Table 3 PH responsive nanotechnology designs
From: The current status of stimuli-responsive nanotechnologies on orthopedic titanium implant surfaces
Response system | Stimulus type | Preparation process | Response point | Drug release | Bacterial strains | Antibacterial principle |
|---|---|---|---|---|---|---|
MSPM-TCS (Liu2016) [146] | Acid Enzyme | MSPM is composed of hydrophilic PEG and β-amino ester PAE | PAE | Low pH sensitivity, targeted to bacterial surfaces Bacteria secrete lipase to degrade PAE and achieve controlled drug release | S. aureus | Enhanced physical penetration Targeting in acidic environments Antimicrobial activity |
TNT-AL-AgNPs (Dong2017 [41]) | Acid | 1. Preparation of TNT by anodic oxidation of Ti, COOH-functionalized TNT 2. AL connection of TNT 3. The AgNPs loaded | AL | AL was sensitive to low pH and dissociates at low pH and releases AgNPs inside TNT | S. aureus E. coli | Antimicrobial activity |
TiO2-PLL-Cu-NaAL (Zhang2018 [36]) | Acid | 1. Preparation of TNTs by anodic oxidation of Ti 2. Modified PLL and amino modified Cu2+ were loaded on TNT to prepare the coordination system 3. NaAL load of TNT | Coordinate bond | Under low pH or acidic conditions, the system coordination bond is broken, releasing TNT internal drugs | – | – |
TNT-CPs (Wang2017 [40]) | Acid | 1. CPs was prepared by BIX combining with metal ions (Zn2+ and Ag+) 2. TNT was prepared by anodic oxidation of Ti 3. Amino functionalized TNT into TNTs 4. IBU, VAN and silver nitrate are loaded into TNTs 5. The CPs TNTs sealing side | Coordinate bond | Under low pH or acidic conditions, the system coordination bond cleavage, CPS destruction, release TNT internal drugs | S. aureus E. coli | Antimicrobial activity |
Ti-PD-(HET/CHT) (Zhou2018 [37]) | Alcali | 1. Preparation of Tob supported micelles 2. PD coating Ti surface 3. HET/CHT layer by layer assembly to Ti-PD | Micelle | In alkaline environment, the amino Tob is deprotonated, the electrostatic interaction between Tob and heparin is reduced, and the drug is released | S. aureus E. coli | Antimicrobial activity Inhibition of initial adhesion |
TNT-ZnO QD-FA-Van (Xiang2018 [39] | Acid | 1. TNT was prepared by anodic oxidation of Ti 2. Modified ZnO QD by FA 3. Van TNT load 4. ZnO QD-FA encapsulated TNT | ZnO | ZnO QD was sensitive to low pH, and the ZnO QD-FA envelope was opened and the drug was released in acidic environment | S. aureus | Antimicrobial activity |