Cost-Effective Bioreactor Housing: Material Optimization Nutthanan Wanluk, Thanapond Kangkhunthot, Patita Phunsuklert, Nicola Green, Jeerawan Thanarak Bmeicon 2025 17th Biomedical Engineering International Conference, 2025 Bioreactor is the device that is being used extensively for in vitro experiments. It supports the investigation of the effects from various stimulations on the particular cells. The selection of appropriate materials for bioreactor housing is critical to ensure the performance and longevity of bioreactor systems. This study evaluates the suitability of five candidate materials-Polylactic Acid (PLA), Expanded Polyamide (ePA), Polyethylene Terephthalate Glycol-modified (PETG), and Acrylonitrile Butadiene (ABS) for bioreactor housing. The materials were subjected to continuous and cyclic submersion in 70% alcohol and tested for their mechanical properties, including Young's Modulus and stress behavior, as well as their hydrophobicity using contact angle testing. Results indicate that PLA is the most suitable material, exhibiting high resistance toward alcohol disinfection, stability under cyclic immersion, and significant hydrophobicity, making it ideal for bioreactor housing applications. The study provides insights into material selection, surface treatments, and their implications on bioreactor system efficiency.
Adipose tissue and adipose-derived stromal cells can reduce skin contraction in an in vitro tissue engineered full thickness skin model Victoria L. Workman, Anna‑Victoria Giblin, Nicola H. Green, Sheila MacNeil, Vanessa Hearnden Adipocyte, 2025 Skin contracts during wound healing to facilitate wound closure. In some patients, skin contraction can lead to the formation of skin contractures that limit movement, impair function, and significantly impact well-being. Current treatment options for skin contractures are burdensome for patients, and there is a high risk of recurrence. Autologous fat grafting can improve the structure and function of scarred skin; however, relatively little is known about the effect of fat on skin contraction. In this study, an in vitro tissue-engineered model of human skin was used to test the effects of adipose tissue and adipose-derived stromal cells on skin contraction. Untreated tissue-engineered skin contracted to approximately 60% of the original area over 14 days in culture. The addition of adipose tissue reduced this contraction by 50%. Adipose tissue, which was emulsified or concentrated and high doses of adipose-derived stromal cells (ADSC) were able to inhibit contraction to a similar degree; however, lower doses of ADSC did not show the same effect. In conclusion, the subcutaneous application of adipose tissue has the potential to inhibit skin contraction. This study provides in vitro evidence to support the use of autologous fat grafting to prevent skin contraction in patients most at risk.
Inhibition and reversal of a TGF-β1 induced myofibroblast phenotype by adipose tissue-derived paracrine factors S. Higginbotham, V. L. Workman, A-V. Giblin, N. H. Green, D. W. Lambert, V. Hearnden Stem Cell Research and Therapy, 2024 Background Hypertrophic scarring results from myofibroblast differentiation and persistence during wound healing. Currently no effective treatment for hypertrophic scarring exists however, autologous fat grafting has been shown to improve scar elasticity, appearance, and function. The aim of this study was to understand how paracrine factors from adipose tissues and adipose-derived stromal cells (ADSC) affect fibroblast to myofibroblast differentiation. Methods The transforming growth factor-β1 (TGF-β1) induced model of myofibroblast differentiation was used to test the effect of conditioned media from adipose tissue, ADSC or lipid on the proportion of fibroblasts and myofibroblasts. Results Adipose tissue conditioned media inhibited the differentiation of fibroblasts to myofibroblasts but this inhibition was not observed following treatment with ADSC or lipid conditioned media. Hepatocyte growth factor (HGF) was readily detected in the conditioned medium from adipose tissue but not ADSC. Cells treated with HGF, or fortinib to block HGF, demonstrated that HGF was not responsible for the inhibition of myofibroblast differentiation. Conditioned media from adipose tissue was shown to reduce the proportion of myofibroblasts when added to fibroblasts previously treated with TGF-β1, however, conditioned media treatment was unable to significantly reduce the proportion of myofibroblasts in cell populations isolated from scar tissue. Conclusions Cultured ADSC or adipocytes have been the focus of most studies, however, this work highlights the importance of considering whole adipose tissue to further our understanding of fat grafting. This study supports the use of autologous fat grafts for scar treatment and highlights the need for further investigation to determine the mechanism.
