Machine learning-assisted screening of small-molecule drugs for suppressing protein aggregation and ROS generation based on ECL and CV dual-mode signals amplified by DNA.

Functionalization of iron oxide nanoparticles with small molecules and the impact on reactive oxygen species generation for potential cancer therapy

Small molecule targeting the Rac1‐NOX2 interaction prevents collagen‐related peptide and thrombin‐induced reactive oxygen species generation and platelet activation

Rapid, highly sensitive, and accurate detection of tumor biomarkers in serum is of great significance in cancer screening, early diagnosis, and postoperative monitoring. In this study, an electrochemiluminescence (ECL) immunosensing platform was constructed by enhancing the ECL signal through in situ growth of platinum nanoparticles (PtNPs) in a nanochannel array, which can achieve highly sensitive detection of the tumor marker carcinoembryonic antigen (CEA). An inexpensive and readily available indium tin oxide (ITO) glass electrode was used as the supporting electrode, and a layer of amino-functionalized vertically ordered mesoporous silica film (NH2-VMSF) was grown on its surface using an electrochemically assisted self-assembly method (EASA). The amino groups within the nanochannels served as anchoring sites for the one-step electrodeposition of PtNPs, taking advantage of the confinement effect of the ultrasmall nanochannels. After the amino groups on the outer surface of NH2-VMSF were derivatized with aldehyde groups, specific recognition antibodies were covalently immobilized followed by blocking nonspecific binding sites to create an immunorecognition interface. The PtNPs, acting as nanocatalysts, catalyzed the generation of reactive oxygen species (ROS) with hydrogen peroxide (H2O2), significantly enhancing the ECL signal of the luminol. The ECL signal exhibited high stability during continuous electrochemical scanning. When the CEA specifically bound to the immunorecognition interface, the resulting immune complexes restricted the diffusion of the ECL emitters and co-reactants towards the electrode, leading to a reduction in the ECL signal. Based on this immune recognition-induced signal-gating effect, the immunosensor enabled ECL detection of CEA with a linear range of 0.1 pg mL-1 to 1000 ng mL-1 with a low limit of detection (LOD, 0.03 pg mL-1). The constructed immunosensor demonstrated excellent selectivity and can achieve CEA detection in serum.

Oxidative stress and protein aggregation during biological aging.

Neurodegenerative disorders, such as Alzheimer’s disease, are a global public health burden with poorly understood aetiology. Neuroinflammation and oxidative stress (OS) are undoubtedly hallmarks of neurodegeneration, contributing to disease progression. Protein aggregation and neuronal damage result in the activation of disease-associated microglia (DAM) via damage-associated molecular patterns (DAMPs). DAM facilitate persistent inflammation and reactive oxygen species (ROS) generation. However, the molecular mechanisms linking DAM activation and OS have not been well-defined; thus targeting these cells for clinical benefit has not been possible. In microglia, ROS are generated primarily by NADPH oxidase 2 (NOX2) and activation of NOX2 in DAM is associated with DAMP signalling, inflammation and amyloid plaque deposition, especially in the cerebrovasculature. Additionally, ROS originating from both NOX and the mitochondria may act as second messengers to propagate immune activation; thus intracellular ROS signalling may underlie excessive inflammation and OS. Targeting key kinases in the inflammatory response could cease inflammation and promote tissue repair. Expression of antioxidant proteins in microglia, such as NADPH dehydrogenase 1 (NQO1), is promoted by transcription factor Nrf2, which functions to control inflammation and limit OS. Lipid droplet accumulating microglia (LDAM) may also represent a double-edged sword in neurodegenerative disease by sequestering peroxidised lipids in non-pathological ageing but becoming dysregulated and pro-inflammatory in disease. We suggest that future studies should focus on targeted manipulation of NOX in the microglia to understand the molecular mechanisms driving inflammatory-related NOX activation. Finally, we discuss recent evidence that therapeutic target identification should be unbiased and founded on relevant pathophysiological assays to facilitate the discovery of translatable antioxidant and anti-inflammatory therapeutics.

