Intense Blue Light Research Articles

Effect of blue light intensity and photoperiods on the growth of diatom Thalassiosira pseudonana

Diatom Thalassiosira pseudonana photosynthetic properties and generation of fucoxanthin and lipid production under different blue light intensity with different photoperiods (dark/light cycle) at temperature 23 ± 1 °C were studied in this work. The growth (cell number) and the biomass concentration of the cells were found to be doubled at 120 μE m−2 s−1 blue light intensity as compared to 200 μE m−2 s−1 at 8:16 h dark light photoperiods. The rise in blue intensity from 40 to 120 μE m−2 s−1 has increased the synthesis of fucoxanthin and lipid in Thalassiosira pseudonana at dark-light cycle 8:16 h. It was found that at optimal amount of blue light and photoperiod ratio, evidently influence the growth of Thalassiosira pseudonana by yielding 35.6 % lipid and 1.18 mg/g fucoxanthin.

Dual-wavelength volumetric stereolithography of multilevel microfluidic devices.

Microfluidic devices are typically fabricated in an expensive, multistep process (e.g., photolithography, etching, and bonding). Additive manufacturing (AM) has emerged as a revolutionary technology for simple and inexpensive fabrication of monolithic structures-enabling microfluidic designs that are challenging, if not impossible, to make with existing fabrication techniques. Here, we introduce volumetric stereolithography (vSLA), an AM method in which polymerization is constrained to specific heights within a resin vat, allowing layer-by-layer fabrication without a moving platform. vSLA uses an existing dual-wavelength chemistry that polymerizes under blue light (λ = 458 nm) and inhibits polymerization under UV light (λ = 365 nm). We apply vSLA to fabricate microfluidic channels with different spatial and vertical geometries in less than 10 min. Channel heights ranged from 400 μm to 1 mm and could be controlled with an optical dose, which is a function of blue and UV light intensities and exposure time. Oxygen in the resin was found to significantly increase the amount of dose required for curing (i.e., polymerization to a gelled state), and we recommend that an inert vSLA system is used for rapid and reproducible microfluidic fabrication. Furthermore, we recommend polymerizing far beyond the gel point to form more rigid structures that are less susceptible to damage during post-processing, which can be done by simultaneously increasing the blue and UV light absorbance of the resin with light intensities. We believe that vSLA can simplify the fabrication of complex multilevel microfluidic devices, extending microfluidic innovation and availability to a broader community.

English

In recent years, plant factories have developed rapidly and played an important role in modern agricultural production. Finding the best lighting formula has become the most basic and important research topic for the industrialization of the plant factory with artificial lighting (PFAL) hydroponic Cichorium endivia L. In this paper, the LED plant growth lamp with adjustable ratio of red, blue and white light intensity was used as the light source for the growth of C. endivia L., with 5R:8B:7W, 6R:7B:7W, 5.5R:8B:6.5W as the treatment group and white LED as the control group, the growth characteristics and nutritional quality of the grown plants of C. endivia L. were compared and analyzed through experiments. It was found that under the combined illumination of 5.5R:8B:6.5W, the leaves of C. endivia L. had the largest number, and the contents of VC (Vitamin C) and carotene were the highest. Under 6R:7B:7W illumination, the content of chlorophyll and soluble sugar was the highest. The combination illumination with the ratio of blue and white light slightly larger than that of red light was the most suitable illumination for hydroponic cultivation of C. endivia L. in PFAL. Key words: Light formula, hydroponic cultivation, plant lighting, plant industrialized production, modern agriculture.

