As mentioned already, there is AngularDart, but we also have a full port of Polymer to Dart, so you can write web components in Dart.

https://www.dartlang.org/polymer-dart/

We also have Dart packages for the Polymer project's core-elements and paper-elements (Material Design, nee Quantum Paper) that were announced at I/O.

http://pub.dartlang.org/packages/paper_elements

Web components and Dart is a really powerful combination for apps.