SYNTHESIS OF BENZOINS BY DYE PHOTOSENSITIZATION

Using heavy-atom-containing xanthene dyes,benzoins can be quanti- tatively prepared by photosensitized reduction from benzils with triethyla- mine.It is an important supplement to'benzoin condensation',asp.for those benzoins with electron-donating substituents.

SINGLET OXYGEN DETECTION DURING PHOTOSENSITIZATION

Singlet oxygen(^(1)O_(2))is a highly reactive oxygen species involved in numerous chemical and photochemical reactions in diferent biological systems and in particular,in photodynamic therapy(PDT).However,the quantifcation of^(1)O_(2) generation during in vitro and in vivo pho-tosensitization is still technically challenging.To address this problem,indirect and direct methods for^(1)O_(2)detection have been intensively studied.This review presents the available methods currently in use or under development for detecting and quantifying^(1)O_(2) generation during photosensitization.The advantages and limitations of each method will be presented.Moreover,the future trends in developing PDT-^(1)O_(2) dosimetry will be briefly discussed.

Gold Nanostars-AIE Theranostic Nanodots with Enhanced Fluorescence and Photosensitization Towards Effective Image-Guided Photodynamic Therapy

Dual-functional aggregation-induced photosensitizers(AIE-PSs)with singlet oxygen generation(SOG)ability and bright fluorescence in aggregated state have received much attention in image-guided photodynamic therapy(PDT).However,designing an AIE-PS with both high SOG and intense fluorescence via molecular design is still challenging.In this work,we report a new nanohybrid consisting of gold nanostar(AuNS)and AIE-PS dots with enhanced fluorescence and photosensitization for theranostic applications.The spectral overlap between the extinction of AuNS and fluorescence emission of AIE-PS dots(665 nm)is carefully selected using five different AuNSs with distinct localized surface plasmon(LSPR)peaks.Results show that all the AuNS s can enhance the 1 O2 production of AIE-PS dots,among which the AuNS with LSPR peak at 585 nm exhibited the highest 1 O2 enhancement factor of15-fold with increased fluorescence brightness.To the best of our knowledge,this is the highest enhancement factor reported for the metalenhanced singlet oxygen generation systems.The Au585@AIE-PS nanodots were applied for simultaneous fluorescence imaging and photodynamic ablation of HeLa cancer cells with strongly enhanced PDT efficiency in vitro.This study provides a better understanding of the metal-enhanced AIE-PS nanohybrid systems,opening up new avenue towards advanced image-guided PDT with greatly improved efficacy.

Cucurbit[8]uril-regulated face-to-face dimerization assembly enhanced photosensitization and photocatalysis

In water, N,N′-diarylpyridinium thiazolo[5,4-d]thiazole guests(G1–G3) were encapsulated by cucurbit[8]uril(Q[8]) to construct Q[8]_(3)/G_(2) complexes, in which the encapsulated G molecules exist as an exact face-to-face dimer. These complexation behaviors have been indicated by proton nuclear magnetic resonance(~1H NMR) spectroscopy and isothermal titration calorimetry(ITC),and have been confirmed by X-ray single crystal structural analysis of Q[8]_(3)/G2_(2). While free guests G1–G3 have no ability to sensitize singlet oxygen, they all become effective singlet oxygen sensitizers when complexed with Q[8]. By irradiation of white light, Q[8]_(3)/G_(2) complexes induced selective oxidation of aryl sulfide to aryl sulfoxide in good yields and selective oxidation of dimethyl sulfide(DMS) to dimethyl sulfoxide(DMSO) in excellent yields without over-oxidation to dimethyl sulfone(DMSO_(2))even for elongated irradiation. High-yield photo-oxidation of DMS to DMSO_(2) was only achieved by irradiation of blue light in the presence of Q[8]_(3)/G1_(2), which was also effective in photobleaching of Rhodamine B in water. The higher photo-oxidation power of Q[8]_(3)/G1_(2) has been ascribed to an additional generation of reactive oxygen species besides singlet oxygen.

Construction of FRET-based metallacycles with efficient photosensitization efficiency and photocatalytic activity

The fabrication of highly effective photosensitizers has received considerable attention because of their attractive functions and applications in the fields of photodynamic therapy, photosynthesis, photocatalysis, etc. Thus, it is highly desirable to develop a new approach to enhance photosensitization efficiency.Herein, through coordination-driven self-assembly, a series of metallacycles with efficient fluorescence resonance energy transfer(FRET) were effectively constructed, which displayed higher photosensitization efficiency and photocatalytic activity than their model metallacycles without FRET due to broadband absorption and singlet energy transfer from the energy acceptor to the energy donor. Moreover, iodization of fluorophores induced a significant enhancement of the photosensitization efficiency and photocatalytic activity of the metallacycles. This research provides an efficient strategy for improving photosensitization efficiency and a promising platform for the preparation of effective photosensitizers and photocatalysts.

