Long-wavelength Visible Light Research Articles

Cs-Doped WO3 with Enhanced Conduction Band for Efficient Photocatalytic Oxygen Evolution Reaction Driven by Long-Wavelength Visible Light.

Cesium doped WO3 (Cs-WO3) photocatalyst with high and stable oxidation activity was successfully synthesized by a one-step hydrothermal method using Cs2CO3 as the doped metal ion source and tungstic acid (H2WO4) as the tungsten source. A series of analytical characterization tools and oxygen precipitation activity tests were used to compare the effects of different additions of Cs2CO3 on the crystal structure and microscopic morphologies. The UV-visible diffuse reflectance spectra (DRS) of Cs-doped material exhibited a significant red shift in the absorption edge with new shoulders appearing at 440-520 nm. The formation of an oxygen vacancy was confirmed in Cs-WO3 by the EPR signal, which can effectively regulate the electronic structure of the catalyst surface and contribute to improving the activity of the oxygen evolution reaction (OER). The photocatalytic OER results showed that the Cs-WO3-0.1 exhibited the optimal oxygen precipitation activity, reaching 58.28 µmol at 6 h, which was greater than six times higher than that of WO3-0 (9.76 μmol). It can be attributed to the synergistic effect of the increase in the conduction band position of Cs-WO3-0.1 (0.11 V) and oxygen vacancies compared to WO3-0, which accelerate the electron conduction rate and slow down the rapid compounding of photogenerated electrons-holes, improving the water-catalytic oxygen precipitation activity of WO3.

Towards Optical Information Recording: A Robust Visible-Light-Driven Molecular Photoswitch with the Ring-Closure Reaction Yield Exceeding 96.3 .

Diarylethene molecular photoswitches hold great fascination as optical information materials due to their unique bistability and exceptional reversible photoswitching properties. Conventional diarylethenes, however, rely on UV light for ring-closure reactions, typically with modest yields. For practical application, diarylethenes driven by visible lights are preferred but achieving high ring-closure reaction yield remains a significant challenge. Herein, we synthesized a novel all-visible-light-driven photoswitch, TPAP-DTE, by facilely endcapping the dithienylethene (DTE) core with triphenylamine phenyl (TPAP) groups. Owing to the electron-donating conjugation effect of TPAP, the open-form TPAP-DTE responds strongly to short-wavelength visible lights with considerable photocyclization quantum yields and molar absorption coefficient. Upon 405 nm visible-light irradiation, TPAP-DTE achieves a ring-closure reaction yield exceeding 96.3 % (confirmed by both nuclear magnetic resonance spectroscopy and high-performance liquid chromatography). Its ring-opening reaction yield is 100 % upon irradiation with long-wavelength visible light. TPAP-DTE could be regarded as a bidirectional "quasi"-quantitative conversion molecular switch. Furthermore, TPAP-DTE exhibits robust fatigue resistance over 100 full photoswitching cycles and great anti-aging property under 85 °C and 85 % humidity for at least 1000 h. Consequently, its rewritable QR-code, multilevel data storage, and anti-counterfeiting/encryption applications are successfully demonstrated exclusively using visible lights, positioning TPAP-DTE as a highly promising medium for information recording.

Red anatase TiO2 microspheres with exposed major {0 0 1} facets and boron-stabilized hydrogen-occupied oxygen vacancies for visible-light-responsive water oxidation

In pursuit of efficient solar energy to chemical energy conversion through band engineering of wide-bandgap photocatalysts such as TiO2, a compromise occurs between a narrow bandgap and high-redox-capacity photo-induced charge carriers, which impairs the potential advantages associated with the widened absorption range. The key to this compromise is an integrative modifier that can simultaneously modulate both the bandgap and band edge positions. Herein, we theoretically and experimentally demonstrate that oxygen vacancies occupied by boron-stabilized hydrogen pairs (OVBH) serve as an integrative band modifier. Compared to hydrogen-occupied oxygen vacancies (OVH), which require the aggregation of nanosized anatase TiO2 particles, oxygen vacancies coupled with boron (OVBH) can be easily introduced into large and highly crystalline TiO2 particles, as shown by density functional theory (DFT) calculations. The coupling with interstitial boron facilitates the introduction of paired hydrogen atoms. The red-colored {001} faceted anatase TiO2 microspheres with OVBH benefit from the narrowed bandgap of 1.84 eV and the down-shifted band position. These microspheres not only absorb long-wavelength visible light up to 674 nm but also enhance visible-light-driven photocatalytic oxygen evolution.