Morphology evolution, tunable multicolor and enhanced upconversion luminescence via Li+ doping in Yb3+/Tm3+/Ho3+ tri-doped NaYF4 microcrystals

In this paper, a range of Yb3+/Tm3+/Ho3+ triple-doped NaYF4 microcrystals (MCs) were successfully prepared by hydrothermal method and characterized by X-ray diffraction, which proved to be a hexagonal phase structure with uniformity. The morphology of NaYF4:20% Yb3+, 1% Ho3+ MCs with different doping amounts of NaOH and citric acid were studied using scanning electron microscope, and the distribution of elements of this doping system was characterized by energy dispersive spectrometer. Upconversion luminescence (UCL) spectra of the MCs using a fluorescence spectrometer with 980 nm excitation were researched, and the results demonstrated that the tunable multi-color of the MCs can be achieved by varying the doping amount of different rare-earth ions. The UC mechanism of the MCs were systematically described. Li+doped the series MCs improved their UCL efficiency. By investigating the UCL the MCs of the Li+-doped system, the emission intensities of blue (450 nm, 475 nm), green (541 nm), and red (648 nm) light of the series MCs were increased by 2.75, 2.095, 2.65, and 2.87 times, which is of great significance for its application in light-emitting diodes and solar cells.

Disentangling the Evidence of Milankovitch Forcing From Tree-Ring and Sedimentary Records

Tree-ring records constitute excellent high-resolution data and provide valuable information for climate science and paleoclimatology. Tree-ring reconstructions of past temperature variations agree to show evidence for annual-to-centennial anomalies in past climate and place the industrial-era warming in the context of the late Holocene climate patterns and regimes. Despite their wide use in paleoclimate research, however, tree rings have also been deemed unsuitable as low-frequency indicators of past climate. The arising debate concerns whether the millennia-long tree-ring records show signals of orbital forcing due to the Milankovitch cycles. Here, we produce a summer-temperature reconstruction from tree-ring chronology running through mid- and late-Holocene times (since 5486 BCE) comprising minimum blue channel light intensity (BI). The BI reconstruction correlates with existing and new tree-ring chronologies built from maximum latewood density (MXD) and, unlike the MXD data, shows temperature trends on Milankovitch scales comparable to various types of sedimentary proxy across the circumpolar Arctic. Our results demonstrate an unrevealed potential of novel, unconventional tree-ring variables to contribute to geoscience and climate research by their capability to provide paleoclimate estimates from inter-annual scales up to those relevant to orbital forcing.

Electrophysiological Methods for Measuring Photopigment Levels in Drosophila Photoreceptors.

The Drosophila G-protein-coupled photopigment rhodopsin (R) is composed of a protein (opsin) and a chromophore. The activation process of rhodopsin is initiated by photon absorption-inducing isomerization of the chromophore, promoting conformational changes of the opsin and resulting in a second dark-stable photopigment state (metarhodopsin, M). Investigation of this bi-stable photopigment using random mutagenesis requires simple and robust methods for screening mutant flies. Therefore, several methods for measuring reductions in functional photopigment levels have been designed. One such method exploits the charge displacements within the photopigment following photon absorption and the huge amounts of photopigment molecules expressed in the photoreceptors. This electrical signal, named the early receptor potential (or early receptor current), is measured by a variety of electrophysiological methods (e.g., electroretinogram and whole-cell recordings) and is linearly proportional to functional photopigment levels. The advantages of this method are the high signal-to-noise ratio, direct linear measurement of photopigment levels, and independence of phototransduction mechanisms downstream to rhodopsin or metarhodopsin activation. An additional electrophysiological method called prolonged depolarizing afterpotential (PDA) exploits the bi-stability of Drosophila photopigment and the absorption-spectral differences of fly R and M pigment states. The PDA is induced by intense blue light, converting saturating amounts of rhodopsin to metarhodopsin, resulting in the failure of light-response termination for an extended time in darkness, but it can be terminated by metarhodopsin to rhodopsin conversion using intense orange light. Since the PDA is a robust signal that requires massive photopigment conversion, even small defects in the biogenesis of the photopigment lead to readily detected abnormal PDA. Indeed, defective PDA mutants led to the identification of novel signaling proteins important for phototransduction.

