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Xingchen Zhao is a PhD student of Biomaterials in the Department of Materials, Imperial College London. He is working on the ‘Cotton-wool-like bioglass scaffold for wound healing’ project supervised by Prof. Julian Jones. He received a bachelor’s degree in Material Science and Engineering, Imperial College London. His main areas of interests are bioactive glasses, electrospinning, and soft tissue repairing.

Xingchen Zhao & Prof. Julian R. Jones*

Chronic wounds are causing great threat to our social health-care system both medically and economically. While inappropriately treated, chronic wounds induce further infection, trauma and cancerization, making the wounds more difficult to be cured. Therefore, development of novel wound care materials is needing and indispensable.

Bioglass is a great candidate in wound healing. It is a highly bioactive material and promote wound healing by degrading and releasing therapeutic ions towards wound area [1]. 3D bioactive glass fibre scaffold would be achieved through electrospinning while all parameters are controlled to induce jet branching. The scaffold mimics the extracellular matrix (ECM and will promote cells attachment, proliferation and differentiation on the fibre surfaces [2].

There are two approaches in improving the healing effect of the resultant scaffold. The first is to alter the therapeutic ions incorporated in glass scaffold. Among all therapeutic ions, Zn has been found to be an excellent trace element to promote wound healing. It promotes angiogenesis, reepithelialization and secretion of growth factors. It also prevents external infection, necrosis of cells due to high ROS, and cancerization of cells [3]. Meanwhile, B as a network former could induce higher bioactivity to glass. B intake is also reported to be beneficial to angiogenesis promotion, and infection and cancer inhibition [4].

The second is to change the operational parameter to improve the morphology of the glass. Humidity and ventilation are two factors involved in electrospinning which greatly contributes to fibre dimensions, scaffold porosity and production rate. Controlling and quantifying their effects would be advantageous to the efficiency and effectiveness of the resultant scaffold.

This study aims to incorporate Zn and B in 3D bioglass electrospun scaffold and investigate its wound healing abilities. Zn and B doped 3D bioglass electrospun scaffold is first prepared in this study. Tetraethyl orthosilicate (TEOS), triethyl borate (TEB), ethanol, water, nitric acid, zinc nitrate and calcium nitrate are mixed and gelled for 1-2 days. The solution is mixed with a polyvinyl butyral binder to increase its viscosity for electrospinning. The morphology and dissolution profiles of the produced fibre scaffold are further characterized. It is found out that these ions will hardly interrupt glass structure and dissolution properties. The release rate of ions would be safe and within the therapeutic range and promote healing process.

Control of humidity and ventilation is also achieved under a plastic dome system. An air tube is used as source for ventilation and argon is applied to reduce humidity. This control induces better modification of glass morphology and thus increases the bioactivity of bioglass. Overall results show that the resultant 3D scaffold has great potential in improving wound healing. Further applications of this scaffold include wound healing and drug delivery when a malignant tumour has been removed.

References

  1. Julian R Jones. Review of bioactive glass: from hench to hybrids. Acta biomaterialia, 9(1):4457– 4486, 2013
  2. Gowsihan Poologasundarampillai, D Wang, S Li, J Nakamura, R Bradley, PD Lee, MM Stevens, David S McPhail, Toshihiro Kasuga, and JR Jones. Cotton-wool-like bioactive glasses for bone regeneration. Acta biomaterialia, 10(8):3733–3746, 2014
  3. Alan BG Lansdown, Ursula Mirastschijski, Nicky Stubbs, Elizabeth Scanlon, and Magnus S ˚Agren. Zinc in wound healing: theoretical, experimental, and clinical aspects. Wound repair and regenera- tion, 15(1):2–16, 2007
  4. Selami Demirci, Ay¸segu¨l Do˘gan, Safa Aydın, Esra C¸ ikler Du¨lger, and Fikrettin S¸ahin. Boron promotes streptozotocin-induced diabetic wound healing: roles in cell proliferation and migration, growth factor expression, and inflammation. Molecular and cellular biochemistry, 417(1-2):119–133, 2016

Figure 1: SEM diagrams for the electrospun 3D bioglass scaffold

Figure 2: SEM diagrams for electrospun 70S27C3Zn fiber scaffold under ’no vent’

Figure 3: SEM diagrams for electrospun 70S27C3Zn fiber scaffold under ’direct vent’

Figure 4: SEM diagrams for electrospun 70S27C3Zn fiber scaffold controlling humidity from 37% to 33%

Figure 1: SEM diagrams for the electrospun 3D bioglass scaffold

Figure 2: SEM diagrams for electrospun 70S27C3Zn fiber scaffold under ’no vent’
Figure 3: SEM diagrams for electrospun 70S27C3Zn fiber scaffold under ’direct vent’

Figure 4: SEM diagrams for electrospun 70S27C3Zn fiber scaffold controlling humidity from 37% to 33%