Zr-doped BaTaO2N photocatalyst modified with Na–Pt cocatalyst for efficient hydrogen evolution and Z-scheme water splitting

Detailed investigation of photocatalysts, cocatalysts and redox mediators provides a Z-scheme overall water splitting system operating under long-wavelength visible light.

Synthesis of Narrow-Band-Gap GaN:ZnO Solid Solution for Photocatalytic Overall Water Splitting

The solid solution of GaN and ZnO (GaN:ZnO) is a promising photocatalyst applicable to visible-light-driven overall water splitting. However, the band gap of active GaN:ZnO remains as large as ca. 2.7 eV because of the loss of ZnO during the widely applied NH3 nitridation process. Herein, particulate GaN:ZnO exhibiting a band gap of 2.3 eV was synthesized via calcination of a mixture of Ga2O3, Zn, and NH4Cl in a sealed evacuated tube. The synthesis method was also featured with a high nitrogen utilization rate of 87%. The prepared narrow-band-gap GaN:ZnO was active in the overall water-splitting reaction. In the presence of sacrificial reagents, the apparent quantum yields of GaN:ZnO at 420 nm for H2 and O2 generation were 5.1 and 14.3%, respectively. GaN:ZnO was applied as an oxygen evolution photocatalyst to construct a Z-scheme overall water-splitting system with SrTiO3:Rh as a hydrogen evolution photocatalyst, which achieved a solar-to-hydrogen energy conversion efficiency of 3.7 × 10–2% and a remarkable photochemical stability up to 100 h. This work provides an approach to the synthesis of narrow-band-gap GaN:ZnO solid solution and shows the potential of this material in H2 production from water under long-wavelength visible light.

Optogenetic restoration of high sensitivity vision with bReaChES, a red-shifted channelrhodopsin

The common final pathway to blindness in many forms of retinal degeneration is the death of the light-sensitive primary retinal neurons. However, the normally light-insensitive second- and third-order neurons persist optogenetic gene therapy aims to restore sight by rendering such neurons light-sensitive. Here, we investigate whether bReaChES, a newly described high sensitivity Type I opsin with peak sensitivity to long-wavelength visible light, can restore vision in a murine model of severe early-onset retinal degeneration. Intravitreal injection of an adeno-associated viral vector carrying the sequence for bReaChES downstream of the calcium calmodulin kinase IIα promoter resulted in sustained retinal expression of bReaChES. Retinal ganglion cells (RGCs) expressing bReaChES generated action potentials at light levels consistent with bright indoor lighting (from 13.6 log photons cm−2 s−1). They could also detect flicker at up to 50 Hz, which approaches the upper temporal limit of human photopic vision. Topological response maps of bReaChES-expressing RGCs suggest that optogenetically activated RGCs may demonstrate similar topographical responses to RGCs stimulated by photoreceptor activation. Furthermore, treated dystrophic mice displayed restored cortical neuronal activity in response to light and rescued behavioral responses to a looming stimulus that simulated an aerial predator. Finally, human surgical retinal explants exposed to the bReaChES treatment vector demonstrated transduction. Together, these findings suggest that intravitreal gene therapy to deliver bReaChES to the retina may restore vision in human retinal degeneration in vivo at ecologically relevant light levels with spectral and temporal response characteristics approaching those of normal human photopic vision.

Magnetoreceptory Function of European Robin Retina: Electrophysiological and Morphological Non-Homogeneity.

