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Three novel polypyridyl‐Co(III)‐vitamin B6 complexes viz. [Co(CF3‐phtpy)(SBVB6)]Cl (Co1), [Co(anthracene‐tpy)(SBVB6)]Cl (Co2), [Co(NMe2‐phtpy)(SBVB6)]Cl (Co3), where 4'‐(4‐(trifluoromethyl)phenyl)‐2,2':6',2"‐terpyridine=CF3‐phtpy, 4'‐(anthracen‐9‐yl)‐2,2':6',2"‐terpyridine=anthracene‐tpy;, 4‐([2,2':6',2"‐terpyridin]‐4'‐yl)‐N,N‐dimethylaniline=NMe2‐phtpy, (E)‐5‐(hydroxymethyl)‐4‐(((2‐hydroxyphenyl)imino)methyl)‐2‐methylpyridin‐3‐ol=H2SBVB6 were successfully developed for aPDT (antibacterial photodynamic therapy) applications. Co1–Co3 exhibited an intense absorption band at ca. 435–485 nm, which is attributed to ligand‐to‐metal charge transfer and was beneficial for antibacterial photodynamic therapy. The distorted octahedral geometry of the complexes with CoIIIN4O2 core was evident from the DFT study. The visible light absorption ability and good photo‐stability of Co1–Co3 made them good photosensitizers for aPDT. Co1–Co3 displayed significant antibacterial responses against gram‐positive (S. aureus) and gram‐negative (E. coli) bacteria upon light exposure (10 J cm−2, 400–700 nm) and showed MIC values between 0.01–0.005 μg mL−1. The aPDT activities of these complexes were due to their ability to damage bacterial cell membranes via ROS generation. Overall, this study shows the photo‐triggered ROS‐mediated bacteria‐killing potential of Co(III) complexes. [ABSTRACT FROM AUTHOR]

The effect of a natural polysaccharide (hyaluronic acid (HA)) on the photocatalytic activity of methylene blue (MB) was studied both under model conditions (a tryptophan photooxidation reaction in water) and with in vitro experiments on P. aeruginosa and S. aureus bacterial cultures. It was shown spectrophotometrically that, in the presence of HA, an increase in the optical density of the absorption bands λ = 665 nm and 620 nm—which correspond to the monomeric and dimeric forms of the dye, respectively—was observed in the EAS of the dye, while the ratio of the optical density of these bands remained practically unchanged. When adding HA to MB, the intensity of singlet oxygen 1O2 photoluminescence and the degree of fluorescence polarization of MB increase. The observed effects are associated with the disaggregation of molecular associates of the dye in the presence of HA. The maximum increase in the photocatalytic activity of MB (by 1.6 times) was observed in the presence of HA, with concentrations in a range between 0.0015 wt.% and 0.005 wt.%. [ABSTRACT FROM AUTHOR]

Healthcare‐associated infections remain a significant health concern, particularly with the emergence of antibiotic resistance. While these antibiotics have saved countless lives, their overuse reduces their efficacy promoting the emergence of multidrug‐resistant (MDR) bacteria. This prompts researchers to explore new alternatives for treating bacteria proliferation. In this context, antibacterial photodynamic therapy (aPDT) has emerged as a promising approach for treating localized infections. It utilizes reactive oxygen species (ROS) as oxidative stress agents, thereby minimizing the risk of developing MDR. The success of aPDT significantly hinges on the careful selection of photosensitizers (PSs) and polymer matrices for the synthesis of polymer‐based photoactive materials. Various light‐absorbing PSs are therefore designed for enhancing ROS production and antimicrobial efficacy. By incorporating PSs into polymer matrices, these materials can harness the light power to generate ROS, destroying bacterial cells upon irradiation. This review aims to provide a comprehensive overview of advancements in this field, specifically focusing on the use of polymer‐based materials. The mechanism of the four main ROS generated in aPDT, the methods used for their detection, and their mode of action against bacteria has been outlined. The recent improvement in polymer‐based aPDT materials and their antibacterial efficacy have been also addressed. [ABSTRACT FROM AUTHOR]

Abstract Persistent biofilm infections pose a critical health threat with their relentless presence and amplified antibiotic resistance. Traditional antibacterial photodynamic therapy can inhibit bacteria extracellularly but struggles to control biofilm formation and virulence. Thus, there is an urgent need to develop photosensitizers, such as ultra‐small gold nanoclusters (AuNCs), that can penetrate biofilms and internalize into bacteria. However, AuNCs still face the challenge of insufficient reactive oxygen species (ROS) production and limited near‐infrared light absorption. This study develops a model of indocyanine green (ICG)‐sensitized AuNCs with atomic‐precision size effect. This approach achieved near‐infrared light absorption while inhibiting radiation transitions, thereby regulating the generation of ROS. Notably, different‐sized AuNCs (Au10NCs, Au15NCs, Au25NCs) yielded varied ROS types, resulting from different energy level distributions and electron transfer rates. ICG‐Au15NCs achieved a treatment efficacy of 99.94% against Staphylococcus aureus infections in vitro and significantly accelerated wound healing in vivo. Moreover, this study highlights the unique role of ICG‐AuNCs in suppressing quorum sensing, virulence, and ABC transporters compared to their larger counterparts. This strategy demonstrates that atomic‐precision size effect of AuNCs paves the way for innovative approaches in antibacterial photodynamic therapy for infection control.

