Lowering the amount of ethanol needed to create gelatin type A nanoparticle crosslinked with EDC and NHS by the addition of NaCl and changing the pH

Abstract

Colloid gels are a promising biomaterial, because they allow a "bottom-up" strategy for designing shape-specific bulk materials by using micro- and nanoparticles. The use of gelatin is a promising source for these nanoparticles, due to it being cheap and biocompatible. One of these methods to create gelatin nanoparticles is the desolvation method, where gelatin is first dissolved in water and then ethanol is added. The ratio between ethanol and water needed to create the gelatin nanoparticles is 7.2 to 1. In this report, the desolvation method for gelatin type A is further developed with a focus on reducing the amount of ethanol needed. Lowering the amount of EtOH will reduce cost and allows for larger production scales. To stabilize the gelatin nanoparticles 1-(3-dimethylaminopropyl)-3-ethyl-carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) are added as crosslinkers.

It is shown that using salt (NaCl) could reduce the amount of EtOH significantly, however too much salt will result in sedimentation. It is also shown that increasing the pH from 3 to 3.5 could save 56% of the EtOH. However, adding both salt and changing the pH doesn't further decrease the ethanol needed. In the end, a reduction of 56% in the volume of ethanol was possible, lowering the ratio of ethanol and water to 3.2 to 1. This allows two times as many gelatin nanoparticles to be created in the same total volume of solvent, making it possible to create 45 gram of gelatin nanoparticles in one 5L batch.