Photosensitive System Research Articles

Photosensitive siRNA delivery system based on water-soluble fullerene

Photosensitive siRNA delivery system based on water-soluble fullerene

Capturing Structural Snapshots during Photochemical Reactions with Ultrafast Raman Spectroscopy: From Materials Transformation to Biosensor Responses.

Chemistry studies the composition, structure, properties, and transformation of matter. A mechanistic understanding of the pertinent processes is required to translate fundamental knowledge into practical applications. The current development of ultrafast Raman as a powerful time-resolved vibrational technique, particularly femtosecond stimulated Raman spectroscopy (FSRS), has shed light on the structure-energy-function relationships of various photosensitive systems. This Perspective reviews recent work incorporating optical innovations, including the broad-band up-converted multicolor array (BUMA) into a tunable FSRS setup, and demonstrates its resolving power to watch metal speciation and photolysis, leading to high-quality thin films, and fluorescence modulation of chimeric protein biosensors for calcium ion imaging. We discuss advantages of performing FSRS in the mixed time-frequency domain and present strategies to delineate mechanisms by tracking low-frequency modes and systematically modifying chemical structures with specific functional groups. These unique insights at the chemical-bond level have started to enable the rational design and precise control of functional molecular machines in optical, materials, energy, and life sciences.

Synthesis of Self-Assembled Porphyrin Nanoparticle Photosensitizers.

The use of nanoparticles as a potential building block for photosensitizers has recently become a focus of interest in the field of photocatalysis and photodynamic therapy. Porphyrins and their derivatives are effective photosensitizers due to extended π-conjugated electronic structure, high molar absorption from visible to near-infrared spectrum, and high singlet oxygen quantum yields as well as chemical versatility. In this paper, we report a synthesis of self-assembled porphyrin nanoparticle photosensitizers using zinc meso-tetra(4-pyridyl)porphyrin (ZnTPyP) through a confined noncovalent self-assembly process. Scanning electron microscopy reveals formation of monodisperse cubic nanoparticles. UV-vis characterizations reveal that optical absorption of the nanoparticles exhibits a red shift due to noncovalent self-assembly of porphyrins, which not only effectively increase intensity of light absorption but also extend light absorption broadly covering visible light for enhanced photodynamic therapy. Electron spin-resonance spectroscopy (ESR) studies show the resultant porphyrin nanoparticles release a high yield of singlet oxygen. Nitric oxide (NO) coordinates to central metal Zn ions to form stabilized ZnTPyP@NO nanoparticles. We show that under light irradiation ZnTPyP@NO nanoparticles release highly reactive peroxynitrite molecules that exhibit enhanced antibacterial photodynamic therapy (APDT) activity. The ease of the synthesis of self-assembled porphyrin nanoparticles and light-triggered release of highly reactive moieties represent a completely different photosensitizer system for APDT application.

Melanopsin and rhodopsin mediate UVA-induced immediate pigment darkening: Unravelling the photosensitive system of the skin

The mammalian skin has a photosensitive system comprised by several opsins, including rhodopsin (OPN2) and melanopsin (OPN4). Recently, our group showed that UVA (4.4 kJ/m2) leads to immediate pigment darkening (IPD) in murine normal and malignant melanocytes. We show the role of OPN2 and OPN4 as UVA sensors: UVA-induced IPD was fully abolished when OPN4 was pharmacologically inhibited by AA9253 or when OPN2 and OPN4 were knocked down by siRNA in both cell lines. Our data, however, demonstrate that phospholipase C/protein kinase C pathway, a classical OPN4 pathway, is not involved in UVA-induced IPD in either cell line. Nonetheless, in both cell types we have shown that: a) intracellular calcium signal is necessary for UVA-induced IPD; b) the involvement of CaMK II, whose inhibition, abolished the UVA-induced IPD; c) the role of CAMK II/NOS/sGC/cGMP pathway in the process since inhibition of either NOS or sGC abolished the UVA-induced IPD. Taken altogether, we show that OPN2 and OPN4 participate in IPD induced by UVA in murine normal and malignant melanocytes through a conserved common pathway. Interestingly, upon knockdown of OPN2 or OPN4, the UVA-driven IPD is completely lost, which suggests that both opsins are required and cooperatively signal in murine both cell lines. The participation of OPN2 and OPN4 system in UVA radiation-induced response, if proven to take place in human skin, may represent an interesting pharmacological target for the treatment of depigmentary disorders and skin-related cancer.

