Meanwhile, for the case of reactions with 4 mol% of catalyst per step, the highest M w , also approx. 13000 g/mol, was obtained with use of ZnAc. The Ð of all obtained macromonomers was similar, approx. 1.75. Likewise, for all macromonomers, the shapes of the chromatograms are similar, with only small shifts observed. Importantly, the obtained macromonomers do not differ significantly in M w from those obtained in our previous work, despite the changes in reaction conditions (catalysts and solvent). The results of dynamic viscosity measurements are presented in Table and Figure . For all of the macromonomers a marked increase in viscosity was observed, as compared to Priplast, indicating successful synthesis. As expected, the data largely correlated with the M w results (see Figure in SI). For use in minimally invasive procedures, the rheological properties of an injectable materials play a key role. They must be viscous enough to be locally retained, but not so much that the material cannot be properly delivered. We conclude that the high viscosity of the obtained macromonomers should ensure that they are well retained at the desired site during the duration of the photocuring process. At the same time, with viscosities <1000 Pa s, the macromonomers show injectability with the use of 16 G needle (Figure and short video in Supplementary Information). While details of a clinical delivery device (syringe, catheter, etc.) are beyond the scope of this work, we conclude that these materials should be well-suited for minimally invasive surgical procedures that use relatively large gauges of instruments, including laparoscopic and catheter procedures, such as those that may be used for cardiac repair .