates with solubilizing efficiency and critical micelle concentration. In this application note mixtures of Triton X-100 and sodium dodecyl sulfate (SDS) were investigated. Comparison to previously published size exclusion chromatography (SEC) data shows excellent agreement.


	Application note: A dynamic light scattering (DLS) Assay for the analysis of aggregated adenovector particles. DLS may be used to monitor and quantify the presence of aggregates of viral proteins. This poster presented at the XY meeting by GenVec compares the native and aggregated viral particles of ~100 nm diameter. DLS is used to demonstrate aging effects of the samples. Aging manifests itself in increased average size, increased polydispersity, and reduction of the monomeric peak in a distribution analysis.