The avian magnetic compass allows orientation during migration and is shown to function properly under short-wavelength but not long-wavelength visible light. Therefore, the magnetoreceptive system is assumed to be light- and wavelength-dependent and localized in the retina of the eye. Putative candidates for the role of primary magnetosensory molecules are the cryptochromes that are known to be expressed in the avian retina and must be able to interact with phototransduction proteins. Previously, we reported that in migratory birds change in magnetic field direction induces significant effects on electroretinogram amplitude in response to blue flashes, and such an effect was observed only in the nasal quadrant of the retina. Here, we report new electroretinographic, microscopic and microspectrophotometric data on European robins, confirming the magnetosensitivity of the retinal nasal quadrant after applying the background illumination. We hypothesized that magnetoreceptive distinction of this region may be related to its morphology and analyzed the retinal distribution and optical properties of oil droplets, the filtering structures within cones. We found that the nasal quadrant contains double cones with the most intensely colorized oil droplets compared to the rest of the retina, which may be related to its magnetosensory function.

Novel Method for Fabricating Visible-Light Phototransistors Based on a Homojunction-Porous IGZO Thin Film Using Mechano-Chemical Treatment.

A homojunction-structured oxide phototransistor based on a mechano-chemically treated indium-gallium-zinc oxide (IGZO) absorption layer is reported. Through this novel and facile mechano-chemical treatment, mechanical removal of the cellophane adhesive tape induces reactive radicals and organic compounds on the sputtered IGZO film surface. Surface modification, following the mechano-chemical treatment, caused porous sites in the solution-processed IGZO film, which can give rise to a homojunction-porous IGZO (HPI) layer and generate sub-gap states from oxygen-related defects. These intentionally generated sub-gap states played a key role in photoelectron generation under illumination with relatively long-wavelength visible light despite the wide band gap of IGZO (>3.0 eV). Compared with conventional IGZO phototransistors, our HPI phototransistor displayed outstanding optoelectronic characteristics and sensitivity; we measured a threshold voltage (Vth) shift from 3.64 to -6.27 V and an on/off current ratio shift from 4.21 × 1010 to 4.92 × 102 under illumination with a 532 nm green light of 10 mW/mm2 intensity and calculated a photosensitivity of 1.16 × 108. The remarkable optoelectronic characteristics and high optical transparency suggest optical sensor applications.

Conjugated Cross-linked Phenothiazines as Green or Red Light Heterogeneous Photocatalysts for Copper-Catalyzed Atom Transfer Radical Polymerization.

Using the power of light to drive controlled radical polymerizations has provided significant advances in synthesis of well-defined polymers. Photoinduced atom transfer radical polymerization (ATRP) systems often employ UV light to regenerate copper activator species to mediate the polymerization. Taking full advantage of long-wavelength visible light for ATRP would require developing appropriate photocatalytic systems that engage in photoinduced electron transfer processes with the ATRP components to generate activating species. Herein, we developed conjugated microporous polymers (CMP) as heterogeneous photocatalysts to exploit the power of visible light in promoting copper-catalyzed ATRP. The photocatalyst was designed by cross-linking phenothiazine (PTZ) as a photoactive core in the presence of dimethoxybenzene as a cross-linker via the Friedel-Crafts reaction. The resulting PTZ-CMP network showed photoactivity in the visible region due to the extended conjugation throughout the network because of the aromatic groups connecting the PTZ units. Therefore, photoinduced copper-catalyzed ATRP was performed with CMPs that regenerated activator species under green or red light irradiation to start the ATRP process. This resulted in efficient polymerization of acrylate and methacrylate monomers with high conversion and well-controlled molecular weight. The heterogeneous nature of the photocatalyst enabled easy separation and efficient reusability in subsequent polymerizations.

