UV Exposure Time Research Articles

Vitamin D Status in Japanese Adults: Relationship of Serum 25-Hydroxyvitamin D with Simultaneously Measured Dietary Vitamin D Intake and Ultraviolet Ray Exposure.

Vitamin D insufficiency/deficiency is prevalent worldwide. We investigated the effect of vitamin D intake and ultraviolet ray (UV) exposure on serum vitamin D concentration in Japan. A total of 107 healthy adult participants were recruited from Hokkaido (43° N) and Kumamoto (33° N) prefectures. All participants undertook surveys in both summer and winter. Serum 25-hydroxyvitamin D (25(OH)D3) was examined, and vitamin D intake was assessed with a diet history questionnaire. UV exposure was measured with a wearable UV dosimeter. Regression analysis was performed to investigate the relationship between these factors, with covariates such as sun avoidance behavior. The prevalence of vitamin D insufficiency (serum 25(OH)D3; 12 ng/mL (30 nmol/L) ≤ and <20 ng/mL (50 nmol/L))/deficiency (<12 ng/mL) was 47.7% in summer and 82.2% in winter. UV exposure time was short in Kumamoto (the urban area), at 11.6 min in summer and 14.9 min in winter. In Hokkaido (the rural area), UV exposure time was 58.3 min in summer and 22.5 min in winter. Vitamin D intake was significantly associated with serum 25(OH)D3, and a 1 μg/1000kcal increase in intake was necessary to increase 25(OH)D3 by 0.88 ng/mL in summer and by 1.7 ng/mL in winter. UV exposure time was significantly associated with serum 25(OH)D3 in summer, and a 10 min increase in UV exposure time was necessary to increase 25(OH)D3 by 0.47 ng/mL. Although consideration of personal occupation and lifestyle is necessary, most Japanese may need to increase both vitamin D intake and UV exposure.

Effect of UV degradation and dynamic loading on durability of acrylic carpets using multiple regression method

The effect of dynamic fatigue loading on the carpet samples subjected to long-time UV radiation exposure has beenstudied. The carpet samples are first subjected to different UV exposure time and then dynamic loading is imposed to thesamples. In each case, the thickness loss of the carpets is measured. The results show that the UV exposure time has a slighteffect on the thickness loss of the carpets. The number of dynamic impacts, on the other hand, shows a significant effect onthe thickness loss with an exponential correlation. Using best curve fitting method based on least square method,a predicting equation is derived for the multiple effect of UV exposure time and number of dynamic loading on the thicknessloss. The experimental verification reveals that the proposed predicting equation can be used with an acceptable accuracy.

Effect of silver and antimony on optical properties of tungsten-phosphate glasses

The effect of silver ions on the photochromic properties of tungsten phosphate glass is investigated. All samples when excited at 377 nm exhibit ~430 nm luminescence attributed to the charge transfer mechanism within the WO42−tungstate anions. The broad absorption band extending from ultraviolet to the visible region, between 500 and 1400 nm, of the NaPO3-WO3 (PW) base matrix due to the small-polarons(Wx5+W1−x6+O3) transferring charges between neighboring tungsten ions according to the following photon absorptionWA5++WB6++hvs→WA6++WB5+. The dual oxidation state of the antimony, Sb3+ and Sb5+, incorporated into the matrix at the 0.5−xNaPO3−0.5WO3−xSb2O3x=0…0.2mol% (PWS) ratio acts as a reducing element of the W5+ ions leading to the suppression of polarons as UV-VIS absorption centers. These results are confirmed by EPR measurements with scanned magnetic field between 2500 and 4500G. The most intense effect is observed for nominal doping aboveAgNO3≥10mol%. The temporal dynamics of luminescence at ~430 nm as a function of UV exposure time shows that both,Wx5+W1−x6+O3 for PW glasses as well as Ag+ for PWSA glasses act as traps for the charge generated by the excitedWO42− anions. Photodarkening due to continuous exposure to UV radiation reduces the pump transmission by ~12% of its initial value for PW and PWSA glasses. This is attributed to F-center formation (Ag+) which acts traps to the photoexcited electrons. This is attributed to oxidation of silver ions (Ag+) becoming metallic silver (Ag0). The effect when compared to PWS glass was observed to be reduced by only 2% over the same interval under the same pumping conditions.

