A novel lipase-catalyzed method for preparing ELR-based bioconjugates

Herein we present a novel one-pot method for the chemical modification of elastin-like recombinamers (ELRs) in a mild and efficient manner involving enzymatic catalysis with Candida antarctica lipase B. The introduction of different functionalities into such ELRs could open up new possibilities for the development of advanced biomaterials for regenerative medicine and, specifically, for controlled drug delivery given their additional ability to respond to stimuli other than pH or temperature, such as glucose concentration or electromagnetic radiation. Candida antarctica lipase B immobilized on a macroporous acrylic resin (Novozym 435) was used to enzymatically couple different aminated substrates to a recombinamer containing carboxylic groups along its amino acid chain by way of an amidation reaction. A preliminary study of the kinetics of this amidation in response to different reaction conditions, such as solvent, temperature or reagent ratio, was carried out using a phenylazobenzene derivative (azo-NH₂) as a model. The optimal amidation conditions were used to couple other amine reagents, such as phenylboronic acid (FB-NH₂) or polyethylene glycol (PEG-NH₂), thus allowing us to obtain photoresponsive, glucose-responsive or PEGylated ELRs that could potentially be useful as sensors in devices for controlled drug delivery.