A supramolecular photosensitizer system based on the host-guest complexation between water-soluble pillar[6]arene and methylene blue for durable photodynamic therapy.

A supramolecular photosensitizer system WP6-MB was synthesized based on water-soluble pillar[6]arene and the photosensitizer methylene blue (MB) via host-guest interaction. MB can complex with WP6 directly with a high complex constant without further modification. In particular, WP6-MB can reduce the dark toxicity of MB remarkably. Furthermore, it can efficiently overcome photobleaching and extend the time for singlet oxygen production of MB upon light irradiation, which is significant for durable photodynamic therapy.

Photo-triggered destabilization of nanoscopic vehicles by dihydroindolizine for enhanced anticancer drug delivery in cervical carcinoma

The efficacy and toxicity of drugs depend not only on their potency but also on their ability to reach the target sites in preference to non-target sites. In this regards destabilization of delivery vehicles induced by light can be an effective strategy for enhancing drug delivery with spatial and temporal control. Herein we demonstrate that the photoinduced isomerization from closed (hydrophobic) to open isomeric form (hydrophilic) of a novel DHI encapsulated in liposome leads to potential light-controlled drug delivery vehicles. We have used steady state and picosecond resolved dynamics of a drug 8-anilino-1-naphthalenesulfonic acid ammonium salt (ANS) incorporated in liposome to monitor the efficacy of destabilization of liposome in absence and presence UVA irradiation. Steady state and picosecond resolved polarization gated spectroscopy including the well-known strategy of solvation dynamics and Förster resonance energy transfer; reveal the possible mechanism out of various phenomena involved in destabilization of liposome. We have also investigated the therapeutic efficacy of doxorubicin (DOX) delivery from liposome to cervical cancer cell line HeLa. The FACS, confocal fluorescence microscopic and MTT assay studies reveal an enhanced cellular uptake of DOX leading to significant reduction in cell viability (∼40%) of HeLa followed by photoresponsive destabilization of liposome. Our studies successfully demonstrate that these DHI encapsulated liposomes have potential application as a smart photosensitive drug delivery system.

Monodispersed Mesoporous Silica Spheres Supported Co3O4 as Robust Catalyst for Oxygen Evolution Reaction

AbstractMonodispersed mesoporous silica spheres (MSS) with fibrous nanostructure and highly open porosity were fabricated by a facile one‐pot synthetic route and loaded with Co3O4 nanoclusters for catalyzing the oxygen evolution reaction with Ru(bpy)32+–S2O82− photosensitizer and sacrificial reagent system. The effect of the loading amount on the morphology and microstructure of Co3O4 was investigated and it was found that lower Co3O4 content in the composite materials results in smaller crystallite size, which in turn leads to significantly enhanced oxygen evolution activity. Furthermore, owing to the monodispersity of the spheres and good accessibility of active species offered by the fibrous pore structure, the material shows a clear advantage over nonsupported Co3O4 nanoparticles and the commonly used ordered mesoporous silica supports such as KIT‐6 and SBA‐15.

Stability and Bifurcation Analysis in the Photosensitive CDIMA System with Delayed Feedback Control

A diffusive photosensitive CDIMA system with delayed feedback subject to Neumann boundary conditions is considered. We derive the conditions of the occurrence of Turing instability. We also investigate the influence of delay on the stability of the positive equilibrium of the system, and prove that delay induces the occurrence of Hopf bifurcation. By computing the normal form on the center manifold, we give the formulas determining the properties of the Hopf bifurcation. Finally, we give some numerical simulations to support and strengthen the theoretical results. Our study shows that diffusion and delayed feedback can effect the stability of the equilibrium of the system.

