Photosensitive Groups Research Articles

Preparation of photosensitive phytic acid doped polyaniline and its application in UV-curable anticorrosive coatings

In this paper, photosensitive phytic acid (PAGA) was synthesized via the ring opening reaction of glycidyl methacrylate and phytic acid (PA), which was used to dope polyaniline (PANI). The doped polyaniline (PAGA/PANI) was added to UV-curable resin to prepare UV-curable polyaniline anticorrosive coating. The doping of PANI by PAGA can effectively improve the dispersion of PANI in coatings. Even when the amount of PAGA/PANI increased to 2.0 wt%, PANI can still achieve uniform dispersion in the UV-curable resin. The gel content test showed that with the addition of PAGA/PANI, the curing degree of the UV-cured coating did not decrease, but slightly increased, which was attributed to the introduction of multiple photosensitive groups in PAGA, compensating for the negative effect caused by PANI. The incorporation of PAGA/PANI can also enhance the adhesion of the UV-cured coating due to the presence of phosphonic group in PAGA. With the increase of the content of photosensitive groups, the adhesion of the coating showed an increasing trend. The corrosion resistance of the coating was investigated by electrochemical impedance spectroscopy, and salt spray experiments. The impedance value of the PAGA/PANI coating was two orders of magnitude higher than that of pure resin coating during 30 days of immersion, and neither rust nor blister were observed in the salt spray test for 1000 h, suggesting the significantly enhanced anti-corrosion performance with the incorporation of PAGA/PANI.

Effects of Photodynamic Therapy on Nav1.7 Expression in Spinal Dorsal Root Ganglion Neurons.

The aim of this study was to examine the effects of photodynamic therapy (PDT) on the expression of Nav1.7 in spinal dorsal root ganglion (DRG) neurons. The primary DRG neurons from newborn SD rats were cultured. The cells were identified by neuron-specific enolase immunofluorescence staining. DRG neurons were divided into four groups: control group, photosensitizer group, laser group, and PDT group. The cell viability was detected by a cell counting kit-8 (CCK8) assay. qRT-PCR and Western blotting were used to determine the mRNA and protein expression levels of Nav1.7 in DRG neurons. The purity of the cultured primary DRG neurons was greater than 90%. Compared with the control group, no significant change was found in the cell viability of the photosensitizer group, while the viability in the laser group and the PDT group was significantly reduced. The mRNA and protein expression levels of Nav1.7 were significantly greater in the laser group and the PDT group than in the control group. At the same time, the mRNA and protein expression levels of Nav1.7 were greater in the laser group than in the PDT group. Both laser and PDT could upregulate the expression of Nav1.7 in DRG neurons, and the promoting effect might be related to the pain induced by clinical treatment. This study provides a research basis for the use of laser and PDT to treat pain. A better understanding of the relationship between Nav1.7 and PDT can help clinicians better manage PDT-related pain.

Rapidly UV-curable resin for soft sensors of embedded 3D printing

3D printing technology with design flexibility can produce soft sensors more efficiently than traditional manufacturing technology, however, the improvement of printing accuracy is an urgent problem to be solved. The rapidly UV-curable speed of the material is helpful to solve the problem. Herein, the new polymeric resins with good softness and rapidly UV-curable speed were prepared, and then a high printing accuracy soft sensor was prepared by imitating embedded 3D printing methods with the resins as components. In synthetic resin, the polybutadiene (PB) with high flexibility was designed as the flexible main chain, pentaerythritol triacrylate (PETA) with multi photosensitive groups as UV-curable groups and oxalyl chloride (COCl) with no forming hard segments as the linker between PB and PETA. The resins have rapidly UV-curable speed that can maintain the shape within 1 s, basically cured within 5 s. The cured samples of resins have small Young’s modulus and good softness similar to biomaterials, and the Tg is around −60 °C. The soft sensors based on the resins have the characteristics of high printing accuracy, good sensitivity, versatility, and a wide temperature range of application, and could be integrated into many joints on the body to detect our motions.

