Amino/quaternary ammonium groups bifunctionalized large pore mesoporous silica for pH-responsive large drug delivery

Abstract

Mesoporous nanoparticles functionalized with amino groups on the pore surface and quaternary ammonium groups on the particle surface with particle sizes of 500-800 nm in length and 300-500 nm in diameter and a pore size of 7.2-7.4 nm, have been obtained through a post-synthesis and cocondensation method. Bleomycin (BLM) has been chosen as a model anti-cancer drug with a large molecular size, and the iron essential for organisms has been utilized for constructing NH 2 -Fe-BLM coordination bond architecture in the pore surface. The BLM was released under mildly acidic pH conditions by cleavage of the Fe-BLM coordination bond triggered by pH reduction. Cell assays show that mesoporous nanoparticles have good dispersity and good cell penetrating properties due to the positively charged quaternary ammonium groups on the outer surface of the nanoparticles. These organic functionalized large pore mesoporous materials can be utilized as carriers in the pHresponsive delivery of an anti-cancer drug with a large molecular size, opening up new opportunities for their further application in controlled release of biomacromolecules.

Ultrasmall Confined Iron Oxide Nanoparticle MSNs as a pH‐Responsive Theranostic Platform

“…Importantly, Fe‐MSNs provide an excellent platform for the loading and stimuli‐responsive release of anti‐cancer drugs due to the special interaction between Fe species evenly distributed within mesopores and anticancer drug molecules via metal ion‐ligand coordination bonding . The metal ion‐ligand coordination bonding between solid‐state metal ions and ligands has been demonstrated in metal oxide solids such as ZnO, which, as we believe, might be also effective in the present case of iron oxides.…”

“…The well‐defined mesopore network favors the free accessibility of water molecules to magnetic centers for enhanced T 1 ‐weighted MR relaxivity (Scheme b‐1). The confined iron oxide NPs provide the anchoring sites for anticancer drug molecules via a special metal‐ligand coordination bonding, which are sensitive to external pH variations (Scheme b‐2) . It is noted that the encapsulation and pH‐responsive anticancer drug release can reversibly change the interaction probability and bonding strength between Fe paramagnetic center and water molecules due to the shielding and exposure of the centers by the loaded drug molecules respectively before and after drug release, which can be potentially used for T 1 ‐weighted MRI‐guided monitoring of the drug release (Scheme b‐3).…”

Effective adsorption of hexavalent chromium through a three center (3c) co-operative interaction with an ionic liquid and biopolymer

“…These changes could be attributed to the effective interaction of the tetraoctylammonium cation with the hydroxyl group of chitosan in the form of an intermolecular hydrogen bonding interaction. Indeed, the interaction of ammonium cation through hydrogen bonding interaction is an interesting phenomenon observed in host-guest interaction [30,31]. The essential point to realize is that the presence of amino groups in the biopolymer also plays a significant role in this interaction.…”

Tailoring stimuli-responsive delivery system driven by metal–ligand coordination bonding

“…[1][2][3][4] The release of guest molecules can be tailored using their responsiveness to external stimuli such as pH, [5][6][7][8][9] temperature 10 and light. [11][12][13] Among these stimuli-responsive systems, the pH-sensitive system is of vast interest because of the acidic microenvironment in solid tumors, which is very different compared with the normal tissues.…”