Fine Resolution Photosensitive Polyimide Dry Film with High Resistance to Electromigration under HAST condition

Abstract We investigated the effects of photosensitive system (positive and negative) and polymer structures on Cu migration under bias HAST test. The HAST condition is 130C for 85% RH. Bias condition is 2MV/m. We found that there is polyimide structure shows big effect is big effect of no big difference between negative photosensitivity and positive photosensitivity in photo sensensitive polyimides. Polyimide structure effects significant difference on Cu migration under bias HAST condition. Cu migration of soft polyimide seems better than that of rigid polyimide. From these results, we developed good reliable photosensitive polyimide B-sheet having fine pattern capability successfully.

(Invited) Upconversion: Photoswitching, Photocleavable

Research on light controlled drug delivery release systems has shown great potential in biomedical applications. However, in general the photo response of molecules is based on UV excitation. In biomedical applications longer wavelength NIR light is preferable since it shows deeper tissue penetration and is less detrimental to tissue. We report on the synthesis of LiYF4:Tm3+/Yb3+ functionalized(UCNP) with a lipid bilayer and azobenzene. The nanoconstruct synthesised is hydrophilic shows excellent colloidal stability and biocompatibility. The nanocomposite can be used as a drug delivery system making use of NIR light excitation (980 nm) to induce the multiphoton process known as upconversion. The LiYF4 Tm3+/Yb3+ nanoparticles emit in the UV, visible and/or near-infrared. Fluorescence energy transfer (FRET) from the upconverting nanoparticles (UV emission) to the azobenzene triggers the photoswitching of the azobenzene from the trans to the cis. The photoswitching of the azobenzene molecules disrupts conformation of the supported lipid bilayer thus releasing the drug.Recently, photosensitive drug delivery systems, which make use of a nitrobenzyl-type ‘photocaged’ anticancer drug conjugated to another small or macromolecule. In each of these cases drug release from the conjugate was mediated by UV light. A major limitation of this approach for in vivo drug release is the low tissue penetration ability of UV light and inevitable DNA damage. A potential solution is afforded by UCNPs loaded with photocaged doxorubicin (DOX) onto the surface of the UCNPs via a photocleavable linkage.

Novel Bodipy- triazine conjugates: Synthesis and the generation of singlet oxygen

Novel Bodipy decorated triazine conjugates were successfully designed and synthesized by the click reaction of azido functionalized di-styryl Bodipys with propargyl alkoxide substituted triazine. The identities of newly synthesized compounds were confirmed by using 1H and 13C NMR spectroscopies. The molecular structure of propargyl alkoxide substituted triazine was also determined by X-ray crystallography. The photophysical (fluorescence lifetime and fluorescence quantum yield) and photochemical (the singlet oxygen generation capabilities and appropriate photo degradation by light irradiation) properties of Bodipy- triazine conjugates were investigated for determination of their fluorescence and photosensitizer abilities. These results will provide further insight and motivation for development of Bodipy based singlet oxygen photosensitizer systems.

Near-Infrared Photoinduced Reactions Assisted by Upconverting Nanoparticles.

The majority of photoreactions reported in the literature rely on wavelengths within the UV and-to a lesser extent-visible regime for activation, either by directly triggering the reaction or by photocatalysis. However, photoreactions induced by near-infrared (NIR) light are highly attractive for biomedical applications as NIR light can penetrate deeper into tissue and causes less damage to photosensitive biological systems. Recently, upconverting nanoparticles (UCNPs) have been employed by us and others to assist NIR photoinduced reactions. UCNPs convert NIR light to UV or visible light, which can trigger photoreactions of conventional UV or visible-light-sensitive compounds. In the current Concept article, we introduce the fundamentals of UCNP-assisted photochemistry and highlight selected future applications and innovative potential for the field.