A common link between all forms of acute and chronic kidney injuries, regardless of species, is enhanced generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) during injury/disease progression. While low levels of ROS and RNS are required for prosurvival signaling, cell proliferation and growth, and vasoreactivity regulation, an imbalance of ROS and RNS generation and elimination leads to inflammation, cell death, tissue damage, and disease/injury progression. Many aspects of renal oxidative stress still require investigation, including clarification of the mechanisms which prompt ROS/RNS generation and subsequent renal damage. However, we currently have a basic understanding of the major features of oxidative stress pathology and its link to kidney injury/disease, which this review summarizes. The review summarizes the critical sources of oxidative stress in the kidney during injury/disease, including generation of ROS and RNS from mitochondria, NADPH oxidase, and inducible nitric oxide synthase. The review next summarizes the renal antioxidant systems that protect against oxidative stress, including superoxide dismutase and catalase, the glutathione and thioredoxin systems, and others. Next, we describe how oxidative stress affects kidney function and promotes damage in every nephron segment, including the renal vessels, glomeruli, and tubules. Despite the limited success associated with the application of antioxidants for treatment of kidney injury/disease thus far, preventing the generation and accumulation of ROS and RNS provides an ideal target for potential therapeutic treatments. The review discusses the shortcomings of antioxidant treatments previously used and the potential promise of new ones. Antioxid. Redox Signal. 25, 119-146.

Electrochemiluminescence (ECL) has manifested a surface-confined emitting character and a low light background occurring near the electrode surface. However, the luminescence intensity and emitting layer are limited by the slow mass diffusion rate and electrode fouling in a stationary electrolyte. To address this problem, we developed an in situ strategy to flexibly regulate the ECL intensity and layer thickness by introducing an ultrasound (US) probe to the ECL detector and microscope. Herein, we explored the ECL responses and the thickness of ECL layer (TEL) under US irradiation in different ECL routes and systems. ECL microscopy with an ultrasonic probe discovered that ultrasonic radiation enhanced the ECL intensity under the catalytic route, while an opposite trend was observed under the oxidative-reduction route. Simulation results demonstrated that US promoted the direct electrochemical oxidation of TPrA radicals by the electrode rather than oxidant Ru(bpy)33+, which made the TEL thinner than that in the catalytic route under the same US condition. In situ US boosted the ECL signal from 1.2 times to 4.7 times by improving the mass transport and weakening electrode fouling due to the cavitation role. It significantly enhanced the ECL intensity beyond the diffusion-controlled ECL reaction rate. In addition, a synergistic sonochemical luminescence is validated in the luminol system to enhance the whole luminescence because cavitation bubbles of US promoted the generation of reactive oxygen species. This in situ US strategy provides a new opportunity to understand ECL mechanisms and a new tool in regulating TEL to meet the needs of ECL imaging.

Striatal neuronal cell death is one of the pathological features of Huntington's disease (HD). Overexpression of some heat shock proteins (HSPs) has been reported to suppress the aggregate formation of mutant huntingtin and concurrent cell death. Heat shock transcription factor-1 (HSF 1), a major transcription factor of HSPs, has also been reported to be increased in HD models. However, the exact role of HSF 1 in the pathogenesis of HD has not been clearly elucidated. 3-Nitropropionic acid (3NP), an irreversible inhibitor of the mitochondrial complex II, induces selective damage to the striatum in animals and produces clinical features of HD. To investigate roles of HSF 1 on 3NP-induced oxidative stress, HSF 1 was transiently overexpressed in striatal cells. Expression of HSF 1 significantly attenuated 3NP-induced apoptotic striatal cell death and resulted in increased expression of HSP 70. Furthermore, expression of HSF 1 significantly attenuated 3NP-induced intracellular reactive oxygen species (ROS) generation. Taken together, the present study clearly demonstrates that HSF 1 attenuates 3NP-induced apoptotic striatal cell death and ROS generation, possibly through HSP70 expression, suggesting that HSF 1 might be a valuable therapeutic target in the treatment of HD.

