Integrating enzyme-nanoparticles bring new prospects for the diagnosis and treatment of immune dysregulation in periodontitis

Abstract

Enzymes play a significant role in mediating inflammatory and immune responses in periodontitis. Effective diagnosis, timely treatment, and continuous management of periodontal enzymes are essential to prevent undesirable consequences; however, this remains a significant challenge. Nanoparticles (NPs) have attracted significant attention in biomedicine because of their advantageous nanosized effects. NPs are conjugated with specific enzyme substrates at responsive sites that are triggered by periodontitis enzyme biomarkers, leading to functional or characteristic changes. In contrast, NPs with enzyme-mimetic activities exhibit catalytic activity, effectively destroying pathogenic biofilms and modulating the immune response in periodontitis. The unique properties of enzyme-targeting NPs have enabled the development of biosensors and fluorescent probes capable of identifying enzyme biomarkers associated with periodontitis. Enzyme-responsive and enzyme-mimetic NPs both exert therapeutic applications in the treatment of periodontitis. In this review, we provide a comprehensive overview of the enzymes associated with periodontitis, the mechanisms of enzyme-responsive and enzyme-mimetic NPs, recent advancements in the use of NPs for detecting these enzymes, and the therapeutic applications of NPs in targeting or mimicking enzyme functions. We also discuss the challenges and prospects of using NPs in the diagnosis and treatment of periodontitis.

Keywords: biosensors; enzyme-responsive nanoparticles; fluorescent probes; inflammatory; nanozymes; periodontitis biomarkers.

Figure 1

Enzymes biomarkers in periodontitis. (A) The periodontal bacteria. Inflammatory immune responses are all common risk factors for periodontitis. Enzymes associated with periodontal disease reveal the progression of periodontitis. (B) Oral microbial proteases. Gingipain secreted by Porphyromonas gingivalis, including arginine protease (Rgp) and lysine gingipain (Kgp), serve as virulence factors, hydrolyzing host proteins, increasing bleeding tendency, activating inflammation, and causing alveolar bone loss. The dipeptidyl peptidase (DPP) orthologs are specifically distributed in anaerobic oral rods. DPP activities in dental plaque are potent biomarkers indicating the presence of periodontopathic bacteria and disease activity. (C) Oxidative stress-related enzymes. Periodontitis is intricately linked with oxidative-reductive imbalance and oxidative stress. Evidence suggests that patients with periodontitis exhibit elevated levels of oxidative stress markers and reduced levels of antioxidants in their serum or saliva. The activity of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, or non-phagocytic cell oxidase (NOX) enzyme complexes, increases in patients with periodontal disease. Enzymatic antioxidants associated with periodontitis include catalase, glutathione reductase (GR), and total antioxidant capacity (TAOC). (D) Proteolytic enzymes. The levels of matrix metalloproteinases (MMPs), neutrophil elastase (NE), and myeloperoxidase (MPO) increase in periodontitis, suggesting these enzymes as potential markers of periodontal inflammation.

Figure 2

Nanoparticles (NPs). (A) Enzyme-responsive NPs and nanozymes (NZs) hold significant potential for advancing both diagnostic and therapeutic applications in periodontitis. These NPs can be used as biosensors and fluorescent probes for diagnosing periodontitis. Enzyme-responsive NPs and NZs both exert therapeutic effects in periodontitis. (B–D) Various effects (such as antibacterial effects, anti-inflammatory activity, and tissue regeneration) of the NPs as a therapeutic approach for periodontitis.

Figure 3

The antibacterial, anti-inflammatory and tissue regeneration mechanisms of nanoparticles (NPs). (A) The antibacterial effects of metallic NPs are attributed to three primary mechanisms: ROS production, ion release, and interaction with the cellular membrane. ROS generated by these NPs degrade essential cellular components (DNA, RNA, and proteins), effectively killing periodontal pathogens. Due to their small size, metallic NPs can penetrate the peptidoglycan layer and damage bacterial cells. The metal ions released by NPs are toxic to bacterial DNA and proteins. (B) Introduction of metallic NPs results in a microenvironment characterized by low levels of inflammatory cytokines and high levels of reparative cytokines, such as bone morphogenetic protein-2 (BMP-2), runt-related transcription factor 2 (Runx2), osteocalcin (OCN), osteopontin (OPN), and alkaline phosphatase (ALP). This favorable environment promotes human periodontal ligament cell (hPDLC) differentiation and periodontal tissue regeneration and halts the progression of periodontitis. (C) NPs exhibit antioxidant properties that help regulate ROS. Metallic NPs reduce inflammation by regulating cytokines and macrophage polarization.

Figure 4

The antibacterial and anti-inflammatory mechanisms of nanozymes (NZs). (A) NZs are NPs with enzyme-mimicking properties. They mimic enzymes such as superoxide dismutase (SOD), catalase (CAT), oxidase (OXD), and peroxidase (POD). POD or oxidase mimics converting hydrogen peroxide (H₂O₂) or superoxide (O₂) into ROS such as hydroxyl radicals (·OH) or singlet oxygen (¹O₂). (B) The antibacterial processes and properties of NZs. Catalytic activities of NZs efficiently eliminate bacterial biofilms, showing broad-spectrum antimicrobial activity with minimal biotoxicity. (C) Various NZs exhibit antioxidant properties that help regulate ROS. NZs suppressed inflammatory responses by eliminating ROS, while also lowering pro-inflammatory cytokines and boosting anti-inflammatory cytokines.

Figure 5

Nanoparticles (NPs) in periodontitis diagnosis. NP-based detection strategies are gaining popularity for the development of quick and efficient diagnostic assays. They include metal (gold, silver, and copper oxide), magnetic, and fluorescent NPs.

Figure 6

Nanoparticles (NPs) in periodontitis treatment. Metal NPs (gold, silver, copper oxide) and nanozymes (NZs) exhibit considerable promise in periodontal disease treatment. NZs are primarily composed of metal‐based, metal oxide/sulfide‐based, and carbon‐based NZs, as well as metal–organic frameworks (MOFs) and single-atom nanozymes (SAzymes).