Biological Materials Analysis


The development of biocompatible and immunocompatible medical products, such as medical devices and drugs, requires consideration of the interaction between materials or active substances and biology (biomolecules, cells, and tissues) to be able to use them safely on and in humans.

The group "Biological Material Analysis" therefore pursues an interdisciplinary approach. At the interface of medical device or drug development and immunobiology, materials, substances and active agents are evaluated, optimized, or newly developed for industrial partners. Standardized diagnostic screening test procedures are also developed for this purpose.

The focus is on cell-based test scenarios, test systems and analytical procedures for in vitro use. The developed processes form the basic framework for the questions to be investigated. In the implementation, the focus is primarily on physiological processes, i.e., processes in the patient. With such in vitro tests in the preclinical phase, the most suitable materials/active substances for the respective application can be identified and evaluated quickly and reliably, thus accelerating the development of novel medical products. The test scenarios are based on suitable acceptance criteria for method development and validation.


Immune cell-based mode of action assays for drug discovery


In the preclinical testing of drugs, bioassays, especially mode of action assays, are indispensable to investigate the desired mechanism of action or to validate it in vitro.

Various scenarios were developed in the working group for this purpose:

A) Because of their key role in inflammatory processes, macrophage-based standardized inflammation models have been established to study different inflammatory or immunomodulatory mechanisms.

B) Various test sequences to investigate the interaction with macrophages and/or mesenchymal stem cells (e.g., in new bone formation) are available for mode of action, functional or safety analyses.

© Fraunhofer IKTS
Response curve of the TNFα expression of an inflammation model in response to varying concentrations of an anti-inflammatory agent.
© Fraunhofer IKTS
Staining of the generated extracellular matrix by human mesenchymal stem cells (green) without (A) and with inflammatory influence (B). Measuring bar 100 µm.
© Fraunhofer IKTS
Inhibition of TNFα secretion of macrophages by secreted factors of immune-activated human mesenchymal stem cells.

Novel testing system for biological material testing


Conventionally, materials are examined in vitro in cell culture plates, which makes quantitative comparisons between materials (test specimens), e.g., with different geometries, difficult.

The patented in vitro test system ClicKit-Well was developed for the reliable analysis of surfaces (DE 102018221415 B3). With its surface standardized areas (e.g., 96-well format) on material test specimens, it allows quantitative comparisons between materials.

The test system thus raises the previously difficult-to-implement or material-dependent cell direct contact test of DIN ISO 10993-5 to a new level: for example, cells can be seeded equally on light and heavy materials and then quantitatively evaluated in the vitality assay with regard to their biocompatibility. This enables a targeted analysis of cytotoxic effects of surface topography or chemistry on cell vitality. A parallel extract test analogous to DIN ISO 10993-5 can also be performed for comparison.

© Fraunhofer IKTS
Modular ClicKit-Well system: The in vitro test system is designed analogous to tissue culture well plates.
© Fraunhofer IKTS
The modules, resembling the common cell culture formats 96-. 48-, 24 well, are easily exchangeable and ready to use.
© Fraunhofer IKTS
Test items with various dimensions and geometries can be inserted for investigation. When closing the test system, standardized surfaces are generated and sealed to prevent leakage.

Biological material analysis for medical products


Establishment of macrophage-based screening and mode of action assays for service and transfer

  • Testing of the immunomodulatory potential of agents, materials, or substances
  • Testing of the cytotoxicity of macrophages in the form of active substances, material extracts or in direct cell-material contact
  • Immunotoxicological tests (analogous to ISO 10993-10, -20 and -22)
  • Cell line based and/or use of primary cells (human)


Investigation of the influence of materials and agents on bone formation

  • Development/establishment of standardized in vitro test scenarios ("New Bone” assay)
  • Combined analysis on osteo-immunological properties of test materials/active substances in bone formation in vitro
  • Differentiation assays cell line based or with bone marrow primary cells (human)


Biological assessment of materials (in the context of research and development) analogous to DIN EN ISO 10993

  • In vitro cytotoxicity tests analogous to ISO 10993 for the assessment of biocompatibility (extract tests, newly developed quantitative cytotoxicity test in direct cell contact (project), cytotoxicity of nanomaterials)


Method development

  • Development of suitable methods and analytical procedures for the biological evaluation of biomaterials/medical products as well as active substances/drugs for industrially transferable screening
  • Development of novel immuno- and cell biological assays, e.g., for direct application on material surfaces (e.g., quantitative cytotoxicity test, “inflammation” assay)
  • Feasibility and validation studies
  • Establishment and validation of marker-free/non-destructive analysis methods (cell-material interaction)
  • Development of suitable (depending on the problem) test procedures, incl. controls, and preparation of corresponding protocols (SOPs)



