That is really neat:

  “By irradiating the paper with a CO laser, we create refusible, sugar-like 
  reaction products that we use instead of the synthetic materials or adhesives 
  that would otherwise be required to seal the paper by the heat sealing 
  process. In this way, we are essentially producing our own adhesive"

I've also seen a glue-less paper binding trick where two pieces of paper are finely crimped together with some high pressure tool in alternating v^v^v^ patterns, actually making tiny tears in the paper. Does anyone know what kind of tool does that?

I guess string was too complicated?