Photo-responsive hydrogel-based re-programmable metamaterials

This paper explores a novel programmable metamaterial using stimuli-responsive hydrogels with a demonstration of bandgap formation and tuning. Specifically, a photo-responsive hydrogel beam that can achieve re-programmable periodicity in geometric and material properties through patterned light irradiation is designed. Hydrogels consist of polymeric networks and water molecules. Many unique properties of hydrogels, including bio-compatibility, stimuli-responsiveness, and low dissipation make them ideal for enabling re-programmable metamaterials for manipulating structural dynamic response and wave propagation characteristics. Bandgap generation and tunability in photo-responsive hydrogel-based metamaterial (in the form of a diatomic phononic chain) as well as the effects of system parameters such as light exposure pattern and photo-sensitive group concentration on the bandgap width and center frequency are systematically studied. In agreement with finite-element model simulations, it is observed that an increase in light exposure region size reduces both the bandgap width and center frequency, while an increase in the concentration of photo-sensitive group increases bandgap width, attenuation and reduces its center frequency. This work unveils the potential of stimuli-response hydrogels as a new class of low-loss soft metamaterials, unlike most other soft materials that are too lossy to sustain and exploit wave phenomena.

Anthraquinone-Based Metal-Organic Frameworks as a Bifunctional Photocatalyst for C-H Activation.

Metal-organic frameworks (MOFs) have gained attention as multifunctional catalytic platforms, allowing us to gain important insights into synergistically activating both C-H bonds and oxygen for improving oxidation. Herein, by ingenious incorporation of anthraquinone, we report an anthraquinone-based MOF as a bifunctional heterogeneous photocatalytic platform to simultaneously activate inert C(sp3)-H bonds and oxygen for C-H bond oxidation. Making use of the rigid framework with the fixation and isolation effect, both a great chemical stability and bifunctional synergistic photocatalytic effects were obtained through the immobilization of anthraquinone into a MOF. Importantly, while decorating two carboxyl groups on anthraquinone, the carbonyl groups of anthraquinone photosensitizers were not involved in coordinating the self-assembly and orderly arranged on the wall of channels that were constructed through a π-π interaction between the anthraquinone moieties in the adjacent layers, which was beneficial to form and stabilize the excited-state radical intermediates in the molecule-fenced channels, and the close proximity between the catalytic sites and the substrates to abstract a hydrogen atom from the substrate through the hydrogen atom transfer process aimed at activating the inertness of C-H bonds. Moreover, high-density-distributed anthraquinone dyes in the confined channels would activate oxygen to form singlet oxygen (1O2) through an energy transfer pathway, further promoting inert C(sp3)-H bond oxidation efficiency. Under visible light irradiation, this anthraquinone-based MOF was successfully applied to explore activation and oxidation of a series of substrates containing benzylic C(sp3)-H bonds in the presence of air or oxygen to produce the corresponding carbonyl products. This bifunctional photocatalytic platform based on a heterogeneous MOF provides an available catalytic avenue to develop a scalable and sustainable synthetic strategy using green and sustainable oxygen as the potent oxidant.

Polyglutamic Acid-Based Elastic and Tough Adhesive Patch Promotes Tissue Regeneration through In Situ Macrophage Modulation.

Adhesive patches are advanced but challenging alternatives to suture, especially in treating fragile internal organs. So far there is no suture‐free adhesive patch based on metabolizable poly(amino acid) materials with excellent mechanical strength as well as immunomodulation functionality. Here, a polyglutamic acid‐based elastic and tough adhesive patch modified by photosensitive groups on the surface to achieve robust light‐activated adhesion and sealing of flexible internal organs is explored. With the porous internal morphology and excellent biodegradability, the patches promote regeneration through a macrophage‐regulating microenvironment. Treated rabbits achieve rapid full‐thickness gastric regeneration with complete functional structure within 14 d, suggesting its robust tissue adhesion and repair‐promoting ability.

Atropisomer-based construction of a new perylene diimide macrocycle as visible-light photocatalyst for selective sulfide oxidation

By using a perylene diimine (PDI) syn -atropisomer as highly preorganized precursor, we successfully constructed a visible-light-active organic macrocycle PDI-M . The formation of macrocyclic structure effectively avoids self-aggregation of PDI cores and enhances the absorption in visible region. As a photocatalyst, PDI-M exhibits excellent activity on aerobic selective oxidation of sulfide into sulfoxide under visible light irradiation at room temperature. Mechanism studies show that both superoxide and singlet oxygen act as reactive oxygen species. This work provides a typical case toward the maximum utilization of photosensitive groups under mild conditions. A visible-light-active organic macrocycle was successfully constructed from a perylene diimide syn -atropisomer as highly preorganized precursor. As a photocatalyst, the macrocycle exhibits excellent activity on aerobic oxidation of sulfide into sulfoxide under visible light irradiation at room temperature.

