| dc.description.abstract | The expansion of bacterial antibiotic resistance is a growing problem today. When medical devices are inserted into the body, it often encounters bacterial infections. For example, bacterial artificial joints infection will face problems. The bacteria will easily form biofilms, and artificial joints infection becomes especially difficult for the body to clear robustly adherent antibiotic-resistant biofilm infections. In addition, concerns about the spread of bacterial genetic tolerance to antibiotics, such as that found in multiple drug-resistant Staphylococcus aureus (MRSA), have significantly increased of late. At present, Rifampicin (RIF) is one of most commonly used MRSA antibiotics. However, serious drug resistance resulted from biofilm formation. To improve the antibacterial efficacy in the clinic, a type of multi-functional poly(lactic-co-glycolic acid) (PLGA) nanoparticles encapsulated with photosensitive substrate indocyanine green (ICG) and antibiotic of Rifampicin (RIF) (ICG-RIF-loaded PLGA Nano-Particles; IRPNPs) was developed in this study.
In this study, the mean size and surface charge of the IRPNPs were 249 ± 21.5 nm and -31.9 ± 3.2 mV, respectively, and the encapsulation efficiencies for ICG and RIF were 89.36± 0.08 % and 42.13± 0.19%, respectively. After analysis of the absorbance at λ = 780 nm for each set, we found that after 48 hours of in vitro simulated human body temperature at 37 °C, the ICG absorption of IRPNPs and the pure ICG aqueous solution group delayed the ICG by 1.89-fold (p < 0.05), which indicates that the carrier has slowed down. The ICG degradation effect, while the RIF release rates were 31.94% and 43.19%, respectively, which can show the stability of IRPNPs. The efficacy of singlet oxygen generated by light treatment of IRPNPs by near-infrared light irradiation shows that the fluorescence value detected by IRPNPs is higher than the maximum ICG fluorescence value of 6.12 at the same concentration (p < 0.05). This can indicate that the ICG is coated with the amount of singlet oxygen that the IRPNPs can indeed enhance. The efficacy data of IRPNPs in phototherapy showed that IRPNPs produced photothermal effects under near-infrared light, resulting in ICG content of 20 μM in IRPNPs reaching 53.42 °C from 25.5 °C in 300 seconds of near-infrared light irradiation, while irradiation in the same concentration of pure ICG aqueous solution group Near-infrared light reaches 81.22 °C from 25.1 °C in 300 seconds, and IRPNPs photothermal therapy has a heating effect. According to the IRPNPs for the biofilm destruction test, our results showed that the highest concentration of IRPNPs (ICG: 20 μM, RIF: 3.5 μM) in the laser group in the laser group at 1 hour and 24 hours of absorption and pure RIF aqueous solution group As a control, it can be as poor as 5.81 and 5.33 times (p < 0.05), which can indicate that IRPNPs have the ability to destroy biofilm. In order to understand whether IRPNPs have bactericidal function, according to IRPNPs for biofilm-containing MRSA bactericidal test, bacterial MRSA was irradiated by 808 nm near-infrared light for 5 minutes, and IRPNPs were reacted for 24 hours at a higher concentration (10 μM ICG and 1.75 μM RIF). After incubation for 10 hours on the agar plate, no bacteria were detected. It is known that IRPNPs are higher than (10 μM ICG and 1.75 μM RIF) and can effectively kill the bacteria, which represents the biofilm of the IRPNPs under the light treatment. Finally, in order to verify whether the IRPNPs in this study are biotoxic, according to the IRPNPs cytotoxicity test of bone cells (MG-63), IRPNPs and bone cells were cultured for 24 hours, and the cell survival rate was calculated by Trypan blue and MTT assay. At 90%, it represents lower biological toxicity of IRPNPs. We anticipate that the developed IRPNPs may exhibit a high potential for use in antimicrobial treatment. | en_US |