A laboratory-scale device for the straightforward production of uniform, small sized cell microcapsules with long-term cell viability Leena-Stiina Kontturi a, ⁎, Marjo Yliperttula b , Pyry Toivanen c,d , Antti Määttä c , Ann-Marie Määttä c , Arto Urtti a a Centre for Drug Research, University of Helsinki, Helsinki,00014,Finland b Division of Biopharmacy and Pharmacokinetics, University of Helsinki, Helsinki,00014,Finland c Ark Therapeutics Oy, Kuopio,70210,Finland d A. I. Virtanen Institute, Department of Biotechnology and Molecular Medicine, University of Eastern Finland, Kuopio,70211,Finland a b s t r a c t a r t i c l e i n f o Article history: Received 16 December 2010 Accepted 6 March 2011 Available online 11 March 2011 Keywords: Cell microencapsulation Device Alginate Recombinant protein Cell viability Microencapsulated and genetically engineered cells may be used for prolonged delivery of therapeutically active proteins. The objective of this study was to develop a simple, inexpensive and flexible laboratory-scale device for the production ofcell microcapsules, especially capsules of small diameter (b300 μm).Many microencapsulation devices are expensive, difficult to assemble and to use, and often more suitable for large- scale experiments. However,the simplicity and low price of the encapsulation system should not limit the quality of capsules and reproducibility of the process: for successful in vitro and in vivo experiments it is important to be able to produce uniform, sphericalmicrocapsules withoutdeformities with high reproducibility.In addition, an advantage ofthe presentprocedure compared to other similar, co-axial laminar gas flow systems is the possibility to produce also small microcapsules, less than 200 μm in diameter, with narrow size distribution.First, design,optimization and reproducibility testing of this custom-built device were carried out. Second,microencapsulated retinal pigment epithelialcells (ARPE-19) capable of secreting soluble vascularendothelialgrowth factor receptor1 (sVEGFR1) were engineered.The cells remained viable in alginate-poly-L-lysine-alginate microcapsules and secreted sVEGFR1 for prolonged periods. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Transplantation of microencapsulated cells secreting therapeutic factors is a potentialalternative for long-term treatment of various disease states such as neurodegenerative, endocrine and mendelian inherited diseases, as well as cancer [1]. Since the original introduc- tion of the concept [2] and the first experimentwith cell micro- capsules [3], many different techniques and devices to produce microcapsules have been developed. The most common techniques applied in cell microencapsulation are emulsification, extrusion and co-extrusion, but also new technol- ogies, such as microfluidics, microlithography and micromolding have emerged (for ref. see[4]). Emulsion methods are simple and easy to scale-up, but only large sized beads with broad size distribution can be produced [4]. Extrusion methods utilize the co-axial laminar gas flow, electrostatic potential, vibrating nozzle and jet cutting [5–8]. In co- axial gas flow extrusion, the beads are produced when the polymer solution is dispersed with a laminar co-axial gas flow.This method was the first cellencapsulation technique to be developed and has thus been used for a long time. It is easy to set up and is a fairly gentle procedure for the encapsulated cells. Furthermore, this method is not severely limited by the high viscosity of the polymer solutions used in the encapsulation process [5,6,8]. At present, cell microencapsulation is often performed with commercial equipment (e.g. Inotech, Nisco). However, there is a need for inexpensive and convenientlaboratory-scale devices for microencapsulation experiments, especially in academia. Some custom-built microencapsulation devices and methods have been developed previously [9–16]. However,in these studies the descrip- tion of the device has not been detailed, the quality and size uniformity of the microcapsules has not been especially good, the production of small sized microcapsules has not been possible or the construction and calibration of the system has required special skills. Our purpose was to design a microencapsulation apparatus that is as simple and convenient as possible, without compromising the quality of the produced capsules. Unlike the previous reports on laboratory- scale devices, we aimed here to produce microcapsules with defined and adjustable sizes,extending also to microcapsules of less than 200 μm in diameter. Advantages of small cell microcapsules include more effective exchange of nutrients and other molecules between Journal of Controlled Release 152 (2011) 376–381 ⁎ Corresponding author at: Centre for Drug Research, University of Helsinki, Viikinkaari 5 E, 00014 Helsinki, Finland. Tel.: +358 9 191 59125, fax: +358 9 191 59725. E-mail address: leena.kontturi@helsinki.fi (L.-S. Kontturi). 0168-3659/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.jconrel.2011.03.005 Contents lists available at ScienceDirect Journal of Controlled Release j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / j c o n r e l