Thermoresponsive Elastin-b-Collagen-Like Peptide Bioconjugate Nanovesicles for Targeted Drug Delivery to Collagen-Containing Matrices

Abstract

Over the past few decades, (poly)peptide block copolymers have been widely employed in generating well-defined nanostructures as vehicles for targeted drug delivery applications. We previously reported the assembly of thermoresponsive nanoscale vesicles from an elastin-b-collagen like peptide (ELP-CLP). The vesicles were observed to dissociate at elevated temperatures, despite the LCST-like behavior of the tethered ELP domain, which is suggested to be triggered by the unfolding of the CLP domain. Here, the potential of using the vesicles as drug delivery vehicles for targeting collagen-containing matrices is evaluated. The sustained release of an encapsulated model drug was achieved over a period of three weeks, following which complete release could be triggered via heating. The ELP-CLP vesicles show strong retention on a collagen substrate, presumably through collagen triple helix interactions. Cell viability and proliferation studies using fibroblasts and chondrocytes suggest that the vesicles are highly cytocompatible. Additionally, essentially no activation of a macrophage-like cell line is observed, suggesting that the vesicles do not initiate an inflammatory response. Endowed with thermally controlled delivery, the ability to bind collagen, and excellent cytocompatibility, these ELP-CLP nanovesicles are suggested to have significant potential in the controlled delivery of drugs to collagen-containing matrices and tissues.

Engineering the Architecture of Elastin‐Like Polypeptides: From Unimers to Hierarchical Self‐Assembly

“…Shorter ELPs, with <10 pentapeptide repeats, are difficult to study due to their lack of phase behavior and the difficulty in synthesizing them recombinantly. Kiick and co‐workers studied the self‐assembly of short ELP sequences by using solid phase peptide synthesis and conjugating the ELP with hydrophilic, triple‐helix‐forming collagen‐like peptides (CLPs) . A fusion of the ELP sequence (VPFGF) 6 with the CLP motif (GPO) 8 showed self‐assembly of nanoparticles 50–200 nm in diameter, at temperatures ranging from 4 to 65 °C.…”

“…TEM imaging experiments confirmed the predicted bilayer morphology with hydrophobic ELP chains forming the interior. The hydrophobic aromatic rings in the bilayer also allowed encapsulation of hydrophobic drugs within the bilayer, and hydrophilic drugs in the interior of the vesicle . These nanostructures are highly stable, with a thermal stability up to 80 °C, making them useful for drug delivery applications.…”

Manipulation of the dually thermoresponsive behavior of peptide‐based vesicles through modification of collagen‐like peptide domains

“…To accomplish this, we synthesized a small library of CLP sequences that have previously been shown to possess T m values lower than that of the (GPO) 4 GFOGER(GPO) 4 GG CLP originally studied. 41,47,[61][62][63] The T m values of these four CLP sequences, as well as the T m values of the corresponding ELP-CLP conjugates (employing the ELP (VPGFG) 6 used in our previous study), were determined by circular dichroism (CD) spectroscopy. The T m values were then used to predict the self-assembly (or lack thereof) and thermal responsiveness of the ELP-CLP conjugates, and the resulting structures of the ELP-CLP assemblies were characterized via dynamic light scattering (DLS), turbidity measurements, and transmission electron microscopy (TEM).…”

“…41,42,44,67 For these reasons, four CLPs with an Nterminal azide (N 3 ) (N 3 -(GPO) 6 GG, N 3 -(GPO) 7 GG, N 3 -(GPO) 3 GFOGER (GPO) 3 GG, and N 3 -(GPP) 10 GG) were chosen for the present study.The (GPO) 3 GFOGER(GPO) 3 GG sequence, owing to its shorter length, exhibits a lower T m relative to the sequence in our previous studies, and the (GPO) n sequences were chosen as they would be good comparators to this sequence without the inclusion of GFOGER residues 62. 61,62 This conjugate exhibited, as measured via CD spectroscopy, a melting temperature of 57 C, while the unconjugated CLP domain (N 3 -(GPO) 4 GFOGER(GPO) 4 GG) exhibited a melting temperature of 50 C. Given that the resulting vesicles formed from this conjugate underwent complete thermal dissociation only at relatively high temperatures (70 C), 61 we employed in the current study CLPs that have previously been shown to possess T m values lower than that of the N 3 -(GPO) 4 GFOGER(GPO) 4 GG sequence.…”

Positively and Negatively Charged Collagen Nanohydrogels: pH‐responsive Drug‐releasing Characteristics

“…Hydrogen bonding is absolutely pivotal in maintaining the structural integrity in CG systems; therefore, it is not easy to modify functional groups (—C(═O)—NH—, —NH 2 , —OH, —SH, —COOH) of the natural polymer with minimal perturbation to the structure and function of the biomolecule . The composites of CG with natural and synthetic polymers have been intensively studied …”