scholarly journals Opportunities for Persistent Luminescent Nanoparticles in Luminescence Imaging of Biological Systems and Photodynamic Therapy

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 2015 ◽  
Author(s):  
Douglas L. Fritzen ◽  
Luidgi Giordano ◽  
Lucas C. V. Rodrigues ◽  
Jorge H. S. K. Monteiro
Keyword(s):  
Photodynamic Therapy ◽  
Light Exposure ◽  
Cell Damage ◽  
Biological Systems ◽  
Continuous Light ◽  
Synthetic Methods ◽  
Luminescent Materials ◽  
Future Directions ◽  
Luminescence Imaging ◽  
Cellular Processes

The use of luminescence in biological systems allows us to diagnose diseases and understand cellular processes. Persistent luminescent materials have emerged as an attractive system for application in luminescence imaging of biological systems; the afterglow emission grants background-free luminescence imaging, there is no need for continuous excitation to avoid tissue and cell damage due to the continuous light exposure, and they also circumvent the depth penetration issue caused by excitation in the UV-Vis. This review aims to provide a background in luminescence imaging of biological systems, persistent luminescence, and synthetic methods for obtaining persistent luminescent materials, and discuss selected examples of recent literature on the applications of persistent luminescent materials in luminescence imaging of biological systems and photodynamic therapy. Finally, the challenges and future directions, pointing to the development of compounds capable of executing multiple functions and light in regions where tissues and cells have low absorption, will be discussed.

scholarly journals Recent Advances in Luminescence Imaging of Biological Systems Using Lanthanide(III) Luminescent Complexes

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2089
Author(s):  
Jorge H. S. K. Monteiro
Keyword(s):  
Recent Literature ◽  
Molecular Level ◽  
Biological Systems ◽  
Spectroscopic Properties ◽  
Future Directions ◽  
High Brightness ◽  
Molecular Systems ◽  
Luminescence Imaging ◽  
Cellular Processes ◽  
Ligand Structure

The use of luminescence in biological systems allows one to diagnose diseases and understand cellular processes. Molecular systems, particularly lanthanide(III) complexes, have emerged as an attractive system for application in cellular luminescence imaging due to their long emission lifetimes, high brightness, possibility of controlling the spectroscopic properties at the molecular level, and tailoring of the ligand structure that adds sensing and therapeutic capabilities. This review aims to provide a background in luminescence imaging and lanthanide spectroscopy and discuss selected examples from the recent literature on lanthanide(III) luminescent complexes in cellular luminescence imaging, published in the period 2016–2020. Finally, the challenges and future directions that are pointing for the development of compounds that are capable of executing multiple functions and the use of light in regions where tissues and cells have low absorption will be discussed.

scholarly journals 111 Artificial Light-Triggered Sleep Deprivation May Lead to Allodynia in Rodent Model

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A45-A46
Author(s):  
Skyler Kanegi ◽  
Armen Akopian
Keyword(s):  
Sleep Deprivation ◽  
Light Exposure ◽  
Light Stimulus ◽  
Continuous Light ◽  
Artificial Light ◽  
Light Cycle ◽  
Tissue Samples ◽  
Mechanical Threshold ◽  
Dim Light ◽  
Von Frey Filaments

Abstract Introduction The combination of artificial light and lack of exposure to natural light can delay the circadian clock, dysregulate the circadian cycle, and decrease alertness upon waking. This effect has been especially significant during the COVID-19 pandemic, where overexposure to artificial light at improper hours has contributed to increased rates of clinical insomnia. Artificial light may also contribute to concomitant neurological conditions such as primary headache, but the mechanisms by which light triggers sleep deprivation-induced headache are not well-understood. Methods To measure pain sensitivity, we habituated 13 wild-type male mice to von Frey filaments applied to the periorbital area until there was no response to 0.6g stimulus. We then applied 5 lux of continuous dim light to mice during their usual 12-hour dark cycle. The 12-hour light cycle remained unchanged with 200 lux continuous light. Three groups of mice experienced the dim light stimulus for one, three, or five consecutive days. Ambulation and rest activity were measured using SOF-812 Activity Monitor machines. After the experiment concluded, we waited 24 hours and measured mechanical threshold using von Frey filaments at 1, 3, 5, 8, and every 3 days subsequently until mice no longer responded to 0.6g stimulus. Results Artificial light triggered changes in circadian behavior including increased number of rest periods during 12-hour dark (dim light) cycle and shortened sleep duration during 12-hour light cycle. Following the artificial light stimulus, there was a significant decrease in mechanical threshold (P<0.05), representing allodynia. The one-day group displayed one day of significant allodynia. The three-day group displayed three days of significant allodynia. The five-day group displayed five days of significant allodynia. Conclusion Artificial light may trigger circadian dysregulation, and the duration of artificial light exposure seemed to be directly correlated to the duration of allodynia up to one week after the stimulus was removed. We will repeat these experiments and analyze CNS and PNS tissue samples to understand the underlying physiological and biochemical bases of how artificial light triggers sleep deprivation-induced headache. This knowledge could increase our understanding of the pathophysiology and comorbidity of sleep deprivation and headache. Support (if any) Funding was received from the National Institute of Health (NS104200).