Cytochrome c release is a central step in the apoptosis induced by many death stimuli. Bcl-2 plays a critical role in controlling this step. In this study, we investigated the upstream mechanism of cytochrome c release induced by ethyl 2-amino-6-bromo-4-(1-cyano-2-ethoxy-2-oxoethyl)-4H-chromene-3-carboxylate (HA14-1), a recently discovered small molecule inhibitor of Bcl-2. HA14-1 was found to induce cytochrome c release from the mitochondria of intact cells but not from isolated mitochondria. Cytochrome c release from isolated mitochondria requires the presence of both HA14-1 and exogenous Ca(2+). This suggests that both mitochondrial and extramitochondrial signals are important. In intact cells, treatment with HA14-1 caused Ca(2+) spike, change in mitochondrial membrane potential (Delta psi(m)) transition, Bax translocation, and reactive oxygen species (ROS) generation prior to cytochrome c release. Pretreatment with either EGTA acetoxymethyl ester or vitamin E resulted in a significant decrease in cytochrome c release and cell death induced by HA14-1. Furthermore pretreatment with RU-360, an inhibitor of the mitochondrial Ca(2+) uniporter, or with EGTA acetoxymethyl ester, but not with vitamin E, prevented the HA14-1-induced Delta psi(m) transition and Bax translocation. This suggests that ROS generation is an event that occurs after the Delta psi(m) transition and Bax translocation. Together these data demonstrate that the Ca(2+) spike, mitochondrial Bcl-2 presensitization, and subsequent Delta psi(m) transition, Bax translocation, and ROS generation are important upstream signals for cytochrome c release upon HA14-1 stimulation. The involvement of endoplasmic reticulum and mitochondrial signals suggests both organelles are crucial for HA14-1-induced apoptosis.

Sensitive detection of procalcitonin (PCT) in serum is crucial for the timely diagnosis and treatment of rheumatoid arthritis. In this work, an electrochemiluminescence (ECL) detection platform is developed based on in-situ growth of Au nanoparticles (AuNPs) in nanochannels and an analyte-gated detection signal, which can realize ECL determination of PCT with high sensitivity. Vertically ordered mesoporous silica films with amine groups and uniform nanochannel array (NH2-VMSF) is easily grown on the supporting indium tin oxide (ITO) electrode through electrochemical assisted self-assembly method (EASA). Anchored by the amino groups, AuNPs were grown in-situ within the nanochannels to catalyze the generation of reactive oxygen species (ROS) and amplify the ECL signal of luminol. An immuno-recognitive interface is constructed on the outer surface of NH2-VMSF, through covalent immobilization of PCT antibodies. In the presence of PCT, the immunocomplex will hinder the diffusion of luminol and co-reactants, leading to a gating effect and decreased ECL signals. Based on this principle, the immunosensor can detect PCT in the range from 10pg/mL to 100ngmL-1 with a limit of detection (LOD) of 7pgmL-1. The constructed immunosensor can also be used for detecting PCT in serum. The constructed sensor has advantages of simple fabrication and sensitive detection, demonstrating great potential in real sample analysis.