Background and Objectives. Infections associated with antibiotic-resistant strains of microorganisms, including Staphylococcus aureus, pose the greatest danger in nasopharyngeal diseases and post-surgical complications. A number of studies have shown that there are interstrain differences in the sensitivity of clinically significant microorganisms to the damaging effects of antimicrobial photodynamic therapy. In this work, in order to quantify interstrain differences in the responses of bacterial cells to photodynamic exposure, we studied the effectiveness of pyridyl porphyrin compounds in combination with LED radiation against three strains of Staphylococcus aureus. Materials and Methods. The objects of the study were: methicillin-sensitive museum strain S. aureus 209 P, methicillin-sensitive clinical strain S. aureus 5, methicillin-resistant clinical strain S. aureus 11. A LED with a maximum emission spectrum at a wavelength of λ = 405 nm and a half-width of 30 nm at a level of 0.1 of the maximum intensity, a power of 1.8 W and an integrated power density of 80 mW/cm2 was used as a radiation source. In all experiments, the radiation mode was continuous. The irradiation time varied from 5 to 30 min (irradiation doses from 24 to 144 J/cm2 , respectively). Water-soluble meso-substituted cationic pyridylporphyrins were used as photosensitizers: meso-tetrakis(N-(2’-hydroxyethyl)pyridinium-4-yl)porphyrin chloride (H2TOE4PyP) and its Zn(II) derivatives – zinc-meso-tetrakis [4-N-(2’-oxyethyl) pyridyl] porphyrin (Zn-TOE4PyP), zinc-meso-tetrakis [3-N-butyl pyridyl] porphyrin (Zn-TBut3PyP). To assess the level of oxidative stress and the tolerance of microorganisms to it, two different methods were used: 1) a method for determining the minimum inhibitory concentration of hydrogen peroxide, and 2) a method for determining the activity of bacterial catalase. Results and Discussion. The greatest sensitivity to the action of LED radiation was demonstrated by cells of the clinical methicillin-resistant strain S. aureus 11, activated by pyridyl porphyrins. It has been shown that when photosensitizers are used in concentrations of 0.01–0.03 mg/ml after 30 minutes of irradiation, a decrease in the number of cells of this strain occurs by 4.8 lgCFU/ml. It has been found that the activity of catalase in the cells of the methicillin-resistant strain S. aureus 11 is 17% lower compared to the activity of catalase in the cells of the standard strain S. aureus 209 P. This indirectly indicates the greater sensitivity of the strain S. aureus 11 to reactive oxygen species, formed during antimicrobial photodynamic exposure. Conclusion. It has been found that the differences in population reduction between strains range from 1.7 to 2.3 lgCFU/ml at the maximum irradiation dose, depending on the pyridylporphyrin modification used. It has been shown that the antibiotic-resistant strain S. aureus 11, which is highly sensitive to the action of ROS in the form of hydrogen peroxide and incapable of active production of catalase, is most susceptible to the complex action of LED radiation (405 nm) in combination with photosensitizers in the form of zinc- meso-tetrakis[3-N-butyl pyridyl]porphyrin (Zn-TBut3PyP).

Antimicrobial photodynamic therapy (aPDT) has emerged as a highly promising strategy for non-antibiotic treatment of infections due to its unique advantages in efficient bactericidal action and reduction of drug resistance. The natural photosensitizing properties of curcumin (Cur) are widely acknowledged; however, its limited bioavailability has impeded its practical application. In this study, we developed a nanomaterial called Cur@ZIF-8@BA by encapsulating Cur within ZIF-8 and modifying the surface with boric acid (BA). The Cur@ZIF-8@BA exhibits pH-responsive properties and enhances bacterial binding, thereby effectively promoting photodynamic therapy. Moreover, its antibacterial activity against E. coli, Staphylococcus aureus and A. baumannii is significantly increased in the presence of light compared to a dark environment. The mechanism behind this may be that BA increases the affinity of Cur@ZIF-8@ BA towards bacteria, and making released Zn[sup 2+] and BA from the nanomaterial increase bacterial cell membrane permeability. This facilitates efficient delivery of Cur into bacterial cells, resulting in generation of abundant reactive oxygen species (ROS) and subsequent bactericidal activity. In conclusion, our prepared Cur@ZIF-8@BA holds great promise as a photodynamically mediated antimicrobial strategy. [ABSTRACT FROM AUTHOR]

Objective To investigate the efficacy of antibacterial photodynamic therapy (aPDT) as an adjunct to subgingival scaling and root planning in the treatment of chronic periodontitis. Methods This study followed medical ethics guidelines, and informed consent was obtained from all patients. Sixteen patients were recruited for this randomized split-mouth controlled trial. The control group underwent subgingival scaling and root planning (SRP), while the experimental group received subgingival scaling and root planing plus aPDT treatment using Perowave® with a toluidine blue O solution photosensitizer. The probing pocket depth (PD), recession, plaque index (PLI), bleeding index (BI) and proportion of positive sites of bleeding on probing (BOP) (BOP%) at all sites were examined at baseline (before treatment) and at 1, 3 and 6 months after treatment. Results Follow-up was completed for 13 patients. On the control side, 356 teeth were tested at 2 136 sites. A total of 360 teeth on the test side and 2 160 sites were included in the study. Before treatment, there was no significant difference in the baseline indicators between the two groups. After treatment, both groups showed significant improvement in clinical parameters, including PD, PLI, BI, and BOP%,compared with baseline. At 3 months, the BOP% and PLI in the experimental group were significantly lower than those in the control group (PP

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Bacterial wound infection has emerged as a pivotal threat to human health worldwide, and the situation has worsened owing to the gradual increase in antibiotic‐resistant bacteria caused by the improper use of antibiotics. To reduce the use of antibiotics and avoid the increase in antibiotic‐resistant bacteria, researchers are increasingly paying attention to photodynamic therapy, which uses light to produce reactive oxygen species to kill bacteria. Treating bacteria‐infected wounds by photodynamic therapy requires fixing the photosensitizer (PS) at the wound site and maintaining a certain level of wound humidity. Hydrogels are materials with a high water content and are well suited for fixing PSs at wound sites for antibacterial photodynamic therapy. Therefore, hydrogels are often loaded with PSs for treating bacteria‐infected wounds via antibacterial photodynamic therapy. In this review, we systematically summarised the antibacterial mechanisms and applications of PS‐loaded hydrogels for treating bacteria‐infected wounds via photodynamic therapy. In addition, the recent studies and the research status progresses of novel antibacterial hydrogels are discussed. Finally, the challenges and future prospects of PS‐loaded hydrogels are reviewed. [ABSTRACT FROM AUTHOR]

The effect of the diphenylalanine (Phe-Phe) amino acid on the rate of tryptophan photooxidation catalyzed by photosensitizers (PS) of different natures: dimegin (DMG), fluorinated tetraphenylporphyrin (FTPP), photoditazine (PD) and methylene blue (MB) was studied. It was shown that in the presence of Phe-Phe, the effective constant of photooxidation of the substrate catalyzed by DMG, PD and MB in the aqueous phase decreases. However, the introduction of the amphiphilic polymer Pluronic F127 into the systems allows not only to restore, but also to increase the activity of the PS in the processes of photosensitized oxidation. In particular, the activity of dimegin solubilized by Pluronic F127 in the presence of Phe-Phe is higher than the activity of both pure porphyrin and solubilized DMG. In addition, the activity of the hydrophobic FTPP solubilized by Pluronic also increases. At the same time, a study of the luminescence of singlet oxygen generated by solubilized FTPP in the absence and presence of Phe-Phe revealed that the dipeptide does not influence the processes of 1О2 generation. It was suggested that micellar catalysis influences the activity of solubilized PS in the presence of a biologically active dipeptide. [ABSTRACT FROM AUTHOR]

The objective: to study the efficacy of antimicrobial photodynamic therapy (APDT) using hydroxyaluminum phthalocyanine (Photosens) as a photosensitizer in the experimental model of tuberculosis infection in mice.Subjects and Methods. Balb/cmice were infected with the multiple drug resistant (MDR) strain of M. tuberculosis Beijing BO/W148. APDT with hydroxyaluminum phthalocyanine and red laser light exposure were started on Day 45. A total of 4 sessions of APDT on the projection of both lungs, liver and spleen were performed. On Day 60, the therapeutic eff ect of APDTwas assessed by evaluation of severity of mycobacterial load and specific granulomatous infiltration in the lungs, liver and spleen. The absorption of light energy of laser radiation by the chest and abdominal walls, as well as tissues of lungs, liver and spleen was determined by photometry using afluovisor.Results. The tissues of the experimental animal retain a significant amount of light energy, however, the residual value of light transmission is sufficient to provide a pronounced therapeutic effect which manifests itself as a significant decrease of mycobacterial load and specific inflammatory process in all the studied internal organs.Conclusion. APDT may be an effective tool to treat some forms of tuberculous infection including those caused by M. tuberculosis with MDR.