scholarly journals Treatment of dental plaque biofilms using photodynamic therapy: a randomised controlled study

2021 ◽  
Author(s):  
A. Alsaif ◽  
J. F. Tahmassebi ◽  
S. R. Wood
Keyword(s):  
Photodynamic Therapy ◽  
Incubation Time ◽  
Dental Plaque ◽  
Continuous Light ◽  
Laser Scanning Microscopy ◽  
Controlled Study ◽  
Bacterial Counts ◽  
Randomised Controlled Study ◽  
Randomised Controlled

Abstract Introduction Photodynamic therapy (PDT) is a treatment modality involving a dye that is activated by exposure to light of a specific wavelength in the presence of oxygen to form oxygen species causing localised damage to microorganisms. Aim To determine the most effective bactericidal incubation and irradiation times of erythrosine-based PDT on in vivo-formed dental plaque biofilms. Methods A randomised controlled study; 18-healthy adult participants wearing intraoral appliances with human enamel slabs to collect dental plaque samples in two separate periods of two weeks each for use in arm-1 and arm-2. These accumulated dental plaque samples were treated with PDT under different experimental conditions. Incubation times with photosensitiser (erythrosine) of 15 min and 2 min were used in arm-1 and arm-2, respectively, followed by light irradiation for either 15 min (continuous) or as a fractionated dose (5 × 30 sec). Following treatment, percentage reductions of total bacterial counts were compared between the different groups. In addition, confocal laser scanning microscopy (CLSM) and LIVE/DEAD® BacLight™ Bacterial Viability Kit were used to visualise the effect of PDT on in vivo-formed biofilms. Results Significant reductions in the percentage of total bacterial counts (~93–95%) of in vivo-formed biofilms were found when using either 2 min or 15min incubation times and applying 15 min continuous light. Although when applying fractionated light, there was more cell death when 15 min incubation time was used (~ 91%) compared with the 2 min incubation time (~ 64%). CLSM results supported these findings. Conclusion Improving the clinical usefulness of PDT by reducing its overall treatment time seems to be promising and effective in killing in vivo-formed dental plaque biofilms.

INTERACTIONS OF THE PINEAL AND EXPOSURE TO CONTINUOUS LIGHT ON ORGAN WEIGHTS OF FEMALE RATS

1961 ◽  
Vol 36 (4) ◽  
pp. 617-624 ◽  
Author(s):  
Richard Jay Wurtman ◽  
Willard Roth ◽  
Mark D. Altschule ◽  
Judith J. Wurtman
Keyword(s):  
Light Exposure ◽  
Continuous Light ◽  
Female Rats ◽  
Constant Light ◽  
Ovarian Weight ◽  
Organ Weights ◽  
Bovine Pineal Extracts ◽  
Pineal Extracts ◽  
Effect Of Light

ABSTRACT Either exposure to constant light for 80 days or pinealectomy produced similar changes in the weights of the ovaries and adrenals of female rats. These were not additive when both procedures were employed. Pinealectomy did not share with light-exposure the capacity to induce uterine hypertrophy. Rats exposed to constant light for 56 days had lighter pineals than animals kept in darkness; this decrease was not affected by administration of bovine pineal extracts. The increase in ovarian weight produced in rats by exposure to light for 56 days was prevented by bovine pineal extracts, but these extracts were without effect on the uterine hypertrophy produced under the same conditions. These data suggest that the effect of light upon the weight of the ovary is mediated via the pineal.

