A Library of Thermoresponsive, Coacervate-Forming Biodegradable Polyesters

Abstract

We report on a new class of thermoresponsive biodegradable polyesters (TR-PE) inspired by polyacrylamides and elastin-like proteins (ELPs). The polyesters display reversible phase transition with tunable cloud point temperatures (T cp ) in aqueous solution as evidenced by UV−vis spectroscopy, 1 H NMR, and DLS measurements. These polyesters form coacervate droplets above their lower critical solution temperature (LCST). The T cp of the polyesters is influenced by the solutes such as urea, SDS, and NaCl. The T cp of the copolymers shows a linear correlation with the composition of the polyesters indicating the ability to tune the phase change temperature. We also show that such thermoresponsive coacervates are capable of encapsulating small molecules such as Nile Red. Furthermore, the polyesters are hydrolytically degradable.

Modification of narrow‐spectrum peptidomimetic polyurethanes with fatty acid chains confers broad‐spectrum antibacterial activity

“…We previously reported a series of bactericidal peptidomimetic polyurethanes based on a library of N ‐substituted diol monomers . These bactericidal polyurethanes are narrow‐spectrum antimicrobial agents effective against Gram‐negative bacteria such as E. coli , but not against Gram‐positive bacteria such as S. aureus .…”

Thermoresponsive polymers based on ring-opening metathesis polymerization

“…3 The transition temperature corresponding to this transformation is often measured as cloud point temperature (T cp ), which is an important parameter for its applications. The T cp is largely dependent on the hydrophilic/hydrophobic balance of the entire polymer, which could be tuned by copolymerization with hydrophilic or hydrophobic comonomers [4][5][6] or transformations of the side groups 7,8 . To date, with the development of the controlled radical polymerization (CRP) techniques including nitroxide-mediated polymerization (NMP), atom transfer radical polymerization (ATRP), and reversible addition-fragmentation chain transfer polymerization (RAFT), a large number of thermoresponsive polymers have been developed and widely used in the fields of drug delivery 9,10 , cell culture 11,12 , bioseparations 13,14 , smart surfaces 15,16 , and enzyme activity regulating 17,18 .…”

Tropoelastin-Inspired, Non-Ionic, Self-Coacervating Polyesters as Strong Underwater Adhesives

“…We base this study on our previously reported serendipitous discovery that a library of thermoresponsive polyesters designed in our lab show 'tropoelastin-like' coacervation behavior. [18][19][20] Tropoelastin, the soluble precursor to elastin, shows lower critical solution temperature (LCST) in aqueous medium, and above LCST, the protein solution segregates to both dilute and proteinrich dense phases. [21] Similarly, our polyester library also shows hydrophobically-driven, single component coacervation.…”

“…[21] Similarly, our polyester library also shows hydrophobically-driven, single component coacervation. Their non-ionic, bioabsorbable, [19] cell-compatible, [20] and modular nature, allows incorporation of various functional groups [18] and hence this platform provides significant advantages over any other reported coacervates to date. In this study, we report an extension of the above polyesters, wherein incorporation of appropriate functional groups provides a new class of non-ionic, self-coacervating polyesters that demonstrate rapid, watertolerant crosslinking, resulting in strong underwater adhesion.…”

“…In contrast to the complex coacervates, these 'charge-free' coacervates are potential candidates as tissue adhesives and sealants, adhesives for sensor attachment to wet skin, and as sprayable adhesives. Their potential use in the clinic arises from their enhanced stability to changes in external conditions, cytocompatibility, [20] biodegradability [19] and modular nature in incorporating various functional groups [18] and crosslinkers.…”