A widely used method to assess how liquids interact with a surface is the sessile drop technique This is an optical drop shape analysis technique to assess a solids wettability by measuring the static (drop sits on the surface) or dynamic (drop is increased or reduced) contact angle of a liquid. For example, dental and bone implant materials with different hydrophilic (water-attracting) or hydrophobic (water-repelling) properties can influence how they interact with physiological environments, making the sessile drop method an effective tool for assessing these surface properties. [12].
Optical tensiometry such as with the KRÜSS DSA100 Drop Shape Analyser, make this process highly precise and automated. A small droplet of liquid (often water) is placed on a flat solid surface. The shape of the droplet is observed and analysed, particularly the contact angle—the angle between the liquid–solid interface and the tangent at the liquid surface. A low contact angle (<90°) indicates the surface is hydrophilic and liquid spreads easily. A high contact angle (>90°) means the surface is hydrophobic and liquid beads up.
This method predicts wettability, adhesion, and biocompatibility of surfaces, making it essential for medical implants, coatings, adhesives, and biomaterials. KRÜSS instruments automate image capture and analysis, providing reproducible, high-precision data suitable for research, quality control, and regulatory documentation.
The sessile drop method also provides information on surface free energy (SFE), a key factor in medical device surface treatments. Developers can use this data to optimise adhesive bonding and surface modifications. Materials with high surface free energy and polarity—approaching that of water—tend to enhance biocompatibility, while low SFE surfaces are more hydrophobic and resist wetting or bonding. Hydrophobic prostheses, including plastics or titanium, are often plasma-treated to increase polarity, and contact angle measurements quantify pretreatment success by evaluating polar (e.g., hydrogen bonding, dipole interactions) and dispersive (van der Waals) components.
For temporary implants, excessively high biocompatibility can be undesirable, as strong adhesion complicates removal. In these cases, hydrophobic materials or coatings are preferred, and a high-water contact angle indicates suitability.
Force tensiometry such as with the KRUSS Tensiio is another technique used for assessing biocompatible coatings. The Tensiio uses the Wilhelmy plate method to measure the contact angle of coatings on solid samples (e.g., implants, stents, catheters). This determines if the surface is hydrophilic (water-attracting) or hydrophobic (water-repelling), which is critical for biocompatibility. Tensiio can detect variations in surface tension to check the uniformity of coatings applied to substrates and helps optimise the hydrophilic character of materials (like dental implants) to ensure proper wetting by body fluids, reducing air pockets and improving biocompatibility.
For rapid quality control of coating uniformity on medical device surfaces, handheld systems like the MSA Mobile Surface Analyser enable one-click surface free energy measurements of the material [13]. After quickly inserting and filling a cartridge, wetting behaviour can be measured within seconds by just pressing a button. The determined polarity of the surface gives direct feedback to the effect of pretreatment methods such as plasma treatment.
- Surface Tension & Contact Angle Application Page
- DSA100 Drop Shape Analyser
- DSA25 Drop Shape Analyser
- MSA Mobile Surface Analyser
- Tensiio Force Tensiometer
Particle Size and Colloidal Stability
The Malvern Panalytical Zetasizer Advanced series are standard tools for characterising particle size and colloidal stability in the development of biocompatible implants and coatings. Using Dynamic Light Scattering (DLS) and electrophoretic light scattering (ELS) these analytical instruments measure the hydrodynamic diameter (particle size), polydispersity index (PDI), and zeta potential of nano- and micro-materials to ensure stability, proper drug release, and biocompatibility.
The Malvern Zetasizer series employs Non-Invasive Back Scatter (NIBS) technology enabling measurements across wide concentration ranges, while M3-PALS technology provides precise zeta potential determination indicating formulation stability. Primary mechanisms of instability include aggregation or coagulation, the joining together of one of more particles, and sedimentation or settling. These mechanisms may occur independently, or in combination, as in the case of aggregation followed by associated sedimentation of the resulting larger particles [14]. Zetasizer Ultra offers advanced multi-angle detection (MADLS) which further enhances resolution of complex or multimodal nanoparticle systems, making the Zetasizer Ultra particularly valuable for hybrid or composite adhesive systems.
For higher resolution analysis of polydisperse samples, Nanoparticle Tracking Analysis using instruments like the NanoSight Pro enables particle-by-particle sizing and concentration measurement. For nanoparticle-based coatings, especially those incorporating polymer nanoparticles, or biologically derived components, understanding particle concentration and distribution is critical for dose control and functional consistency. Fluorescence capabilities also allow selective measurement of labelled nanoparticles within complex biological media — a significant advantage when evaluating adhesive systems intended for in vivo applications [15].
Together, the Zetasizer Ultra and NanoSight Pro provide orthogonal, complementary data. DLS offers rapid, bulk measurement of size and stability, while NTA delivers single-particle resolution and accurate concentration analysis.