Light-induced suppression of the rat circadian system

1995 ◽  
Vol 268 (5) ◽  
pp. R1111-R1116 ◽  
Author(s):  
P. Depres-Brummer ◽  
F. Levi ◽  
G. Metzger ◽  
Y. Touitou
Keyword(s):  
Locomotor Activity ◽  
Body Temperature ◽  
Circadian Rhythms ◽  
Prolonged Exposure ◽  
Light Exposure ◽  
Continuous Light ◽  
Circadian System ◽  
Short Exposure ◽  
Complete Suppression ◽  
Continuous Darkness

In a constant environment, circadian rhythms persist with slightly altered period lengths. Results of studies with continuous light exposure are less clear, because of short exposure durations and single-variable monitoring. This study sought to characterize properties of the oscillator(s) controlling the rat's circadian system by monitoring both body temperature and locomotor activity. We observed that prolonged exposure of male Sprague-Dawley rats to continuous light (LL) systematically induced complete suppression of body temperature and locomotor activity circadian rhythms and their replacement by ultradian rhythms. This was preceded by a transient loss of coupling between both functions. Continuous darkness (DD) restored circadian synchronization of temperature and activity circadian rhythms within 1 wk. The absence of circadian rhythms in LL coincided with a mean sixfold decrease in plasma melatonin and a marked dampening but no abolition of its circadian rhythmicity. Restoration of temperature and activity circadian rhythms in DD was associated with normalization of melatonin rhythm. These results demonstrated a transient internal desynchronization of two simultaneously monitored functions in the rat and suggested the existence of two or more circadian oscillators. Such a hypothesis was further strengthened by the observation of a circadian rhythm in melatonin, despite complete suppression of body temperature and locomotor activity rhythms. This rat model should be useful for investigating the physiology of the circadian timing system as well as to identify agents and schedules having specific pharmacological actions on this system.

scholarly journals Photosensitizers and Exposure Times To Light Showed Tissue Compatibility In Isogenic Mice

2021 ◽  
Vol 24 (2) ◽  
Author(s):  
Raquel Assed Bezerra da Silva ◽  
Daniela Silva Barroso de Oliveira ◽  
Katharina Morant Holanda de Oliveira ◽  
Carolina Maschietto Pucinelli ◽  
Paulo Nelson Filho ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Diode Laser ◽  
Chloride Solution ◽  
Light Exposure ◽  
Subcutaneous Tissue ◽  
Phase 1 ◽  
Tissue Response ◽  
Phase 2 ◽  
Small Magnitude ◽  
Tissue Compatibility

Objective: The aim of this study was to evaluate the subcutaneous tissue response after different protocols to photodynamic therapy (PDT). In Phase 1, were tested the diode laser (used for 1min) associated to the photosensitizer phenothiazine chloride solution (PCS) in different concentrations. In Phase 2 – the diode laser and LED were tested associated to two different photosensitizers, PCS and Curcumin, in different exposure times of light application. Material and Methods: After 7, 21 and 63-days the animals were euthanized and the subcutaneous tissue processed to histological analysis. Qualitative and semi-quantitative descriptions of the inflammatory process and immunohistochemical technique were performed. The obtained data were analyzed by Kruskal-Wallis and Dunn’s post-test (alpha = 0.5). Results: On Phase 1, the tissue response was very similar among the groups. For the inflammatory infiltrate, PCS with concentration of 10mg/mL exhibited the most intense reaction (p > 0.05). On Phase 2, at 7-days period, the analyzed parameters presented small magnitude and after 21 and 63-days, all the parameters demonstrated tissue compatibility. Conclusion: Both photosensitizers presented proper tissue compatibility regardless the different concentrations used on Phase 1 and different durations of light exposure on Phase 2.   Keywords Photodynamic therapy; Phenothiazine chloride solution; Curcumin; Isogenic mice; Subcutaneous tissue.

scholarly journals Metal Nanozymes: New Horizons in Cellular Homeostasis Regulation

2021 ◽  
Vol 11 (19) ◽  
pp. 9019
Author(s):  
Hanna Lewandowska ◽  
Karolina Wójciuk ◽  
Urszula Karczmarczyk
Keyword(s):  
Biomedical Applications ◽  
Redox Status ◽  
Design Strategies ◽  
Future Directions ◽  
Cellular Homeostasis ◽  
Cellular Redox ◽  
New Horizons ◽  
Cellular Processes ◽  
Homeostasis Regulation ◽  
State Changes

Nanomaterials with enzyme-like activity (nanozymes) have found applications in various fields of medicine, industry, and environmental protection. This review discusses the use of nanozymes in the regulation of cellular homeostasis. We also review the latest biomedical applications of nanozymes related to their use in cellular redox status modification and detection. We present how nanozymes enable biomedical advances and demonstrate basic design strategies to improve diagnostic and therapeutic efficacy in various diseases. Finally, we discuss the current challenges and future directions for developing nanozymes for applications in the regulation of the redox-dependent cellular processes and detection in the cellular redox state changes.

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