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The Zetasizer Helix delivers structural information at the molecular level, providing mechanistic insight into the formation of oligomers, unfolding, and aggregation processes of biopharmaceuticals.


The system retains all of the functionality of the Zetasizer Nano ZSP and adds Raman spectroscopy to determine secondary and tertiary structure of proteins and protein-based biotherapeutics. This wealth of characterization data provided by a single instrument platform provides the understanding to enable more efficient drug development processes, shortening time to market, and increasing drug product quality. The exceptional performance also enables the measurement of the molecular weight and second virial coefficient, A2, of macromolecules and kD, the DLS interaction parameter.

Information can be derived from non-experts through powerful software – where trends of a pre-determined set of parameters are graphed and fitted with no expertise required.

To keep from sacrificing analytical power though, an advanced processing mode provides a full suite of tools – from data pre-processing to multivariate analysis.  The use of the instrument is therefore enabled for applications method development.

  • Study formulations without or with minimal dilution
  • Understand mechanisms of aggregation and oligomerization
  • Identify Critical to Quality product attributes
  • “Expertise Optional” data analysis software provides trend results without making expert level decisions
  • Advance data analysis tools include a full suite of spectroscopic analysis tools, from pre-treatment to multivariate analysis.
  • Temperature ramp data gives insights into product stability and mechanisms of aggregation
  • Isothermal incubation data enables kinetics and reversibility to be investigated
  • Sample series allows the cause of batch-to-batch variation to be investigated
  • In-depth analysis of secondary and tertiary protein structure

How it works

By combining Raman spectroscopy (to characterize secondary and tertiary protein structure) with dynamic light scattering (to characterize particle size) the Zetasizer Helix can differentiate between the following mechanisms:

  • Formation of oligomers at the same time as 2e and/or 3e structural change
  • Formation of oligomers with no change to 2e and/or 3e structure
  • Protein unfolding without resulting aggregation
  • Aggregation as a result of unfolding/structural change
  • Aggregation without unfolding/structural change

Because of richness of detail provided by the Raman spectra, it is possible to correlate the above processes (pertaining to structure and aggregation) with specific protein moieties and their environments.  This information can be provided on a single product, or used to compare these properties between different products and/or batches

The system has significant flexibility in enabling a variety of sample stressors to be applied, and the effects studied.

Data collection options and results obtained:   

  • Kinetics / Isothermal Incubation / Temperature Jump
    • Determine kinetics of oligomerization and/or aggregation events
    • Investigate reversibility of size and structural changes during these processes
  • Thermodynamics / Temperature Ramp
    • Determination of thermodynamic properties
      • Tonset, Tmelt
      • Enthalphy/coopertivity of transitions
    • Compare relative stability of samples
    • Mechanistic understanding of oligomerization and aggregation events
  • Sample Series
    • Evaluate impact of a perturbation across a range of samples
    • Compare stability and molecular structure of different batches, or as a function of stability testing,
    • Perturbation other than temperature  (pH, denaturant, etc.)


Data collection and data analysis are handled separately to present a clearly delineated work flow.  Data collection is controlled by ZSHelixAcquire, which provides a “wizard-type” interface, guiding the user through experimental setup. This interface is launched in the Zetasizer software.  Frequently used settings are saved as “experiments” (methods), and can be loaded and reused for ease-of-use and guaranteed reproducibility of experimental conditions.

ZS HelixAnalyze is the powerful yet easy to use data analysis platform. The default “Expertise Optional” mode combines data pre-treatment, processing and trend analysis into a single automated sequence that requires no “Expert” decision to complete. To keep from sacrificing analytical power though, an advanced processing mode provides a full suite of spectroscopic tools – from data pre-processing to multivariate analysis.  The use of the instrument for novel and unanticipated uses is therefore not limited, enabling applications method development, and ensuring the usefulness of the system for as yet unidentified applications.



