This newspaper is printed on paper made from cellulose fibers obtained from wood pulp. The fibers are fairly large, on the order of tens of micrometers wide, and the resulting paper is fairly weak  pull on it and it tears easily.

Researchers in Sweden and Japan have developed a much stronger paper, made from much smaller fibrils of cellulose. This “nanopaper,” they report in the journal Biomacromolecules, has a tensile strength greater than that of cast iron.

Marielle Henriksson of the Royal Institute of Technology in Stockholm and colleagues used enzymes and a gentle beating technique to produce fibrils on the order of tens of nanometers wide, roughly one-thousandth of the width of conventional fibers. The nanofibrils were then mixed with water, and the suspension was vacuum filtered to make paper.

The researchers report that the papers are rather porous, yet greatly resist tearing. They suggest that this property is a result of the high strength of individual fibrils and the way they adhere to one another. The researchers say that if it were developed commercially, the paper might have applications in construction or as a reinforcing material.