768 wileyonlinelibrary.com full papers © 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Combinatorial On-Chip Study of Miniaturized 3D Porous Scaffolds Using a Patterned Superhydrophobic Platform Mariana B. Oliveira, Christiane L. Salgado, Wenlong Song, and João F. Mano* 1. Introduction The achievement of the fast regeneration of injured tissues is the ultimate goal of tissue engineering (TE). Although in the last decades the research in this area undergone significant progress, the achievement of fully effective systems for the regeneration of body tissues is still unaccomplished. This research is mainly based in trial/error logic and usually a low number of conditions are tested in each study. However, the complete understanding of the therapeutic potential of a given system requires the full study of all possible combi- nations as each of them lead to unpredictable results. [1] The large number of combinations of biomaterials, cells and other stimuli that can be varied during a TE system development make this area especially resource spending. In order to facilitate the rapid and effective study of complex TE systems, the miniaturization and automation of experimental systems to a lab-on-chip scale has been pro- posed. [2] Nonetheless, most manufacturing approaches for high-throughput analysis involve costly setups, lengthy fab- rication processes and non-versatile platforms. Most of cell- biomaterials combinatorial assays have been performed in 2D substrates, that is: biomaterials are dispensed as thin coat- ings in specific regions of chips and cells are put over such spots. [3] However, in the physiological environment cells are DOI: 10.1002/smll.201201436 One of the main challenges in tissue engineering (TE) is to obtain optimized products, combining biomaterials, cells and soluble factors able to stimulate tissue regeneration. Multiple combinations may be considered by changing the conditions among these three factors. The unpredictable response of each combination requires time-consuming tests. High-throughput methodologies have been proposed to master such complex analyses in TE. Usually, these tests are performed using cells cultured into 2D biomaterials or by dispensing arrays of cell-loaded hydrogels. For the first time an on-chip combinatorial study of 3D miniaturized porous scaffolds is proposed, using a patterned bioinspired superhydrophobic platform. Arrays of biomaterials are dispensed and processed in situ as porous scaffolds with distinct composition, surface characteristics, porosity/pore size, and mechanical properties. On-chip porosity, pore size, and mechanical properties of scaffolds based on chitosan and alginate are assessed by adapting microcomputed tomography equipment and a dynamic mechanical analyzer, as well as cell response after 24 hours. The interactions between cell types of two distinct origins—osteoblast-like and fibroblasts—and the scaffolds modified with fibronectin are studied and validated by comparison with conventional destructive methods (dsDNA quantification and MTS tests). Physical and biological on-chip analyses are coherent with the conventional measures, and conclusions about the most favorable conditions for each cell type are taken. Scaffolds M. B. Oliveira, [+] Dr. C. L. Salgado, [+] Dr. W. L. Song, Prof. J. F. Mano 3B’s Research Group–Biomaterials Biodegradables and Biomimetics University of Minho Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine AvePark, 4806-909 Taipas, Guimarães, Portugal E-mail: jmano@dep.uminho.pt M. B. Oliveira, Dr. C. L. Salgado, Dr. W. L. Song, Prof. J. F. Mano ICVS/3B’s - PT Government Associate Laboratory Braga/Guimarães, Portugal [ +] M.B.O. and C.L.S. contributed equally to this work. small 2013, 9, No. 5, 768–778