Evaluation of theranostic nanocarriers for near-infrared imaging and photodynamic therapy on human prostate cancer cells

This paper evaluates how effectively chloroaluminum phthalocyanine (ClAlPc) entrapped in colloidal nanocarriers, such as nanocapsule (NC) and nanoemulsion (NE), induces photodamage in human prostate cancer cells (LNCaP) during photodynamic therapy (PDT). The MTT cell viability assay showed that both ClAlPc-NC and ClAlPc-NE induced phototoxicity and efficiently killed LNCaP cells at low ClAlPc-NC and ClAlPc-NE concentrations (0.3μgmL−1) as well as under low light doses of 4Jcm−2 and 7Jcm−2, respectively, upon PDT with a 670-nm diode laser line.Confocal imaging studies indicated that ClAlPc-NC and ClAlPc-NE were preferentially localized in the perinuclear region of LNCaP cells both in the dark and upon irradiation with laser light. After PDT treatment, ClAlPc-NC-treated LNCaP cells exhibited a higher green fluorescence signal, possibly due to the larger shrinkage of the actin cytoskeleton, compared to ClAlPc-NE-treated LNCaP cells. Additionally, ClAlPc-NC or ClAlPc-NE and mitochondria showed a relatively high co-localization level. The cellular morphology did not change in the dark, but confocal micrographs recorded after PDT revealed that LNCaP cells treated with ClAlPc-NC or ClAlPc-NE underwent morphological alterations.Our preliminary in vitro studies reinforced the hypothesis that biocompatible theranostic ClAlPc-loaded nanocarriers could act as an attractive photosensitizer system in PDT and could serve as an interesting molecular probe for the early diagnosis of prostate cancer and other carcinomas.

Photochemical solar power and storage through photogalvanic cells: Comparing performance of dye materials

ABSTRACTThe comparative photogalvanic study of Fast Green FCF, Brilliant Cresyl Blue, and Rhodamine B dye photosensitizer systems with fructose as reductant has been done for finding relatively better dye photosensitizer for further improvement in electrical performance of photogalvanic cells. It has been observed that processes occurring during charging and discharging of the cells based on three dye systems are similar, and suggestive of similar mechanistic aspect of power generation and storage for three systems. The light-weight Rhodamine B dye-SCE of combination electrode–small-area Pt electrode based system has relatively better electrical performance, so suggested for future research. The conversion efficiencies for Fast Green FCF, Brilliant Cresyl Blue, and Rhodamine B systems are 0.41%, 0.49%, and 6.49%, respectively.

Dexamethasone Modulates Nonvisual Opsins, Glucocorticoid Receptor, and Clock Genes in Danio rerio ZEM-2S Cells.

Here we report, for the first time, the differential cellular distribution of two melanopsins (Opn4m1 and Opn4m2) and the effects of GR agonist, dexamethasone, on the expression of these opsins and clock genes, in the photosensitive D. rerio ZEM-2S embryonic cells. Immunopositive labeling for Opn4m1 was detected in the cell membrane whereas Opn4m2 labeling shows nuclear localization, which did not change in response to light. opn4m1, opn4m2, gr, per1b, and cry1b presented an oscillatory profile of expression in LD condition. In both DD and LD condition, dexamethasone (DEX) treatment shifted the peak expression of per1b and cry1b transcripts to ZT16, which corresponds to the highest opn4m1 expression. Interestingly, DEX promoted an increase of per1b expression when applied in LD condition but a decrease when the cells were kept under DD condition. Although DEX effects are divergent with different light conditions, the response resulted in clock synchronization in all cases. Taken together, these data demonstrate that D. rerio ZEM-2S cells possess a photosensitive system due to melanopsin expression which results in an oscillatory profile of clock genes in response to LD cycle. Moreover, we provide evidence that glucocorticoid acts as a circadian regulator of D. rerio peripheral clocks.

A mitochondria-targeting supramolecular photosensitizer based on pillar[5]arene for photodynamic therapy

A mitochondria-targeting supramolecular photosensitizer system TPP-QAS/WP5/DTAB was constructed based on a host-guest inclusion complex. The supramolecular system could efficiently release and activate TPP-QASs in an acidic environment, which have been demonstrated to preferentially accumulate in mitochondria. Singlet oxygen (1O2) could be in situ generated in mitochondria under light irradiation, further enhancing the PDT efficacy.