Intracellular Staphylococcus aureus (S. aureus), especially the methicillin resistant staphylococcus aureus (MRSA), are difficult to detect and eradicate due to the protection by the host cells. Antibacterial photodynamic therapy (aPDT) offers promise in treating intracellular bacteria, provided that selective damage to the bacteria ranther than host cells can be realized. According to the different nitroreductase (NTR) levels in mammalian cells and S. aureus, herein NTR‐responsive photosensitizers (PSs) (T)CyI−NO2 were designed and synthesized. The emission and 1O2 generation of (T)CyI−NO2 are quenched by the 4‐nitrobenzyl group, but can be specifically switched on by bacterial NTR. Therefore, selective imaging and photo‐inactivation of intracellular S. aureus and MRSA were achieved. Our findings may pave the way for the development of more efficient and selective aPDT agents to combat intractable intracellular infections. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Recently, photodynamic therapy (PDT) has attracted wide attention due to its less susceptibility to drug resistance, broad‐spectrum biocidal activity and biosafety in normal tissues. However, the traditional photosensitizers (PSs) face the disadvantage of poor therapeutic efficacy due to the requirement of an aerobic environment to generate 1O2 through Type ІI pathway. Herein, we designed and synthesized a novel cationic conjugated oligomer oligo(phenylene vinylene) (OPV) and studied its antibacterial photodynamic activity against both Gram‐negative Escherichia coli (E. coli) and Gram‐positive bacteria methicillin‐resistant Staphylococcus aureus (MRSA). Importantly, the OPV can rapidly produce reactive oxygen species (ROS) through double pathways, Type I and II mechanism under white light irradiation, and efficiently kill E. coli and MRSA at a nanomolar level. The dual type photosensitizing capability makes OPV promising for enhanced PDT to treat pathogens and tumors in complex environments. [ABSTRACT FROM AUTHOR]

Abstract With the increasing prevalence of infectious diseases caused by drug‐resistant bacteria, there is an urgent need to develop innovative therapies alternative to antibiotics. Among these alternatives, the aggregation‐induced emission (AIE) photosensitizers (PSs) stand out with their integrated imaging and therapeutic functionalities, allowing for early monitoring and image‐guided ablation of bacteria. AIE fluorescent probes with unique optical properties excel in selective bacterial imaging. Furthermore, AIE‐enabled reactive oxygen species (ROS)‐mediated antibacterial photodynamic therapy can operate on multiple targets to oxidize bacteria. Also, as they are able to specifically target bacteria, AIE PSs can ameliorate the limitations of the small‐scale action of ROS. This review methodically discusses the different strategies that can be employed using AIE PSs for targeting bacteria, including sheltered bacteria. The challenges and future opportunities of using AIE PSs in this emerging field are also briefly discussed.

Nowadays, infectious diseases persist as a global crisis by causing significant destruction to public health and the economic stability of countries worldwide. Especially bacterial infections remain a most severe concern due to the prevalence and emergence of multi-drug resistance (MDR) and limitations with existing therapeutic options. Antibacterial photodynamic therapy (APDT) is a potential therapeutic modality that involves the systematic administration of photosensitizers (PSs), light, and molecular oxygen (O2) for coping with bacterial infections. Although the existing porphyrin and non-porphyrin PSs were effective in APDT, the poor solubility, limited efficacy against Gram-negative bacteria, and non-specific distribution hinder their clinical applications. Accordingly, to promote the efficiency of conventional PSs, various polymer-driven modification and functionalization strategies have been adopted to engineer multifunctional hybrid phototherapeutics. This review assesses recent advancements and state-of-the-art research in polymer-PSs hybrid materials developed for APDT applications. Further, the key research findings of the following aspects are considered in-depth with constructive discussions: i) PSs-integrated/functionalized polymeric composites through various molecular interactions; ii) PSs-deposited coatings on different substrates and devices to eliminate healthcare-associated infections; and iii) PSs-embedded films, scaffolds, and hydrogels for regenerative medicine applications.

Xincong Li,1,* Shuangshuang Ren,1,* Lutong Song,1 Deao Gu,2 Haoran Peng,1 Yue Zhao,1 Chao Liu,2 Jie Yang,3 Leiying Miao1 1Department of Cariology and Endodontics, Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210008, People’s Republic of China; 2Department of Orthodontics, Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210008, People’s Republic of China; 3Department of Periodontology, Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, 210008, People’s Republic of China*These authors contributed equally to this workCorrespondence: Leiying Miao; Jie Yang, Email miaoleiying80@163.com; dorothy0314@sina.comIntroduction: Antibacterial photodynamic treatment (aPDT) has indispensable significance as a means of treating periodontal disorders because of its extraordinary potential for killing pathogenic bacteria by generating an overpowering amount of reactive oxygen species (ROS). The elevated ROS that may result from the antibacterial treatment procedure, however, could exert oxidative pressure inside periodontal pockets, causing irreparable damage to surrounding tissue, an issue that has severely restricted its medicinal applications. Accordingly, herein, we report the use of black phosphorus nanosheets (BPNSs) that can eliminate the side effects of ROS-based aPDT as well as scavenge ROS to produce an antibacterial effect.Methods: The antibacterial effect of ICG/aPDT was observed by direct microscopic colony counting. A microplate reader and confocal microscope enabled measurements of cell viability and the quantification of ROS fluorescence. BPNS administration regulated the oxidative environment. IL-1β, IL-6, TNF-α, IL-10, TGF-β, and Arg-1 mRNA expression levels were used to assess the inflammatory response after BPNS treatment. In vivo, the efficacy of the combination of BPNSs and ICG/aPDT was evaluated in rats with periodontal disease by histomorphometric and immunohistochemical analyses.Results: The CFU assay results verified the antibacterial effect of ICG/aPDT treatment, and ROS fluorescence quantification by CLSM indicated the antioxidative ability of the BPNSs. IL-1β, IL-6, TNF-α, IL-10, TGF-β, and Arg-1 mRNA expression levels were significantly decreased after BPNS treatment, confirming the in vitro anti-inflammatory effect of this nanomaterial. The histomorphometric and immunohistochemical analyses showed that the levels of proinflammatory factors decreased, suggesting that the BPNSs had anti-inflammatory effects in vivo.Conclusion: Treatment with antioxidative BPNSs gives new insights into future anti-inflammatory therapies for periodontal disease and other infection-related inflammatory illnesses and provides an approach to combat the flaws of aPDT.Graphical Abstract: Keywords: periodontitis, black phosphorus nanosheets, reactive oxygen species, antibacterial photodynamic therapy, macrophage polarization

