The copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) is a 1,3-dipolar cycloaddition between an azide and a terminal or internal alkyne to give a 1,2,3-triazole. CuAAC reaction is versatile in numerous applications due to its “click reaction” features such as simplicity, fast reaction rate with high yields, orthogonal reactivity and tolerance of various solvents. Our interest is to develop a new strategy to spatially and temperately control CuAAC reaction in three demensions. The anchor groups (azide or alkyne) were firstly immobilized preciously via multiphoton grafting. The levels of immobilization can be spatially and temperately controlled by simply altering the irradiation exposure time or laser intensity during the photografting process. Then the anchor groups reacted with corresponding functionalities via CuAAC reaction to obtained desired functions.  

Thiol-Ene polymerization is also known since the 50’s of the last century and has gained tremendously increasing interest during the last decade, thanks to the rediscovery by Hoyle [1] and recent efforts by Bowman [2]. Advantages such as low oxygen inhibition and shrinkage, uniform networks with significantly improved mechanical properties are accompanied by up to now unsolved disadvantages such as unpleasant odour and poor storage stability.

Very recently we were able to introduce a new concept in thiol-ene stabilization which gives excellent storage stability with nearly no increase in viscosity with several months up to one year [3].

Vinylesters and vinylcarbonates [4] are a promising class of new, low toxic monomers not only for biomedical applications [5] but also for classical coatings. The only limitation of moderate reactivity between those of methacrylates and acrylates has been circumvented by thiol-ene polymerization [6].

With newly designed two photon initiators we were also able to show the 3D printing of hydrogels based on vinylester-modified gelatin with free thiol-groups of bovine serum albumin, for potential tissue engineering application.

[1]  Hoyle, C. E.; Hensel, R. D.; Grubb, M. B. J Polym Sci, Polym Chem (1984), 22(8), 1865-73

[2] Cramer, Neil B.; Bowman, Christopher N. J Polym Sci, Polym Chem (2001), 39(19), 3311-3319.

[3] (a) Cherkaoui Z.; Esfandiari P.; Frantz R.; Lagref J.-J.; Liska R. WO2012126695  (A1)

      (b) Esfandiari P.; Ligon S. C.; Cherkaoui Z.; Frantz R.; Lagref J.-J.; Liska R. Macromol. Rapid Comm. 2013 submitted.

[4] B. Husaar, R. Liska; Chem Soc Rev 2012;41(6):2395-2405

[5] C. Heller, M. Schwentenwein, G. Russmüller, T. Koch, D. Moser, C. Schopper, F. Varga, J. Stampfl, R. Liska: J Polym Sci, Polym Chem 49 (2011), 3; 650 - 661.

[6] A. Mautner, X. Qin, B. Kapeller, G. Russmueller, T. Koch, J. Stampfl, R. Liska, Macromol. Rapid Comm., 2012, in print DOI: 10.1002/marc.201200502