Influence of Substrate Surface Properties on Spin Dewetting, Texture, and Phase Transitions of 5CB Liquid-Crystal Thin Films.

We report how the texture and stability of a nematic liquid-crystal (LC) thin film of 5CB vary as a function of UV-ozone (UVO) exposure of the underlying poly(methyl methacrylate) (PMMA) substrate. UVO exposure of the PMMA substrate not only increases its surface energy, making it more wettable, but also results in the generation of oxygen-containing polar functional groups on the PMMA surface due to photolysis of ester. While the stability of the 5CB films is expectedly enhanced on UVO-exposed PMMA substrates against thermally induced dewetting, the texture of the film also changes as a function of the UV exposure time (tE). We show that the films continue to exhibit the nematic Schlieren texture for tE ≤ 20 min, although the disclination point density (|m|) gradually reduces with an increase in tE. However, the texture changes completely to a spherulite or fanlike texture in tE ≥ 20 min due to enhanced anchoring of the 5CB molecules on the substrates. In addition, enhanced wettability and stronger anchoring by the UVO-exposed PMMA substrates also suppress the tendency of spin dewetting of the 5CB films due to spontaneous rupture of the dispensed solution layer during spin coating, particularly when the solute concentration (Cn) is very low. The latter observation allows possible creation of thinner LC films, which are otherwise difficult to form by spin coating due to enhanced cohesive interactions between the anisotropic LC molecules. Finally, we show that in continuous films, the nematic-to-isotropic (N → I) and I → N phase transitions with gradual heating and cooling remain completely reversible, irrespective of the texture of the film and wettability of the substrate.

Role of UV fluence on the thermal regeneration characteristics of fiber Bragg gratings: experiment and analysis

In this paper, the effect of UV exposure time on the thermal regeneration characteristics of fiber Bragg gratings (FBGs) inscribed using 255 nm laser radiation is presented for the first time. This effect is studied in terms of reflectivity, refractive index (RI) modulation and thermal stability of the gratings. Type-I FBGs of RI modulation varying from 2.03 × 10−4 to 3.38 × 10−4 were inscribed in hydrogenated SMF-28 fiber by controlling UV exposure fluence from 0.9 kJ cm−2 to 28.8 kJ cm−2. Thermally regenerated gratings were fabricated from type-I FBGs by applying a step-annealing schedule up to 900 °C. The reflectivity of the regenerated FBGs increases with UV fluence and after reaching a maximum value of 46.05%, it decreases. The different behavior of the thermal regeneration characteristics of FBGs is linked with the stress developed inside the fiber during the writing of FBGs and their relaxation during thermal annealing. The theoretical calculations using the defect center and densification model provided an indirect novel approach to estimate the contribution of stress relaxation in thermal regeneration. The work presented in this paper is significant for optimizing the thermal regeneration of FBGs with the final aim of developing a highly reflective regenerated grating for high temperature sensing applications.

Electrically-Tunable Blue Phase Liquid Crystal Microlens Array Based on a Photoconductive Film.

This paper proposes an effective approach to fabricate a blue phase liquid crystal (BPLC) microlens array based on a photoconductive film. Owing to the characteristics of photo-induced conducting polymer polyvinylcarbazole (PVK), in which conductivity depends on the irradiation of UV light, a progressive mask resulting in the variation of conductivity is adopted to produce the gradient distribution of the electric field. The reorientations of liquid crystals according to the gradient distribution of the electric field induce the variation of the refractive index. Thus, the incident light experiences the gradient distribution of the refractive index and results in the focusing phenomenon. The study investigates the dependence of lens performance on UV exposure time, the focal length of the lens, and focusing intensities with various incident polarizations. The BPLC microlens array exhibits advantages such as electrically tunability, polarization independence, and fast response time.

Rapid microneedle fabrication by heating and photolithography.

Many fabrication methods for microneedle (MN) involve harsh conditions and long drying time. This study aims to fabricate a dissolving MN patch in a simple and efficient manner under mild conditions, using a combination of thermal and photo polymerisation. The MN patch was fabricated by pre-polymerisation of vinylpyrrolidone solution with heating followed by photolithography. The heating temperature and time of pre-polymer solution curing were optimized based on viscosity measurement. The MN properties including shape, size, skin penetration, dissolution, moisture absorption were determined. The fabricated MNs were sharp and consistent. The heated N-vinylpyrrolidone solution required less UV exposure time, thus reducing the total fabrication time. The percentage of MN penetration in human cadaver skin was more than 33.9%. The MN was dissolved within 1-2min in water, or 40min in saturated water vapor.