Objective To investigate the antibacterial effect of a new photosensitizer, indocyanine green (ICG)-mediated photodynamic therapy, on a biofilm of Fusobacterium nucleatum (F. nucleatum) in vitro. Methods The biocompatibility of the photosensitizer ICG was detected by CCK8. F. nucleatum (108 CFU/mL) was cultured in anaerobic conditions (80% N2, 10% H2 and 10% CO2) mixed with the photosensitizer ICG at concentrations of 0, 10, 20, 30, and 40 μg/mL and then treated with antibacterial photodynamic therapy (808 nm near infrared light with an intensity of 0.1 W/cm2 for 3 min), and a mature biofilm was formed after 2 days. The bacteriostatic effects of different concentrations of ICG on F. nucleatum biofilms were compared by colony formation unit count (CFU). The effect of ICG on the formation of F. nucleatum biofilms and biofilm metabolic activity was determined by crystal violet quantification and MTT assays. The effect of ICG on the formation of extracellular polysaccharides in F. nucleatum biofilms was determined by the phenol-sulfuric acid method. The change in the number of bacteria was observed by confocal microscopy. Results CFU and biomass of the biofilm gradually decreased with increasing ICG concentration, and there were significant differences compared with the control group. Meanwhile, the metabolic activity of the biofilm and the production of extracellular polysaccharides also showed a significant difference between the ICG groups and the control group (P

The 'dusting' technique of lithotripsy for the removal of infected urinary calculi and the wide use of drainage after endoscopic surgery may stimulate spreading of multidrug-resistant bacterial strains. Antibacterial photodynamic therapy (PDT) is one promising method for the elimination these strains. The purpose of our study was to evaluate alterations of renal pelvis morphology and renal function in laboratory animals after bactericidal regimens of PDT. Renal pelvises of pigs were filled with Photoditazine and then assessed either by examining the accumulation of Photoditazine in the urothelium or by illumination with a laser at a wavelength of 662 nm. A renal test and a complete blood count was performed to assess a negative effect of the treatment on health. Structural alterations of the kidney tissues were analyzed by histological examination. No photosensitizer fluorescence was detected in the urothelium of the pelvis. Histological study showed that PDT caused minor changes to the urothelium of the renal pelvis but did not affect the underlying connective tissue. No renal function abnormalities were found after PDT. Thus, the study indicates that antibacterial PDT is a safety technique that can complement common antibiotic therapy in the surgical treatment of urolithiasis. [ABSTRACT FROM AUTHOR]

The development of novel wound dressings, such as aerogels, with rapid hemostasis and bactericidal capacities for pre-hospital care is necessary. To prevent the occurrence of bacterial resistance, antibacterial photodynamic therapy (aPDT) with broad-spectrum antibacterial ability and negligible bacterial resistance has been intensively studied. However, photosensitizers often suffer from poor water solubility, short singlet oxygen (1O2) half-life and restricted 1O2 diffusion distance. Herein, sodium alginate was covalently modified by photosensitizers and phenylboronic acid, and cross-linked by Ca(II) ions to generate SA@TPAPP@PBA aerogel after lyophilization as an antibacterial photodynamic wound dressing. Afterwards, its photodynamic and bacterial capture activities were intensively evaluated. Furthermore, its hemostasis and bactericidal efficiency against Staphylococcus aureus were assessed via in vitro and in vivo assays. First, chemical immobilization of photosensitizers led to an enhancement of its solubility. Moreover, it showed an excellent hemostasis capacity. Due to the formation of reversible covalent bonds between phenylboronic acid and diol groups on bacterial cell surface, the aerogel could capture S. aureus tightly and dramatically enhance aPDT. To sum up, the prepared aerogel illustrated excellent hemostasis capacity and antibacterial ability against S. aureus. Therefore, they have great potential to be utilized as wound dressing in clinical trials.

Infectious diseases remain a serious global challenge threatening human health. Oral infectious diseases, a major neglected global problem, not only affect people’s lifestyles but also have an intimate association with systemic diseases. Antibiotic therapy is a common treatment. However, the emergence of new resistance problems hindered and enhanced the complication of the treatment. Currently, antimicrobial photodynamic therapy (aPDT) has long been the topic of intense interest due to the advantage of being minimally invasive, low toxicity, and high selectivity. aPDT is also becoming increasingly popular and applied in treating oral diseases such as tooth caries, pulpitis, periodontal diseases, peri-implantitis, and oral candidiasis. Photothermal therapy (PTT), another phototherapy, also plays an important role in resisting resistant bacterial and biofilm infections. In this mini-review, we summarize the latest advances in photonics-based treatments of oral infectious diseases. The whole review is divided into three main parts. The first part focuses on photonicsbased antibacterial strategies and mechanisms. The second part presents applications for photonics-based treatments of oral infectious diseases. The last part discusses present problems in current materials and future perspectives. [ABSTRACT FROM AUTHOR]

Due to the porous and interconnected structure, cryogels significantly facilitate blood exudate absorption and support rapid hemostasis as novel wound dressings. However, cryogels suffer from insufficient inherent antibacterial properties, which seriously limits their clinical applications. Herein, we developed a chitosan (CHI) and sodium alginate (SA) composite-based antibacterial photodynamic therapy (aPDT) cryogel for rapid hemostasis and infected wound healing. In this cryogel, the photosensitizer protoporphyrin IX (PpIX) was chemically immobilized onto CHI (CHI-PpIX), while the phenylboronic acid (PBA) molecules were coupled onto SA (SA-PBA). The resulting CHI-PpIX/SA-PBA (CPSP) hydrogel was created by mixing CHI-PpIX and SA-PBA, followed by freeze-drying to form the CPSP cryogel. Through forming dynamic boronic ester bonds between PBA and diol groups on bacterial cell walls, CPSP was endowed with bacterial capturing capacity and enhanced aPDT. In vitro antibacterial experiments revealed its enhanced aPDT efficiency owing to PBA-mediated bacterial targeting. In addition, in vivo assays demonstrated its effective hemostatic, antibacterial and wound healing-promoting capacities. By effectively integrating aPDT with bacterial capturing capabilities and addressing the limitations of existing wound dressings, the CPSP cryogel offers a promising solution for rapid hemostasis and the treatment of infected wounds., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 Elsevier B.V. All rights reserved.)

