Instrument for electrohydrodynamic print-patterning three-dimensional complex structures

Abstract

A print-patterning instrument coupling electrohydrodynamics and servo and stepper motor motion has been developed. It has been used to pattern and form a 10mm×30mm rectangular walled container from zirconia. The incorporation of electrohydrodynamics allows the generation of finer droplets, compared with ink-jet technology, from a concentrated two-phase medium. The precision servo/stepper system consists of a three-axis motion planner, which is computer controlled and allows three cradles to be in motion according to a predetermined sequence created on any computer aided design package. The problems encountered in forming three-dimensional (3D) structures using this method are explained and possible solutions incorporating future work are discussed. This instrument has the potential of being developed into a powerful device for 3D solid freeform fabrication of structural, functional, and biological structures.

Direct Writing of Polycaprolactone Polymer for Potential Biomedical Engineering Applications

“…Variations in EH processing from random to controlled deposition were carried out using a similar method invented by us [17] but the needle diameter used in the equipment was different (inner diameter ¼ 750 mm, outer diameter ¼ 1 175 mm). The needle was coupled to a high-voltage power supply, which can supply up to 30 kV (Glassman Europe Ltd, Tadley, UK) and the desired solutions were made to flow into the needle orifice by specially designed perfusor pumps (Harvard Apparatus, Edenbridge, UK).…”

“…[15,16] In addition to these other EH variations include, but are not restricted to multiple co-axial forming and more recently printing. [17,18] These techniques allow the generation of micrometer and nanometer scale morphologies which are appreciated in the biomaterials remit to cover a broad range of applications in particular, biomedical engineering, and drug delivery and may also be used for surface modification of implantable devices. [19,20] EH printing has been recently used to fabricate 3D polymeric scaffolds, [21] and also generate ceramic patterns leading to topographic interactions.…”

A review of electrospinning manipulation techniques to direct fiber deposition and maximize pore size

“…A control system must be used to increase the accuracy of the electrospinning process. There are several methods that can be used to manipulate the created nanofibers described in previous studies, such as electric field manipulation, alternating current (AC) electrospinning, and magnetic field manipulation [80,[96][97][98][99][100][101][102][103][104][105][106][107][108][109][110][111][112].…”

“…This repulsion has only a small effect on the total outcome of the resulting scaffold, but it increases material loss and reduces precision. To overcome this repulsion, high-voltage alternating current (AC) power source, instead of or in combination with DC power, can be utilized to create a "direct-writing" effect ( Figure 6) with electrospinning [98,100,[102][103][104][105][106][107][108][109][110].…”

Generation of multilayered structures for biomedical applications using a novel tri-needle coaxial device and electrohydrodynamic flow

“…The process can result in the formation of a jet, which may subsequently break up to form fine droplets or remain intact to produce fibres or threads (Zeleny 1914;Formhals 1934). Using this basic principle, processes such as EHD printing (Jayasinghe et al 2002;Wang et al 2005), EHD microbubbling (Farook et al 2007a) and various types of EHD micro-encapsulation ( Farook et al 2008) have evolved. The last two processes are different manifestations of coaxial EHD atomization in which two fluids simultaneously undergo EHD flow, in coaxial needles subject to the same voltage to generate coaxial jetting or spinning.…”