Stability of a calibrant as certified reference material for determination of trans-zearalenone by high performance liquid chromatography-diode array detection-triple quadrupole tandem mass spectrometry.

In this study, a trans-zearalenone (trans-ZEN) calibrant in acetonitrile as certified reference material (CRM) was prepared and intensively investigated the stability by high performance liquid chromatography coupled diode array detection and triple quadrupole tandem mass spectrometry (HPLC-DAD-MS/MS). The photoisomerization and degradation of main component and related impurities in trans-ZEN calibrant CRM was studied in detail under different light conditions such as UV light (254nm), sunlight, and visible light. Trans-ZEN in acetonitrile was confirmed a significant shift toward cis-ZEN up to a 52% cis-isomerization rate after exposing to UV light (254nm) in transparent ampule for 1day. The unsaturated double bond photosensitive groups of trans-ZEN and cis-ZEN will further undergo photoreaction to generate more isomers and related products with the increase of UV irradiation time. The calibrant in amber ampules was relatively stable after exposing to sunlight for 28days, with only 0.35% cis-isomer observed. The results indicated that trans-ZEN solution calibrant should be packed in amber ampules to avoid UV rays. Thermal stability test exhibited this calibrant was stable over 6weeks even at 60°C. Trans-ZEN was found to be more stable in acetonitrile than in methanol since an unknown impurity was observed in methanol after 6weeks placed at 25°C. The stability study of trans-ZEN calibrant provided a basis for the usage, storage, and transportation of the CRM. A concentration and expanded uncertainty of the trans-ZEN calibrant CRM of 11.01 ± 0.18µg/mL was developed.

Oxospirochlorins as new promising photosensitizers against priority pathogens

Chlorins belong to a group of photosensitizers that are significant and promising for photodynamic therapy (PDT). The newly synthesized oxospirochlorins presented in this study revealed an outstanding ability to generate singlet oxygen and high photostability. The obtained porphyrinoids were incorporated into liposomes, and then their antimicrobial activity against priority pathogens: MRSA, E. coli (ESBL+), and fluconazole-resistant C. albicans was examined. The excellent activity against both Gram-positive and Gram-negative bacteria was observed. Moreover, the synergism between sublethal antibacterial PDT and antibiotics with limited efficacy against resistant strains was investigated. As a result of the photodynamic activity of chlorins, it was possible to partially restore the sensitivity of bacteria to antibiotics from the group of cephalosporins and carbapenems.

Ferrocene-Functionalized Crystalline Biomimetic Catalysts for Efficient CO2 Photoreduction.

Photoreducing carbon dioxide (CO2) into highly valued chemicals or energy products has been recognized as one of the most promising proposals to degrade atmospheric CO2 concentration and achieve carbon neutrality. Adenine with a photosensitive amino group and aromatic nitrogen atom can strongly interact with CO2 and has been authenticated for its catalytic activity for the CO2 photoreduction reaction (CO2RR). Herein, two adenine-constructed crystalline biomimetic photocatalysts (Co2-AW and Co2-AF) were designed and synthesized to achieve CO2RR. Between them, Co2-AF displayed higher photocatalytic activity (225.8 μmol g-1 h-1) for CO2-to-HCOOH conversion than that of Co2-AW. It was found that the superior charge transfer capacity of the functional ferrocene group in Co2-AF is the primary reason to facilitate the photocatalytic performance efficiently. Additionally, this work also demonstrated the great potential of the ferrocene group as an electron donor and mediator in improving the photocatalytic activity of crystalline coordination catalysts.

