pH-Responsive Materials: Properties, Design, and Applications

The pH has a significant role in the proper physiological functions of organs, tissue, cells, or sub-cellular organism. The deviation from the characteristic pH indicates some perturbation of their vital role in healthy conditions. It thereby leads to unwanted issues or diseases in the body, such as abnormal growth of cells leading to the tumor with an intrinsic acidic micro-environment that vastly differs from the normal physiological pH. Therefore, the detection of pH could be used as an alarm for disease diagnosis of organs or tissues. Researchers further focused on the therapy of the disease as the basis of the changed pH stimuli. Therefore, the 'pH-alarm' brought enormous attention to the synthesis, characterization, and therapeutic applications of pH-responsive materials in the biomedical field. In particular, Polymer exhibited considerable potential in drug delivery by introducing the pH stimuli for changing morphology, or assembly-disassembly and on-demand delivery of drugs at the alarming pH environment. Herein, we mainly focus on the different aspects of pH-sensitive polymer-based systems and their biomedical applications, like cancer, tuberculosis, inflammation, etc. These pH-responsive polymers provide satisfactory results in biomedical applications and could enter preclinical or clinical trials after proper evaluation.