Services

We perform the development and continuous production of customer-specific particle types on the basis of our existing product line and technologies.
Customer-specific product properties relate to the particle structure (matrix modification), the functionality (functional groups, dyes, antibodies or other biomarkers) and the formulation (concentration, buffer, stabilizers and other additives).
Final product specifications and production modalities are typically regulated in bilateral supply agreements.

We perform the surface modification of particles, provided by our customers, on the basis of existing technologies.
Depending on the individual particle structure, surface modification can be carried out by reactive polymerization or co-condensation in one or more steps.
This service is also available for organic polymer particles as well as for inorganic (mineral) particle types.

We can produce your particles under controlled hygienic conditions.
In all production areas laminar flow boxes are available for particle handling. In our standard production area and in our IvD area the laminar flow boxes are used for packaging of products under controlled conditions. In our clean room facilities the laminar flow box increases the purity level from C to B for final filtration and filling.
The requirements and commitments for particle production under controlled hygienic conditions (hygiene of the environment, garment guidelines) are regulated by our hygiene concept. Our hygiene areas are classified according to the ICH Q7A Good Manufacturing Praxis for drugs, the European GMP guideline for Good Manufacturing Praxis for drugs and investigational products, and according to DIN EN ISO 14644-1 for clean rooms and related clean room areas – Part 1: Classification of the air purity (ISO 14644-1:1999).
Our production water is filtered through 0.2 µm filters and is routinely checked for microbiological contamination. These hygiene arrangements are complemented by a pest control system.

We provide the conjugation of biomolecules or other application-relevant target molecules on a variety of our particles. Thereby we recommend the binding of thiolated antibodies, peptides or other proteins on the surface of maleimide-functionalized particles [1]-[4].
Oligonucleotides with a terminal amino group can be bound to carboxylated particles via carbodiimide chemistry.
Other conjugation strategies, e.g. Click chemistry variants, can be applied on request.

1. Grüttner C., Müller K., Teller J., Westphal F., Foreman A. R., Ivkov R., Synthesis and antibody conjugation of magnetic nanoparticles with improved specific power absorption rates for alternating magnetic field cancer therapy. J. Magn. Magn. Mat., 2007, 311:181-186.

2. Natarajan A., Xiong C.-Y., Grüttner C., DeNardo G. L., DeNardo S. J., Development of multivalent radioimmunonanoparticles for cancer imaging and therapy. Cancer Biother. Radiopharm., 2008. 23:82-91.

3. Natarajan A., Xiong C.-Y., Grüttner C., DeNardo G. L. , DeNardo S. J. Development of 111-In-DOTA-di-scFv-NP (Bioprobes) for cancer therapy. J. Nucl. Med., 2008. 48 (Suppl. 2):71 P.

4. Rimkus G.. Design und Validierung einer mVCAM-1-spezifischen magneto-optischen Nanopartikelsonde für die Molekular Bildgebung. PhD Thesis, Biologisch-Pharmazeutische Fakultät, Jena: Friedrich-Schiller-Universität, 2011.

We deliver kits of particle samples according to your special requirements, e.g.

• kits of particles of a certain matrix material and different diameters

• kits of particles of a certain matrix material and different zetapotentials

• kits of particles with different densities of functional groups

• kits of particles of a certain matrix material and different fluorescence or dye intensities.

We would be happy to advise you on the composition of individual kits which can be tailored to suit your needs.

We perform particle size measurements for a price of 30 € (45 US$) per sample. Depending on the particle diameter we use the following measurement methods:

Size measurement of particles with diameters below 2 µm

The size of nanoparticles with diameters smaller than 2 µm is measured by photon correlation spectroscopy (PCS) according to DIN ISO 133211 with a Zetasizer NanoZS90, MALVERN Instruments Ltd., UK.
Photon correlation spectroscopy uses dynamic light scattering to estimate the mean hydrodynamic particle diameter and the polydispersity index as measure for the degree of the size distribution [1].
The calibration of the PCS measurement occurs according to the DIN EN ISO 9001 with Nanosphere® size standards (Duke Scientific Corp., USA).

Size measurement of particles with diameters of 2 µm to 30 µm

The size of microparticles with diameters of 2 µm to 30 µm is carried out with a flexible multi-channel analyzer (Multisizer II, COULTER® Electronics Ltd., U.K.) [2].
The calibration of the Coulter® size measurement occurs according to the DIN EN ISO 9001 with Nanosphere® size standards (Duke Scientific Corp., USA).

[1] http://www.malvern.com/common/downloads/campaign/MRK656-01.pdf
[2] https://www.beckmancoulter.com/wsrportal/wsrportal.portal

We perform zetapotential measurements of particles with diameters smaller than 20 µm on request.
The price for determining the pH-dependant zetapotential within the pH range of 3 to 9 is 60 € (90 US$) per sample.
The price for a single zetapotential measurement in an electrolyte of your choice is 35 € (50 US$) per sample.

The Zetasizer NanoZS90 (MALVERN Instruments Ltd., UK) is used to measure the zetapotential of particles with diameters smaller than 20 µm. The combination of the zetasizer with an autotitrator also allows the zetapotential measurement at different pH values.
Determination of the zetapotential of nano- and microparticles is achieved using Laser-Doppler-Anemometry, which follows particle movement in an electrical field [1].
The verification of our zetapotential occurs according to the DIN EN ISO 9001 with the  zetapotential transfer standards from MALVERN Instruments Ltd., UK.

[1] For further information on the theory of zetapotential measurements see http://www.malvern.de/LabGer/technology/zeta_potential/zeta_potential_LDE.htm

All particles from our product line, with a plain, aminated or carboxylated surfaces, are available as 1 ml test samples for 20 € (30 US$) if the catalog volume is 10 ml, and for 40 € (60 US$) if the catalog volume is 5 ml (plus international shipping fee).
Test samples of all other products are available on request. Particle concentrations in the test samples correspond to the concentration of listed catalog packages.

In principle, the drying of our particles can be perfromed for an additional charge of 30 € (45 US$). However, after drying the product specifications detailed in the technical data sheets can not be guaranteed. The drying process irreversibly influences the particle structure of magnetic polysaccharide particles and BNF particles. If silica particles with diameters between 50 nm and 300 nm are to be used as powder, we would recommend a prior trimethylsilyl coating.
We would be happy to advise you on the drying of our various particle types.

Our products can be tailored regarding filling volume, concentration, dispersion medium and packaging according to customer-specific requirements for the application as system components.
Application-related formulations of our particles can be provided in consultation with our customers.

We provide measurements of the dynamic AC-susceptibility of magnetic nanoparticles with the DYNOMAG-Suszeptometer (IMEGO AB, Schweden, www.imego.com) on request. These measurements give the initial susceptibility in a frequency range between 5 Hz and 100.000 Hz at sinusoidal field amplitudes below 400 A/m, where a quasi-linear magnetization without saturation effects is expected. The materials can be investigated in an aqueous colloidal state or immobilized in agarose gel, respectively. Results are normalized to the total iron content for iron concentrations larger than 0.5 mg [Fe]/mL within the sample. These measurements, based on the correlation of Brownian  and Nèel relaxation, provide information on particle magnetization, hydrodynamic diameter and the degree of thermal blocking due to magnetic particle anisotropy.
The price for batch specific AC-susceptometry measurement is 60 €, if the iron concentration is known (standard price for micromod particles), and 85 € for customer-supplied samples.