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Published on: April 16, 2018
A pH-Gated Functionalized Hollow Mesoporous Silica Delivery System for Photodynamic Sterilization in Staphylococcus
Nanxin Zhao1, Rongfeng Cai1, Yuting Zhang1
1The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China.
Abstract:
Multidrug-resistant bacteria are increasing, particularly those embedded in microbial biofilm. These bacteria account for most microbial infections in humans. Traditional antibiotic treatment has low efficiency in sterilization of biofilm-associated pathogens, and thus the development of new approaches is highly desired. In this study, amino-modified hollow mesoporous silica nanoparticles (AHMSN) were synthesized and used as the carrier to load natural photosensitizer curcumin (Cur). Then glutaraldehyde (GA) and polyethyleneimine (PEI) were used to seal the porous structure of AHMSN by the Schiff base reaction, forming positively charged AHMSN@GA@PEI@Cur. The Cur delivery system can smoothly diffuse into the negatively charged biofilm of Staphylococcus aureus (S. aureus). Then Cur can be released to the biofilm after the pH-gated cleavage of the Schiff base bond in the slightly acidic environment of the biofilm. After the release of the photosensitizer, the biofilm was irradiated by the blue LED light at a wavelength of 450 nm and a power of 37.4 mV/cm2 for 5 min. Compared with the control group, the number of viable bacteria in the biofilm was reduced by 98.20%. Therefore, the constructed pH-gated photosensitizer delivery system can efficiently target biofilm-associated pathogens and be used for photodynamic sterilization, without the production of antibiotic resistance.
Insights
A novel pH-gated delivery system using curcumin-loaded nanoparticles effectively targets and eradicates Staphylococcus aureus biofilms. This photodynamic sterilization approach significantly reduces bacterial load without promoting antibiotic resistance.
Area of Science:
- Nanotechnology
- Antimicrobial Research
- Biomedical Engineering
Background:
- Multidrug-resistant bacteria in biofilms are a major cause of persistent human infections.
- Conventional antibiotics show limited efficacy against biofilm-associated pathogens.
- Novel strategies are urgently needed for effective biofilm sterilization.
Purpose of the Study:
- To develop a pH-gated photosensitizer delivery system for targeting microbial biofilms.
- To evaluate the efficacy of curcumin-loaded nanoparticles in photodynamic sterilization of *Staphylococcus aureus* biofilms.
Main Methods:
- Synthesis of amino-modified hollow mesoporous silica nanoparticles (AHMSN) loaded with curcumin (Cur).
- Encapsulation of Cur within AHMSN using glutaraldehyde and polyethyleneimine to form AHMSN@GA@PEI@Cur.
- Photodynamic therapy using blue LED light (450 nm) on *S. aureus* biofilms after pH-triggered Cur release.
Main Results:
- The AHMSN@GA@PEI@Cur system effectively diffused into negatively charged *S. aureus* biofilms.
- Curcumin release was triggered by the slightly acidic pH within the biofilm.
- Photodynamic treatment resulted in a 98.20% reduction in viable bacteria within the biofilm compared to controls.
Conclusions:
- The developed pH-gated photosensitizer delivery system demonstrates high efficiency in targeting and eliminating biofilm-associated pathogens.
- This photodynamic sterilization method offers a promising alternative to antibiotics for combating biofilm infections.
- The approach avoids the development of antibiotic resistance.
