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Stimuli-Responsive Polymer Coatings
Published in Sanjay Mavinkere Rangappa, Jyotishkumar Parameswaranpillai, Suchart Siengchin, Polymer Coatings, 2020
Fabrice Ofridam, Mohamad Tarhini, Waisudin Badri, Wei Liao, Noureddine Lebaz, Émilie Gagnière, Denis Mangin, Emilie Dumas, Sami Ghnimi, Abdelhamid Errachid El Salhi, Adem Gharsallaoui, Hatem Fessi, Abdelhamid Elaissari
pH-sensitive polymers are a group of stimuli-responsive polymers that can respond to environment pH through structural and property changes such as surface activity, chain, conformation, solubility, and configuration [46]. Materials referred to as pH-responsive polymers present the property to have potential ionizable groups in their structure. These groups are weak acidic or basic moieties sensible to pH variations and confer the pH sensitivity to the overall molecule [4]. Sensitivity to pH in response to environmental pH modification is made through the acceptance or the release of protons leading to conformational changes and changes in the colloidal behaviour of the polymer, such as flocculation, chain collapse or extension, and/or precipitation of homopolymers [46,47]. pH-responsive polymers can be produced using different polymerization techniques. Emulsion polymerization is the technique used for the preparation of most of the pH-responsive polymers due to the well-controlled size distribution. Moreover, anionic polymerization, group transfer polymerization, stable free radical polymerization, atom transfer radical polymerization, atom transfer radical polymerization, and reversible addition–fragmentation chain-transfer polymerization are other polymerization techniques used for the preparation of pH-responsive polymers [48].
Application of “Smart Polymers” as Biomaterials
Published in Yaser Dahman, Biomaterials Science and Technology, 2019
pH-sensitive polymers are polyelectrolytes that have a weak acidic structure and which, with change in the pH of the environment, release or add protons to their structure. The ionization of these acidic or basic groups of the polyelectrolytes are the same as acidic or basic groups of monoacids, but it’s more difficult due to the electrostatic effects of other ionized groups, which lead to a different dissociation constant (Ka) from similar monoacids. Also, by changing the electrolyte concentration or charges in the polymer backbone, the physical properties (chain conformation, solubility, etc.) could change.
Applications of smart polymers in emerging areas
Published in Badal Jageshwar Prasad Dewangan, Maheshkumar Narsingrao Yenkie, Novel Applications in Polymers and Waste Management, 2018
U. V. Gaikwad, A. R. Chaudhari, S. V. Gaikwad
pH-sensitive polymers have been used in several biomedical applications, the most important being their use as drug and gene delivery systems, and glucose sensors. Between all the systems described in the literature, we report in this section the most attractive examples reported in the last years.3
Graphene-based composites for biomedical applications
Published in Green Chemistry Letters and Reviews, 2022
Selsabil Rokia Laraba, Wei Luo, Amine Rezzoug, Qurat ul ain Zahra, Shihao Zhang, Bozhen Wu, Wen Chen, Lan Xiao, Yuhao Yang, Jie Wei, Yulin Li
GBC materials have played a significant role in the biomedical field (Figure 6). Acrylic-based nanoconjuctant systems have piqued attention as a platform for cancer theranostics efficiency in polymer- and protein-based nanotechnologies. Zhang et al. (97) have investigated a wide range of pH-sensitive polymers, including poly(N,N-dialkyl aminoethyl methacrylate), poly(acrylic acid), and poly(methacrylic acid), as well as drug delivery systems, stimuli-responsive hydrogels, and even dental restorative substances. In the past 30 years, the resin-based filler composites technique has been modified for clinical research (77). In dentistry, for example, amalgams compounds based on graphene nanocomposites had higher aesthetic features, increased safety guard matter, thereby providing relatively satisfying clinical outcomes. Enhancements in their formulation, such as new green/organic monomers and fillers techniques, have progressively enhanced the characteristics and functions of these materials over time (98). The graphene use in medical applications is wide. Current investigations majorly focus on utilizing the characteristics of graphene and its 2D material for novel medical instruments or devices that could be used to improve the healthcare community. This includes testing kits and smart implants such as medical sensors and 3D scaffolds (99).
Review of pH sensing materials from macro- to nano-scale: Recent developments and examples of seawater applications
Published in Critical Reviews in Environmental Science and Technology, 2022
Roberto Avolio, Anita Grozdanov, Maurizio Avella, John Barton, Mariacristina Cocca, Francesca De Falco, Aleksandar T. Dimitrov, Maria Emanuela Errico, Pablo Fanjul-Bolado, Gennaro Gentile, Perica Paunovic, Alberto Ribotti, Paolo Magni
Carbon nanoparticles, despite having attracted a large research effort, are not stable in their response (sensitive to surface defects, functional groups and morphology), nor easy to produce and handle. Polymer-based sensors, finally, seem to be noncompetitive in terms of precision and stability. However, the limitations shown by these classes of materials can be overcome by properly combining them. In this respect, the synergy observed between polymeric components, and inorganic nanomaterials seems to be a key factor for the realization of robust and affordable sensors. Polymers can be used as efficient ion-selective or protective elements, to enhance the response of inorganic sensing elements and decrease the interference of dissolved ions. On the other hand, the response and the stability of pH sensitive polymers can be greatly improved by combining them with conductive and semiconductive nanomaterials, as shown for the most common electroactive polymer, PANI, and for polydopamine.
Tumor-targeting and imaging micelles for pH-triggered anticancer drug release and combined photodynamic therapy
Published in Journal of Biomaterials Science, Polymer Edition, 2020
Qianqian Qi, Xianwu Zeng, Licong Peng, Hailiang Zhang, Miao Zhou, Jingping Fu, Jianchao Yuan
For most tumor tissues, the pH is usually 6.5 - 7.0, the pH of lysosomes and endosomes is 4.5 - 5.5, and the subcutaneous tissue of humans is maintained at a median pH of 7.4. Thus, pH-sensitive polymers will release encapsulated drug molecules under acidic conditions [26]. To confirm the drug release performances dependent pH values, in vitro release profiles of DOX were recorded in PBS with pH 7.4 (physiological conditions), and 5.0 (intracellular environment), as shown in Figure 5. The results show that the DOX release rate of the micelle was significantly accelerated in buffer solution with pH 5.0, while it was slow in buffer solution with pH 7.4. The reason is that the protonation of C7A in pH 5.0 buffer solution results in the release of DOX. Moreover, in buffer solution with pH 7.4, DOX release was only 22.3% in 24 h, while in buffer solution with pH 5.0, DOX release reached about 53.5% within the first 8 h, and 83.7% after 24 h. It indicated that the drug carrier can circulate in the normal pH of the human body and release the drug under acidic conditions of cancer cells.