Biomaterials Biomaterials

Analyzing the Thermal Properties of Biomaterials

Trident - MTPS - Front View

Trident Instrument with MTPS

The thermal properties of biomaterials can have a significant effect on the performance of the material with regards to implantation and interfacing with biological tissues. With the advent of more sophisticated implants, including those that contain electrical components, thermal conductivity and diffusivity have become more of a concern. Thermal management for the electrical components can be a problem, as traditional polymeric materials tend to act more like thermal insulators rather than conductors. This can damage the electrical components, or more likely, damage the surrounding tissue.

Typically, heat transfer within a polymeric material occurs through phonons, a heatwave that can propagate through the crystalline matrix of a polymeric material. The degree of crystallinity will affect the thermal conductivity of such materials. To create more thermally conductive polymer materials, the degree of crystallinity and stacking of a polymer material must be high as to conduct heat away from the electrically active components. Typically, this means that materials that are more amorphous tend to act as good thermal insulators, and these amorphous materials also tend to be abundant in more biologically derived materials. One method to increase the thermal conductivity of an amorphous material would be to create self-assembled structures that are highly organized. These materials can be gels or self-assembled coated materials. Gel materials have several options for implantation, including acting as cell scaffolds for implantation or as artificial tissues for implantation. Coated materials for implants can consist of polymers that coat the metal circuits.

C-Therm’s Trident platform can provide unique insight into the thermal behavior of these more difficult materials in employing the modified transient plane source (MTPS) technique. Gel-type materials can be explored using MTPS measurements ensuring that the thermal properties of these tissue-mimicking materials match the surrounding implantation environment. MTPS measurements of thermal conductivity can explore electrical components or coating materials, which often possess difficult geometric constraints which other techniques find difficult to measure.

  • Centre for Industrial Rheology

    “Our lab is frequently asked to identify the best practical methods for characterizing fundamental physical properties of soft materials, for a myriad of industries including pharma, food, cosmetics, specialty chemicals, and electronics. The MTPS method available on C-Therm’s Trident System is a perfect fit for us, providing a simple, highly accurate, practical, and versatile route for measuring thermal conductivity of semi-solids, powders, and fluids. The MTPS is a welcome addition to our capabilities, helping to complete our service offering, and has been a boon to the growth of our business.”

    Neil Cunningham,
    Founder & CEO

    Centre for Industrial Rheology More Testimonials
  • Kimberly Clark

    “C-Therm’s MTPS sensor is a fast and accurate instrument which has been an invaluable addition to our lab. The MTPS sensor allows us to quickly understand the thermal properties of our non-woven textile materials, diapers, and wipes. The thermal properties of these materials were previously unknown. [...] I would definitely recommend C-Therm thermal conductivity instruments to those looking to know the thermal properties for their materials.”

    Fang Wang,
    Lead Material Scientist

    More Testimonials

Case Highlights

Thermal shielding performance of self-healing hydrogel in tumor thermal ablation

This is an example of the TPS method being used in the biomedical/biomaterials context.

Abstract from the original publication: Thermal ablation therapy is widely used in the surgical treatment of tumors. Clinically, normal saline is generally used as an insulator to protect adjacent tissues from local high-temperature burns caused by thermal ablation. However, the flow of saline causes fluid loss, requiring frequent injections and complex operation, which is easy to lead to complications such as secondary injury and hematoma. Here, a self-healing chitosan-PEG (CP) hydrogel was proposed as a protective medium to challenge the clinical preparations. Compared with saline and non-self-healing hydrogel F127, CP hydrogel exhibited outstanding thermal shielding performance in the thermal ablation of thyroid nodule in a Beagle dog model. The transient plane source (TPS) method is used to measure thermal properties, including thermal conductivitythermal diffusivity and specific heat capacity. The thermal shielding mechanism and clinical advantages including operability, biodegradability, and biological safety of self-healing hydrogel are then revealed in-depth. Therefore, self-healing hydrogel can achieve much better thermal management in tumor thermal ablation. [1]

biomaterials - case 1

Heat insulation mechanism of CP hydrogel. (a) Schematic diagram of thermal insulation mechanism of different media (normal saline, polymer solution, hydrogel). (b) Schematic representation of TPS method for measuring hydrogel thermal property. (c) Curves of temperature versus time for 2.5% CPH and 20% F127. [1]

[1] Lifei Huang, Shiyuan Yang, Mingyu Bai, Yuxuan Lin, Xue Chen, Guofeng Li, Li-gang Cui, Xing Wang, Thermal shielding performance of self-healing hydrogel in tumor thermal ablation, Colloids and Surfaces B: Biointerfaces, Volume 213, 2022, 112382, ISSN 0927-7765, https://doi.org/10.1016/j.colsurfb.2022.112382.


Thermally drawn biodegradable fibers with tailored topography for biomedical applications

In this study, the thermal conductivity of the PCL samples was measured using a C-therm’s TCi thermal conductivity analyzer.

Abstract from original publication: There is a growing demand for polymer fiber scaffolds for biomedical applications and tissue engineering. Biodegradable polymers such as polycaprolactone have attracted particular attention due to their applicability to tissue engineering and optical neural interfacing. Here we report on a scalable and inexpensive fiber fabrication technique, which enables the drawing of PCL fibers in a single process without the use of auxiliary cladding. We demonstrate the possibility of drawing PCL fibers of different geometries and cross-sections, including solid-core, hollow-core, and grooved fibers. The solid-core fibers of different geometries are shown to support cell growth, through successful MCF-7 breast cancer cell attachment and proliferation. We also show that the hollow-core fibers exhibit a relatively stable optical propagation loss after submersion into a biological fluid for up to 21 days with potential to be used as waveguides in optical neural interfacing. The capacity to tailor the surface morphology of biodegradable PCL fibers and their non-cytotoxicity make the proposed approach an attractive platform for biomedical applications and tissue engineering. [2]

biomaterials case 2

Degree of crystallinity and thermal conductivity of PCL samples as functions of molecular weight [2]

[2] Farajikhah S, Runge AFJ, Boumelhem BB, Rukhlenko ID, Stefani A, Sayyar S, Innis PC, Fraser ST, Fleming S, Large MCJ. Thermally drawn biodegradable fibers with tailored topography for biomedical applications. J Biomed Mater Res B Appl Biomater. 2021 May;109(5):733-743. doi: 10.1002/jbm.b.34739. Epub 2020 Oct 18. PMID: 33073509.


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