Highly porous polycaprolactone microspheres for skeletal repair promote a mature bone cell phenotype in vitro Thomas E. Paterson, Robert Owen, Colin Sherborne, Hossein Bahmaee, Amy L. Harding, Nicola H. Green, Gwendolen C. Reilly, Frederik Claeyssens Journal of Materials Chemistry B, 2024 Porous, biodegradable polycaprolactone microspheres support mesenchymal progenitor cell growth and differentiation. Only cells inside the microspheres differentiate into an osteocyte-like phenotype, indicating the role of physical environmental cues.
The use of microphysiological systems to model metastatic cancer Caitlin E Jackson, Nicola H Green, William R English, Frederik Claeyssens Biofabrication, 2024 Cancer is one of the leading causes of death in the 21st century, with metastasis of cancer attributing to 90% of cancer-related deaths. Therefore, to improve patient outcomes there is a need for better preclinical models to increase the success of translating oncological therapies into the clinic. Current traditional static in vitro models lack a perfusable network which is critical to overcome the diffusional mass transfer limit to provide a mechanism for the exchange of essential nutrients and waste removal, and increase their physiological relevance. Furthermore, these models typically lack cellular heterogeneity and key components of the immune system and tumour microenvironment. This review explores rapidly developing strategies utilising perfusable microphysiological systems (MPS) for investigating cancer cell metastasis. In this review we initially outline the mechanisms of cancer metastasis, highlighting key steps and identifying the current gaps in our understanding of the metastatic cascade, exploring MPS focused on investigating the individual steps of the metastatic cascade before detailing the latest MPS which can investigate multiple components of the cascade. This review then focuses on the factors which can affect the performance of an MPS designed for cancer applications with a final discussion summarising the challenges and future directions for the use of MPS for cancer models.
Development of a tissue-engineered skin model with epidermal, dermal and hypodermal components V. L. Workman, A-V. Giblin, N. H. Green, S. MacNeil, V. Hearnden In Vitro Models, 2023 Tissue-engineered models of skin have evolved over the past 50 years, have successfully been translated to clinical use and continue to be improved using new technologies. However, very few of these constructs incorporate a hypodermal component. The hypodermis is critical to skin homeostasis, skin function and many skin diseases, but our understanding of the hypodermis is limited in comparison to our knowledge of the epidermis and dermis, in part due to a lack of suitable in vitro models.The purpose of this study was to develop and characterise a tissue-engineered model of skin consisting of epidermal, dermal and hypodermal layers, namely a trilayer skin model. Models were produced by culturing human keratinocytes and fibroblasts on decellularised human dermis in combination with explanted human adipose tissue.Bilayer models of skin, comprising of an epidermis and dermis, had a thicker epidermal component compared to trilayer models but exhibited similar cytokeratin expression patterns (AE1/AE3 and cytokeratin 14). Addition of adipose tissue improved the appearance of the dermal-epidermal junction, increased the number of rete ridge-like features and cells maintained similar levels of proliferation (Ki-67) compared to native tissues over 28 days in culture.This technique enabled us to create a physiologically relevant model of human skin with representative morphology across the hypodermis, dermis and epidermis. This model maintained native extracellular matrix architecture, contained a heterogeneous population of cells and has the potential to be applied to a range of different applications where research questions require the inclusion of a hypodermis.
Synthesis and characterisation of photocurable poly(glycerol sebacate)-co-poly(ethylene glycol) methacrylates Mina Aleemardani, Louis Johnson, Michael Zivojin Trikić, Nicola Helen Green, Frederik Claeyssens Materials Today Advances, 2023 Poly (glycerol sebacate)-co-poly (ethylene glycol) (PGS-co-PEG) copolymers have multifunctional and tunable properties and great potential as high-performance biomaterials. However, the application of these materials is currently limited by harsh crosslinking conditions that include high temperatures and long reaction times. In this study, in order to overcome these limitations, the methacrylation process was conducted on PGS-co-PEG, resulting in photocurable (PGS-co-PEG)-M copolymers. Methacrylation of PGS-co-PEG, formulated respectively from polyethylene glycol (PEG2) or glycerol ethoxylate (PEG3), was investigated for the first time. (PGS-co-PEG2)-M and (PGS-co-PEG3)-M were found to be biodegradable, biocompatible, bioadhesive, pH-responsive and photocurable. Multifunctional characteristics remained after methacrylation, they were, however, drastically altered. Mechanical strength was enhanced significantly for (PGS-co-PEG)-M copolymers. Tensile Young's moduli of (PGS-co-PEG2)-M samples ranged from 0.08 to 0.48 MPa, while those of (PGS-co-PEG3)-M ranged from 2.67 to 35.47 MPa, indicating the mechanical properties of the materials can be tuned via crosslinking density. In contrast, bioadhesive properties, such as lap-shear and adhesion strengths, were almost halved due to methacrylation. The degradation and swelling rates were slightly reduced, but pH-responsive behaviours at pH = 5.0, 7.4 and 9.1 were still observed. Cell metabolic activity and double-stranded DNA content, investigated by resazurin and PicoGreen® assays, demonstrated that the (PGS-co-PEG)-M copolymers were biocompatible. Photocurable (PGS-co-PEG)-M copolymers facilitate a simple and user-friendly curing process (photocrosslinking) that could be used for biomedical applications. Moreover, these photocurable copolymers are beneficial for various biofabrication methods, including emulsion techniques and additive manufacturing, either directly or indirectly.