INQUIRY OF PHOTOSENSITIZATION MECHANISM OF YANGZHOU HEMATOPORPHYRIN DERIVATIVE(YHPD)

By the use of the advanced ESR technique and through comparing with BHPD, the characteristic of YHPD photosensitization is discussed in this paper in the respect of the primary process of photosensitization. The experiment results showed: （ⅰ） not only 1O2, but also free radicals（O2· OH and YHPD）can be formed by the aid of YHPD; and （ⅱ） as to the ability of producing 1O2, YHPD【BHPD, while for generating O2 and-OH, YHPD】BHPD. Two points are indicated: first, the photosensitized damage of YHPD is interrelated to not only 1O2, but also free radicals （O2. OH and YHPD）; second, although the photosensitized damage of YHPD is stronger than that of BHPD, yet the photosensitized damage is negatively correlated to the yield of 1O2 but positively correlated to those of O2 and OH. Based on these two points, it is suggested that activated oxygen free radicals（O2 and. OH） instead of 1O2 play the main role as instantaneously activated material in the photosensitized damage of YHPD.

Studying dynamic process of photosensitization by ESR method

By kinetic methods, functional relation of TAN radical, produced in the process of TEMPONE trapping O2, vs. time during photosensitization was established. Accordingly relative rate constants of generating all kinds of active intermediates through types I and II mechanism of photosensitization can be calculated. Using the formula and experimental results, the relative rate constants of generating O2, O2 and PS2 of three kinds of perylenequinone photosensitizer: HA, HB and CP in DMF-H20 and DMSO-H2O system were calculated, and then the structure-activity relationship of perylenequinone photosensitizer and the relation between photosensitivity and solvent was studied.

Characteristics of photosensitization of Pheophorbide a in liposomal media

Pheophorbide a （PPa）, a decomposition product of chlorophyll a, is a photosensitizer. The photosensitization mechanisms （Type Ⅰ and Type Ⅱ） of PPa in simple buffer solutions and in buffer solutions containing double-layered DPPC liposomes have been studied using techniques of ESR, spin-trapping, spin-counteraction and laser flash photolysis. The results showed that adding DPPC liposomes to the buffer solution caused an increase of efficiency of generating 1O2 and PPa- by photoactivating PPa. The increase could be ascribed to the disaggregation of hydrophobic PPa caused by the addition of liposomes and the protective effect of liposomal media on the triplet state of PPa. It is concluded that the photosensitization of PPa in liposomal systems is different from that in simple aqueous solutions, and shows higher efficacy. The results will be useful to elucidating the mechanisms of photodynamic therapy of cancer.

CHARACTERISTICS OF THE PRIMARY REACTION OF HYPOCRELLIN A PHOTOSENSITIZATION

The primary reaction of photosensitization of Hypocrellin A （HA） has been studied byusing techniques of ESR, spin-trapping and spin-counteraction. The experiments show thatHA is able to generate not only 1O2,but also O2-·OH and HA- which are observed for thefirst time. The conversion of generating active oxygen into generating nonoxygen free rad-ical is confirmed as well. Based on the characteristics of the primary reaction which gene-rates these active substances （transient products）, it is proposed that the photosensitized dam-age for the biological system by HA is probably related to not only 1O2 itself, but also amultiple effect from 1O2 as well as O2-,·OH and HA+ free radical.

Synthesis and Characterization of Novel Schiff Base for Enhanced Dye-Sensitized Solar Cell Photo-Response Mechanism

