A Kidney-targeted Protein Biopolymer Drug Delivery System

Elastin-like Polypeptides (ELPs) are bioengineered protein polymers that can be used as drug carriers. ELPs are composed of a repeating pentapeptide motif, their sequence is genetically encoded, and they are produced by recombinant expression in E. coli. Simple molecular biology strategies are used to change the number of pentapeptide repeats to tune the polymer's size and to modify the sequence's N- and C-termini to add targeting peptides and therapeutic peptides, therapeutic proteins, or reactive sites for drug conjugation. In addition to its amenability to sequence modification, ELP is a thermally responsive biopolymer. It self-associates into aggregates above a user defined transition temperature, and the aggregation process is fully reversible. This allows ELP and ELP-fusion proteins to be purified using simple thermal precipitation. We previously showed that ELP has a high affinity for the kidney when administered by systemic injection. Here, we assessed the ability of targeting peptides to increase...