Drug eluting contact lenses

Description
An LbL coating was applied to bind drug-filled liposomes to the surface of contact lenses, enabling the controlled release of active ophthalmic ingredients over time. Additionally, the contact lenses were coated with lubricating, fully transparent glycopolymer films that reduce friction on the cornea while allowing unrestricted oxygen permeability.

Partner

• Klinik und Poliklinik für Augenheilkunde der Universitätsmedizin Rostock, Rostock, Germany
• Fraunhofer IAP, Potsdam, Germany

Reference

• Jo Sing Julia Tang, Aline Debrassi Smaczniak, Lucas Tepper, Sophia Rosencrantz, Mina Aleksanyan, Lars Dähne, Ruben R. Rosencrantz „Glycopolymer Based LbL Multilayer Thin Films with Embedded Liposomes“ Macromolecular Bioscience (2022) 2100461

Polymer particles for fluorescence immunoassay

Description
Monodisperse, polymeric nanoparticles in sizes of 100-400 nm with very intense fluorescence or even phosphorescence have been developed, whose use in test strips significantly improves both sensitivity and quantifiability compared to the gold nanoparticles commonly used to date.

Due to the wide variation of excitation and emission properties, they can be used in multiplex assays that simultaneously address different diseases.

Partner

• FZMB GmbH, Bad Langensalza, Germany
• Senova GmbH, Weimar, Germany

Biofunctionalization of surfaces

Description
To use nanoparticles in test strips, they must be functionalized with antibodies. This is usually achieved via EDC/NHS activated carboxyl groups, which are located on the surface of the particles.

In order to achieve the highest possible sensitivity and specificity, the parameters of biofunctionalization (number of carboxyl groups, amount of protein per bead, deactivation of NHS esters, blocking, running buffer) must be optimized in terms of sensitivity and specificity.

This assay development has already been successfully carried out with the manufactured beads using antibodies for various analytes.

Partner

• FZMB GmbH, Bad Langensalza, Germany
• Diarect AG, Freiburg, Germany

LbL coating of stents with drugs

Description
Pure metal stents can cause problems after insertion into the arteries.

These are short-term thrombosis formation, which is currently suppressed systemically by the addition of blood thinners such as Clopidogrel.

We have developed LbL heparin layers on the stents, which dissolve within 30-60 days and prevent the formation of thromboses by releasing heparin locally.

A longer-term problem is the growth of endothelial cells through the stents (residual thrombosis), which can be prevented by growth-inhibiting drugs such as Paclitaxel or Rapamycin.

For this purpose, a suitable LbL coating with slow drug release is also realized by esterification of polyelectrolytes with Paclitaxel.

Partner

• Boston Scientific Scimed, Inc., Minneapolis, MN, USA

DNA control particles for PCR detection of pathogenic germs

Description
DNA extraction of pathogenic germs from serum, urine or biopsies is carried out using chemical and/or mechanical lysis as well as DNA adsorption and desorption processes.

Valid results for the subsequent PCR can only be expected if all extraction steps are carried out by the employees exactly according to the instructions.

To ensure this, process control particles with known DNA were developed, which only release a defined amount of the control DNA if the instructions are followed exactly.Using the LbL coating developed by us, the known DNA was stably immobilized in special LbL layers on the surface of the microparticles and even protected from degradation by DNAs.

As soon as lysis buffer hits the particles, a reproducible amount of DNA is released and detected in the PCR. To demonstrate mechanical lysis, mesoporous particles were filled with the known DNA and coated with a cross-linked LbL layer that is stable to chemical lysis.

Only after breaking the particles in the mechanical lysis is the control DNA released in the subsequent chemical lysis.

Partner

• Qiagen N.V. , Hilden, Germany

Reference

• Jing Kang, Lars Dähne* (2011), "Strong response of multilayer polyelectrolyte films to cationic surfactants” Langmuir. 27(8) 4627-34.
• Katharina Beller Thomas Doedt Dirk Heckel Rainer Söller: „Cell- or virus simulating means comprising encapsulated marker molecules“ US Patent 10221445B2 2012

Glucose sensor for the eye

Description
The aim was to develop a reversible glucose sensor system for the eye that can be accommodated in simple contact lenses. Semipermeable microcapsules were produced and filled with the sensor system Concanavalin A and Dextran.

