Powering rotary molecular motors with low-intensity near-infrared light

Light-controlled artificial molecular machines hold tremendous potential to revolutionize molecular sciences as autonomous motion allows the design of smart materials and systems whose properties can respond, adapt, and be modified on command. One long-standing challenge toward future applicability has been the need to develop methods using low-energy, low-intensity, near-infrared light to power these nanomachines. Here, we describe a rotary molecular motor sensitized by a two-photon absorber, which efficiently operates under near-infrared light at intensities and wavelengths compatible with in vivo studies. Time-resolved spectroscopy was used to gain insight into the mechanism of energy transfer to the motor following initial two-photon excitation. Our results offer prospects toward in vitro and in vivo applications of artificial molecular motors.

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Experimental and Clinical Applications of Red and Near-Infrared Photobiomodulation on Endothelial Dysfunction: A Review

Biomedicines ◽

10.3390/biomedicines9030274 ◽

2021 ◽

Vol 9 (3) ◽

pp. 274 ◽

Cited By ~ 1

Author(s):

Esteban Colombo ◽

Antonio Signore ◽

Stefano Aicardi ◽

Angelina Zekiy ◽

Anatoliy Utyuzh ◽

...

Keyword(s):

Endothelial Dysfunction ◽

Near Infrared ◽

Disease Risk ◽

In Vivo Studies ◽

Infrared Light ◽

Animal Cells ◽

Atp Production ◽

Main Regulator

Background: Under physiological conditions, endothelial cells are the main regulator of arterial tone homeostasis and vascular growth, sensing and transducing signals between tissue and blood. Disease risk factors can lead to their unbalanced homeostasis, known as endothelial dysfunction. Red and near-infrared light can interact with animal cells and modulate their metabolism upon interaction with mitochondria’s cytochromes, which leads to increased oxygen consumption, ATP production and ROS, as well as to regulate NO release and intracellular Ca2+ concentration. This medical subject is known as photobiomodulation (PBM). We present a review of the literature on the in vitro and in vivo effects of PBM on endothelial dysfunction. Methods: A search strategy was developed consistent with the PRISMA statement. The PubMed, Scopus, Cochrane, and Scholar electronic databases were consulted to search for in vitro and in vivo studies. Results: Fifty out of >12,000 articles were selected. Conclusions: The PBM can modulate endothelial dysfunction, improving inflammation, angiogenesis, and vasodilatation. Among the studies, 808 nm and 18 J (0.2 W, 2.05 cm2) intracoronary irradiation can prevent restenosis as well as 645 nm and 20 J (0.25 W, 2 cm2) can stimulate angiogenesis. PBM can also support hypertension cure. However, more extensive randomised controlled trials are necessary.

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Generalizability of Deep Learning Models for Caries Detection in Near-Infrared Light Transillumination Images

Journal of Clinical Medicine ◽

10.3390/jcm10050961 ◽

2021 ◽

Vol 10 (5) ◽

pp. 961 ◽

Cited By ~ 1

Author(s):

Agnes Holtkamp ◽

Karim Elhennawy ◽

José E. Cejudo Grano de Oro ◽

Joachim Krois ◽

Sebastian Paris ◽

...

Keyword(s):

Deep Learning ◽

Near Infrared ◽

Infrared Light ◽

Learning Models ◽

Near Infrared Light ◽

In Vivo Models ◽

Lower Accuracy ◽

Caries Lesions

Objectives: The present study aimed to train deep convolutional neural networks (CNNs) to detect caries lesions on Near-Infrared Light Transillumination (NILT) imagery obtained either in vitro or in vivo and to assess the models’ generalizability. Methods: In vitro, 226 extracted posterior permanent human teeth were mounted in a diagnostic model in a dummy head. Then, NILT images were generated (DIAGNOcam, KaVo, Biberach), and images were segmented tooth-wise. In vivo, 1319 teeth from 56 patients were obtained and segmented similarly. Proximal caries lesions were annotated pixel-wise by three experienced dentists, reviewed by a fourth dentist, and then transformed into binary labels. We trained ResNet classification models on both in vivo and in vitro datasets and used 10-fold cross-validation for estimating the performance and generalizability of the models. We used GradCAM to increase explainability. Results: The tooth-level prevalence of caries lesions was 41% in vitro and 49% in vivo, respectively. Models trained and tested on in vivo data performed significantly better (mean ± SD accuracy: 0.78 ± 0.04) than those trained and tested on in vitro data (accuracy: 0.64 ± 0.15; p < 0.05). When tested in vitro, the models trained in vivo showed significantly lower accuracy (0.70 ± 0.01; p < 0.01). Similarly, when tested in vivo, models trained in vitro showed significantly lower accuracy (0.61 ± 0.04; p < 0.05). In both cases, this was due to decreases in sensitivity (by −27% for models trained in vivo and −10% for models trained in vitro). Conclusions: Using in vitro setups for generating NILT imagery and training CNNs comes with low accuracy and generalizability. Clinical significance: Studies employing in vitro imagery for developing deep learning models should be critically appraised for their generalizability. Applicable deep learning models for assessing NILT imagery should be trained on in vivo data.

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Photothermal ablation of murine melanomas by Fe3O4 nanoparticle clusters

10.3762/bxiv.2021.63.v1 ◽

2021 ◽

Author(s):

Xue Wang ◽

Lili Xuan ◽

Ying Pan

Keyword(s):

Near Infrared ◽

Underlying Mechanism ◽

Local Heat ◽

In Vivo Studies ◽

Infrared Light ◽

Microscopy Imaging ◽

Development Of Resistance ◽

Nanoparticle Clusters

Melanoma is one of the deadliest forms of cancer, for which therapeutic regimens are usually limited by the development of resistance. Here, we fabricated the Fe3O4 nanoparticle clusters (NPCs) that have drawn widespread attention and investigated their role in the treatment of melanoma by photothermal therapy (PTT). Transmission electron microscopy imaging shows that our synthesized NPCs are spherically shaped with an averaged diameter of 329.2 nm. They are highly absorptive at the near-infrared 808 nm wavelength and efficient at converting light into local heat. In vitro experiments using light-field microscopy and MTT assay showed that Fe3O4 NPCs, in conjunction with near-infrared irradiation, effectively ablated A375 melanoma cells by inducing overt apoptosis. Consistently, in vivo studies using BALB/c mice found that intratumoral administration of Fe3O4 NPCs and concomitant in situ exposure to near-infrared light significantly inhibited growth of implanted tumor xenografts. Finally, we revealed, by experimental approaches including semi-quantitative PCR, western blot and immunohistochemistry, the heat shock protein HSP70 to be upregulated in response to PTT, suggesting this chaperone protein could be a plausible underlying mechanism for the observed therapeutic outcome. Altogether, our results highlight the promise of Fe3O4 NPCs as a new PTT option to treat melanoma.

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