Dual-emission fluorescent nanoprobe based on Ag nanoclusters for sensitive detection of Cu(II)

Noble metal nanoclusters have attracted much attention because of their excellent fluorescence properties. In this work, we demonstrated a dual-emission fluorescent nanocomposite based on silver nanoclusters. First, we synthesized positively charged His-AgNCs, which emits intense blue light, and then Ag nanoclusters with stable red emission were synthesized using DHLA as the ligand. Thus a dual-emission fluorescent nanoprobe was successfully obtained through electrostatic self-assembly, with the advantages of good water solubility and excellent stability. Based on the intensity ratio of the two emission peaks, the nanoprobe can be used for selective and sensitive detection of copper ions, and presents a good linear relationship within a certain concentration range. In addition, we also designed a polymer film, and our dual-emission nanoprobe was successfully loaded onto it, which means that the visual detection of copper ions is possible. This indicates that our dual-emission fluorescent nanoprobe has potential application prospects in environmental analysis, medical diagnosis, biological detection, etc.

The beneficial functions of blue light supplementary on the biosynthesis of glucosinolates in pakchoi (Brassica rapa L. ssp. chinensis) under greenhouse conditions

Blue light can improve the nutritional value of vegetables grown in greenhouse, while the mechanisms about the biosynthesis and accumulation of glucosinolates regulated by light signaling still unknown. Here, the soluble amino acid and glucosinolate profiles under supplementary different blue light intensities (T50, T100, T150) for 10 days were investigated in green-leaf and red-leaf pakchoi. The results indicated that blue light could significantly increase the contents of glucoalyssin, glucobrassicin, glucobrassicanapin, gluconapin and total glucosinolates, and shown a dose effect. The soluble amino acid profiles and the contents of glucosinolates precursor amino acid were also enhanced to varying degrees. Besides, in green-leaf and red-leaf pakchoi, the expression levels of photoreceptor genes under T100 were significantly higher compared with the CK. Supplementary blue light also promoted the expression of key transcription factors and key genes of glucosinolate biosynthesis pathway in two cultivars pakchoi. Therefore, the beneficial functions of blue light supplementary on the biosynthesis of glucosinolates in pakchoi under greenhouse conditions are owing to the promoted in the contents of precursor amino acids and the expressions of glucosinolate-related genes mediated by light signal transduction. • Supplementary bule light could increase the glucosinolate profiles of pakchoi leaves. • The increasing of glucosinolate content be linked to glucosinolate biosynthesis and photoreceptor gene-related expressions. • The increasing of light-controlled amino acids profiles provides the material basis for glucosinolate biosynthesis. • The respond sensitivity to bule light was different in green-leaf and red-leaf pakchoi.

Effects of chronic, daily exposures to low intensity blue light on human retinal pigment epithelial cells: Implications for the use of personal electronic devices

• Repeated exposures of RPE cells to blue light can alter their physiology. • Daily exposure to blue light produced defects in all types of RPE cell layers. • Electronic devices could produce retinal damage over a lifetime of use.

Comparison of Anterior Corneal Aberrometry, Keratometry and Pupil Size with Scheimpflug Tomography and Ray Tracing Aberrometer.