Due to their size, these molecules cannot escape from the capsules, whereas the glucose can diffuse in or out through the capsule wall unhindered. The dextran bound to the concanavalin A is displaced by increasing glucose concentration, which is measured by a fluorescence resonance energy transfer (FRET) dye pair on the labeled polymers.

A small hand-held device was developed for the partner, which displays the current glucose concentration in the eye when looking at it.

Partner

• ALCON / CIBA VISION GmbH, Großwallstadt, Germany
• Novartis AG, Basel, Switzerland

Microencapsulated antibodies for diagnostics

Description
For homogeneous assays for rapid analysis of small antigen molecules, antibodies with antigen were enclosed in 5 µm semipermeable LbL capsules.

The antigen-antibody complex was labeled with a FRET pair. If the antigen is present in a sample, it penetrates through the semi-permeable capsule wall and replaces the labeled antigen, which diffuses out of the capsule over time and causes a detectable color change.

This can be registered microscopically as in the attached image or macroscopically in the ratio of red/green emission with a spectrometer.

Partner

• FZMB GmbH, Bad Langensalza, Germany

Magnetic nanoparticles with surface functionalization for proteomics

Description
There are over 10,000 proteins in human blood, which can provide broad information about the state of health, past or potential diseases.

However, the ratio between many of these proteins is less than 1:5,000, which is why many proteins are not analyzed by mass spectrometry or only after separation using specific antibodies. In order to further improve the analysis and to detect as many proteins as possible in one analysis, magnetic nanoparticles with different surface properties are used to semi-specifically enrich certain proteins from the blood or serum.

The company SEER has done pioneering work in this field, but its particle production technology has so far been too expensive to carry out standard tests. We are therefore developing similar particles using a simpler technology, which can be offered at a factor of 100 lower cost and are therefore suitable for the broad market.

Partner

• Max Delbrück Center, Berlin, Germany

Nanomedicine against cancer (I – DireCT)

Description
Drugs are used to treat cancer which, due to their side effects on healthy tissue, should be released exclusively at the tumor if possible.

Various strategies are being researched for this purpose. The project aimed to address so-called checking points with bispecific antibodies that inform the natural immune system that these are dangerous cells that need to be destroyed. Porous nanoparticles made of calcium carbonate or polymeric sugar molecules were used as cargo systems.

The antibodies Cetuximab and Rituximab were used to find and dock onto the cancer cells, as the cancer cells present the complementary EGFR on the surface.

The interactions were effectively investigated using whispering gallery mode analysis.

Partner

• University Medical Center Groningen, Groningen, Netherlands

Reference

• Ghizlane Choukrani, Jimena Álvarez Freile, Natasha Ustyanovska Avtenyuk, Wei Wan, Kerstin Zimmermann, Edwin Bremer, Lars Dähne „High Loading Efficiency and Controlled Release of Bioactive Immunotherapeutic Proteins Using Vaterite Nanoparticles“ Particle 38/7 (2021) 2170013.
• Jimena Alvarez Freile, Ghizlane Choukrani, Kerstin Zimmermann, Edwin Bremer, Lars Dähne „Whispering Gallery Modes-based biosensors for real-time monitoring and binding characterization of antibody-based cancer immunotherapeutics“ Sensors and Actuators B: Chemical 364, (2021), 130512

Production of cancer cell contrast agents for photoacoustic and NIR imaging (Metadetect)

Description
In order to track the distribution and bioavailability of drugs in living animals and to monitor them by means of targeting, optical examinations that are harmless to small animals are used.

Near infrared (NIR) light, which penetrates deep enough into the body, is used for this purpose. With contrast agents, the location of the drugs can be tracked three-dimensionally using near infrared spectroscopy via fluorescence or photoacoustic imaging via light absorption.

For this purpose, we have developed nanoparticles with NIR dyes with high fluorescence or absorption intensity and immobilized nanobody antibodies on the surface that specifically bind to cancer cells.