The efficient photo-response mechanism is one of the key factors in the commercialization of dye-sensitized solar cells in a bid to satisfy renewable energy demands. Progress in green technology has put solar energy on the front burner as a provider of clean and affordable energy for a sustainable society. We report the synthesis of a novel Schiff base with optical transparency in the visible and near IR region of the solar spectrum that can find application in the DSSCs photo-response mechanism. The synthesized crystal exhibited features that could handle some of the shortcomings of dye-sensitized solar cells which include wide band solar spectrum absorption and capability for swift charge transfer within the photoelectrodes. The synthesized Schiff base was characterized using x-ray diffractometer, UV/Visible spectrometer, Frontier transmission infrared spectrometer and conductometer. XRD data revealed the grown crystal to have an average crystallite size of 2.08 nm with average microstrain value of about 269.43. The FT-IR recorded transmission wave ѵ (CO) at 1207.7 cm−1 while dominant wave occurred at ѵ1654.9 and ѵ1592.3 cm−1 relating to ѵ (CN) stretching and ѵ (NH) bending respectively were observed. The IR spectrum revealed the bonding species and a probable molecular structure of 2,6-bis(benzyloxy)pyridine. The UV/Visible spectra convoluted to maximum peak within the near IR region suggesting that 2,6-bis(benzyloxy)pyridine can absorb both the visible and near IR region while its electrical conductivity was determined to be 4.58 µS/cm. The obtained result of the present study revealed promising characteristics of a photosensitizer that can find application in the photo-response mechanism of DSSCs.

Double-Stranded DNA Matrix for Photosensitization Switching

Photosensitization,originated from the activation of triplet states,is the basis of many photodynamic applications,but often competes with a series of nonradiative processes.Herein,we communicate a new function of double-stranded DNA(dsDNA)for label-free photosensitization switching.Up to∼70-fold singlet oxygen generation boosting was observed for SYBR Green I(SG)upon binding with dsDNA.Detailed photophysical and theoretical studies have revealed the role of dsDNA as a matrix,which could efficiently suppress the nonradiative transitions of SG.

Taming Reactive Oxygen Species:Mitochondria-Targeting Aggregation-Induced Emission Luminogen for Neuron Protection via Photosensitization-Triggered Autophagy

Oxidative damage to cells leads to accumulated harmful wastes,which in turn aggravate the imbalance of reactive oxygen species(ROS)and related diseases.Therefore,provoking the cellular defense system against severe oxidation and maintaining ROS homeostasis are desired.Herein,we designed and synthesized a powerful mitochondria-targeting aggregation-induced emission photosensitizer(named DTCSPY)by maximal restriction of heat dissipation.It is demonstrated that taming ROS generation within mitochondria through photosensitization-triggered autophagy via DTCSPY achieved a better neuroprotective effect against oxidative damages than Nacety-L-cysteine and vitamin C.This work not only provides a new way to design high-performance photosensitizers by regulating the photophysical property,but also verifies the concept that taming ROS can be used for cell protection against destructive oxidation,thereby displaying broad prospects for alleviating oxidation-related diseases and promoting cell-based therapy.

THE MOLECULAR MECHANISM OF PHOTOPORPHYRIN (YHPD)'S PHOTOSENSITIZATION——LASER RAMAN SPECTROSCOPIC STUDY OF MICROCOSMIC AND PHOTOSENSITIVE DAMAGE OF YHPD TO PROTEIN

Laser Raman spectroscopy was used to investigate the microcosmic and photosensitive damage of YHPD to lysozyme, of which the three-dimensional structure has been elucidated. The experimental results shown by various damages of the main-chain and side-chain of lysozyme are as follows: (ⅰ) Phe and Cys are also damaged by photosensitization of YHPD, except for Trp, Tyr, Met, 1/2Cys and His; (ⅱ) the order of the photosensitized sensitivity of various groups of these amino acids have been described; (ⅲ) Trp and Tyr buried in the three-dimensional structure of the protein are damaged very greatly, and (ⅳ) the main-chain conformation of the protein has changed considerably, such as a decrease in orderly structure (α-helix, β-sheet and β-turn) and a simultaneous increase in random coil.

Fine-mapping and transcriptome analysis of the photosensitive leaf-yellowing gene CaLY1 in pepper(Capsicum annuum L.)

Leaf color is directly related to altered photosynthesis.Hence,leaf yellowing mutants can be widely used for the researching plant physiology and functional genomes,for cultivating new varieties of popular horticultural plants,and for identifying hybrid purity(as markers).Here,we constructed a^(60)Co-γF_(2)population from the leaf-yellowing mutant R24 via radiation mutation with the inbred line WT21 of pepper.Genetic analysis showed that the leaf-yellowing of the mutant was controlled by a single recessive gene.By applying the Bulk Segregation Analysis and Kompetitive Allele Specific PCR markers,the leaf-yellowing gene CaLY1(Capsicum annuum Leaf yellow 1)was mapped on chromosome 9,SNP5791587-SNP6011215,with a size of 214.5 kb.One non-synonymous mutated gene Capana09g000166 was found in the interval.The gene encoded a Psb X,which is the core complex of PSⅡ.Transcriptome analysis further showed that 2301 differentially expressed genes were identified under shading treatment for 24 h in R24.The Gene Ontology enrichment pathways were related to photosynthesis light harvesting,cell wall,activity of quercetin 3-O-glucosyltransferase and flavonoid metabolic process,which likely regulate the response of pepper leaves to different light levels.Functional enrichment analysis indicated that the most abundant pathways were photosynthesis antenna proteins and metabolic.