This study aimed to assess the anterior corneal wavefront aberrations, keratometry, astigmatism vectors and pupil size between Pentacam HR® (Oculus Optikgeraete GmbH, Wetzlar, Germany) and iTrace® (Tracey Technologies Corp., Houston, TX, USA). In this observational study, 100 eyes (50 healthy volunteers) were scanned in mesopic light condition with a Pentacam HR® and iTrace®. Anterior corneal aberrations (spherical aberration (Z40), vertical coma (Z3 − 1), horizontal coma (Z3 + 1)), keratometry in the flattest (K1) and steepest meridian (K2), mean astigmatism, astigmatic vectors (J0 and J45), and pupil size were measured. We found a significant difference in Z40 (Pentacam®: +0.30 ± 0.11 µm and iTrace®: −0.03 µm ± 0.05 µm; p < 0.01) with no correlation between the devices (r = −0.12, p = 0.22). The devices were in complete agreement for Z3 − 1 (p = 0.78) and Z3 + 1 (p = 0.39), with significant correlation between the machines (r = −0.38, p < 0.01 and r = −0.6, p < 0.01). There was no difference in K1, K2 and mean astigmatism. J0 was negative with both devices (against-the-rule astigmatism), but there was no correlation. J45 was negative with the Pentacam HR® (more myopic oblique astigmatism) but significantly correlated between the devices. Pupil size was smaller with Pentacam HR® (p < 0.01). In summary, these devices cannot be used interchangeably. Corneal Z40 was significantly different with more negative Z40 with iTrace® compared to Pentacam HR®. iTrace® operates with lower illumination, giving larger pupil size than Pentacam HR®, which uses intense blue light during measurement. No correlation was found for J0. Pentacam HR® had a trend to record more negative J45 (myopic oblique astigmatism).

Seeking eye protection from biomass: Carbon dot-based optical blocking films with adjustable levels of blue light blocking

The intensity of blue light in white light emitting diodes is typically higher than that of the green and red-light components in screen displays and lighting systems. To reduce the potential harm of in white light emitting diodes to the eyes, in this paper, we have used microcrystalline cellulose to synthesize biomass-based carbon dots (Bio-CD), which not only absorb short wavelength light to produce longer wavelength emissions, but also show concentration-dependent maximum excitation and maximum emission. The Bio-CDs were mixed with polyvinyl alcohol (PVA) to produce optical blocking films (OBF) that preferentially block blue light. OBFs have good transparency and also block blue light effectively. With OBFs containing 9.9% of Bio-CDs, the film blocked 99.6% and 98.6% of 395 nm light and 450 nm light respectively, and also blocked 93.4% and 97%, respectively, of the blue light emitted by computers and mobile phone screens. OBFs containing more than 9.9% Bio-CDs block blue light more than commercially available blue light blocking glasses. By adjusting the amount of Bio-CDs in the OBFs, it is possible to produce films with different degrees of blue light blocking to meet the requirements of different applications.

High relative-intensity blue light of supercontinuum generation in photonic crystal fibers

A distinct blue peak at 430 nm of the supercontinuum spectrum is generated in 4.6 m photonic crystal fiber with a high air-filling ratio, which is pumped by a 200 ps pulse laser at 1 µm. The amplitude of the blue peak is higher than that of the remaining pump pulse, and the relative intensity blue light of supercontinuum generation is 114%. We have systematically analyzed the formation mechanism and influence factors of the distinct blue peak with different fiber lengths and input pulses. The experimental results show that the wavelength position of the blue peak in the supercontinuum spectrum is almost unchanged, and both the fiber length and pulse width have a great influence on the intensity of the blue peak. In addition, we have discussed the fact that the dynamic changes of the blue peak may be affected by the ∼ 2200 n m peak through cross-phase modulation (XPM). It is possible that the high relative intensity of the blue peak in high-order modes may be originated from the XPM effect and the third-harmonic wave of the fundamental mode.

Research on Comfort Evaluation Model of Urban Residents’ Public Space Lighting Integrating Public Perception and Nighttime Light Remote Sensing Data

With the development of a sustainable lifestyle, people are paying more and more attention to the comfort of their own living environment, including public space lighting, which is immediately accessible to residents. The demand on its quality and comfort has thus gained attention recently. However, there is still a lack of related research on public space lighting comfort evaluation models that combine nighttime light remote sensing data and field measurement data, and link lighting attributes with the comfort of residents. This research uses nighttime light remote sensing data to select typical test areas, measures the lighting data of the survey points on the spot, develops an intelligent WeChat applet that collects public perception data, analyzes different lighting parameters, and builds a public space lighting comfort model based on the structural equation model analysis method. The results show that the factor that the areas with high light intensity are more comfortable than the areas with low light intensity. In areas with high light intensity, people pay more attention to the uniformity, security and comfort of the light, while in areas with low light intensity or high blue light, people’s perception of glare will be more obvious. This research can provide a basis for the intelligent optimization of public space lighting from the perspective of public preference.

