Paper accepted: “Parameters influencing the size of chitosan-TPP nano- and microparticles”

After almost a full year, Sruthi Sreekumar’s paper describing how to control the size of chitosan-TPP particles from below 100 nm to more than 1 µm in diameter has finally been accepted for publication in Nature’s open access journal “Scientific Reports”. In the past, the formation of soft nanoparticles, i.e. nanoparticles made of biopolymers such as chitosan, has been the result of trial and error rather than of a well-understood and predictable process. Under the supervision of our former postdoc Gustavo Rivera, Sruthi has now performed a systematic investigation of different parameters such as the type and concentration of the chitosan used, the ratio of the polycationic chitosan to the negative counterion tripolyphosphate, or the concentration of salt in the medium that all influence the size of the particles formed. Together with Francisco Goycoolea, they even found a physico-chemical explanation for the unexpected ability to form chitosan-TPP microparticles by using unusually high chitosan concentrations in the absence of salt. We believe that this paper represents an important step towards developing rational protocols for the production of soft nano- and microparticles, but its publication has come close to a nightmare. We had to submit the manuscript four times, each time we had to wait for months before finally receiving a new set of critical remarks from the editor who never even added the original comments from any referees. This has been an experience we will not want to repeat - but the paper is now finally accepted, just in time for Sruthi’s doctoral thesis.