New Method to Deliver Exogenous Material Into Developing Planarian Embryos JOSE ´ MARI ´ A MARTI ´ N-DURA ´ N 1Ã , MARTI ´ DUOCASTELLA 2 , PERE SERRA 2 , AND RAFAEL ROMERO 1 1 Departament de Gene`tica, Universitat de Barcelona, Barcelona, Spain 2 Departament de Fı´sica Aplicada i O ´ ptica, Universitat de Barcelona, Barcelona, Spain ABSTRACT The ability to report or modify the embryological processes in living embryos is pivotal for developmental biology research. Planarian embryology has experienced renewed interest as the genetic pathways that drive adult regeneration were found to be involved in the development of embryos. The major drawback to the study of planarian embryology is the absence of methods that give access to the embryos and enable their manipulation. Herein, we report on a novel method for delivering external material into developing embryos using nanosecond laser pulses. When focused on the eggshell surface under optimal parameters, laser pulses ablate the protective case and open a pathway throughout which foreign material can be delivered. In this study, we used egg capsules from Schmidtea polychroa (Schmidt, 1861) to microinject 1 mm fluorescein isothiocyanate fluorescent beads into the live embryos. We obtained viability values ranging from 15% in early egg capsules to 100% in late developmental stages. Moreover, we measured the delivery effectiveness as the number of hatchlings containing fluorescent beads per microinjected egg capsule, reaching 100% in early stages and almost 40% in late stages. This is the first time that planarian embryos have been modified without compromising normal development. We consider that this technique will be of extreme value to future work on planarian developmental biology and regeneration, enabling the application of modern functional tools to the study of this Lophotrochozoan. J. Exp. Zool. (Mol. Dev. Evol.) 310B, 2008. r 2008 Wiley-Liss, Inc. How to cite this article: Martı ´n-Dura ´n JM, Duocastella M, Serra P, Romero R. 2008. New method to deliver exogenous material into developing planarian embryos. J. Exp. Zool. (Mol. Dev. Evol.) 310B:[page range]. Developmental biology requires methods to describe the processes that take place in the embryo on both a morphological and molecular basis, and procedures to manipulate and disturb the developing system. The latter are particularly well established in common biological models, whereas emerging developmental models still have a shortage of them. Planarians (Turbellaria, Tricladida) have arisen as a convenient model to address many biological questions, mainly those focused on the extreme capabilities of the adults to regenerate a whole organism from any part of their body (for review see Agata and Watanabe, ’99; Newmark and Sa ´nchez-Alvarado, 2002; Hand- berg-Thorsager et al., 2008). In parallel, a renewed interest in planarian embryology has come about, for the most part, owing to the possibility of comparing the regenerative and embryological processes in the same species (Sa ´nchez-Alvarado, 2003; Cardona et al., 2005a; Ferna ´ndez-Rodrı ´guez, 2007; Handberg-Thorsager and Salo´, 2007). The investigation of planarian development has also other implications. Its morphological characteriza- tion (Cardona et al., 2005a; 2006) has revealed a mixture of derived and simple features, which Published online in Wiley InterScience (www.interscience.wiley. com). DOI: 10.1002/jez.b.21243 Received 24 June 2008; Revised 11 August 2008; Accepted 23 September 2008 Grant sponsors: Ministerio de Educacio´n y Ciencia; Grant numbers: BFU-2007-63209; and MAT2007-62357; Fondo Europeo de Desarrollo Regional (FEDER) and DURSI of the Catalan Government; Grant number: 2005 SGR00464. Ã Correspondence to: Jose´ Marı ´a Martı ´n-Dura ´n, Departament de Gene`tica, Universitat de Barcelona, Avda. Diagonal 645, E-08028 Barcelona, Spain. E-mail: chemamartin@ub.edu Permission for the publication herein of Sadtler Spectra has been granted by Bio-Rad Laboratories, Inc., Informatics Division. Additional Supporting Information may be found in the online version of this article. r 2008 WILEY-LISS, INC. JOURNAL OF EXPERIMENTAL ZOOLOGY (MOL DEV EVOL) 310B (2008)