Passivation engineering via silica‐encapsulated quantum dots for highly sensitive photodetection

Organometal halide perovskites are promising semiconducting materials for photodetectors because of their favorable optoelectrical properties.Although nanoscale perovskite materials such as quantum dots(QDs)show novel behavior,they have intrinsic stability issues.In this study,an effectively silane barrier-capped quantum dot(QD@APDEMS)is thinly applied onto a bulk perovskite photosensitive layer for use in photodetectors.QD@APDEMS is synthesized with a silane ligand with hydrophobic CH_(3)-terminal groups,resulting in excellent dispersibility and durability to enable effective coating.The introduction of the QD@APDEMS layer results in the formation of a lowdefect perovskite film with enlarged grains.This is attributed to the grain boundary interconnection effect via interaction between the functional groups of QD@APDEMS and uncoordinated Pb^(2+)in grain boundaries.By passivating the grain boundaries,where various trap sites are distributed,hole chargecarrier injection and shunt leakage can be suppressed.Also,from the energy point of view,the deep highest occupied molecular orbital(HOMO)level of QD@APDEMS can work as a hole charge injection barrier.Improved charge dynamics(generation,transfer,and recombination properties)and reduced trap density of QD@APDEMS are demonstrated.When this perovskite film is used in a photodetector,the device performance(especially the detectivity)stands out among existing perovskites evaluated for energy sensing device applications.

Photodynamic therapy with TBZPy regulates the PI3K/AKT and endoplasmic reticulum stress-related PERK/eIF2α pathways in HeLa cells

Background:((1-triphenylaminebenzo[c][1,2,5]thiadiazole-4-yl)styryl)-1-methylpyridin methylpyridin-1-ium iodide salt(TBZPy)is a novel photosensitizer that displays excellent photodynamic properties.However,There are few reports on the mechanism of action of the TBZPy photodynamic.Previous studies revealed that photodynamic therapy(PDT)could induce endoplasmic reticulum stress by acting on the endoplasmic reticulum.Therefore,in this study,we investigated the effects of endoplasmic reticulum stress induced by TBZPy-PDT in treating High-risk human papillomavirus(HR-HPV)infection and their underlying mechanisms.Methods:The human cervical cancer cell line HeLa(containing whole genome of HR-HPV18)was treated with TBZPy-PDT.Cell migration,invasion,and colony-forming ability were evaluated using wound-healing,Transwell invasion,and colonyforming assays,respectively.Through western blot analysis,we determined the level of expression of the PI3K/AKT and PERK/eIF2αpathway proteins and the proteins associated with calcium trafficking and apoptosis.The calcium levels in the cytoplasm were detected via flow cytometry.Results:The result shows that TBZPy-PDT could inhibite the migration,invasion,and colony forming ability of infected HeLa cells by downregulating the PI3K/AKT pathway in vitro.And we found that TBZPy-PDT induced endoplasmic reticulum stress-specific apoptosis via the PERK/eIF2αpathway.Moreover,TBZPy-PDT increased the levels of calcium and calmodulin,while decreasing the levels of endoplasmic reticulum calcium-binding proteins.Conclusions:TBZPy-PDT is effective on treating human papillomavirus-infected cells.Targeting the PI3K/AKT and PERK/eIF2αpathways and the endoplasmic reticulum stress process may help improve the effects of TBZPy-PDT for treating high-risk human papillomavirus infection.