The rise of antibiotic-resistant Gram-positive bacterial infections poses a significant threat to public health, necessitating the exploration of alternative therapeutic strategies. A photosensitizer (PS) can convert energy from absorbed photon into reactive oxygen species (ROS) for damaging bacteria. This photoinactivation action bypassing conventional antibiotic mechanism is less prone to resistance development, making antibacterial photodynamic therapy (aPDT) highly efficient in combating Gram-positive bacteria. Photodynamic transition metal complexes leveraging the unique properties of metals to enhance the aPDT activity are the next-generation PS. This review provides an overview of metal-based PS for combating Gram-positive bacteria. Based on the structures, these metal-PS could be mainly classified as metal-tetrapyrrole derivatives, ruthenium complexes, iridium complexes, and zinc complexes. PS based on complexes of other transition metals such as silver, cobalt, and rhenium are also presented. Finally, we summarize the advantages and shortcomings of these metal- PS, conclude some critical aspects impacting their aPDT performances and give a perspective on their future development.

Biofilm-induced chronic bacterial infections represent a significant challenge in modern medicine due to their resistance to conventional antibiotic treatments. Although photodynamic therapy (PDT) has emerged as a promising antibiotic-free antibacterial strategy, the hypoxic condition within biofilms and the lack of an effective local drug delivery system have limited the clinical effectiveness of photosensitizer (PS) agents. Herein, we propose a type of charge regulation-enhanced type I PS-loaded hydrogel dressing for treating biofilm infection. The charge regulation enables the multiple alkylation Nile blue (EB series) to exhibit substantially improved absorbance (∼2-fold), alkaline tolerance, and superoxide anion yield (2.2-4.2-fold) compared to the representative type I PS, sulfur-substituted Nile blue. Specifically, the enhanced electronic push-pull capabilities promote a more efficient electron recycling process, significantly boosting the efficiency of type I PDT. The superior PDT effect and enhanced bacterial uptake via charge regulation render the EB series more pronounced in hypoxic bacterial inhibition under red light or sunlight irradiation. Moreover, the hydrogel, constructed from oxidized dextran and quaternized chitosan, facilitates the localization and sustained retention of type I PSs, accelerating the healing of biofilm-infected wounds. This type I PS-based hydrogel could provide an efficient and user-friendly wound dressing for the clinical treatment and prevention of biofilm infections.

Until now, in clinical dentistry, antibacterial photodynamic therapy (aPDT) has been restricted to in-office treatments, which hampers repeated applications. This pilot study tested the benefit of a commercially available Lumoral® device designed for regular periodontal dual-light aPDT treatment at home. Seven patients with peri-implant disease applied dual-light aPDT daily in addition to their normal dental hygiene for four weeks. A single Lumoral® treatment includes an indocyanine green mouth rinse followed by 40 J/cm2 radiant exposure to a combination of 810 nm and 405 nm light. A point-of-care analysis of active-matrix metalloproteinase (aMMP-8), visible plaque index (VPI), bleeding on probing (BOP), and peri-implant pocket depth (PPD) measurements was performed on day 0, day 15, and day 30. Reductions in aMMP-8 (p = 0.047), VPI (p = 0.03), and BOP (p = 0.03) were observed, and PPD was measured as being 1 mm lower in the implant (p = ns). These results suggest a benefit of regular application of dual-light aPDT in peri-implantitis. Frequently repeated application can be a promising approach to diminishing the microbial burden and to lowering the tissue destructive proteolytic and inflammatory load around dental implants. Further studies in larger populations are warranted to show the long-term benefits.

A single-site, randomized clinical trial was designed to determine the efficacy of regular home use of Lumoral® dual-light antibacterial aPDT in periodontitis patients. For the study, 200 patients were randomized to receive non-surgical periodontal treatment (NSPT), including standardized hygiene instructions and electric toothbrush, scaling and root planing, or NSPT with adjunctive Lumoral® treatment. A complete clinical intraoral examination was conducted in the beginning, at three months, and at six months. This report presents the three-month results of the first 59 consecutive randomized subjects. At three months, bleeding on probing (BOP) was lower in the NSPT + Lumoral®-group than in the NSPT group (p = 0.045), and more patients in the NSPT + Lumoral®-group had their BOP below 10% (54% vs. 22%, respectively, p = 0.008). In addition, patients in the NSPT + Lumoral®-group improved their oral hygiene by visible-plaque-index (p = 0.0003), while the NSPT group showed no statistical improvement compared to the baseline. Both groups significantly reduced the number of deep periodontal pockets, but more patients with a reduction in their deep pocket number were found in the NSPT + Lumoral® group (92% vs. 63%, p = 0.02). Patients whose number of deep pockets was reduced by 50% or more were also more frequent in the NSPT + Lumoral®-group (71% vs. 33%, p = 0.01). Patients with initially less than ten deep pockets had fewer deep pockets at the three-month follow-up in the Lumoral® group (p = 0.01). In conclusion, adjunctive use of Lumoral® in NSPT results in improved treatment outcomes at three months post-therapy. [ABSTRACT FROM AUTHOR]

Objective This systematic review and meta-analysis was undertaken to evaluate the efficacy of antibacterial photodynamic therapy (aPDT) in the treatment of periodontitis in type-2 diabetes mellitus (T2DM) patients and to provide better treatment for patients with T2DM complicated with periodontitis.Methods The PubMed, Cochrane, Embase, Web of Science, CNKI, CBM, and Wanfang databases were searched for relevant randomized controlled trials (RCTs). RevMan 5.3 was applied for the meta-analysis, and a systematic evaluation was conducted. Results A total of 8 RCTs were included. The results showed that compared to simple subgingival scaling and root planing (SRP), aPDT assisted SRP had a better effect on improving the probing depth (PD) at 3 months after treatment, The difference was statistically significant [WMD=-0.32,95%CI（-0.45, -0.2）, P < 0.05], but 6 months after treatment, there was no significant difference in the two groups [ WMD=-0.15,95%CI（-0.40, 0.10）,P=0.23]. During the 6-month follow-up period, there were no significant differences in the clinical attachment level (CAL), bleeding on probing (BOP) or hemoglobin A1c (HbA1c) between the two groups (P> 0.05).Conclusion aPDT-assisted periodontal nonsurgical treatment in T2DM patients can improve PD in the short term but has no significant effect on the improvement of CAL, BOP and HbA1c.