Multi-material 3D bioprinting of porous constructs for cartilage regeneration.

The current gold standard for nasal reconstruction after rhinectomy or severe trauma includes transposition of autologous cartilage grafts in conjunction with coverage using an autologous skin flap. Harvesting autologous cartilage requires a major additional procedure that may create donor site morbidity. Major nasal reconstruction also requires sculpting autologous cartilages to form a cartilage framework, which is complex, highly skill-demanding and very time consuming. These limitations have prompted facial reconstructive surgeons to explore different techniques such as tissue engineered cartilage. This work explores the use of multi-material 3D bioprinting with chondrocyte-laden gelatin methacrylate (GelMA) and polycaprolactone (PCL) to fabricate constructs that can potentially be used for nasal reconstruction. In this study, we have investigated the effect of 3D manufacturing parameters including temperature, needle gauge, UV exposure time, and cell carrier formulation (GelMA) on the viability and functionality of chondrocytes in bioprinted constructs. Furthermore, we printed chondrocyte-laden GelMA and PCL into composite constructs to combine biological and mechanical properties. It was found that 20% w/v GelMA was the best concentration for the 3D bioprinting of the chondrocytes without comprising the scaffold's porous structure and cell functionality. In addition, the 3D bioprinted constructs showed neocartilage formation and similar mechanical properties to nasal alar cartilage after a 50-day culture period. Neocartilage formation was also observed in the composite constructs evidenced by the presence of glycosaminoglycans and collagen type II. This study shows the feasibility of manufacturing neocartilage using chondrocytes/GelMA/PCL 3D bioprinted porous constructs which could be applied as a method for fabricating implants for nose reconstruction.

Crosslinking process, mechanical and antibacterial properties of UV-curable acrylate/Fe3O4-Ag nanocomposite coating

In this paper, an antibacterial nanocomposite coating has been prepared by a green method based on photocroslinking with the addition of new synthesized Fe3O4-Ag nanohybrids. Fe3O4-Ag hybrid nanoparticles (0.1 wt.%) were dispersed in UV-curable acrylate resin stystem (BGDM and HDDA). The kinetic of UV-curing reaction of the nanocomposite was studited by measuring the coversion of acrylate double bonds, the variation of relative hardness, gel fraction and swelling degree of the coating. The structural morphology, mechanical and antibacterial properties of the nanocomposite were characterized. The analysis data demonstrated that the addition of 0.1 wt.% of Fe3O4-Ag hybrid nanoparticles into the coating affected insignificantly to its crosslinking process; the UV-exposure time to achieve a full crosslinking coating was about 4.8 s; the hybrid nanoparticles were homogeneously dispersed in network polymer matrix. The addition of the nanohybrids into the UV curing coating improved its its abrasion resistance from 98.24 to 126.54 lite/mil. The antibacterial testing indicated that the antimicrobial activity of the nanocomposite against E. coli was inversely proportional to its crosslinking density. Adding the nanocomposite in the culture, the growth rate of culture reduced about 3–5 % compared to that of the pure culture, after 5 h of cultivation while no antibacterial activity was observed for the neat coating.

A Multifunctional Lipid Incorporating Active Targeting and Dual-Control Release Capabilities for Precision Drug Delivery.