Photoluminescence Properties of Copolyimides Containing Naphthalene Core and Analysis of Excitation Energy Transfer between the Dianhydride Moieties

The photoluminescence (PL) properties of semi-aromatic polyimide (PI) films and their model compounds (MCs) prepared from dianhydrides having a rigid naphthalene core were analyzed. The PMMA-dispersed MC and copolymerized PI (CoPI) films derived from 2,3,6,7-naphthalenetetracarboxylic dianhydride (NTDA) exhibited long-lived phosphorescence owing to the suppression of molecular motion by the rigidity of a naphthalene core. Additionally, the PMMA-dispersed MC and the CoPI films derived from 1,5-dibromo derivative of NTDA (DBrNT) exhibited room-temperature phosphorescence due to the enhancement of spin-orbit coupling by bromine atoms. The photophysical processes of the CoPI films prepared from NTDA/DBrNT and 4,4'-oxydiphtalic dianhydride (ODPA) in which the latter absorption band is located at a shorter wavelength than the former were analyzed. After UV irradiation, efficient excitation energy transfer occurs from the ODPA to NTDA/DBrNT moieties, and only the emission from the latter moieties was observed. These results demonstrate that the CoPI films derived from two dianhydrides absorbing different UV wavelengths can be used as spectral conversion films that convert a wide range of UV-light into longer wavelength visible light.

Oxygen Evolution Activity of LaNbN2O-Based Photocatalysts Obtained from Nitridation of a Precursor Oxide Structurally Modified by Incorporating Volatile Elements

The perovskite-type oxynitride LaNbN2O is a photocatalyst that can evolve oxygen from aqueous solutions in response to long-wavelength visible light. However, it is challenging to obtain active LaNbN2O because of the facile reduction of Nb5+ during the nitridation of the precursor materials. The present study attempted to synthesize a perovskite-type oxide La0.6Na0.4Zn0.4Nb0.6O3, containing equimolar amounts of La3+ and Nb5+ in addition to volatile Na+ and Zn2+, followed by the nitridation of this oxide to generate LaNbN2O. The obtained oxide was not the intended single-phase material but rather comprised a cuboid perovskite-type oxide similar to La0.5Na0.5Zn0.33Nb0.67O3 along with spherical LaNbO4 particles and other impurities. A brief nitridation was found to form a LaNbN2O-like shell structure having a light absorption onset of approximately 700 nm on the cuboid perovskite-type oxide particles. This LaNbN2O-based photocatalyst, when loaded with a CoOx cocatalyst, exhibited an apparent quantum yield of 1.7% at 420 nm during oxygen evolution reaction from an aqueous AgNO3 solution. This was more than double the values obtained from the nitridation products of LaNbO4 and LaKNaNbO5. The present work demonstrates a new approach to the design of precursor oxides that yield highly active LaNbN2O and suggests opportunities for developing efficient Nb-based perovskite oxynitride photocatalysts.

Double Insurance of Continuous Band Structure and N-C Layer Induced Prolonging of Carrier Lifetime to Enhance the Long-Wavelength Visible-Light Catalytic Activity of N-Doped In2O3.

Nonmetallic doped metal oxides can be broad in their visible-light-response range. However, the half-filled or isolated impurity state can also be the new recombination center for photogenerated electrons/holes, which seriously influence the photocatalytic activity of the catalyst in the visible-light region. Therefore, how to prolong the photogenerated carrier life of nonmetallic doping metal oxides is the difficult and challenging topic in the field of photocatalysis. In this work, the hexagonal nanosheets assembled by N-doped C (N-C)-coated N-doped In2O3 (N-In2O3) nanoparticles (N-C/N-In2O3 HS) was obtained by simply pyrolyzing the In(2,5-PDC) hexagonal sheets. The N-C/N-In2O3 HS catalyst exhibit good photocatalytic activity and cycle stability in the long-wavelength region of visible light (λ = 520 and 595 nm). The effective utilization of long-wavelength visible light for N-C/N-In2O3 HS was mainly attributed to the acceptor-donor-acceptor compensation mechanism between the oxygen vacancy (VO) and substitutional N-doping (Ns) sites, which made the N-C/N-In2O3 HS possess a continuous band structure, without the half-filled or isolated impurity state in the band gap, and extended its light absorption edge to 733 nm. The compensation mechanism of nitrogen doping on In2O3 can promote the photocatalytic activity under longer-wavelength yellow light (595 nm) irradiation. The N-C layer coated on the N-In2O3 nanoparticles acted as a good acceptor of photogenerated electrons, facilitating the effective spatial separation of photogenerated carriers and extend photogenerated carrier lifetimes. The comparative photocatalytic experiments (N-In2O3 HS and N-C/N-In2O3 HS) show that the presence of N-doped C layer can enhance the photocatalytic efficiency by nearly 10-fold. This double-doping and carbon-coating strategy provided a novel research idea to solve the problem that nonmetal atoms doped metal oxides led to the secondary combination of photogenerated electrons/holes.