Development of PCL PolyHIPE Substrates for 3D Breast Cancer Cell Culture Caitlin E. Jackson, David H. Ramos-Rodriguez, Nicholas T. H. Farr, William R. English, Nicola H. Green, Frederik Claeyssens Bioengineering, 2023 Cancer is a becoming a huge social and economic burden on society, becoming one of the most significant barriers to life expectancy in the 21st century. In particular, breast cancer is one of the leading causes of death for women. One of the most significant difficulties to finding efficient therapies for specific cancers, such as breast cancer, is the efficiency and ease of drug development and testing. Tissue-engineered (TE) in vitro models are rapidly developing as an alternative to animal testing for pharmaceuticals. Additionally, porosity included within these structures overcomes the diffusional mass transfer limit whilst enabling cell infiltration and integration with surrounding tissue. Within this study, we investigated the use of high-molecular-weight polycaprolactone methacrylate (PCL–M) polymerised high-internal-phase emulsions (polyHIPEs) as a scaffold to support 3D breast cancer (MDA-MB-231) cell culture. We assessed the porosity, interconnectivity, and morphology of the polyHIPEs when varying mixing speed during formation of the emulsion, successfully demonstrating the tunability of these polyHIPEs. An ex ovo chick chorioallantoic membrane assay identified the scaffolds as bioinert, with biocompatible properties within a vascularised tissue. Furthermore, in vitro assessment of cell attachment and proliferation showed promising potential for the use of PCL polyHIPEs to support cell growth. Our results demonstrate that PCL polyHIPEs are a promising material to support cancer cell growth with tuneable porosity and interconnectivity for the fabrication of perfusable 3D cancer models.
Surfactant-free gelatin-stabilised biodegradable polymerised high internal phase emulsions with macroporous structures Rachel Furmidge, Caitlin E. Jackson, María Fernanda Velázquez de la Paz, Victoria L. Workman, Nicola H. Green, Gwendolen C. Reilly, Vanessa Hearnden, Frederik Claeyssens Frontiers in Chemistry, 2023 High internal phase emulsion (HIPE) templating is a well-established method for the generation of polymeric materials with high porosity (>74%) and degree of interconnectivity. The porosity and pore size can be altered by adjusting parameters during emulsification, which affects the properties of the resulting porous structure. However, there remain challenges for the fabrication of polyHIPEs, including typically small pore sizes (∼20–50 μm) and the use of surfactants, which can limit their use in biological applications. Here, we present the use of gelatin, a natural polymer, during the formation of polyHIPE structures, through the use of two biodegradable polymers, polycaprolactone-methacrylate (PCL-M) and polyglycerol sebacate-methacrylate (PGS-M). When gelatin is used as the internal phase, it is capable of stabilising emulsions without the need for an additional surfactant. Furthermore, by changing the concentration of gelatin within the internal phase, the pore size of the resulting polyHIPE can be tuned. 5% gelatin solution resulted in the largest mean pore size, increasing from 53 μm to 80 μm and 28 μm to 94 µm for PCL-M and PGS-M respectively. In addition, the inclusion of gelatin further increased the mechanical properties of the polyHIPEs and increased the period an emulsion could be stored before polymerisation. Our results demonstrate the potential to use gelatin for the fabrication of surfactant-free polyHIPEs with macroporous structures, with potential applications in tissue engineering, environmental and agricultural industries.
Porous biomaterials for tissue engineering: a review Fouad Junior Maksoud, María Fernanda Velázquez de la Paz, Alice J. Hann, Jeerawan Thanarak, Gwendolen C. Reilly, Frederik Claeyssens, Nicola H. Green, Yu Shrike Zhang Journal of Materials Chemistry B, 2022