Active targeting and precise control of drug release based on nanoparticle therapies are urgently required to precisely treat cancer. We have custom-synthesized a functional lipid (termed Fa-ONB) by introducing a folic acid-targeting group into an o-nitro-benzyl ester lipid. As designed, the liposomes formed by Fa-ONB combine active targeting and dual trigger release capabilities, which help to improve drug efficacy and reduce the toxicity of traditional liposomes. We first verified that both pH-induced hydrolysis and light treatment were able to cleave the Fa-ONB lipid. We then prepared a series of liposomes (termed FOBD liposomes) by compounding the Fa-ONB lipid with DOPC at different ratios. After encapsulation of doxorubicin (DOX), we found that the particle size of DOX-loaded FOBD liposomes (DOX/FOBD) first increased (290 to 700 nm) and then decreased again (to 400 nm) under continuous UV irradiation (120 min). The photocatalytic release efficiency under different pH conditions was investigated by dialysis experiments, and it was found that the release efficiency in an acidic environment was significantly increased relative to neutral pH. This pH-triggered release response helps distinguish pathological tissues such as lysosomal compartments and tumors. The light-induced formation of a DOX precipitate increases in efficiency with increasing UV exposure time as well as with increasing environmental acidity or alkalinity. In addition, confocal imaging and flow cytometry showed that the ability of FOBD lipids to actively target HeLa cells increased with increasing Fa-ONB lipid content. Real-time in vivo fluorescence small animal experiments proved targeting to tumors and pH- and photo-induced release properties. Furthermore, therapeutic experiments using a mouse model found a significant tumor inhibitory effect for DOX/FOBD55 liposomes with UV irradiation, clearly demonstrating the benefit of light treatment: the tumor size of the control (PBS) group was 7.59 times that of the light treatment group. Therefore, this research demonstrates the benefits of combining triggerable release functions and effective active tumor targeting in one small lipid molecule for precise cancer treatment.

Controlled release of curcumin from electrospun fiber mats with antibacterial activity

Nanofibers of polyvinyl alcohol (PVA) loaded with different concentration of curcumin was fabricated through electrospinning process. The nanofiber mats were crosslinked through heat treatment at different temperatures and UV exposure for different times with the aim to stabilize and control the release of curcumin from the mat. The average fiber diameter of PVA nanofibers was larger than PVA nanofibers with curcumin. The diameter of nanofibers decreased with the increase of curcumin content. While heat treatment increased the fiber diameters, no significant change in diameter was observed after UV exposure of the nanofiber mats. XRD analysis revealed that crystallinity of crosslinked samples increased gradually with the increase of heat treatment temperature and UV exposure time. The crosslinking methods showed no deterioration in mechanical properties of the nanofiber mats. The release of curcumin was controlled up to maximum 20% through heat treatment and maximum 9% through UV exposure compared to the non-crosslinked samples. The swelling ratio of all the crosslinked samples was observed over 300%. All the PVA/curcumin crosslinked samples showed antibacterial efficacy against both gram-positive and gram-negative bacteria. Thus, this study fabricates a stable antibacterial nanofibrous mat with controlled curcumin release capability through a facile way.

Features of curing polyester binder due to the different duration of exposure to ultraviolet radiation

Samples of polyester binder RO-4761 were irradiated using an ultraviolet device. The investigations established that the microhardness of the polymer along its cross section, from the surface to core of the sample, varies according to a parabolic law. With increasing time of UV exposure the sample, its microhardness increases. When the binder is fully cured, the parabolic curve transforms into a straight line. A new term is proposed that characterizes the change in microhardness in the volume of the cured polymer: “Volume anisotropy coefficient”.

One step facile in-situ photochemical synthesis of hollow, doughnut-like ZnO nanoparticles and their alcohol vapor sensing properties

Parameters such as the type of photoinitiator and UV exposure time are investigated in order to tailor the growth of ZnO nanostructures into a variety of dimensions and structures. Based on the type of photoinitiator, by means of specific photoreducing radicals, hollow, doughnut and spherical-shaped ZnO nanoparticles are prepared in one step. 2-Mercapto-thioxanthone (TX-SH), Thioxanthone (TX) and α-aminoketone (Irg-907) are employed as the photoinitiators in formulations of PEGMEA/PEGDA (Poly (ethylene glycol) methyl ether acrylate/Poly (ethylene glycol) diacrylate). TX-SH containing formulations lead to the formation of hollow, doughnut-like shaped ZnO nanocomposites at early or prolonged irradiation times. Aggregation is much more prominent when TX is added to the formulation. Addition of Ph-SH to the TX containing formulation reduced agglomeration. Rather small and well-distributed ZnO nanoparticles are obtained for formulations consisting of Irg-907. Here we report an easy and fast photochemical preparation technique for these unique structures. The conduction behavior of the novel doughnut-like ZnO nanocomposite under various types of alcohol vapor (ethanol, methanol, and propanol) concentrations between 100 and 500 ppm has been investigated. It was found that the presence of alcohol vapor leads to an increase in sensor current. The ZnO nanocomposite based sensor showed maximum sensitivity toward methanol vapor for all the concentrations investigated.