Controlled Photodynamic Action of Axial Fluorinated DiethoxyP(V)tetrakis(p-methoxyphenyl)porphyrin through Self-Aggregation.

DiethoxyP(V)tetrakis(p-methoxyphenyl)porphyrin (EtP(V)TMPP) and its fluorinated derivative (FEtP(V)TMPP) were synthesized to examine their photodynamic action. These P(V)porphyrins were aggregated in an aqueous solution, resulting in the suppression of their photodynamic activity. In the presence of human serum albumin (HSA), a water-soluble protein, the aggregation states were resolved and formed a binding complex between P(V)porphyrin and HSA. These P(V)porphyrins photosensitized the oxidation of the tryptophan residue of HSA under the irradiation of long-wavelength visible light (>630 nm). This protein photodamage was explained by the electron transfer from tryptophan to the photoexcited state of P(V)porphyrins and singlet oxygen generation. The axial fluorination reduced the redox potential of the one-electron reduction of P(V)porphyrin and increased the electron transfer rate constant. However, this axial fluorination decreased the binding constant with HSA, and the quantum yield of photosensitized HSA damage through electron transfer was decreased. The photocytotoxicity of these P(V)porphyrins to HaCaT cells was also confirmed, and FEtP(V)TMPP demonstrated stronger phototoxicity than EtP(V)TMPP. In summary, a self-aggregation of porphyrin photosensitizers and resolving by targeting biomacromolecules may be used to target selective photodynamic action. The redox potential and an association with a targeting biomolecule are the important factors of the electron transfer-mediated mechanism, which is advantageous under hypoxic tumor conditions.

Vis-NIR responsive Bi24O31Br10 and corresponding composite with up-conversion phosphor towards efficient photocatalytic oxidation

Abstract In this work, series of Bi24O31Br10 semiconductors were respectively synthesized by precipitation, solvothermal and calcination methods to explore the influence of preparation methods on the photocatalytic performances of photocatalysts. The refractory antibiotics (CIP and TC) and low concentration of continuous flowing NO gas were used as photocatalytic targets with the irradiation of visible or NIR lights. Interestingly, Bi24O31Br10 fabricated by a simple room-temperature precipitation method (BOB-R) exhibited the best photocatalytic activity compared to the other two samples with high cost preparation. The characterizations and trapping experiments verified that the smaller nanoparticles, oxygen vacancy concentration, band structure and charge combination probability were contributed to the superior photocatalytic performance of Bi24O31Br10 prepared by precipitation method. Besides, due to the generation of oxygen vacancies, BOB-R sample not only showed excellent removal efficiency of NO by UV and short-wavelength visible light, but also had considerable photocatalytic activity induced by long-wavelength visible light (λ > 510 nm). To further broaden the range of light response to near-infrared light, the up-conversion phosphors were used to couple with BOB-R sample at room temperature. The up-conversion phosphors/BOB-R composites exhibited good UV light, short-wavelength and long-wavelength visible lights caused photocatalytic removal of NO, meanwhile valuable NIR light driven performance was found.

Copolymerization Approach to Improving Ru(II)-Complex/C3N4 Hybrid Photocatalysts for Visible-Light CO2 Reduction

Copolymerized carbon nitride nanosheets (NS-C3N4) were used as a light absorbing unit while paired with a Ru(II) complex that served as a catalyst for CO2 reduction, forming a hybrid photocatalytic system. Copolymerization with urea and phenylurea in air at 823 K resulted in a carbon nitride material that had wide visible light absorption extending to 650 nm, significantly red-shifted compared to the absorption edge of pristine NS-C3N4, an analogue prepared with only urea (ca. 435 nm). While a hybrid system consisting of pristine NS-C3N4 was found to be inactive under longer wavelength visible light (λ > 500 nm) due to its large band gap, the copolymerized material was able to catalytically convert CO2 to HCOOH under λ > 500 nm irradiation. Furthermore, its activity toward HCOOH production is doubled under λ > 400 nm irradiation after 5 h compared to pristine NS-C3N4. Transient absorption spectroscopy clearly showed improved lifetime of photogenerated free (and/or shallowly trapped) electrons, which shoul...