The phosphorylation status of NONPHOTOTROPIC HYPOCOTYL3 affects phot2-dependent phototropism in Arabidopsis

ABSTRACT The blue light photoreceptors, phototropin 1 (phot1) and phot2, and their signal transducer, NONPHOTOTROPIC HYPOCOTYL3 (NPH3), are activators of the phototropic responses of Arabidopsis hypocotyls. In a recent study, we reported that the control of NPH3 phosphorylation at serine 7 (S7: or S5), S213, S223, S237, S467, S474 (or S476), and S722 (or S723) contributes to the photosensory adaptation of phot1 signaling during the phototropic response. Phosphomimetic NPH3SE mutant and unphosphorylatable NPH3SA mutant on those serine residues function efficiently under blue light conditions at fluence rates of 10−5 µmol m–2 s–1 and 10–3 µmol m–2 s–1 or more, respectively. We here demonstrate that phosphomimetic NPH3SE, but not unphosphorylatable NPH3SA, promotes phot2-dependent phototropism under blue light condition at 100 µmol m–2 s–1. This result suggests that phot1 negatively controls phot2 signaling through the dephosphorylation of NPH3 at those residues and that the hyperactivation of phot1- and phot2-NPH3 complexes does not occur at the same time under high intensity blue light. We hypothesize that the dephosphorylation of NPH3 on those serine residues suppresses both phot1 and phot2 signaling, which results in different impacts on phot1- and phot2-dependent hypocotyl phototropism due to the differences in the photosensitivity and activation levels of phot1 and phot2.

White, blue and cyan luminescence from thermally oxidized porous silicon coated by green synthesized carbon nanostructures

White light emitting nanostructured composites were produced in this work after annealing of aged thermally oxidized porous silicon (PS) coated by green synthesized Carbon Nanostructures (CNs). According to the photoluminescence (PL) spectra of the nanostructured composites, a broad band emission (white luminescence) was observed from ultraviolet to near infrared. Depending on the presence of hydrogen species, the interaction of nanostructures with oxide layers and the quality of the oxide layers, significantly affected the luminescence mechanism. Intense blue light emitting and cyan light emitting nanostructured composites were also obtained during the production process. In this work, a new method is proposed for obtaining white, blue and cyan luminescence by coating the thermally oxidized PS with the green synthesized CNs, which enables a tremendously cheap, clean and effortless production procedure for the redesign of instruments such as LEDs, photodetectors and biosensors which are extremely important for optoelectronic and biomedical applications. This new method enables the tailoring of the luminescence through thermal oxidation and aging of PS, and annealing of the nanostructured composites.

The influence of different light spectra on physiological responses, antioxidant capacity and chemical compositions in two holy basil cultivars