Photochromic Materials: Photochromic Response and Steady‐State Photoconductivity of Fibrous‐Reticulated α‐MoO3 Thin Films Prepared by Modified Spray Pyrolysis Technique (Crystal Research and Technology 10/2019)

Crystal Research and TechnologyVolume 54, Issue 10 1970028 Cover PictureFree Access Photochromic Materials: Photochromic Response and Steady-State Photoconductivity of Fibrous-Reticulated α-MoO3 Thin Films Prepared by Modified Spray Pyrolysis Technique (Crystal Research and Technology 10/2019) First published: 07 October 2019 https://doi.org/10.1002/crat.201970028AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Graphical Abstract Molybdenum oxide thin films show considerable changes in their physical and chemical properties after UV exposure. In article number 1900122, Aly M. Badr and co-workers use a modified spray pyrolysis technique for preparing α-MoO3 thin films. The thickness effect on the structural, morphological, optical, electrical, and photo-electrical properties of the films is studied. The UV exposure time effect as well as the thickness effect on the photochromic response of the samples are investigated and discussed based on the particle size analysis. Additionally, the photosensitivity is elucidated, and the mechanism of the recombination processes in these films is determined. Volume54, Issue10October 20191970028 RelatedInformation

Photochromic Response and Steady‐State Photoconductivity of Fibrous‐Reticulated α‐MoO3 Thin Films Prepared by Modified Spray Pyrolysis Technique

AbstractA modified spray pyrolysis technique is used for preparing α‐MoO3 thin films after subsequent heat treatment at a relatively low temperature. The spray parameters are selected through a wide variety of elaboration conditions for best photochromic features. Different numbers of spraying and drying cycles are performed to investigate the thickness effect on the structural, morphological, optical, electrical, and photo‐electrical properties of the nanostructured α‐MoO3 films. These film samples are characterized by X‐ray diffraction (XRD) and scanning electron microscopy (SEM), and thus the film thickness effect is elucidated and correlated to the crystallite shape and size. The SEM micrographs show fibrous‐reticulated morphology for all the film samples investigated here. The photochromic properties of α‐MoO3 sprayed thin films are investigated by measuring the transmission spectra before and after UV‐light exposure. The changes in the optical transmission of these film samples are monitored for different exposure times. The UV exposure time effect as well as the thickness effect on the photochromic response of the film samples is investigated and discussed based on the particle size analysis. The photosensitivity is evaluated in various illumination levels to elucidate the carrier transport in the α‐MoO3 films and to determine the type of the recombination processes in these films.

Water Contaminated by Industrial Textile Dye: Study on Decolorization Process

This work aims to investigate possible interferences due to the presence of sodium carbonate on the photodegradation of the reactive Black 5 azoic dye, both in systems containing only titanium oxide and those containing titanium oxide and hydrogen peroxide. The role of hydrogen peroxide is explicitly treated. Sodium carbonate, in fact, is often present in the wastewater of textile industries as it is used in the fiber dyeing phases. The use of TiO2 nanoparticles is emphasized, and the possible danger is underlined. Each system was subjected to ultraviolet irradiation (UV) by varying the exposure time. After the photodegrading tests, the resulting solutions were analyzed by UV-vis spectrophotometry and High-Resolution Nuclear Magnetic Resonance to measure the residual concentrations of dye. The dye degradation curves and reaction rates for different UV exposure times were obtained and discussed as a function of the used additives. All the data are repeated three times, and they differ only by a maximum of 5%. The results indicated a reduction of about 50% of the initial concentration of Reactive Black 5 after 30 min under optimal experimental conditions. The NMR analysis indicated the formation of a series of aromatic structures that were generated by the UV-induced photochemical fragmentation of the original molecule.

