Surface modification of collagen using low-energy noble gas ion implantation

Due to its versatility, biodegradability, and biocompatibility, collagen is an increasingly important building block for sustainable manufacturing. Consequently, it is becoming more important to develop methods to tune col-lagen's properties for a given application. We propose employing a tool often reserved to microelectronics, low -energy ion implantation, to modify the top surface of collagen sheets, increasing surface sp2 carbon without altering significantly the amide structure while retaining the bulk properties of collagen. Implantation of He+, Ne+, Ar+ and Xe+ was performed at varying energies from 5 to 25 keV, with beam current density from 5 x 10-2 to 5 & mu;A cm -2. The resulting changes in chemical structure were investigated using Raman and FTIR spectros-copies. Monte Carlo simulations of the interaction of the ion beams with collagen are used to quantify the energy deposited in the implanted module. A model is proposed that relates the observed changes to these ion im-plantation conditions.