The ‘dusting’ technique of lithotripsy for the removal of infected urinary calculi and the wide use of drainage after endoscopic surgery may stimulate spreading of multidrug-resistant bacterial strains. Antibacterial photodynamic therapy (PDT) is one promising method for the elimination these strains. The purpose of our study was to evaluate alterations of renal pelvis morphology and renal function in laboratory animals after bactericidal regimens of PDT. Renal pelvises of pigs were filled with Photoditazine and then assessed either by examining the accumulation of Photoditazine in the urothelium or by illumination with a laser at a wavelength of 662 nm. A renal test and a complete blood count was performed to assess a negative effect of the treatment on health. Structural alterations of the kidney tissues were analyzed by histological examination. No photosensitizer fluorescence was detected in the urothelium of the pelvis. Histological study showed that PDT caused minor changes to the urothelium of the renal pelvis but did not affect the underlying connective tissue. No renal function abnormalities were found after PDT. Thus, the study indicates that antibacterial PDT is a safety technique that can complement common antibiotic therapy in the surgical treatment of urolithiasis.

Good oral hygiene at home is the foundation for optimal treatment response and long-term periodontal disease control. Antibacterial photodynamic therapy (aPDT) provides a very potent adjunctive treatment for plaque control. However, the literature regarding repeated aPDT use is sparse. aPDT has been a modality applied mainly in the dental office environment, and when applied once a year or every few months, the results have been usually disappointing. Recently, LED development has brought aPDT for repeated and practical use at home. We present the very positive results and clinical outcome of daily applied dual-light aPDT-technology treatment in conjunction with mechanical cleaning of a 78-year-old male patient with severe periodontal disease (Stage IV and Grade B). [ABSTRACT FROM AUTHOR]

Introduction: Antibacterial photodynamic therapy is a promising treatment modality in the anti-infective therapy of numerous oral diseases. It involves photo activation of a reactive substance (dye), thus releasing reactive oxygen species (ROS-radicals) which are highly destructive to the bacterial cell. However, thorough investigation of radical production properties of different dyes is not common in literature.Aim: The aim of this study was to investigate and evaluate oxygen radical-producing potential of two commonly used photoactive dyes in the context of antibacterial photodynamic therapy.Materials and methods: The radical-producing properties of two commonly used dyes for photodynamic therapy in oral medicine, methylene blue and indocyanine green, irradiated under laser irradiation are investigated using electron paramagnetic resonance (EPR) spectroscopy. The detection of reactive oxygen species is performed with “spin-trapping” technique.Results: The selected photoactive dyes showed promising yields of reactive oxygen species (ROS) in aqueous solutions. The comparative analysis of the results deemed methylene blue as the more productive photoactive agent.Conclusions: By employing the spin-trapping technique, this study indicates EPR-spectroscopy as a promising method of relative quantification of reactive oxygen species released by the photodynamic reaction in aqueous solutions.

The rise of antibacterial drug resistance means treatment options are becoming increasingly limited. We must find ways to tackle these hard-to-treat drug-resistant and biofilm infections. With the lack of new antibacterial drugs (such as antibiotics) reaching the clinics, research has switched focus to exploring alternative strategies. One such strategy is antibacterial photodynamic therapy (aPDT), a system that relies on light, oxygen, and a non-toxic dye (photosensitiser) to generate cytotoxic reactive oxygen species. This technique has already been shown capable of handling both drug-resistant and biofilm infections but has limited clinical approval to date, which is in part due to the low bioavailability and selectivity of hydrophobic photosensitisers. Nanotechnology-based techniques have the potential to address the limitations of current aPDT, as already well-documented in anti-cancer PDT. Here, we review recent advances in nanoparticle-based targeting tactics for aPDT. [ABSTRACT FROM AUTHOR]

Multidrug‐resistant Pseudomonas aeruginosa (MDR‐P. aeruginosa) cannot be extirpated with any of the antipseudomonal antibiotics available in clinic because P. aeruginosa exhibit natural resistance to antibiotics and form a stable biofilm. Biofilm formed by P. aeruginosa is a leading cause of bacterial keratitis which may cause corneal perforation and even blindness. Antibacterial photodynamic therapy (aPDT) is a promising bactericidal method in combatting drug‐resistant bacteria. Unfortunately, the use of broad‐spectrum aPDT that kills bacteria indiscriminately may lead to microbiota imbalance and cause serious side effects in normal cells. Herein, PαGal50‐b‐PGRB20, which can effectively disperse biofilms and selectively kill MDR‐P. aeruginosa inside biofilms by binding to Lec A in the extracellular polymeric substances and on the P. aeruginosa membrane with low phototoxicity caused by broad‐spectrum aPDT, is designed and synthesized. PαGal50‐b‐PGRB20 has bactericidal activities by damaging DNA, RNA, protein, and membrane. In vivo study of the MDR‐P. aeruginosa biofilm infected keratitis model demonstrates the potential of PαGal50‐b‐PGRB20 for a better corneal recovery. This work provides a dedicated antibacterial material for preferentially killing MDR‐P. aeruginosa over normal cells and other bacteria. [ABSTRACT FROM AUTHOR]

Neutrophil extracellular traps (NETs) are web-like complexes of DNA and proteins that are extruded by activated neutrophils and play critical roles as major components of the innate immune response against pathogen invasion. However, some microbes have developed strategies to evade NET attacks, leading to impaired immune defenses and persistent infections. In this study, an engineered neutrophil strategy for enhancing the antibacterial activity of NETs is developed. A nucleus-targeting photosensitizer (NCP) with strong reactive oxygen species production and a strong DNA-binding capacity is synthesized. NCP-loaded neutrophils are subsequently constructed via direct incubation of NCP with neutrophils, and the NCP is closely inserted into the nucleus DNA. Upon activation by bacteria-related toxins, NCP-coupled NETs can be released rapidly, actively trapping bacteria and providing a high local concentration of NCP around them. Both in vitro and in vivo results revealed that NCP-coupled NETs can effectively eradicate various multidrug-resistant bacteria and biofilms through photodynamic therapy, overcome bacterial immune evasion, and promote tissue recovery from severe wound infections. This design can significantly strengthen NET function, providing a non-antibiotic alternative platform for treating bacterial infectious diseases., (© 2024 Wiley‐VCH GmbH.)