Identification of Degradation By-Products of Selected Pesticides During Oxidation and Chlorination Processes

Abstract Advanced oxidation processes (AOPs) are considered to be one of the most effective methods for the decomposition of a wide range of hardly-biodegradable organic compounds, including pesticides. The implementation of such processes in the water streams treatment often leads to the formation of decomposition by-products of micropollutants occurring in water. These compounds, even in concentrations of a few ng/dm3, may negatively affect the water quality. Therefore, there is a need for detailed analyses that will allow to identify intermediates found in the AOP solutions and to assess their impact on the aquatic environment. The paper presents an attempt to identify by-products of three pesticides: triclosan, triallat and oxadiazon during ozonation, chlorination and UV irradiation of their water solutions. The identification of compounds was performed based on the results of the GC-MS analysis using the NIST v17 mass spectral library. It has been shown that during all of tested advanced oxidation processes, incomplete degradation of pesticides occurs. The number of micropollutant decomposition by-products increases with the increase of the applied ozone dose and UV exposure time. During the chlorination process Cl− atoms were added to the tested compound molecules. In the case of triclosan, it led to the generation of compounds containing four or five chlorine atoms in their structure. The toxicological analysis performed by the use of the Microtox® and Lemna sp. Growth Inhibition Test showed the toxic nature of post-process solutions. The decomposition by-products of triclosan and triallate, generated during the UV irradiation process, were highly toxic against the test organisms (toxic effect &gt; 75 %). This makes it impossible to drain these solutions into the natural environment.

OSCILLATORY STRAIN SWEEPS OF HYDROGELS FROM METHACRYLATED ALGINATE MACROMONOMERS: ASSESSMENT OF SYNTHESIS AND ACQUISITION VARIABLES

The objective of this study is the rheological characterization of photocrosslinked alginate hydrogels synthesized from methacrylated alginate macromonomers. We first optimized the rheological acquisition parameters for this hydrogels, that is, we studied the influence of the geometries diameter, distance between plates (gap), and solvent trap in the rheological response. Our results show important variations of shear storage modulus, G’, and yield strain with the three parameters measured. Secondly, with the optimized experimental parameters, rheological tests were performed on hydrogels synthesized under different conditions. Three parameters were studied; UV exposure time (polymerization time), macromonomer concentration and photoinitiator concentration. Our data indicate that the polymerization time and the macromonomer concentration have an important effect on the viscoelastic properties of the hydrogel, significantly modifying the shear storage modulus, G’, and the yield strain while the photoinitiator concentration did not influence the viscoelastic properties.

Effect of Photo Initiator Content and Light Exposure Time on the Fabrication of Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; Ceramic by DLP-3D Printing Method

In this study, a process is developed for 3D printing with alumina (Al2O3). First, a photocurable slurry made from nanoparticle Al2O3 powder is mixed with hexanediol diacrylate binder and phenylbis(2,4,6- trimethylbenzoyl) phosphine oxide photoinitiator. The optimum solid content of Al2O3 is determined by measuring the rheological properties of the slurry. Then, green bodies of Al2O3 with different photoinitiator contents and UV exposure times are fabricated with a digital light processing (DLP) 3D printer. The dimensional accuracy of the printed Al2O3 green bodies and the number of defects are evaluated by carefully measuring the samples and imaging them with a scanning electron microscope. The optimum photoinitiator content and exposure time are 0.5 wt% and 0.8 s, respectively. These results show that Al2O3 products of various sizes and shapes can be fabricated by DLP 3D printing.

Photoluminescence of carbon dots prepared by ball milling and their application in Hela cell imaging

Carbon dots are small carbon nanoparticles with various surface passivation schemes. The deliberate functionalization of carbon nanoparticles and carbonization of organic or carbon-rich species are two main synthesis routes for carbon dots. However, these two synthesis routes suffer from drawbacks such as critical reaction conditions and uncontrollable structure and performance. In our present work, a hybrid approach combining the advantageous characteristics of these two synthesis routes was applied to prepare carbon dots. The spherical and hydrophilic carbon dots were prepared by high-energy ball milling of active carbon and potassium carbonate. The carbon dots prepared are disperse and fine with an average size of 3.5 nm and a size distribution of 1.6–6.0 nm. They exhibit a nearly excitation-independent and high photostable blue photoluminescence behavior with the maximal emission wavelength at 430 nm. They also show an excellent photostability under high NaCl concentrations or long UV exposure time and a stable photoluminescence behavior in a wide pH range from 3 to 11. They are nearly not cytotoxic to Hela cells, can be taken up by Hela cells, and applied to Hela cell imaging. Our hybrid approach did not use any strong basic and can be scaled up for large-scale preparation of carbon dots.