Research Articles,

Disinfection of Cariogenic Pathogens in Planktonic Lifestyle, Biofilm and Carious Dentine with Antimicrobial Photodynamic Therapy,

Minjing Wu, Li Xu, Zhiyu Cai, Shan Huang, Yijun Li, Lishan Lei, Xiaojing Huang

Version of Record online: 22 October 2019

We compared the antibacterial effects of antimicrobial photodynamic therapy (aPDT) and 0.12% chlorhexidine (CHX) on Streptococcus mutans and Lactobacillus acidophilus in planktonic lifestyle, biofilm and carious dentine. Samples were treated with 0.1 mg mL⁻¹ toluidine blue O followed by irradiation with a light emission diode (λ − 635 ± 10 nm; 500 mW; 31.5 J cm⁻²; 60 s) and 0.12% CHX (60 s), respectively. Microbial culture analysis showed that aPDT achieved comparable antibacterial effects with 0.12% CHX against Lactobacillus acidophilus and showed greater bactericidal potential against Streptococcus mutans biofilm. Photosensitizer and light parameters need further optimization to eradicate Streptococcus mutans in dentine caries.

Research Articles

Photoinactivation Sensitivity of Staphylococcus carnosus to Visible‐light Irradiation as a Function of Wavelength

Katharina Hoenes, Ulla Wenzel, Barbara Spellerberg, Martin Hessling

Version of Record online: 22 October 2019

Approach of applying LEDs in a broad range but spectrally resolved (left) on a bacterial strain, to get knowledge about its endogenous photosensitizers (middle). Absorption spectra of possibly involved photosensitizers are measured and variably combined, while the mathematical calculation of a fit with the measured action spectrum of bacterial inactivation carves out the best match (right). The calculated factors indicate to which extent a certain photosensitizer contributes to the measured bactericidal effect. In this investigation, we derived flavins and zinc protoporphyrin IX most relevant for the photosensitizer composition of S. carnosus between 405 and 500 nm.

Special Issue Research Articles

Evaluation of Light Fluence Distribution Using an IR Navigation System for HPPH‐mediated Pleural Photodynamic Therapy (pPDT)

Timothy C. Zhu, Yihong Ong, Michele M. Kim, Xing Liang, Jarod C. Finlay, Andreea Dimofte, Charles B. Simone 2nd, Joseph S. Friedberg, Theresa M. Busch, Eli Glatstein, Keith A. Cengel

Version of Record online: 22 October 2019

 

Uniform light fluence distribution for patients undergoing photodynamic therapy (PDT) is critical to ensure predictable PDT outcomes. We have developed a real‐time infrared (IR) tracking camera to follow the movement of the light point source and to determine the surface contour of the treatment area. We conclude that it is feasible to use an IR camera‐based system to track the motion of the light source during PDT and demonstrate its use to quantify the uniformity of light distribution, which deviated by a standard deviation of 18% from the prescribed light dose.

Special Issue Research Articles

Weather‐informed Light–tissue Model–Based Dose Planning for Indoor Daylight Photodynamic Therapy

Ethan P. M. LaRochelle, Michael Shane Chapman, Edward V. Maytin, Tayyaba Hasan, Brian W. Pogue

Version of Record online: 21 October 2019

 

A one‐time site assessment can be used to determine appropriate sites for daylight‐PDT treatments throughout the year. Spectral measurements taken during this site assessment can then be correlated with real‐time weather data to improve light dose estimates.

Research Articles

Analyzing the Synergistic Effects of Antioxidants in Combating Photoaging Using Model Nematode, Caenorhabditis elegans

Mani Iyer Prasanth, Subramanyam Gayathri, James Prabhanand Bhaskar, Venkateswaran Krishnan, Krishnaswamy Balamurugan

Version of Record online: 21 October 2019

Schematic representation showing the initiation of aging and photoaging process inside the cells exposed to UV‐A. Treating the cells with antioxidants has reduced the level of aging and photoaging. Further, the combination of selective antioxidants could reduce the level of aging and photoaging in a greater manner than that of the individual effects.

Research Articles

A Dual Emissive Coumarin–urea Derivative with an Electron‐withdrawing Substituent in the Presence of Acetate Anion

Tomoyuki Shinoda, Yoshinobu Nishimura, Tatsuo Arai

Version of Record online: 20 October 2019

 

Coumarin–urea derivatives showed significant differences in tautomer formation depending on the positions of a urea moiety substituted on the coumarin ring in the presence of acetate ion. Furthermore, the substitution of a CF₃ group resulted in a remarkable improvement of its fluorescence quantum yield. These findings will contribute to new molecular design of highly fluorescent anion sensors.