Влияние фотодинамической терапии на грамположительные и грамотрицательные бактерии слизистой оболочки полости рта у детей с ограниченными возможностями

This literature review on the antibacterial photodynamic therapy (aPDT) use in dentistry, its latest achievements, prospects and effectiveness in children with disabilities. The treatment methods using in modern clinical practice often turn out to be insufficiently effective, and the steady development of periodontal pathologies is determined in all social groups of the population, and especially in such children. They cannot independently carry out the rational oral care, and the oral cavity hygienic condition deteriorates, which means that the problem of the prevention and treatment of dental diseases in such children is an urgent task of the modern dentistry. The bacterial microflora composition of the oral cavity plays the special role in the periodontal disease development, and the structure of bacterial cell walls affects the effectiveness of aPDT. The article provides the information about the microbiological composition prevailing in the oral cavity in periodontal diseases, reflects the structural features of gram-positive and gram-negative bacteria, which have a significant impact on the photosensitizer penetration and the further procedure effectiveness. Various photosensitizer groups and sources for their excitation are also investigated. Various methods of the application and the latest approaches in the treatment of periodontal diseases with PDT in children with disabilities are described. APDT with various photosensitizers is considered as the most promising alternative approach to the periodontal disease elimination. Key words: photodynamic therapy, photosensitizer, periodontal disease, periodontal pathogenic microflora, gingivitis, cerebral palsy

Nonadiabatic excited-state dynamics of ReCl(CO)3(bpy) in two different solvents.

We present a study of excited-states relaxation of the complex ReCl(CO)3(bpy) (bpy = 2,2-bipyridine) using a nonadiabatic TD-DFT dynamics on spin-mixed potential energy surfaces in explicit acetonitrile (ACN) and dimethylsulfoxide (DMSO) solutions up to 800 fs. ReCl(CO)3(bpy) belongs to a group of important photosensitizers which show ultrafast biexponential subpicosecond fluorescence decay kinetics. The choice of solvents was motivated by the different excited-state relaxation dynamics observed in subpicosecond time-resolved IR (TRIR) experiments. Simulations of intersystem crossing (ISC) showed the development of spin-mixed states in both solvents. Transformation of time-dependent populations of spin-mixed states enabled to monitor the temporal evolution of individual singlet and triplet states, fitting of bi-exponential decay kinetics, and simulating the time-resolved fluorescence spectra that show only minor differences between the two solvents. Analysis of structural relaxation and solvent reorganization employing time-resolved proximal distribution functions pointed to the factors influencing the fluorescence decay time constants. Nonadiabatic dynamics simulations of time-evolution of electronic, molecular, and solvent structures emerge as a powerful technique to interpret time-resolved spectroscopic data and ultrafast photochemical reactivity.

Dextran-Coated Latex Nanoparticles via Photo-RAFT Mediated Polymerization Induced Self-Assembly.

Polysaccharide coated nanoparticles represent a promising class of environmentally friendly latex to replace those stabilized by small toxic molecular surfactants. We report here an in situ formulation of free-surfactant core/shell nanoparticles latex consisting of dextran-based diblock amphiphilic copolymers. The synthesis of copolymers and the immediate latex formulation were performed directly in water using a photo-initiated reversible addition fragmentation chain transfer-mediated polymerization induced self-assembly strategy. A hydrophilic macromolecular chain transfer-bearing photosensitive thiocarbonylthio group (eDexCTA) was first prepared by a modification of the reducing chain end of dextran in two steps: (i) reductive amination by ethylenediamine in the presence of sodium cyanoborohydride, (ii) then introduction of CTA by amidation reaction. Latex nanoparticles were then formulated in situ by chain-extending eDexCTA using 2-hydroxypropyl methacrylate (HPMA) under 365 nm irradiation, leading to amphiphilic dextran-b-poly(2-hydroxypropyl methacrylate) diblock copolymers (DHX). Solid concentration (SC) and the average degree of polymerization -- of PHPMA block (X) were varied to investigate their impact on the size and the morphology of latex nanoparticles termed here SCDHX. Light scattering and transmission electron microscopy analysis revealed that SCDHX form exclusively spherical nano-objects. However, the size of nano-objects, ranging from 20 nm to 240 nm, increases according to PHPMA block length.

One-photon red light-triggered disassembly of small-molecule nanoparticles for drug delivery

