MATERIALS IN NEW ZEALAND Effects of the molecular format of collagen on characteristics of electrospun fibres Kathleen Hofman • Nick Tucker • Jon Stanger • Mark Staiger • Susan Marshall • Bronwyn Hall Received: 13 February 2011 / Accepted: 7 July 2011 / Published online: 20 July 2011 Ó Springer Science+Business Media, LLC 2011 Abstract Electrospinning is a process that is used to create nanofibres, which have the potential to be used in many medical and industrial applications. The molecular structure of the raw material is an important factor in determining the structure and quality of the electrospun fibres. In this study, we extracted collagen from a cold water fish species, hoki (Macruronus novaezelandiae), and prepared it in several different molecular formats (native triple helical collagen, denatured whole chains, denatured atelocollagen chains and gelatin) for electrospinning. Low molecular weight gelatin and atelocollagen did not form fibres. Treatment with 1,1,1,3,3,3 hexafluoro-2-propanol or 40% acetic acid denatured collagen molecules into intact a-chains prior to the electrospinning process. When using intact denatured collagen chains, 10% acetic acid was an effective aqueous-based solvent for producing uniform fibres. This information will be useful for the development of a non-toxic, aqueous solvent system suitable for indus- trial scale-up of the electrospinning process. Our results show that this low imino marine collagen is a suitable biopolymer for producing electrospun fibres. Introduction Electrospinning is a well-established, century-old process used to create nanofibres [1]. It is an entirely physical process, relying on the extremely high surface-to-volume ratio of the fibre strand for evaporation of the solvent and formation of the solid fibre. Since there are no require- ments for coagulation chemistry, high temperatures and/or highly volatile organic solvents, electrospinning is partic- ularly suitable for producing fibres from biological poly- mers such as proteins. Electrospun fibres have potential in a wide range of applications including regenerative medicine, energy cap- ture and storage and pollution control [2]. Currently, electrospun nanofibres are used extensively in filtration applications, including liquid and air purification systems [3]. Fossil-fuel derived substances are predominantly used as raw materials for industrial production of nanofibres [4]. Recently, there has been an increasing focus on biological materials, including collagen, as alternative raw materials, because of the finite nature of oil reserves [5]. Many studies have reported on electrospinning of col- lagen. Calf skin acid-soluble collagen (type I) and various type II collagens have been electrospun using 1,1,1,3,3,3- hexa fluoro-2-propanol (HFP) as the solvent [6–11]. HFP has also been used to electrospin collagen fibres in asso- ciation with other extracellular matrix components, e.g. chondroitin-6-sulphate [12, 13] elastin [14] and silk fibroin [15]. More recently, collagen fibres have been spun from 16% collagen dissolved in phosphate buffered saline/ ethanol mixtures [16]. Huang et al. [17] successfully spun a mixture of collagen and polyethylene polymer in an aqueous solvent (10 mM HCl). Stephens used formic acid as an aqueous-based delivery solvent for electrospinning of collagen [18], and noted that the low flow rates using this K. Hofman (&) Á S. Marshall Á B. Hall Bioresources, Engineering and Chemistry, The New Zealand Institute for Plant & Food Research Ltd, 300 Wakefield Quay, Port Nelson, P.O. Box 5114, Nelson 7043, New Zealand e-mail: kathleen.hofman@plantandfood.co.nz N. Tucker Á J. Stanger Bioresources, Engineering and Chemistry, The New Zealand Institute for Plant & Food Research Ltd, Private Bag 4704, Christchurch 8140, New Zealand M. Staiger Department of Mechanical Engineering, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand 123 J Mater Sci (2012) 47:1148–1155 DOI 10.1007/s10853-011-5775-2