Nanotizing biosealant components offer a multitude of chemical functionalities for superior adhesion-cohesion, delivering unique properties for comprehensive wound healing that are otherwise impossible to achieve using commercial variants. For the first time, a two-step controlled hydrothermal pyrolysis is reported to nanotize dopamine, phloroglucinol, and glutaraldehyde into carbon dot (CD) to be subsequently converted into carbonized polymer dot (CPD) with gelatin as a co-substrate. Chemical crosslinking of CD with gelatin through Schiff base formation before the second pyrolysis step ensures a complex yet porous polymeric network. The retention of chemical functionalities indigenous to CD substrates and gelatin along with the preservation of CD photoluminescence in CPD for optical tracking is achieved. A unique nanoformulation is created with the CPD through tannic acid (TA) grafting evolving CPD-TA nanoglue demonstrating ≈1.32 MPa strength in lap shear tests conducted on porcine skin, surpassing traditional bioadhesives. CPD-TA nanoglue uploaded insulin as chosen cargo disbursal at the wound site for healing normal and in vitro diabetic wound models using HEKa cells with extraordinary biocompatibility. Most importantly, CPD-TA can generate reactive oxygen species (ROS) and scavenge simultaneously under ambient conditions (23 W white LED or dark) for on-demand sterilization or aiding wound recovery through ROS scavenging., (© 2024 The Author(s). Small published by Wiley‐VCH GmbH.)

Photodynamic inactivation of microorganisms known as antibacterial photodynamic therapy (APDT) is one of the most promising and innovative approaches for the destruction of pathogenic microorganisms. Among the photosensitizers (PSs), compounds based on cationic porphyrins/metalloporphyrins are most successfully used to inactivate microorganisms. Series of meso-substituted cationic pyridylporphyrins and metalloporphyrins with various peripheral groups in the third and fourth positions of the pyrrole ring have been synthesized in Armenia. The aim of this work was to determine and test the most effective cationic porphyrins and metalloporphyrins with high photoactivity against Gram negative and Gram positive microorganisms. It was shown that the synthesized cationic pyridylporphyrins/metalloporphyrins exhibit a high degree of phototoxicity towards both types of bacteria, including the methicillin-resistant S. aureus strain. Zinc complexes of porphyrins are more phototoxic than metal-free porphyrin analogs. The effectiveness of these Zn–metalloporphyrins on bacteria is consistent with the level of singlet oxygen generation. It was found that the high antibacterial activity of the studied cationic porphyrins/metalloporphyrins depends on four factors: the presence in the porphyrin macrocycle of a positive charge (+4), a central metal atom (Zn2+) and hydrophobic peripheral functional groups as well as high values of quantum yields of singlet oxygen. The results indicate that meso-substituted cationic pyridylporphyrins/metalloporphyrins can find wider application in photoinactivation of bacteria than anionic or neutral PSs usually used in APDT.

Lignin, a natural biopolymer, is a sustainable and safe source to fabricate nanomaterials and coating agents for use in biomedical applications. We have therefore developed a simple, one-pot, and green strategy to prepare lignin-based cadmium sulfide quantum dots (L@CdS QDs) for use in sensing and photodynamic therapy applications. Initially, such lignin-based QDs were utilized in heavy metal sensing by screening a large range of metals. These QDs were highly selective toward sensing mercury and copper ions present in various water samples. The lignin-based QDs were also effective toward bacterial sensing. The promising reactive oxygen generation capability of such quantum dots prompted us to explore their potential in light-assisted antibacterial photodynamic activity (aPDT). Benefiting from the ease of synthesis and promising photodynamic properties, the QDs were next employed for the fabrication of wearable coatings. Interestingly, such lignin-based QD-derived coatings were highly effective in eradicating bacteria from personal protective equipment and biomedical devices (such as mask, gloves, scissors, etc.). This work paves a smart way to design natural biopolymer-based nanomaterials with the capability of disinfecting personal protective equipment and biomedical devices. [ABSTRACT FROM AUTHOR]

To realize clinical application of antibacterial photodynamic therapy (aPDT), one of the most arduous challenges is how to render aPDT agents high selectivity against bacterial pathogens. In light of the fact that amino group‐containing lipids are rich on the outer surfaces of Gram‐positive bacteria, we herein constructed an alkynyl‐dangling ruthenium(II) polypyridine complex (Ru2) to preferentially label Staphylococcus aureus (S. aureus) and methicillin‐resistant Staphylococcus aureus (MRSA) over mammalian cells via the amino‐yne bio‐orthogonal click reaction. Thanks to the strong singlet oxygen generation ability, Ru2 could photo‐inactivate S. aureus and MRSA effectively and specifically. Phosphatidylethanolamine (PE) molecules also exist in mammalian cells but are not accessible for Ru2, leading to its poor binding/uptake and negligible cytotoxicity in the dark and upon irradiation towards mammalian cells as well as low hemolysis, all favorable for aPDT application. [ABSTRACT FROM AUTHOR]

Photodynamic inactivation of microorganisms known as antibacterial photodynamic therapy (APDT) is one of the most promising and innovative approaches for the destruction of pathogenic microorganisms. Among the photosensitizers (PSs), compounds based on cationic porphyrins/metalloporphyrins are most successfully used to inactivate microorganisms. Series of meso-substituted cationic pyridylporphyrins and metalloporphyrins with various peripheral groups in the third and fourth positions of the pyrrole ring have been synthesized in Armenia. The aim of this work was to determine and test the most effective cationic porphyrins and metalloporphyrins with high photoactivity against Gram negative and Gram positive microorganisms. It was shown that the synthesized cationic pyridylporphyrins/metalloporphyrins exhibit a high degree of phototoxicity towards both types of bacteria, including the methicillin-resistant S. aureus strain. Zinc complexes of porphyrins are more phototoxic than metal-free porphyrin analogs. The effectiveness of these Zn–metalloporphyrins on bacteria is consistent with the level of singlet oxygen generation. It was found615 that the high antibacterial activity of the studied cationic porphyrins/metalloporphyrins depends on four factors: the presence in the porphyrin macrocycle of a positive charge (+4), a central metal atom (Zn 2 +) and hydrophobic peripheral functional groups as well as high values of quantum yields of singlet oxygen. The results indicate that meso-substituted cationic pyridylporphyrins/metalloporphyrins can find wider application in photoinactivation of bacteria than anionic or neutral PSs usually used in APDT. [ABSTRACT FROM AUTHOR]

Photodynamic inactivation is an effective treatment that uses light irradiation, photosensitizer and oxygen. The aim of this study was to determine photodynamic effectiveness of laser diode combined with ozone to reduce Staphylococcus aureus biofilm using exogenous chlorophyll (Chlo). The chlorophyll was extracted from leave of Dracaena angustifolia. To determine the antibacterial effect of S. aureus biofilm treatments, samples were separated into Chlo, Laser, Chlo+Laser, Ozone, Ozone+Laser, Chlo+Ozone+Laser categories. The data were analyzed using ANOVA test. The result of this study showed that Chlo+Ozone+Laser combine treatment at 20 s exposure of ozone with 4 min of irradiation time lead to 80.26 % reduction of biofilm activity, which was the highest efficacy of all the treatment groups. The combination of laser, chlorophyll and lower ozone concentration increases the effectiveness of photodynamic inactivation.