BackgroundPhotoresponsive drug delivery can achieve spatiotemporal control of drug accumulation at desired sites. Long-wavelength light is preferable owing to its deep tissue penetration and low toxicity. One-photon upconversion-like photolysis via triplet–triplet energy transfer (TTET) between photosensitizer and photoresponsive group enables the use of long-wavelength light to activate short-wavelength light-responsive groups. However, such process requires oxygen-free environment to achieve efficient photolysis due to the oxygen quenching of triplet excited states.ResultsHerein, we report a strategy that uses red light to trigger disassembly of small-molecule nanoparticles by one-photon upconversion-like photolysis for cancer therapy. A photocleavable trigonal molecule, BTAEA, self-assembled into nanoparticles and enclosed photosensitizer, PtTPBP. Such nanoparticles protected TTET-based photolysis from oxygen quenching in normoxia aqueous solutions, resulting in efficient red light-triggered BTAEA cleavage, dissociation of nanoparticles and subsequent cargo release. With paclitaxel as the model drug, the red light-triggered drug release system demonstrated promising anti-tumor efficacy both in vitro and in vivo.ConclusionsThis study provides a practical reference for constructing photoresponsive nanocarriers based on the one-photon upconversion-like photolysis.Graphical

Effect of substrates on covalent surface modification of graphene using photosensitive functional group

Abstract Graphene has gained much significance for its potential applications in optics and electronics owing to its unique physical and chemical properties. Nevertheless, its gapless band structure greatly limits its wider application in optoelectronic devices. The present study seeks to explore chemical functionalization as an effective method to tune the properties of graphene. Covalent modification of graphene by aryl diazonium salt of a photosensitive functional group (azobenzene) has been used to achieve this goal. This is based on the fact that graphene is a two-dimensional, atomically thin lattice of sp2-bonded carbon atoms, therefore, its properties can be modulated by modifying the underlying dielectric surface with a self-assembled monolayer resulting in doping control. In the study, a clear difference in the rate of electron-transfer reactions with the photosensitive functional group is shown for monolayer graphene supported on SiO2/Si substrates and organic molecule functionalized SiO2/Si substrates. Graphene supported on SiO2/ Si is more reactive towards functionalization than graphene on organic molecule functionalized surfaces, as shown by Raman spectroscopy. The transport characteristics of functionalized graphene on conventional SiO2/Si substrates as well as substrates modified with organic molecule octadecyltrichlorosilane self-assembled monolayers are also explored and compared.

A Photochromic Zinc–Viologen Framework with a High-Contrast Nonlinear Optical Switchable Behavior

As an important branch of nonlinear optical (NLO) switches, second-harmonic-generation (SHG) switches undergoing reversible SHG-on and SHG-off states upon external stimuli exposure have been the focus of intense scientific research due to their potential applications in photoelectric technologies. The high-contrast switching of SHG, a key issue for the potential applications of SHG optical switches, has been a challenge but is undoubtedly very interesting. Incorporating stimuli-responsive molecules into the SHG-active materials is an efficient approach to construct high-contrast SHG switches. In this paper, by using the ligand 1-(4-cyanobenzyl)-4,4′-bipyridinium (CBbpy) as a photosensitive group, a noncentrosymmetric photochromic zinc–viologen framework, {[(CBbpy)Zn3(TBC)(HTBC)(OH)]·NO3}n (1; H3BTC = 1,3,5-benzenetricarboylic acid), has been obtained. It shows an SHG intensity of 1.1 × KH2PO4 (KDP) due to the synergistic effect of the coplanar and parallel arrangement of NO3– anions, the asymmetric disposition of electron densities, and the large permanent dipole moment, as confirmed by Bader charge and dipole moment calculations. More importantly, an outstanding SHG switching contrast was found to be at least 23 times larger than that of the coloration sample under a 1064 nm laser beam, originating from the large difference in the dipole moment and the self-absorption effect before and after coloration. Such excellent SHG switching is reversible and can be cycled several times, indicating that 1 is a good candidate as a new solid-state SHG-switching material. This work should prompt researchers to explore novel high-performance SHG switches based on devisable stimuli-responsive groups.

Silacyclobutane‐functionalized cyclosiloxanes as photoactive precursors for high thermal stability, low dielectric constant and low dielectric loss polymers

AbstractLow dielectric photoactive materials have significant potential as components in future microelectronics. Although a number of photosensitive groups have been used to construct photopatternable materials, it remains challenging to introduce these groups into polymer chains via facile yet controlled polymerization techniques. The present work demonstrates the synthesis of a new class of photoactive cyclosiloxane monomers having hybrid siloxane‐carbosilane main chains. These compounds can be cured by applying ultraviolet radiation and heat to promote the reaction of the silacyclobutene units and form hyper‐cross‐linked cyclosiloxanes. The cured resins show high thermal stability (with T5% values in the range of 460–550°C), low dielectric constants (2.36–2.76 at 10 MHz) and low dielectric losses (10−3 at 10 MHz). Thus, these polymers could possibly be used as high‐performance dielectric materials.