High aspect ratio patterning of photosensitive polyimide with low thermal expansion coefficient and low dielectric constant

A photosensitive polyimide system based on amine catalyzed imidization of a precursor poly(amic ester) is described. The material is based on the meta ethyl ester of pyromellitic dianhydride and 2,2’ bis(trifluoromethyl)benzidine. It acts as a negative tone resist when formulated with a photobase generator. The material exhibits a dielectric constant of 3.0 in the gigahertz range, a coefficient of thermal expansion of 6±2 ppm/K, and can be patterned to aspect ratios of >2 when formulated with a highly quantum efficient cinnamide type photobase generator.

Controlled Generation of Singlet Oxygen in Living Cells with Tunable Ratios of the Photochromic Switch in Metal–Organic Frameworks

AbstractDevelopment of a photosensitizing system that can reversibly control the generation of singlet oxygen (1O2) is of great interest for photodynamic therapy (PDT). Recently several photosensitizer–photochromic‐switch dyads were reported as a potential means of the 1O2 control in PDT. However, the delivery of such a homogeneous molecular dyad as designed (e.g., optimal molar ratio) is extremely challenging in living systems. Herein we show a Zr‐MOF nanoplatform, demonstrating energy transfer‐based 1O2 controlled PDT. Our strategy allows for tuning the ratios between photosensitizer and the switch molecule, enabling maximum control of 1O2 generation. Meanwhile, the MOF provides proximal placement of the functional entities for efficient intermolecular energy transfer. As a result, the MOF nanoparticle formulation showed enhanced PDT efficacy with superior 1O2 control compared to that of homogeneous molecular analogues.

Controlled Generation of Singlet Oxygen in Living Cells with Tunable Ratios of the Photochromic Switch in Metal-Organic Frameworks.

Development of a photosensitizing system that can reversibly control the generation of singlet oxygen ((1) O2 ) is of great interest for photodynamic therapy (PDT). Recently several photosensitizer-photochromic-switch dyads were reported as a potential means of the (1) O2 control in PDT. However, the delivery of such a homogeneous molecular dyad as designed (e.g., optimal molar ratio) is extremely challenging in living systems. Herein we show a Zr-MOF nanoplatform, demonstrating energy transfer-based (1) O2 controlled PDT. Our strategy allows for tuning the ratios between photosensitizer and the switch molecule, enabling maximum control of (1) O2 generation. Meanwhile, the MOF provides proximal placement of the functional entities for efficient intermolecular energy transfer. As a result, the MOF nanoparticle formulation showed enhanced PDT efficacy with superior (1) O2 control compared to that of homogeneous molecular analogues.

Evaluation of thiol-ene photo-curable resins using in rapid prototyping

Purpose The purpose of this paper is to evaluate the properties of several thiol-acrylate photosensitive systems and compare with corresponding acrylate free-radical systems. The potential stereolithography applications of thiol–ene photosensitive systems are also discussed. Design/methodology/approach In the both thiol–ene and acrylate free-radical photosensitive systems, various key performances were characterized. The function group conversions were characterized by real-time Fourier transform infrared spectroscopy. The tension strength was determined according to the standard ASTM D638-2003, the flexible strength was determined according to ASTM D790-07 and the hardness was measured according to ASTM D2240-05. The volume shrinkage was measured by dilatometer method. The glass transition temperature was analyzed by differential scanning calorimeter. Findings As adding mercapto propionates into acrylate system, the inhibition of polymerization by oxygen was controlled and the flexible performance was improved. In addition, the photosensitive resin showed better tension strength, higher elongation at break and lower volume shrinkage. Among the four mercapto propionates, rigid TEMPIC showed most obvious affect, followed hexa-functional DPMP, tetra-functional PETMP and tri-functional TMMP. Originality/value Although the thiol–ene photosensitive resin has unmatched advantages in performance, there are no reports on the thiol–ene photosensitive resin in the stereolithography application. In this study, thiol–ene photopolymerization material was first tentatively implemented in stereolithography area. Several critical performance parameters were compared between thiol–ene and acrylate free-radical photosensitive systems.