DLS light source:
He-Ne laser 633nm, Max 10mW
Raman light source:
Diode laser 785nm, Max 280mW at the sample
Laser safety:
Class 1
< 100VA (DLS)
<300VA, typical operating output ~135VA (Raman)
Dimensions (W, D, H):
320 x 600 x 375mm (Zetasizer)
580 x 450 x 200mm (Raman)
19kg + sidecar (Zetasizer)
28kg (Raman)

Raman Spectrometer

Structural and chemical analysis:
Raman spectroscopy
Raman spectrometer:
Kaiser Optical Systems Inc. RamanRxn1
Spectral performance:
150 cm-1 to 1850 cm-1, 6 cm-1 resolution
Laser spot size at sample:
<300 µm
Protein secondary and tertiary structural markers:
Backbone  – amount of α-helix, ß-sheet, and random coil content
Tyrosine – hydrogen bonding extent, hydrophilic or hydrophobic environment
Tryptophan – indole ring dihedral angle to backbone, extent of cation-π interaction, if indole ring is buried or exposed, hydrophilic or hydrophobic environment
Disulfide – differentiate conformers,  loss of covalent bond
Data collection modes:
Isothermal Incubation, Temperature Ramp, Temperature Jump, Sample/Formulation Series



The Zetasizer Nano range is protected by the following patents: Non-Invasive Back Scatter (NIBS) EP884580, US6016195, JP11051843 High and Low Frequency Electrophoreses (M3) EP1154266, US7217350, JP04727064 Light Scattering Measurements using Simultaneous Detection EP2235501, CN102066901, JP2011523451, US20090251696 Surface Potential Determination in a Dip Cell WO2012172330
The Zetasizer Helix is the subject of patent application WO2013027034 A1


Protect your investment and ensure optimized performance at all times with Malvern’s service plans.

When you purchase a Malvern product we understand that this is just the first stage of a working relationship that will last for the lifetime of the instrument. Depending on your needs, Malvern will provide the support for your business.

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For laboratories where maximizing instrument up-time is critical to its daily performance. Our highest level of response and the 'all inclusive' price plan takes care of those unexpected repair bills should the unfortunate occur.


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Enhance your laboratory productivity by maintaining instrument efficiency. Still receive that priority response, combined with specialist technical and software support, we'll keep your instrument performance on track to deliver.


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*including labour & travel costs***available at an additional cost


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Characterizing the size, aggregation number and CMC of surfactant micelles using Dynamic Light Scattering Webinar - Live (English)

Surfactant micelles are used in a wide variety of applications from personal care products to pharmaceutical formulations. Dynamic light scattering can be used to characterise micelle size and charge, determine the critical micelle concentration and ...

Zetasizer range
June 23 2016

Metal colloids - their preparation, application and characterization Webinar - Recorded (English)

Metal colloids represent a very interesting system known since Roman times (the Lycurgus Cup). We'll look at the preparation of these systems looking mainly at gold, silver, and the platinum group metals. All these find extensive application in in...

NanoSight range,Zetasizer range
Date recorded:
February 18 2016

Suspension stability: Why particle size, zeta potential and rheology are important Webinar - Recorded (English)

Suspensions or dispersions of particles or droplets in a liquid medium are encountered in a variety of industries and find use in a diverse range of applications. These include liquid abrasives, ceramics, medicines, foodstuffs and inks to name a few....

Mastersizer range,Kinexus range,Zetasizer range
Date recorded:
February 11 2016

Size: What is the z-average? FAQ

The z-average diameter is the mean intensity diameter i.e. it is a diameter based upon the intensity of scattered light of a material in its native state (including electrical double layers and surface structure). The z-average is derived from a Cumulants analysis of the measured correlation curve, wherein a single particle size is assumed and a single exponential fit is applied to the autocorrelation function. It is unique to dynamic light scattering and it is sensitive to the presence of aggregates/dust due to the intensity of light scattered by any larger particles present.

Comparison of Statistical Measures Reported by NTA and DLS Techniques Technical Note (English)

As the Nanoparticle Tracking Analysis (NTA) technique has gained in popularity in recent years, comparison to Dynamic Light Scattering (DLS) results has become more frequent. When comparing results, it is important to understand the differences betwe...

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