NIPAm-Based Modification of Poly(L-lysine): A pH-Dependent LCST-Type Thermo-Responsive Biodegradable Polymer

Stamou, A.; Iatrou, Hermis; Tsitsilianis, Constantinos

doi:10.3390/polym14040802

Cited by 11 publications

(9 citation statements)

References 31 publications

(38 reference statements)

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“…Boc-PLL polypeptide was synthesized by ring opening polymerization of the ε-tert-butyloxycarbonyl-L-lysine-N-carboxy anhydride (NCA), with the following molecular weight characteristics: Mw= 11,980 Daltons, Mn = 11,365 Daltons (degree of polymerization 50) and molecular polydispersity, Mw/Mn, = 1.054. Details are reported elsewhere [ 32 ]. PAA (Mw = 450,000 Daltons) was purchased from Polysciences (Warrington, USA).…”

Section: Methodsmentioning

confidence: 99%

pH-Responsive, Thermo-Resistant Poly(Acrylic Acid)-g-Poly(boc-L-Lysine) Hydrogel with Shear-Induced Injectability

Karga

Kargaki

Iatrou

et al. 2022

Gels

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In this study we report the rheological behavior of aqueous solutions of an amphiphilic graft copolymer constituting a polyacrylic acid (PAA) grafted by poly(boc-L-lysine), P(b-LL). Due to the highly hydrophobic nature of the grafted chains, the copolymer self-assembles spontaneously in aqueous media forming three-dimensional (3D) finite size networks (microgels). The rheological analysis demonstrated that the copolymer behaves as a strong elastic hydrogel, showing characteristics of a “frozen” network. Moreover, it is noteworthy that the formulation shows the above-described characteristics in very small concentrations (0.25–1.20 wt%) compared to other naturally cross-linked hydrogels that have been studied so far. Concentration significantly affects the rheological properties of the hydrogel, showing considerable increase in elastic modulus, following the scaling law G’~C1.93. At the same time, the hydrogels can be described as intelligent stimuli-responsive systems, showing pH and shear responsiveness as well as stability with temperature changes. Thanks to the pH dependance of the degree of ionization of the weak polyelectrolyte PAA backbone, stiffness and swelling of the hydrogels can be tuned effectively by adjusting the pH conditions. Simulating conditions such as those of injection through a 28-gauge syringe needle, the gel demonstrates excellent response to shear, due to its remarkable shear thinning behavior. The combination of pH-sensitivity and shear responsiveness leads to excellent injectability and self-healing properties, given that it flows easily upon applying a low stress and recovers instantly in the site of injection. Therefore, the physically cross-linked PAA-g-P(b-LL) hydrogel exhibits remarkable features, namely biocompatibility, biodegradability of cross-links, pH responsiveness, shear-induced injectability and instantaneous self-healing, making it a potential candidate for various biomedical applications.

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Section: Methodsmentioning

confidence: 99%

pH-Responsive, Thermo-Resistant Poly(Acrylic Acid)-g-Poly(boc-L-Lysine) Hydrogel with Shear-Induced Injectability

Karga

Kargaki

Iatrou

et al. 2022

Gels

Self Cite

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“…This result is consistent with the reported literature, in which the pH could alter the LCST of temperature-sensitive materials, and the improvement in material hydrophilicity could lead to an increase or even disappearance of the LCST. [14,15,23] This phenomenon occurred because the protonation of the tertiary amine groups increased the hydrophilicity and disrupted the intrinsic hydrophobic-hydrophilic balance of temperature-sensitive materials. As a result, higher temperatures were needed to weaken the binding between water molecules and hydrophilic groups, thereby unmasking hydrophobic segments or even neutralizing their hydrophobic effects.…”

Section: Sensibility To Phmentioning

confidence: 99%

A Temperature and pH Dual‐Sensitive Multifunctional Polyurethane with Bacteria‐Triggered Antibacterial Activity

Gao,

Chen,

Yang

2023

Macromol. Rapid Commun.

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An effective and practical antibacterial strategy is to design multifunctional and stimuli‐responsive materials that exhibit antibacterial activity in response to bacterial triggers. In this study, because the metabolism of Staphylococcus aureus can acidify the surrounding environment and pH level can affect the lower critical solution temperature of temperature/pH dual‐sensitive polymers, a monomer containing a temperature‐sensitive N‐isopropyl amide derivative and pH‐sensitive tertiary amine groups is first synthesized. Then, the monomer is copolymerized with a polyurethane chain, and partial tertiary amine groups are quaternized to obtain bactericidal activity. The modified polyurethane exhibits temperature/pH sensitivity, antibacterial adhesion activity, bactericidal activity and good cytocompatibility. An in situ investigation of bacterial behavior and pH changes in the bacterial suspension during the process confirms that the temperature/pH dual‐sensitive polyurethane successfully achieves antibacterial activity though the metabolic activity of Staphylococcus aureus without external intervention. This design concept provides a new perspective for antibacterial material design.This article is protected by copyright. All rights reserved

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“…Poly-L-lysine (PLL) polymer, composed of lysine amino acids, is hydrophilic, biocompatible, biodegradable [ 56 ], and a polypeptide isomer of polylysine [ 57 ]. Since PLL is a biocompatible, biodegradable, and hydrophilic polypeptide [ 56 ], it is used in various biomedical applications [ 58 , 59 , 60 , 61 ], especially gene delivery [ 59 , 62 ].…”

Section: Biodegradable Materials For Soft Robotsmentioning

confidence: 99%

Advances in Biodegradable Soft Robots

2022

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Biodegradable soft robots have been proposed for a variety of intelligent applications in soft robotics, flexible electronics, and bionics. Biodegradability offers an extraordinary functional advantage to soft robots for operations accompanying smart shape transformation in response to external stimuli such as heat, pH, and light. This review primarily surveyed the current advanced scientific and engineering strategies for integrating biodegradable materials within stimuli-responsive soft robots. It also focused on the fabrication methodologies of multiscale biodegradable soft robots, and highlighted the role of biodegradable soft robots in enhancing the multifunctional properties of drug delivery capsules, biopsy tools, smart actuators, and sensors. Lastly, the current challenges and perspectives on the future development of intelligent soft robots for operation in real environments were discussed.

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NIPAm-Based Modification of Poly(L-lysine): A pH-Dependent LCST-Type Thermo-Responsive Biodegradable Polymer

Cited by 11 publications

References 31 publications

pH-Responsive, Thermo-Resistant Poly(Acrylic Acid)-g-Poly(boc-L-Lysine) Hydrogel with Shear-Induced Injectability

pH-Responsive, Thermo-Resistant Poly(Acrylic Acid)-g-Poly(boc-L-Lysine) Hydrogel with Shear-Induced Injectability

A Temperature and pH Dual‐Sensitive Multifunctional Polyurethane with Bacteria‐Triggered Antibacterial Activity

Advances in Biodegradable Soft Robots

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