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2021 ◽  
Author(s):  
Jianpan Gao ◽  
Handi Deng ◽  
Hanqing Duan ◽  
Haoming Huo ◽  
Yizhou Bai ◽  
...  

iScience ◽  
2021 ◽  
pp. 103284
Author(s):  
Han-Joon Kim ◽  
Yunxia Jin ◽  
Sippanat Achavananthadith ◽  
Rongzhou Lin ◽  
John S. Ho

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 921
Author(s):  
Sergi Garcia-Segura ◽  
Omotayo A. Arotiba ◽  
Enric Brillas

Photoelectrocatalysis is a hybrid photon/electron-driven process that benefits from the synergistic effects of both processes to enhance and stabilize the generation of disinfecting oxidants. Photoelectrocatalysis is an easy to operate technology that can be scaled-up or scaled-down for various water treatment applications as low-cost decentralized systems. This review article describes the fundamentals of photoelectrocatalysis, applied to water disinfection to ensure access to clean water for all as a sustainable development goal. Advances in reactor engineering design that integrate light-delivery and electrochemical system requirements are presented, with a description of photo-electrode material advances, including doping, nano-decoration, and nanostructure control. Disinfection and cell inactivation are described using different model microorganisms such as E. coli, Mycobacteria, Legionella, etc., as well the fungus Candida parapsilosis, with relevant figures of merit. The key advances in the elucidation of bacterial inactivation mechanisms by photoelectrocatalytic treatments are presented and knowledge gaps identified. Finally, prospects and further research needs are outlined, to define the pathway towards the future of photoelectrocatalytic disinfection technologies.


2021 ◽  
Author(s):  
Hadi Karimi

The importance of the rate of light delivery and the length of photodynamic therapy as an alternative treatment modality for brain glioma have been investigated and shown that optimized PDT regimens would have the potential to reduce the tumor recurrence and the treatment-induced morbidity. In a rat glioma model, using photosensitizer ALA-PpIX, we further investigated the effect of extended-time low-fluence-rate PDT on the number of apoptotic, necrotic, surviving, and infiltrated tumor cells, associated with three fluence rates of 0.5, 1.0, and 1.5 mW cm⁻², each at three treatment lengths of 24, 48, and 72 hours. Our results demonstrated that lowest fluence rate used in our study has an improved apoptosis to necrosis ratio; however higher fluence rates show a clear supremacy for tumor control in shorter treatment times. Therefore, low-fluence-rate brain ALA-PDT may only be more beneficial for tumor control at longer treatment periods.


2021 ◽  
Author(s):  
Hadi Karimi

The importance of the rate of light delivery and the length of photodynamic therapy as an alternative treatment modality for brain glioma have been investigated and shown that optimized PDT regimens would have the potential to reduce the tumor recurrence and the treatment-induced morbidity. In a rat glioma model, using photosensitizer ALA-PpIX, we further investigated the effect of extended-time low-fluence-rate PDT on the number of apoptotic, necrotic, surviving, and infiltrated tumor cells, associated with three fluence rates of 0.5, 1.0, and 1.5 mW cm⁻², each at three treatment lengths of 24, 48, and 72 hours. Our results demonstrated that lowest fluence rate used in our study has an improved apoptosis to necrosis ratio; however higher fluence rates show a clear supremacy for tumor control in shorter treatment times. Therefore, low-fluence-rate brain ALA-PDT may only be more beneficial for tumor control at longer treatment periods.


2021 ◽  
Vol 8 ◽  
Author(s):  
Aleksandra Rapacka-Zdończyk ◽  
Agata Woźniak ◽  
Klaudia Michalska ◽  
Michał Pierański ◽  
Patrycja Ogonowska ◽  
...  

Photodynamic inactivation of microorganisms (aPDI) is an excellent method to destroy antibiotic-resistant microbial isolates. The use of an exogenous photosensitizer or irradiation of microbial cells already equipped with endogenous photosensitizers makes aPDI a convenient tool for treating the infections whenever technical light delivery is possible. Currently, aPDI research carried out on a vast repertoire of depending on the photosensitizer used, the target microorganism, and the light delivery system shows efficacy mostly on in vitro models. The search for mechanisms underlying different responses to photodynamic inactivation of microorganisms is an essential issue in aPDI because one niche (e.g., infection site in a human body) may have bacterial subpopulations that will exhibit different susceptibility. Rapidly growing bacteria are probably more susceptible to aPDI than persister cells. Some subpopulations can produce more antioxidant enzymes or have better performance due to efficient efflux pumps. The ultimate goal was and still is to identify and characterize molecular features that drive the efficacy of antimicrobial photodynamic inactivation. To this end, we examined several genetic and biochemical characteristics, including the presence of individual genetic elements, protein activity, cell membrane content and its physical properties, the localization of the photosensitizer, with the result that some of them are important and others do not appear to play a crucial role in the process of aPDI. In the review, we would like to provide an overview of the factors studied so far in our group and others that contributed to the aPDI process at the cellular level. We want to challenge the question, is there a general pattern of molecular characterization of aPDI effectiveness? Or is it more likely that a photosensitizer-specific pattern of molecular characteristics of aPDI efficacy will occur?


Author(s):  
Sherif A. Mohamad ◽  
Michael R. Milward ◽  
Mohammed A. Hadis ◽  
Sarah A. Kuehne ◽  
Paul R. Cooper

AbstractMesenchymal stem cells (MSCs) and photobiomodulation (PBM) both offer significant therapeutic potential in regenerative medicine. MSCs have the ability to self-renew and differentiate; giving rise to multiple cellular and tissue lineages that are utilised in repair and regeneration of damaged tissues. PBM utilises light energy delivered at a range of wavelengths to promote wound healing. The positive effects of light on MSC proliferation are well documented; and recently, several studies have determined the outcomes of PBM on mineralised tissue differentiation in MSC populations. As PBM effects are biphasic, it is important to understand the underlying cellular regulatory mechanisms, as well as, provide accurate details of the irradiation conditions, to optimise and standardise outcomes. This review article focuses on the use of red, near-infra-red (R/NIR) and blue wavelengths to promote the mineralisation potential of MSCs; and also reports on the possible molecular mechanisms which underpin transduction of these effects. A variety of potential photon absorbers have been identified which are reported to mediate the signalling mechanisms, including respiratory chain enzymes, flavins, and cryptochromes. Studies report that R/NIR and blue light stimulate MSC differentiation by enhancing respiratory chain activity and increasing reactive oxygen species levels; however, currently, there are considerable variations between irradiation parameters reported. We conclude that due to its non-invasive properties, PBM may, following optimisation, provide an efficient therapeutic approach to clinically support MSC-mediated hard tissue repair. However, to optimise application, further studies are required to identify appropriate light delivery parameters, as well as elucidate the photo-signalling mechanisms involved.


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