  • Cell secretome (e.g., ELISA, Luminex)
  • Surface markers (e.g., immunofluorescence microscopy, FACS)
  • Gene expression (qPCR)
  • Enzyme activity determination
  • Biochemical assays (e.g., protein, calcium determination)
  • MSC characterization according to ISCT criteria (incl. immune potential)
  • Non-destructive imaging techniques (including digital holographic microscopy, acoustic microscopy (under development))


Further competences of the working group "Biological Material Analysis":

  • Regulatory matters for medical devices (Medical device regulation, EU 745/2017)
  • Active participation in ISO 10993 (member of DIN committee NA 027-07-12 AA / expert in ISO TC194, contact person: Dr. Susanne Kurz)
  • LEAN principles/process optimization
  • New Work

Selected projects and current research cooperation


  • BMWi - WIPANO project (knowledge and technology transfer through patents and standards) with the aim of developing a quantitative direct cytotoxicity test (as a standard test method) for medical devices - cooperation project with Eurofins BioPharma Product Testing Munich GmbH and DIN
  • German Korean AiF/ZIM cooperation project to establish a marker-free and specific analysis method for the standardized evaluation of non-transparent biomaterials in macrophage activation (cell holography/laser-assisted cell dissection) - Cooperation project with HICS Company and Pixel Inc. (South Korea), LLS ROWIAK LaserLabSolutions GmbH (Germany)
  • Project in the Fraunhofer Anti-Corona Program for biocompatibility evaluation of 3D-printed components in medical technology - cooperation project with the University of Leipzig, Neuro-Tec and the Leipzig Research and Transfer Center e. V. (FTZ) at the University of Applied Sciences (HTWK)
  • Fraunhofer SME cooperation project (IKTS and IMWS) Process optimization for the evaluation of desensitizing dental care products via the production of an artificial dentin structure based on ceramics
  • Fraunhofer cooperation: IAP, IFAM, ICT within Simpromat (BMBF-funded; funding code: FKZ 01IO1902): Further development of the in-house developed in vitro test system with focus on the serial production of individual components and the application in the field of anti-viral testing.
  • Dissertations within the Fraunhofer Attract project on the topics "Development of a combined in vitro test procedure for the evaluation of osteo-immunological properties of medical products", "Investigation of the influence of experimental conditions on the differentiation of THP-1 cells into polarized macrophages".




Reference | Patent

  • Ißleib, C.; Spohn, J.; Kurz, S. (2018). Anordnung zur Durchführung von in vitro Biokompatibilitätsprüfungen. DE102018221415, Espacenet 2020/03/13 [LINK].


Current publications

  • Ißleib C.; Kurz S.; Scholl S.; Amberg B.; Spohn J. Plasticity of proinflammatory macrophages depends on their polarization stage during human  MSC immunomodulation—an in vitro study using THP-1 and human primary macrophages. Immuno 2021, 1, 518-528. [LINK DOI | LINK Open Access]
  • Blaschke, D.; Pahlow, S.; Fremberg, T.; Weber, K.; Müller, A. D.; Kurz, S.; Spohn, J.; Dhandapani, V.; Rebohle, L.; Skorupa, I.; Schmidt, H. Functionalized silicon substrates with stripe-patterned surface-near electrostatic forces for the self-organized, stable immobilization of biomolecules. Applied Surface Science 545 (2021) 148729.
  • Balakin, S.; Yun, Y.-S.; Lee, J.; Kang, E.-H.; Spohn, J.; Yun, I.-S.; Opitz, J.; Cuniberti, G.; Yeo, J.-S. In vitro characterization of osteoblast cells on polyelectrolyte multilayers containing detonation nanodiamonds. Biomed. Mater. 15 (2020) 055026.
  • Balakin, S.; Dennison, N. R.; Klemmed, B; Spohn, J.; Cuniberti, G; Romhildt, L.; Opitz, J. Immobilization of Detonation Nanodiamonds on Macroscopic Surfaces. Appl. Sei. 9 (2019) 1064.
  • Spohn, J.; Markhoff, J.; Tillmann, J.; Krogull, M.; Pisowocki, P.; Bader, R. Direct Influence of titanium and zirconia particles on the morphology and functionality of mature human osteoclasts. J Biomed Mater Res A. 105 (2017) 36114.

This link (ResearchGate) leads to publications on biological materials analysis by Dr. Juliane Spohn.

Current research

New bone formation after acute inflammation – assessment in vitro

Current research

Analysis of cell attachment and cell spreading on silicon nitride

Current research

Biomaterial testing 2.0 – standardized, resource-efficient: ClicKit-Well


Ellipsometry in biological materials analysis