Light-emitting diodes (LEDs) are an artificial light source used in indoor cultivation to influence plant growth, photosynthesis performance and secondary metabolite synthesis. Holy basil plants (Ocimum tenuiflorum) were cultivated under fully controlled environmental conditions with different red (R) and blue (B) light intensity ratios (3R:1B, 1R:1B and 1R:3B), along with combined green (G) LED (2R:1G:2B). The photosynthetic activities of both cultivars were maximal under 3R:1B. However, the highest fresh (FW) and dry (DW) weight values of green holy basil were recorded under 3R:1B and 2R:1G:2B, significantly higher than those under alternative light conditions. For red holy basil, the highest FW and DW were recorded under 1R:3B. Moreover, 2R:1G:2B treatment promoted pigment (chlorophyll and carotenoid) accumulation in green holy basil, while red holy basil was found to be rich in both pigments under 3R:1B. Antioxidant capacity was also influenced by light spectrum, resulting in greater total phenolic content (TPC) and DPPH accumulation in both cultivars under 1R:3B. The highest content of flavonoid in green holy basil was detected under 1R:1B; meanwhile, 1R:3B treatment significantly promoted flavonoid content in red holy basil. In addition, anthocyanin content increased in red holy basil under 1R:3B conditions. Gas chromatography coupled with mass spectrometry (GC–MS/MS) analysis of chemical composition showed higher proportional accumulation in Methyleugenol and Caryophyllene of two cultivars grown under all light spectrum ratios at two developmental stages. Overall, specific light spectrum ratios induced different chemical composition responses in each cultivar and at each developmental stage. These results suggest that 3R:1B was favorable for biomass accumulation and photosynthetic responses in green holy basil, while 1R:3B provided antioxidant accumulation. For red holy basil cultivation, 1R:3B provided optimal growing conditions, promoting improvements in plant biomass, and physiological and antioxidant capacities.

The impact of light intensity and wavelength on the performance of algal-bacterial culture treating domestic wastewater

Light is the main energy source for microalgae, and the intensity and wavelength of light influence cell metabolism and biomass composition, which, in turn, affects wastewater treatment. The objective of this study is to examine how different light intensities and light wavelengths affect the growth of mixed algal-bacterial culture while treating sewage. Three different light intensities (100, 200, and 300 μmol/m2-s) of four different light wavelengths (blue, red, white, and yellow) were selected for this study. The dissolved organic carbon (DOC), dissolved nitrogen (DN), and dissolved phosphorus (DP) in influent and effluent samples were measured, along with chlorophyll content in the biomass. The highest chlorophyll concentration of 3.5 mg/L was observed at 100 μmol/m2-s intensity of red light. The concentration of chlorophyll decreased as light intensity increased, with exception of white light. The highest DOC removal of 84% was observed at 300 μmol/m2-s intensity of blue light whereas the highest DN (51%) and DP (80%) removal was observed with a red light intensity of 100 μmol/m2-s. Overall, blue light with an intensity of 300 μmol/m2-s and red light with an intensity of 100 μmol/m2-s were found to be the most efficient at removing carbon and nutrients. The results suggested that the color and intensity of light influence algal-bacterial growth and wastewater treatment efficiency.

Ratio of Intensities of Blue and Red Light at Cultivation Influences Photosynthetic Light Reactions, Respiration, Growth, and Reflectance Indices in Lettuce.

Simple SummaryIllumination is an important factor for plant life because light is the basis of photosynthesis and productivity, the regulator of physiological processes, and a potential cause of damage. The development of LED technology has contributed to increasing the efficiency of illumination during plant cultivation through the use of light sources with narrow spectral bands. However, the characteristics of influence of light sources with different spectra on specific species of agricultural plants require further investigation. In the present work, we analyzed the influence of two variants of LED illumination (with increased intensity of red or blue light) on physiological processes in lettuce. These variants were selected because they corresponded to two maximums of photosynthetic light absorption. It was shown that, under the increased intensity of the blue light, both respiration and cyclic electron flow were stimulated; theseprocesses are known to be related to stress changes in plants. In contrast, under the increased intensity of the red light, linear electron flow was stimulated, a process that is related to plant productivity, and the biomass during cultivation was increased. The reflectance of leaves was also dependent on the variant of illumination. In the future, our results can be used to increase the efficiency of lettuce cultivation.LED illumination can have a narrow spectral band; its intensity and time regime are regulated within a wide range. These characteristics are the potential basis for the use of a combination of LEDs for plant cultivation because light is the energy source that is used by plants as well as the regulator of photosynthesis, and the regulator of other physiological processes (e.g., plant development), and can cause plant damage under certain stress conditions. As a result, analyzing the influence of light spectra on physiological and growth characteristics during cultivation of different plant species is an important problem. In the present work, we investigated the influence of two variants of LED illumination (red light at an increased intensity, the “red” variant, and blue light at an increased intensity, the “blue” variant) on the parameters of photosynthetic dark and light reactions, respiration rate, leaf reflectance indices, and biomass, among other factors in lettuce (Lactuca sativa L.). The same light intensity (about 180 µmol m−2s−1) was used in both variants. It was shown that the blue illumination variant increased the dark respiration rate (35–130%) and cyclic electron flow around photosystem I (18–26% at the maximal intensity of the actinic light) in comparison to the red variant; the effects were dependent on the duration of cultivation. In contrast, the blue variant decreased the rate of the photosynthetic linear electron flow (13–26%) and various plant growth parameters, such as final biomass (about 40%). Some reflectance indices (e.g., the Zarco-Tejada and Miller Index, an index that is related to the core sizes and light-harvesting complex of photosystem I), were also strongly dependent on the illumination variant. Thus, our results show that the red illumination variant contributes a great deal to lettuce growth; in contrast, the blue variant contributes to stress changes, including the activation of cyclic electron flow around photosystem I.

