NIR-responsive MnO₂-functionalized mesoporous silica hydrogel: Fabrication and antibacterial activity evaluation

Area of Science:

• Biomaterials Science
• Nanotechnology
• Wound Healing

Background:

• Bacterial wound infections pose significant clinical challenges, requiring innovative therapeutic strategies.
• Current treatments often face issues like antibiotic resistance and limited efficacy.
• Advanced hydrogel systems offer potential for localized and controlled drug delivery.

Purpose of the Study:

• To develop an 808 nm near-infrared (NIR)-responsive hydrogel (NOR-MSN@MnO2-gel) for treating bacteria-infected wounds.
• To investigate the synergistic effects of chemotherapy and photothermal therapy (PTT) for enhanced antibacterial activity.
• To evaluate the in vivo efficacy and safety of the developed hydrogel system.

Main Methods:

• Fabrication of norfloxacin (NOR)-loaded manganese dioxide-modified mesoporous silica (NOR-MSN@MnO2) nanoparticles.
• Encapsulation of NOR-MSN@MnO2 nanoparticles into a furfuryl amine-modified hyaluronic acid hydrogel (HA-FAgel).
• Characterization of hydrogel properties (structure, injectability, water absorption, photothermal efficiency) and assessment of dual pH/NIR-responsive drug release.
• In vitro evaluation of antibacterial activity against Staphylococcus aureus and Escherichia coli.
• In vivo studies on infected wounds to assess bacterial inhibition, inflammation, re-epithelialization, collagen deposition, and angiogenesis.

Main Results:

• The developed MSN@MnO2-gel exhibited a 3D porous structure, good injectability, water absorption, and efficient photothermal conversion.
• The hydrogel demonstrated controllable NOR release due to pH/NIR dual-responsive characteristics.
• Synergistic PTT and chemotherapy effectively eliminated S. aureus and E. coli in vitro.
• In vivo studies showed that NOR-MSN@MnO2-gel + NIR irradiation significantly inhibited bacterial growth, reduced inflammation, promoted wound healing, and enhanced angiogenesis.
• The treatment maintained satisfactory biological safety.

Conclusions:

• The NOR-MSN@MnO2-gel + NIR regimen offers a promising strategy for the clinical treatment of bacterial infected wounds.
• The combination of chemotherapy and photothermal therapy within a responsive hydrogel system enhances therapeutic outcomes.
• This approach provides localized, controlled treatment with potential to overcome antibiotic resistance and improve wound healing processes.