Erythrosine as a photosensitizer for antimicrobial photodynamic therapy with blue light-emitting diodes – An in vitro study

BackgroundThis study aims to test the absorbance of a new composition of erythrosine, its pH, cell viability and potential as a photo sensitizer against Candida albicans when irratiaded with blue light emitting-diode (LED). MethodsFor pH and absorbance tests, erythrosine was prepared at a concentration of 0.03/ml. The cells of the L929 strain were cultured and the alamarBlue® assay was performed on samples to assess cell viability. For the microbiological essay, the strain of Candida albicans ATCC 90028 was selected. Yeast suspensions were divided into the following groups: control without irradiation or photosensitizer (C), irradiated group without photosensitizer (L), photosensitizer group without irradiation (0), and groups that received photosensitizer and irradiation, called aPDT groups. ResultsErythrosine had no significant changes in pH and its absorbance was also consistent (≅400 nm). When it came to cell viability, on the first day, the group that was in contact with the dye and irradiated with the LED in minimun power was found to have the higher cell proliferation. On day 3, both irradiated groups (maximum and minimum) showed the highest cell proliferation. In the microbiological essay with C. albicans, aPDT groups started to show microbial reduction after 60 and 90 s of irradiation and when irradiated for 120 s, 6 microbial reduction logs were found. ConclusionsThe erythrosine in question is a PS, with pH stability, blue light absorbance, cell viability and efficacy against C. albicans. More studies with this PS should be encouraged in order to verify its performance in aPDT.

The recent studies about the interaction of phthalocyanines with DNA

Cancer is one of the major diseases affecting all humanity with high mortality rates worldwide. Its treatment is difficult, long-term and expensive. Due to its side effects, it is troublesome for both the patient and their attendants. Cancer treatment is basically divided into three: surgery, chemotherapy and radiotherapy. Photodynamic therapy offers one of the most important and promising treatment methods, especially in recent years. Photodynamic therapy takes the steps of administering the photo-sensitizing compound to the body and stimulating it with a light of appropriate wavelength after its accumulation in the target tissue. With the formation of complex processes that take place in the target area with the reactive oxygen species formed by the stimulated compounds, death or the inhibition of the proliferation of the cells causes situations such as the destruction of the target tissue. Phthalocyanines constitute an important group of photo-sensitizers used in photodynamic therapy. Stability of these compounds and their strong absorption close to therapeutic window make these compounds important. With large Π systems, they can bind with many biological macromolecules, including DNA, with high affinity by many mechanisms, including the Π - Π stacking. This review article describes the last three years of studies in the WOS database about the interactions of phthalocyanines with DNA. The interactions of phthalocyanines with DNA are important as they can make a difference in the proliferation of tumor cells. On the other hand, DNA replication and transcription has increased due to the increasing metabolic rate of these cells. The DNA double strand opened during replication, and gene expression allows the formation of different secondary structures such as hairpin, triple, junctions, and G-quadruplex. The interaction of G-quadruplex DNA structures with these compounds, which can be formed in the guanine-rich regions of the DNA sequences opened in these processes, has been described in studies.

Titanium content influence on the optical response characteristics of TiO2/ormosils composite films doped with azobenzene.

TiO2-based organic-inorganic composite films doped with azobenzene and photosensitive groups were prepared by combining a low-temperature solgel technique and a spin-coating method. The influence of TiO2 content on the optical and structural properties of the composite films including the film thickness, the refractive index, the transmission loss, the thermal gravity analysis, and Fourier transform infrared spectroscopy spectra was studied. Photoisomerization and optical switching characteristics of the composite film were investigated under the irradiation of 365 nm ultraviolet light and 450 nm visible light. Results indicate that several micrometer thick films can be easily obtained at room temperature and there is a proportional relationship between the refractive index value and the TiO2 content. In addition, the composite films have a low optical propagation loss of about 0.1 dB/cm. The composite films with 0.2 M TiO2 content have an obvious photoisomerization and good optical switching properties. Finally, the hexagonal microlens array was fabricated in the composite films by using an ultraviolet nanoimprint technology. All these results above indicate that the as-prepared TiO2-based organic-inorganic composite film has potential applications in optical switching devices and photonic elements.