- Zetasizer Pro
- Zetasizer Lab
- Zeta Potential Application Page
- NanoSight Pro
Microscopy and Morphological Analysis
Understanding the structure and morphology of biocompatible adhesives and coatings is essential for predicting performance, adhesion strength, degradation, and biological response. Imaging techniques provide direct insight into particle shape, surface uniformity, coating thickness, dispersion, and interfacial interactions — supporting both formulation optimisation and quality control.
Two powerful and complementary tools for this purpose are the Morphologi 4-ID from Malvern Panalytical and the Phenom ProX from Thermo Fisher Scientific.
The Morphologi 4-ID combines automated static image analysis with chemical identification using Raman spectroscopy. Automated imaging provides statistically robust shape information on thousands of individual particles. The addition of Raman identification allows chemical verification of specific particle populations within complex mixtures — particularly valuable for multi-component coatings where distribution of active ingredients must be controlled [16].
For detailed surface and interfacial characterisation, scanning electron microscopy (SEM) provides rapid characterisation of coating microstructure, particle distribution, and surface topology at nanometer resolution. Desktop SEM systems such as the Phenom ProX combine high-resolution imaging (< 6 nm) with integrated EDS elemental analysis, providing chemical composition verification alongside structural imaging without the additional costs and complex infrastructure requirements of traditional floor-model SEMs. The rapid time-to-image (< 30 seconds) and intuitive operation enable high-throughput quality control in medical device manufacturing [17].
- Phenom Desktop SEM Series
- Phenom ProX Desktop SEM
- SEM & Imaging Field Page
Formulation Development and Processing
Micropore’s membrane-based technologies can directly support the development of hydrogel-based biocompatible coatings by enabling controlled formation and sizing of hydrogel particles — a key factor in performance and consistency.
Membrane emulsification can form hydrogel droplets as water‑in‑oil emulsions with very uniform size and shape, generating spherical hydrogel particles smaller than ~50 µm with tight size control. This precise control helps produce coatings with predictable hydration, adhesion properties, and surface coverage. Because hydrogels are often used to mimic the extracellular matrix or to deliver actives in biomedical coatings (e.g., wound dressings, tissue engineering scaffolds, or sustained release systems), producing monodisperse hydrogel particles reduces variability and improves reproducibility in coating formulations. The controlled droplet formation also minimises defects and improves stability relative to conventional high‑shear emulsification [18].
Australian Research Spotlight
Australian biomedical engineering research is a rapidly growing, high-impact field focusing on medical devices and tissue engineering and AI driven diagnostics. Major initiatives include personalised 3D-printed implants, neural engineering (bionics), and advanced imaging.
Researchers at UNSW Biomedical engineering are working on developing brain-machine interfaces focused on improving bionic eyes for vision restoration in blind humans as well as developing other devices for chronic pain and inflammatory bowel disease. It is hoped that their work could one day offer dramatic benefits for paralysed individuals to regain use of limbs [19].
At the University of Melbourne, Department of Biomedical Engineering, researchers together with Anatomics – manufacturer of titanium cranio-facial implants – have developed a technique to make polymer-based skull implants more bone-like in their structure, leading to improved outcomes for patients relying on implants to repair head injuries [20].
Harry Perkins Institute of Medical Research [21] in Western Australia has developed biopolymer 3D-printed heart valve technology to be commercialised in Australia to help millions globally suffering from aortic stenosis.
The CSIRO holds the patent and provisional patents in surface modification technology, which is being used in multiple SIEF projects designing coatings for medical devices biocompatibility, hemocompatibility and to minimise foreign body responses [22, 23].
Current Challenges and Future Directions
Biocompatible coatings and tissue adhesives face several persistent challenges in moving from laboratory research to clinical use:
- Balancing strong adhesion with low toxicity
- Achieving controlled degradation that matches tissue healing rates
- Maintaining stability in complex, dynamic biological environments
- Incorporating therapeutic agents without compromising mechanical performance
- Scaling up manufacturing while meeting strict regulatory requirements
Looking ahead, research is focused on bioinspired wet-adhesion strategies, smart and stimuli-responsive materials, nanostructured designs for improved strength and controlled release, scalable GMP-ready manufacturing, and more predictive characterisation and modelling tools — all aimed at creating safer, more clinically translatable systems.
ATA Scientific’s Commitment to Biomedical Research
At ATA Scientific, we support researchers with proven technologies from leading partners including Malvern Panalytical, KRÜSS, and ThermoScientific — helping ensure critical material properties are understood, controlled, and optimised.
From early-stage formulation through to final product optimisation, comprehensive material characterisation underpins innovation in tissue adhesives and biocompatible coatings. By combining complementary analytical techniques, researchers gain the insights needed to design safer, more effective materials that perform as intended in complex biological environments.
If you’d like to explore how these technologies can support your biomaterials research, our team is here to help—offering expert advice, applications support, and local service every step of the way.
Contact us today to discuss your project with our team