3D printing of high-precision and ferromagnetic functional devices

The development of projection-based stereolithography additive manufacturing techniques and magnetic photosensitive resins has provided a powerful approach to fabricate miniaturized magnetic functional devices with complex three-dimensional spatial structures.However,the present magnetic photosensitive resins face great challenges in the trade-off between high ferromagnetism and excellent printing quality.To address these challenges,we develop a novel NdFeB-Fe_(3)O_(4) magnetic photosensitive resin comprising 20 wt.%solid loading of magnetic particles,which can be used to fabricate high-precision and ferromagnetic functional devices via micro-continuous liquid interface production process.This resin combining ferromagnetic NdFeB microparticles and strongly absorbing Fe_(3)O_(4) nanoparticles is able to provide ferromagnetic capabilities and excellent printing quality simultaneously compared to both existing soft and hard magnetic photosensitive resins.The established penetration depth model reveals the effect of particle size,solid loading,and absorbance on the curing characteristics of magnetic photosensitive resin.A high-precision forming and ferromagnetic capability of the NdFeB-Fe_(3)O_(4) magnetic photosensitive resin are comprehensively demonstrated.It is found that the photosensitive resin(NdFeB:Fe_(3)O_(4)=1:1)can print samples with sub-40μm fine features,reduced by 87%compared to existing hard magnetic photosensitive resin,and exhibits significantly enhanced coercivity and remanence in comparison with existing soft magnetic photosensitive resins,showing by an increase of 24 times and 6 times,respectively.The reported NdFeB-Fe_(3)O_(4) magnetic photosensitive resin is anticipated to provide a new functional material for the design and manufacture of next-generation micro-robotics,electromagnetic sensor,and magneto-thermal devices.

Advances in photodynamic therapy for port-wine stain and our experience

Port-wine stain(PWS)is a congenital capillary malformation that occurs in 0.3%–0.5%of newborns.The pulsed dye laser is the current gold standard treatment for PWS;however,its efficacy is poor.Photosensitizer photodynamic therapy(PDT)is considered a promising treatment for PWS.Here we provide a comprehensive overview of PDT.

Imaging assessment of photosensitizer emission induced by radionuclide-derived Cherenkov radiation using charge-coupled device optical imaging and long-pass filters

BACKGROUND Radionuclides produce Cherenkov radiation(CR),which can potentially activate photosensitizers(PSs)in phototherapy.Several groups have studied Cherenkov energy transfer to PSs using optical imaging;however,cost-effectively identifying whether PSs are excited by radionuclide-derived CR and detecting fluorescence emission from excited PSs remain a challenge.Many laboratories face the need for expensive dedicated equipment.AIM To cost-effectively confirm whether PSs are excited by radionuclide-derived CR and distinguish fluorescence emission from excited PSs.METHODS The absorbance and fluorescence spectra of PSs were measured using a microplate reader and fluorescence spectrometer to examine the photo-physical properties of PSs.To mitigate the need for expensive dedicated equipment and achieve the aim of the study,we developed a method that utilizes a chargecoupled device optical imaging system and appropriate long-pass filters of different wavelengths(manual sequential application of long-pass filters of 515,580,645,700,750,and 800 nm).Tetrakis(4-carboxyphenyl)porphyrin(TCPP)was utilized as a model PS.Different doses of copper-64(^(64)CuCl_(2))(4,2,and 1 mCi)were used as CR-producing radionuclides.Imaging and data acquisition were performed 0.5 h after sample preparation.Differential image analysis was conducted by using ImageJ software(National Institutes of Health)to visually evaluate TCPP fluorescence.RESULTS The maximum absorbance of TCPP was at 390-430 nm,and the emission peak was at 670 nm.The CR and CRinduced TCPP emissions were observed using the optical imaging system and the high-transmittance long-pass filters described above.The emission spectra of TCPP with a peak in the 645-700 nm window were obtained by calculation and subtraction based on the serial signal intensity(total flux)difference between^(64)CuCl_(2)+TCPP and^(64)CuCl_(2).Moreover,the differential fluorescence images of TCPP were obtained by subtracting the^(64)CuCl_(2)image from the^(64)CuCl_(2)+TCPP image.The experimental results considering different^(64)CuCl_(2)doses showed a dosedependent trend.These results demonstrate that a bioluminescence imaging device coupled with different longpass filters and subtraction image processing can confirm the emission spectra and differential fluorescence images of CR-induced TCPP.CONCLUSION This simple method identifies the PS fluorescence emission generated by radionuclide-derived CR and can contribute to accelerating the development of Cherenkov energy transfer imaging and the discovery of new PSs.

Design of Intelligent Agricultural Greenhouse Environment Monitoring System

Aiming at the problem of greenhouse environmental information collection in agricultural production,this paper designs a greenhouse monitoring system based on STM32 microcontroller.The system uses STM32F103 series MCU as the main control unit,which is used to receive the detection results of the sensor.The host computer software displays and processes the monitoring data.The temperature and humidity sensors monitor air temperature and humidity.The capacitive soil moisture detection sensor monitors soil moisture.The carbon dioxide sensor monitors the concentration of carbon dioxide.The photosensitive sensor monitors light intensity.This design has low hardware cost and high data acquisition accuracy,which can be applied to the actual greenhouse agricultural production and has wide practicability.