Partner

• QVQ Holding B.V., Ultrecht, Netherlands
• Karolinska Institutet, Solna, Sweden

Reference

• Åsa Barrefelt, Maryam Saghafian, Raoul Kuiper, Fei Ye, Gabriella Egri, Moritz Klickermann, Torkel B Brismar, Peter Aspelin, Mamoun Muhammed, Lars Dähne, Moustapha Hassan “Biodistribution, kinetics, and biological fate of SPION microbubbles in the rat” ScienceOpen (2013) , PubMed ID: 24023513, Article ID: 3767493; doi:10.2147/IJN.S49948
• Åsa Barrefelt, Torkel B Brismar, Gabriella Egri, Peter Aspelin, Annie Olsson, Letizia Oddo, Silvia Margheritelli, Kenneth Caidahl, Gaio Paradossi, Lars Dähne, Rimma Axelsson, Moustapha Hassan “Multimodality imaging using SPECT/CT and MRI and ligand functionalized 99mTc-labeled magnetic microbubbles” EJNMMI Research 3 (2013), doi:10.1186/2191-219X-3-12.

Development of multifunctional contrast agents for imaging procedures

Description
In a joint European project (3 Micron), we developed contrast agents based on stable, air-filled polyvinyl alcohol capsules, whose fate in the body could be tracked not only with ultrasound diagnostics, but also with other imaging techniques such as magnetic resonance tomography (MRT), computer tomography (CT), positron emission tomography (PET) and single photon emission computer tomography (SPECT).

Partner

• Esaote AG, Genua, Italy

Reference

• Sha Wan, Gabriella Egri, Letizia Oddo, Barbara Cerroni, Lars Dähne, Gaio Paradossi, Anna Salvati, Iseult Lynch, Kenneth A. Dawson, Marco P. Monopoli “Biological in situ characterization of polymeric microbubble contrast agents” International journal of biochemistry & cell biology NanoBioMed (2016) 75: 232-243
• Mona Ahmed, Björn Gustafsson, Silvia Aldi, Philip Dusart, Gabriella Egri, Lynn M Butler, Dianna Bone, Lars Dähne, Ulf Hedin, Kenneth Caidahl: “Molecular Imaging of a New Multimodal Microbubble for Adhesion Molecule Targeting” Cellular and Molecular Bioengineering (2019) 12, 15-32

Topical vaccination: Vaccine particles for vaccination via the skin

Description
Vaccine peptides should penetrate the body through the skin and induce immunization. As the skin provides effective protection against the penetration of the vaccines, they should be delivered via the hair follicles.

It is known that 300-800 nm particles effectively penetrate the hair follicles when massaged. Using our own pH microsensors, we measured a pH of 7.2 at the root of the hair, compared to 5.3 on the skin and the hairline.

Therefore, at pH 5, two vaccine peptides and an adjuvant with glutamic acid tags and negative charge were bound to 600 nm particles with an isoelectric point of 6.2 on the cationically charged particles and massaged into the hair follicles.

At pH 7.2 in the hair follicle, the charge of the particle reversed and 50-90% of the negatively charged vaccine peptides were released and diffused to the Langerhans cells in the dermis.

Partner

• EMC Microcollections GmbH, Tübingen, Germany
• Charité – Universitätsmedizin Berlin, Berlin, Germany

Reference

• Alexa Patzelt, Heike Richter , Lars Dähne, Peter Walden, Karl-Heinz Wiesmüller, Ute Wank, Wolfram Sterry and Jürgen Lademann “Influence of the Vehicle on the Penetration of Particles into Hair Follicles”, Pharmaceutics (2011), 3, 307-314;
• Baleeiro RB, Wiesmüller KH, Dähne L, Lademann J, Barbuto JA, Walden P. „Direct activation of human dendritic cells by particle-bound but not soluble MHC class II ligand.” PLoS One 8. (2013) 8; doi: 10.1371/journal.pone.0063039. PMID: 23658796
• Renato B Baleeiro , Karl-Heinz Wiesmüller, Yoran Reiter, Barbara Baude, Lars Dähne, Alexa Patzelt, Jürgen Lademann, José A Barbuto and Peter Walden “Topical Vaccination with Functionalized Particles Targeting Dendritic Cells” J. Invest. Dermatology 133 (2013), 1933-1941.