Micellar Self-Assembly of Recombinant Resilin-/Elastin-Like Block Copolypeptides

Abstract

Reported here is the synthesis of perfectly sequence defined, monodisperse diblock copolypeptides of hydrophilic elastin-like and hydrophobic resilin-like polypeptide blocks and characterization of their self-assembly as a function of structural parameters by light scattering, cryo-TEM, and small-angle neutron scattering. A subset of these diblock copolypeptides exhibit lower critical solution temperature and upper critical solution temperature phase behavior and self-assemble into spherical or cylindrical micelles. Their morphologies are dictated by their chain length, degree of hydrophilicity, and hydrophilic weight fraction of the ELP block. We find that (1) independent of the length of the corona-forming ELP block there is a minimum threshold in the length of the RLP block below which self-assembly does not occur, but that once that threshold is crossed, (2) the RLP block length is a unique molecular parameter to independently tune self-assembly and (3) increasing the hydrophobicity of the corona-forming ELP drives a transition from spherical to cylindrical morphology. Unlike the self-assembly of purely ELP-based block copolymers, the self-assembly of RLP-ELPs can be understood by simple principles of polymer physics relating hydrophilic weight fraction and polymer-polymer and polymer-solvent interactions to micellar morphology, which is important as it provides a route for the de novo design of desired nanoscale morphologies from first principles.

Fine structural tuning of the assembly of ECM peptide conjugates via slight sequence modifications

“…In their studies, macromolecules with the same ELP A/G,80 hydrophilic block exhibited different morphologies depending on the molecular weight (MW) of the hydrophobic resilin-like polypeptide (RLP) block. Increasing the length of the hydrophobic RLP block led to a morphology transition from spherical to cylindrical nanoparticles (53), which is in contrast to our observations in which increasing the length of the hydrophobic domain results in morphologies with greater curvature. This difference in observed behavior may be due to the difference in molecular weights between the two systems and/or due to the rod-coil nature of the ELP(coil)-CLP(rod) conjugates, which likely also supports the ready formation of relatively large nanoscale platelets for conjugates with low ELP/CLP ratios (33,34); these structures are not observed at all for the resilin/elastin polypeptides.…”

Complex microparticle architectures from stimuli-responsive intrinsically disordered proteins

“…1b). The interesting thermodynamic properties of these polymers have allowed ELP diblock and multiblock copolymers to be successfully self-assembled into an array of nanostructures and in at least one instance into a vesicular microparticle 40,44,45 . Using water-in-oil droplet microfluidics, we also recently demonstrated that the miscibility of different ELPs can be finely controlled to create spherical core-shell particles of ELP coacervates 46 .…”

Elastin‐Like Recombinamers: Deconstructing and Recapitulating the Functionality of Extracellular Matrix Proteins Using Recombinant Protein Polymers

“…Interesting biomaterials with customized properties can be achieved by combining ELRs with order-promoting protein domains ( Table 1) such as leucine zippers, [194] coiled-coils, [195,196] or SADs from other structural proteins, such as silk or resilin. [197][198][199][200][201] Additionally, self-assembling properties of different SADs can converge synergistically leading the formation of physical hydrogels with improved features. For instance, an innovative bioink has been fabricated by the rational combination of silk-like blocks, leucine zippers, and ELRs: [202] In this arrangement, silk domains promote the formation of highly stable and insoluble β-sheets, thus imparting thermal and mechanical resistance, leucine zipper-containing motif selfassembles into α-helical structures that dimerizes specifically, and the amphiphilic elastin-like block co-recombinamer undergoes thermal coacervation.…”