Effects of Bright Light with Reduced Blue Light on Sleepiness on Rising: A Small Exploratory Study.

Bright light therapy is a treatment modality for seasonal affective disorder and circadian rhythm disorders in which artificial light of 2,500 lux or higher at the eye is effective. Although short-wavelength visible light is more effective than long-wavelength visible light, it may be hazardous to the retina. Recently, light-emitting diodes (LEDs) have been used as the light source in bright light therapy apparatuses. We developed goggles for bright light therapy equipped with LEDs as the light source. The aim of this study was to examine the efficacy and safety of our goggles when emitting 10,000-lux light with its short-wavelength light content reduced by 30% or 50% (denoted as 30%-cut and 50%-cut light, respectively, henceforth). Six healthy young males participated in this study. They were administered no light, 50%-cut light, and 30%-cut light for 30 min early in the morning for 4 days each. Subjective sleepiness and sleep quality were evaluated by the Stanford Sleepiness Scale (SSS) and the Oguri–Shirakawa–Azumi sleep inventory MA version (OSA-MA), respectively. Subjective sleepiness evaluated by the SSS and the subscale of the OSA-MA significantly decreased with 30%-cut light compared with no light. Psychomotor performance evaluated by a calculation task improved with the 30%-cut light, although not significant after multiple comparisons were considered. No abnormality was found by ophthalmoscopy and the vision test. In conclusion, our goggles with 30%-cut light may be safe and have an awakening effect.

Synergistic effects of long-wavelength ultraviolet A1 and visible light on pigmentation and erythema

SummaryBackground Visible light (VL) induces multiple cutaneous effects. Sunscreen testing protocols recommended by regulatory bodies throughout the world require the use of solar simulators with spectral output in ultraviolet (UV) domain only. However, sunlight contains VL and infrared radiation also. Objective This study aimed to evaluate the contributions of VL and UVA on pigmentation and erythema, and optimize parameters for in-vivo testing. Methods Ten subjects with Fitzpatrick skin phototype IV-VI were enrolled. Subjects were irradiated on their back with VL using two light sources: one containing pure VL and one containing VL with less than 0.5% UVA1 (VL+UVA1). Four different irradiances were administered to investigate reciprocity behaviour. Assessments, including photography, investigator's global assessment, colorimetry, and spectroscopy, were performed immediately, 24 hours, 7 days and 14 days post-irradiation. Results Pigmentation was observed with both light sources; however, pigment intensity was greater with VL+UVA1 than pure VL. Reciprocity was observed in pure VL sites, but not VL+UVA1. Variation in spectral output had greater impact on pigment intensity than irradiance. Clinical erythema was observed on the VL+UVA1 side, but not on the pure VL side. Protocol for testing photoprotection product efficacy against VL induced effects has been proposed. Conclusions The findings suggest a synergistic relationship between VL and UVA1 and emphasize the need for developing means of photoprotection against VL. This article is protected by copyright. All rights reserved.

Correction to Dinuclear PhotoCORMs: Dioxygen-Assisted Carbon Monoxide Uncaging from Long-Wavelength-Absorbing Metal-Metal-Bonded Carbonyl Complexes.

