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. 2008 Oct 6;5(27):1255-61.
doi: 10.1098/rsif.2008.0247.

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

Z Ahmad  1 , H B Zhang, U Farook, M Edirisinghe, E Stride, P Colombo
Affiliations

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

Z Ahmad et al. J R Soc Interface. .

Abstract

In this short communication, we describe the scope and flexibility of using a novel device containing three coaxially arranged needles to form a variety of novel morphologies. Different combinations of materials are subjected to controlled flow through the device under the influence of an applied electric field. The resulting electrohydrodynamic flow allows us to prepare double-layered bubbles, porous encapsulated threads and nanocapsules containing three layers. The ability to process such multilayered structures is very significant for biomedical engineering applications, for example, generating capsules for drug delivery, which can provide multistage controlled release.

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Figures

Figure 1
Figure 1
Details of the three-needle coaxial device: (a) needle assembly, (b) needle dimensions and (c) relative placement of needles in the device. ID and OD represent internal and outer diameters, respectively.
Figure 2
Figure 2
Droplet encapsulation resulting in layered relics. (a) Flow arrangement of materials during processing, (b) coaxial two-needle product with olive oil and glycerol, (c) non-concentric coaxial two-needle encapsulation and (d) coaxial tri-needle encapsulation with air, glycerol and olive oil.
Figure 3
Figure 3
Thread encapsulation. (a) Flow arrangement, (b) air encapsulation in twin-layered thread with olive oil and PEO solution, (c) instabilities during thread formation and (d) two-needle (third needle switched off) coaxial non-concentric thread encapsulation using olive oil and PEO solution.
Figure 4
Figure 4
Nanocapsule formation. (a) Flow arrangement of mediums used, (b) scanning electron micrograph of nanocapsules, (c) high magnification scanning electron micrograph of nanocapsules showing different regions (densities), (d) transmission electron micrograph of nanocapsule with non-concentric multiple layers and (e) transmission electron micrograph of nanocapsule with concentric multiple layers.
See this image and copyright information in PMC

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