Inflammatory diseases of the sinuses – one of the most common nosologies in the practice of otorhinolaryngologist; its pathogenesis is well studied, and treatment recommendations are detailed. Following them, however, cannot completely prevent chronic disease or recurrence. Antimicrobial photodynamic therapy is a promising method of treating sinusitis, which has proved its effectiveness, but has not yet been widely used. This work describes our experience in photodynamic therapy with chlorin e6 of chronic sinusitis using a new laser diode-based irradiation source. For patients who had previous sinus surgery an adapter for penetration into the sinus through anastomosis was developed and tested. First group of the patients underwent photodynamic therapy (PDT) according to the conventional scheme, using a laser with a wavelength of 662 nm; while the second one underwent PDT using a 405 nm laser. With daily washing of the nasal sinus, the period of inflammation relief (evaluated by the absence of pathological discharge during washing) amounted to 3.8 full days on average in the first group of patients, compared to 5.4 days on average for the second group. We carried out the comparative analysis of the treatment results based on clinical assessment and radiological evaluation (CT) at the time of discharge from the hospital and 1 month later.

A single-site, randomized clinical trial was designed to determine the efficacy of regular home use of Lumoral® dual-light antibacterial aPDT in periodontitis patients. For the study, 200 patients were randomized to receive non-surgical periodontal treatment (NSPT), including standardized hygiene instructions and electric toothbrush, scaling and root planing, or NSPT with adjunctive Lumoral® treatment. A complete clinical intraoral examination was conducted in the beginning, at three months, and at six months. This report presents the three-month results of the first 59 consecutive randomized subjects. At three months, bleeding on probing (BOP) was lower in the NSPT + Lumoral®-group than in the NSPT group (p = 0.045), and more patients in the NSPT + Lumoral®-group had their BOP below 10% (54% vs. 22%, respectively, p = 0.008). In addition, patients in the NSPT + Lumoral®-group improved their oral hygiene by visible-plaque-index (p = 0.0003), while the NSPT group showed no statistical improvement compared to the baseline. Both groups significantly reduced the number of deep periodontal pockets, but more patients with a reduction in their deep pocket number were found in the NSPT + Lumoral® group (92% vs. 63%, p = 0.02). Patients whose number of deep pockets was reduced by 50% or more were also more frequent in the NSPT + Lumoral®-group (71% vs. 33%, p = 0.01). Patients with initially less than ten deep pockets had fewer deep pockets at the three-month follow-up in the Lumoral® group (p = 0.01). In conclusion, adjunctive use of Lumoral® in NSPT results in improved treatment outcomes at three months post-therapy.

Good oral hygiene at home is the foundation for optimal treatment response and long-term periodontal disease control. Antibacterial photodynamic therapy (aPDT) provides a very potent adjunctive treatment for plaque control. However, the literature regarding repeated aPDT use is sparse. aPDT has been a modality applied mainly in the dental office environment, and when applied once a year or every few months, the results have been usually disappointing. Recently, LED development has brought aPDT for repeated and practical use at home. We present the very positive results and clinical outcome of daily applied dual-light aPDT-technology treatment in conjunction with mechanical cleaning of a 78-year-old male patient with severe periodontal disease (Stage IV and Grade B).

Objectives: The aim of this pilot study was to evaluate the clinical and microbiological outcomes of light-activated disinfection (LAD) alone or combined with probiotics as an adjunct to non-surgical periodontal treatment. Materials and methods: In this single-blinded, randomized, controlled clinical pilot study, 48 patients (28 females and 20 males) with untreated periodontitis (stages II and III, grade B) were included. Using a parallel-group design, patients were randomly assigned into 3 groups to receive subgingival debridement (SD) alone (group 1, n = 16), SD with LAD (group 2, n = 16), or SD with LAD plus probiotic treatment (group 3, n = 16). Probing pocket depth (PPD), clinical attachment level (CAL), bleeding on probing (BOP), gingiva-index simplified (GIs), plaque-control record (PCR), and subgingival microbiological samples were analyzed at baseline, 3 months, and 6 months of follow-up. Results: All treatment modalities demonstrated clinical improvements in PPD and CAL at 6 months compared to baseline but without a statistical significant difference between the groups. The combination of SD + LAD + probiotic treatment (group 3) demonstrated significantly greater reductions in BOP, GIs, and red complex bacteria P. gingivalis and T. forsythia compared with other groups at 6 months (p < 0.05). Conclusions: A single application of LAD as an adjunct to SD provided no additional clinical and microbiological benefits compared to SD alone. The combination of SD + LAD + probiotic treatment in group 3 led to further improvements of the inflammatory parameters. Clinical relevance: The additional use of probiotics in periodontal treatment can be a useful approach to support inflammation and infection control of periodontal tissues. Further studies are necessary to determine the extent of added benefit for this treatment approach. [ABSTRACT FROM AUTHOR]

The spread of multi-drug-resistant bacterial strains causing serious infectious diseases dictates the development of new approaches to combat these diseases. In addition to drug resistance, the important causative agent of tuberculosis (Mycobacterium tuberculosis (Mtb)) is able to persist asymptomatically in individuals for many years, causing latent forms of tuberculosis. In such a dormant state, Mtb cells are also resistant to known antibiotics. In this regard, photodynamic inactivation (PDI) could be an effective alternative to antibiotics as its action is based on the generation of active forms of oxygen independently on the presence of specific antibiotic targets, thereby inactivating both drug-resistant and dormant bacteria. In this review, we summarise examples of the application of PDI for the elimination of representatives of the genus Mycobacteria, both in vitro and in vivo. According to published results, including photosensitisers in the PDI regime results in a significantly higher lethal effect. Such experiments were mainly performed using chemically synthesised photosensitisers, which need to be transported to the areas of bacterial infections, limiting PDI usage by surface (skin) diseases. In this regard, endogenous photosensitisers (mainly porphyrins) could be used to solve the problem of transportation. In vitro experiments demonstrate the effective application of PDI for mycobacteria, including Mtb, using endogenous porphyrins; the intracellular contents of these substances can be elevated by administration of 5-aminolevulenic acid, a precursor of porphyrin synthesis. Photodynamic inactivation can also be used for dormant mycobacteria, which are characterised by high levels of endogenous porphyrins. Thus, PDI can effectively eliminate drug-resistant mycobacteria. The exploitation of modern light-transmitting techniques opens new possibilities to use PDI in clinical settings. Key points: •The potential effects of photodynamic inactivation of mycobacteria are critically reviewed. •Approaches to photoinactivation of mycobacteria using exogenous and endogenous photosensitisers are described. •Prospects for the use of photodynamic inactivation in the treatment of tuberculosis are discussed. [ABSTRACT FROM AUTHOR]