Surface disinfection with white-violet illumination device

&lt;abstract&gt; &lt;p&gt;The spread of infections, as in the coronavirus pandemic, leads to the desire to perform disinfection measures even in the presence of humans. UVC radiation is known for its strong antimicrobial effect, but it is also harmful to humans. Visible light, on the other hand, does not affect humans and laboratory experiments have already demonstrated that intense visible violet and blue light has a reducing effect on bacteria and viruses. This raises the question of whether the development of pathogen-reducing illumination is feasible for everyday applications. For this purpose, a lighting device with white and violet LEDs is set up to illuminate a work surface with 2,400 lux of white light and additionally with up to 2.5 mW/cm&lt;sup&gt;2&lt;/sup&gt; of violet light (405 nm). Staphylococci are evenly distributed on the work surface and the decrease in staphylococci concentration is observed over a period of 46 hours. In fact, the staphylococci concentration decreases, but with the white illumination, a 90% reduction occurs only after 34 hours; with the additional violet illumination the necessary irradiation time is shortened to approx. 3.5 hours. Increasing the violet component probably increases the disinfection effect, but the color impression moves further away from white and the low disinfection durations of UVC radiation can nevertheless not be achieved, even with very high violet emissions.&lt;/p&gt; &lt;/abstract&gt;

MOF-coated upconversion nanoconstructs for synergetic photo-chemodynamic/oxygen-elevated photodynamic therapy.

Excessive production of intracellular reactive oxygen species (ROS) can induce apoptosis of cancer cells; however, it is often limited by severe triggering conditions and hypoxic microenvironments of solid tumors. To address these issues, herein, we have designed a MOF-coated upconversion nanoconstruct (UCTSCF, referring to UC@Ce6/TFS@mSiO2@MIL-100(Cu/Fe)) for synergetic photochemodynamic therapy (PCT)/oxygen-elevated photodynamic therapy (PDT). The MOF (MIL-100(Fe)) coating with Cu-doping was designed to catalyze H2O2 overexpression in cancer cells to generate the most cytotoxic ˙OH via chemodynamic therapy (CDT). It is noted that UC, representing 808 nm driven upconversion nanoparticles with high tissue penetration depth/low over-heating effects, was designed to provide intense blue light which can relieve the severe triggering conditions of CDT via PCT. Furthermore, the functional layer of the photosensitizer chlorin e6 (Ce6) and O2-carrying triethoxy(1H,1H,2H,2H-nonafluorohexyl)silane (TFS) co-doped mesoporous silicon (Ce6/TFS@mSiO2) can cause oxygen-elevated 1O2 production upon 671 nm light irradiation. In such a simple ROS generation nanoplatform, we heighten the antitumor effect via oxygen-elevated synergetic tumor PCT/PDT.