Making polymeric nanoparticles stimuli-responsive with dynamic covalent bonds

Abstract

Drug delivery represents one of the most important research fields within the pharmaceutical industry. Different strategies are reported every day in a dynamic search for carriers with the ability to transport drugs across the body, avoiding or decreasing toxic issues and improving therapeutic activity. One of the most interesting strategies currently under research is the development of drug delivery systems sensitive to different stimuli, due to the high potential attributed to the selective delivery of the payload. In this work, a stimuli-sensitive nanocarrier was built with a bifunctional acrylic polymer, linked by imine and disulfide bonds to thiolate chitosan, the latter being a biopolymer widely known in the field of tissue engineering and drug delivery by its biodegradability and biocompatibility. These polymer nanoparticles were exposed to different changes in pH and redox potential, which are environments commonly found inside cancer cells. The results proof the ability of the nanoparticles to keep the original structure when either changes in pH or redox potential were applied individually. However, when both stimuli were applied simultaneously, a disassembly of the nanoparticles was evident. These special characteristics make these nanoparticles suitable nanocarriers with potential for the selective delivery of anticancer drugs.

Injectable Hydrogel: Amplifying the pH Sensitivity of a Triblock Copolypeptide by Conjugating the N-Termini via Dynamic Covalent Bonding

“…38,39 The dynamic covalent bonds endow the hydrogels with sharper stimuli-responsive sol-gel transition, enhancing considerably their potential in delivery applications. While the literature covering the use of dynamic bonds on polymer chains or on random coil polypeptide chain is quite abundant, [31][32][33] to the best of our knowledge, there is no report on the influence of such functionality on more ordered peptide structures such as α-helix or β-sheet.…”

Stimuli-responsive cross-linked micelles for on-demand drug delivery against cancers

“…Cross-linking strategy has been utilized to solve the above mentioned stability problems following the pioneer work by Wooley’s group [27]. Since then, this strategy has been exploited by a number of other groups [28–33].…”

“…Since then, this strategy has been exploited by a number of other groups [28–33]. Covalent cross-links between specific domains of the micelles are formed in order to improve the micelles’ structural stability suitable to drug delivery rather than the weak non-covalent intermolecular hydrophobic interactions existing in the conventional polymeric micelles that facilitate polymer micelles assembly and integrity [27]. To be more effective, anticancer drugs should be released exclusively in tumor tissue or inside tumor cell.…”

Nanophotonics and supramolecular chemistry

“…Nanotechnology involving bottom-up approaches often requires supramolecular systems to produce an output implying some useful functionality including electronic, photonic, chemical and biological outputs [16][17][18]. Of these, systems based on photonic outputs are of increasing current interest with various possibilities for practical application.…”