Dual Thermoresponsive Boc-Lysine-Based Acryl Polymer: RAFT Kinetics and Anti-Protein-Fouling of Its Zwitterionic Form

Abstract

There are significant developments on the responsive polymers that are programmed for various stimuli such as temperature, pH, light, and so forth. Such focus and progress remain mainly centered around conventional polymers compared to amino acid-based polymers offering a diverse range of applications in biomedical area. Thus, this study focuses on designing of a Boc-lysine-based monomer and its reversible addition-fragmentation chain transfer (RAFT) polymerization to poly(Boc-L-lysinylacrylamide)s [P(Boc-lysA)s] of controllable molecular weights (M n s) and low dispersities (D̵ s ≤ 1.23). This RAFT polymerization follows a first order rate kinetics up to very high monomer conversions (ca. 91.4%) with a good control over M n and excellent agreement with the theoretical value. P(Boc-lysA) exhibits an interesting reversible upper critical solution temperature (UCST)-type phase behavior in mixed solvents comprising water and different polar organics (e.g., N,Ndimethylformamide, dimethyl sulfoxide, and methanol). The UCST-type cloud point (T cU ) increases linearly with increase of molecular weight of P(Boc-lysA) and percentage of water content in the mixed solvent. The addition of large organic cations in the aqueous solution of P(Boc-lysA) at pH 8.5 induces a lower critical solution temperature (LCST)-type phase transition with a tunable cloud point (T cL ) with respect to polymer concentration and its M n as well as nature of added ion and its concentration. Furthermore, the Boc-deprotection of P(Boc-lysA) produces zwitterionic PlysA, which shows excellent anti-protein-fouling property compared to those of conventional antifouling polymers when tested with bovine serum albumin and monitored by dynamic light scattering.

Activation of Upper Critical Solution Temperature Behaviors of Zwitterionic Poly(l-methionine-g-poly(sulfobetaine methacrylate)m) with a Bottlebrush Structure

“…The characterizations of a range of MS- m bottlebrush polypeptides are summarized in Table . Four MS- m polymers (where m = 25, 34, 50, and 70, representing the DPs of MS-25, MS-34, MS-50, and MS-70 in the side chain, respectively), were selected from entries 1 to 10 based on their distinct side-chain DPs and narrow molecular weight distribution …”

“…When the polymerization reaches a conversion of 70%, the D̵ value increases, which is consistent with the results of a little increase of monomer conversion at the end of stages. 51 The characterizations of a range of MS-m bottlebrush polypeptides are summarized in Table 1. Four MS-m polymers (where m = 25, 34, 50, and 70, representing the DPs of MS-25, MS-34, MS-50, and MS-70 in the side chain, respectively), were selected from entries 1 to 10 based on their distinct sidechain DPs and narrow molecular weight distribution.…”

Multitunable LCST and UCST Behaviors of Y-Junction-Bearing Polyacrylamides

“…In contrary, PNAGA is subjected to a hydrophobic-to-hydrophilic transition upon heating due to the destabilization of hydrogen bonding (HB) related to the glycinamide moiety . Rational integration of thermosensitive groups in architectural polymers allows on-demand control over types and temperatures of phase transitions. − ,− Among them, the heterofunctional Y junction is a promising building block to construct multistimulus-responsive systems; especially, the incorporation of multifunctional Y junctions into polyacrylamides can endow the resultant Y-junction-bearing polymers (YJPs) with multitunable LCST/UCST phase transitions. − Meanwhile, thermoresponsive polymers can serve as ideal choices to achieve shape-shifting nano-objects . As a consequence of thermoresponsiveness, abundant morphological transformations among spheres, worms, nanocapsules (e.g., vesicles and nanobowls), and lamellae can occur upon heating, in which the shape shifts are driven by the variation of the packing parameter. − Given the promising multi-in-one functions of Y junctions, it is desirable to rationally design YJPs to achieve on-demand phase transitions and nanostructures.…”

Self-assembly and salt-induced thermoresponsive properties of amphiphilic PEG/cation random terpolymers in water

“…8 Lower critical solution temperature (LCST)-type thermoresponsive polymers can switch the solubility in water or organic solvents upon heating: the homogeneous polymer solution is turbid or phase-separated upon heating above the cloud point (Cp) temperature and reversibly becomes homogeneous upon cooling below the Cp. Various LCST-type thermoresponsive polymers [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] have been designed and developed for targeted thermoresponse, func-tions, and applications, e.g., poly(N-isopropylacrylamide) (PNIPAM), [10][11][12][13][14] Pluronics, [15][16][17] and poly(ethylene glycol) (PEG) or poly(ethylene oxide) (PEO)-based compounds and (co) polymers. [18][19][20][21][22][23] Polymers with LCST-type solubility in water mostly consist of both hydrophilic units and hydrophobic units.…”