Designing peptide actuators for enzyme-responsive particles

We will report on enzyme-responsive hydrogel particles for capture and controlled release applications. These particles are functionalised with peptide actuators that simultaneously act as biorecognition elements and molecular actuators, triggering swelling or collapse of particles in response to enzymes under constant, physiological conditions. Amino-functionalised poly(ethylene glycol acrylamide) (PEGA) hydrogel particles were functionalised with peptide actuators using solid-phase synthesis approach directly on the polymer material. We demonstrate that these enzyme responsive particles can be designed to (i) achieve an increase or decrease of molecular accessibility of the polymer, as required; (ii) match the specificity of the target enzyme; (iii) match the size and charge properties of the to-be released protein payload, thereby uniquely allowing for tuneable release profiles and (iv) match the ionic strength of the environment. Release profiles were analysed using a combination of fluorescence spectroscopy of the solution and two-photon fluorescence microscopy to analyse enzymatically triggered molecular events within hydrogel particles during the initial stages of release