<p>Novel nanomaterial-based antibacterial photodynamic therapies to combat oral bacterial biofilms and infectious diseases</p>

Abstract

Oral diseases such as tooth caries, periodontal diseases, endodontic infections, etc., are prevalent worldwide. The heavy burden of oral infectious diseases and their consequences on the patients’ quality of life indicates a strong need for developing effective therapies. Advanced understandings of such oral diseases, e.g., inflammatory periodontal lesions, have raised the demand for antibacterial therapeutic strategies, because these diseases are caused by viruses and bacteria. The application of antimicrobial photodynamic therapy (aPDT) on oral infectious diseases has attracted tremendous interest in the past decade. However, aPDT had a minimal effect on the viability of organized biofilms due to the hydrophobic nature of the majority of the photosensitizers (PSs). Therefore, novel nanotechnologies were rapidly developed to target the delivery of hydrophobic PSs into microorganisms for the antimicrobial performance improvement of aPDT. This review focuses on the state-of-the-art of nanomaterials applications in aPDT against oral infectious diseases. The first part of this article focuses on the cutting-edge research on the synthesis, toxicity, and therapeutic effects of various forms of nanomaterials serving as PS carriers for aPDT applications. The second part discusses nanomaterials applications for aPDT in treatments of oral diseases. These novel bioactive nanomaterials have demonstrated great potential to serve as carriers for PSs to substantially enhance the PDT therapeutic effects. Furthermore, the novel aPDT applications not only have exciting therapeutic potential to inhibit bacterial plaque-initiated oral diseases, but also have a wide applicability to other biomedical and tissue engineering applications.

Future antiviral surfaces: Lessons from COVID-19 pandemic

“…Some noble or heavy metal nanoparticles, including gold, copper, and silver nanoparticles exhibit an interesting localized surface plasmon resonance (LSPR) effect under visible light irradiation [ 29 ]. It was reported that the generated surface plasmons are effective to provide photodynamic killing of bacteria [ 30 ]. If taking the much smaller size and vulnerability of viruses into consideration, these metal nanoparticles with the surface plasmon effect would also be effective against viral infection under normal visible light irradiations.…”

Promising Therapeutic Strategies Against Microbial Biofilm Challenges

“…PDT was used as an antimicrobial strategy to inhibit biofilms formed by a broad spectrum of microorganisms by effectively damaging the cell membrane within the biofilm in vitro (Wood et al, 1999 ). Subsequently, antimicrobial PDT was found to nonspecifically attack microorganisms by generating cytotoxic ROS, which have strong oxidation ability and high reactivity, thus causing rapid lipid oxidation of the bacteria (Qi et al, 2019 ). It has been found that the antibiofilm activity of PDT is also associated with inhibition of the ability of microorganisms to adhere to surfaces, destroying biofilm structures, damaging some organelles, inducing virulence factor secretion, and inhibiting efflux capacity and QS (Arciola et al, 2011 ; Li et al, 2017 ; Tan et al, 2018 ; Hendiani et al, 2019 ; Mahdizade-Ari et al, 2019 ).…”

“…Most antibiofilm studies of PDT have used this technique for dental plaque-related diseases and chronic wound infections (Zanin et al, 2005 ; Dilsiz et al, 2013 ; Mahmoudi et al, 2019 ); however, some studies have also used PDT to combat biofilm-related infections in ventilator-associated pneumonia and chronic rhinosinusitis (Krespi and Kizhner, 2011 ; Geralde et al, 2017 ). A majority of photosensitizers are poorly soluble in water and hydrophobic; however, with the application of NMs, this limitation might be overcome (Qi et al, 2019 ). PDT has emerged during the era of nanotechnology, and these combination strategies have been shown to have good effects (Khan et al, 2012 ).…”

“…PDT has emerged during the era of nanotechnology, and these combination strategies have been shown to have good effects (Khan et al, 2012 ). NMs can serve as photosensitizers to enhance photostability and the production of ROS, such as fullerenes, while NMs can also serve as nanocarriers for photosensitizers to increase stability, dispersity, and hydrophilicity, such as gold and silica-based NPs (Qi et al, 2019 ). Because of the continuous development of protocols and light sources, PDT has been used in long-term clinical trials.…”

Microporous Frameworks as Promising Platforms for Antibacterial Strategies Against Oral Diseases

“…The feature of structural variability is beneficial to wide application in different fields through the design of holes and skeletons, such as semiconduction, photoconductor, gas adsorption and storage, diagnoses, and treatment (Wan et al, 2008(Wan et al, , 2009Fang et al, 2015;Huang et al, 2016;Mitra et al, 2017;Zhu and Zhang, 2017). Recently, nanomaterial-based antibacterial photodynamic therapy gradually gained increasing attention (Qi et al, 2019). The antibacterial photodynamic therapy bases on the interaction of harmless nanosized-photosensitizers, tissue oxygen, and visible light to yield high level of ROS, which has a strong oxidation and high reactivity, thus causing rapid lipid oxidation of the bacteria.…”