We describe a new strategy for triggering the photochemical release of caged carbon monoxide (CO) in aerobic media using long-wavelength visible and near-infrared (NIR) light. The dinuclear rhenium–manganese carbonyl complexes (CO)5ReMn(CO)3(L), where L = phenanthroline (1), bipyridine (2), biquinoline (3), or phenanthrolinecarboxaldehyde (4), each show a strong metal–metal-bond-to-ligand (σMM → πL*) charge-transfer absorption band at longer wavelengths. Photolysis with deep-red (1 and 2) or NIR (3 and 4) light leads to homolytic cleavage of the Re–Mn bonds to give mononuclear metal radicals. In the absence of trapping agents, these radicals primarily recombine to reform dinuclear complexes. In oxygenated media, however, the radicals react with dioxygen to form species much more labile toward CO release via secondary thermal and/or photochemical reactions. Conjugation of 4, with an amine-terminated poly(ethylene glycol) oligomer, gives a water-soluble derivative with similar photochemistry. In this contex...

Photosensitized Protein-Damaging Activity, Cytotoxicity, and Antitumor Effects of P(V)porphyrins Using Long-Wavelength Visible Light through Electron Transfer.

Photodynamic therapy (PDT) is a less-invasive treatment for cancer through the administration of less-toxic porphyrins and visible-light irradiation. Photosensitized damage of biomacromolecules through singlet oxygen (1O2) generation induces cancer cell death. However, a large quantity of porphyrin photosensitizer is required, and the treatment effect is restricted under a hypoxic cellular condition. Here we report the phototoxic activity of P(V)porphyrins: dichloroP(V)tetrakis(4-methoxyphenyl)porphyrin (CLP(V)TMPP), dimethoxyP(V)tetrakis(4-methoxyphenyl)porphyrin (MEP(V)TMPP), and diethyleneglycoxyP(V)tetrakis(4-methoxyphenyl)porphyrin (EGP(V)TMPP). These P(V)porphyrins damaged the tryptophan residue of human serum albumin (HSA) under the irradiation of long-wavelength visible light (>630 nm). This protein photodamage was barely inhibited by sodium azide, a quencher of 1O2. Fluorescence lifetimes of P(V)porphyrins with or without HSA and their redox potentials supported the electron-transfer-mediated oxidation of protein. The photocytotoxicity of these P(V)porphyrins to HeLa cells was also demonstrated. CLP(V)TMPP did not exhibit photocytotoxicity to HaCaT, a cultured human skin cell, and MEP(V)TMPP and EGP(V)TMPP did; however, cellular DNA damage was barely observed. In addition, a significant PDT effect of these P(V) porphyrins on a mouse tumor model comparable with the traditional photosensitizer was also demonstrated. These findings suggest the cancer selectivity of these P(V)porphyrins and lower carcinogenic risk to normal cells. Electron-transfer-mediated oxidation of biomacromolecules by P(V)porphyrins using long-wavelength visible light should be advantageous for PDT of hypoxic tumor.

Far-red light-mediated programmable anti-cancer gene delivery in cooperation with photodynamic therapy

Effective anti-cancer therapy is hurdled by the complicated extracellular and intracellular barriers, and thus a smart gene vector that can enable programmable gene delivery is highly demanded. Photo-manipulation of gene delivery processes features spatial and temporal precision, while majority of current strategies utilizes short-wavelength UV/visible light with poor tissue penetration or high-power-density near-infrared (NIR) light that would cause undesired heat damage. Herein, an ROS-degradable polycation was designed and co-delivered with a photosensitizer (PS), thus realizing photo-programmable gene delivery using far-red light (661 nm) at low optical power density (down to 5 mW cm−2). Thioketal-crosslinked polyethylenimine (TK-PEI) was synthesized to condense p53 gene to form nanocomplexes (NCs), and hyaluronic acid (HA) modified with pheophytin a (Pha) was coated onto NCs to enhance their colloidal stability and enable cancer cell targeting. Short-time (8-min) light irradiation produced non-lethal amount of ROS to disrupt the endosomal membranes and facilitate p53 gene release via degradation of TK-PEI, which collectively enhanced p53 expression levels toward anti-cancer gene therapy. Long-time (30-min) light irradiation at the post-transfection state generated lethal amount of ROS, which cooperatively killed cancer cells to strengthen p53 gene therapy. To the best of our knowledge, this study represents the first example of an “one stone, three birds” approach to realize cooperative anti-cancer gene therapy using low-power-density, long-wavelength visible light as a single stimulus.