Open AccessCCS ChemistryRESEARCH ARTICLE22 Apr 2022Photonic Crystal-Enhanced Photodynamic Antibacterial Therapy Yujie Gao†, Xiaodong Chen†, Miaomiao Li, Lianbin Zhang and Jintao Zhu Yujie Gao† Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074 , Xiaodong Chen† Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074 , Miaomiao Li Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074 , Lianbin Zhang *Corresponding authors: E-mail Address: [email protected] E-mail Address: [email protected] Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074 and Jintao Zhu *Corresponding authors: E-mail Address: [email protected] E-mail Address: [email protected] Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074 https://doi.org/10.31635/ccschem.022.202201795 SectionsSupplemental MaterialAboutAbstractPDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareFacebookTwitterLinked InEmail Photodynamic antibacterial therapy (PDAT) is a kind of rejuvenating strategy that combats bacterial infection due to its admirable characteristics of noninvasiveness and broad-spectrum antibacterial capability. However, the efficiency of PDAT can be greatly hindered by limited light irradiation. Herein, we propose an enhanced PDAT by employing photonic composite films (PCFs) via slow photon and multiple scattering effects. The PCFs are obtained by UV light-initiated polymerization of poly(ethylene glycol) phenyl ether acrylate with a self-assembled SiO2 colloidal particle array, followed by the deposition of photosensitizers (PSs). The PCFs can prompt the PSs with matched absorption, which are deposited on their surface, to sufficiently utilize the incident light and generate more reactive oxygen species based on the slow photon phenomenon of photonic crystals and multiple scattering effects of the SiO2 colloidal particles. This finding demonstrates the great potential and significance of PCFs in the field of PDAT, which may reduce the requirements of excitation equipment and avoid damage to normal tissues from exposure to huge light energy. Download figure Download PowerPoint Introduction Bacterial infection is one of the most worrying public health problems worldwide.1–7 Many serious infectious diseases, including tetanus,8,9 pulmonary tuberculosis,10–12 and bacteremia,13,14 are closely related to pathogenic bacteria. Several strategies have been developed to combat pathogenic bacteria, including the use of antibiotics and inorganic antibacterial agents, which, however, may suffer the drawbacks of microbial resistance and systemic toxicity.4,15–20 Recently, photodynamic therapy (PDT) has been recognized as an emerging technique for antibacterial purposes, that is, photodynamic antibacterial therapy (PDAT).21–23 During the process of PDAT, photosensitizers (PSs) are excited by the appropriate light, and then the excited PSs react with the surrounding oxygen molecules to generate reactive oxygen species (ROS), which cause oxidative damage to the surrounding biomolecules, including proteins, lipids, and nucleic acids, and finally lead to the death of bacteria.24–28 Especially, due to fact that ROS does not act on specific bacterial targets, PDAT does not develop any bacterial resistance and has ignorable systemic toxicity.3,21,29 These unique characteristics of PDAT make it suitable for combating local bacterial infections and sterilizing the surface of medical equipment, and so on.30–33 PSs, excitation light, and molecular oxygen are the three necessary components to achieve effective PDAT.21,34 However, biological tissues usually absorb and scatter most of the incident light. Accordingly, only limited light can be utilized by PSs, further restricting the effective application of PDAT.35,36 With regard to the insufficient excitation source, increasing the intensity of the light source is the most direct strategy to enhance PDAT, while it not only requires a higher standard of equipment but also leads to security risks due to huge light energy.37 To this end, some attempts have been made to enhance PDAT without increasing the requirement for light intensity. For example, Wang et al.35 utilized the bioluminescence of luminol to enhance PDAT to treat microbial infections through the process of bioluminescence resonance energy transfer. More recently, a PDAT system was also constructed by combining electrochemiluminescence (ECL) and PS.38 Although the process of ECL was largely controllable, the charging technology and complicated construction of the instrument still require careful consideration. Therefore, the development of a facile, convenient yet effective strategy to overcome the deficient excitation light source in PDAT remains highly desirable. Photonic crystals (PCs) are a kind of optical material with periodic nanostructures comprised of materials with different dielectric constants, which have a photonic bandgap (PBG) and exhibit unique light manipulation performance and slow photon phenomenon; that is, the photon at the edge of the PBG has a slow group velocity.39,40 Recently, some studies have shown that the slow photon phenomenon and multiple scattering effects of PCs can significantly enhance the photoluminescence of fluorophores and the photocatalytic performance of photocatalysts via promoting photon capture.40–42 We hypothesize that PCs should also be able to manipulate the light in PDAT, thereby increasing the absorption of excitation light by PSs, ultimately improving the efficiency of PDAT. In this study, by using photonic composite films (PCFs) with PS deposited on their surface, we demonstrate that PCs can effectively enhance PDAT via their slow photon phenomenon and multiple scattering effects. The PCFs were obtained by UV light-initiated crosslinking of poly(ethylene glycol) phenyl ether acrylate (PEGPEA) with the self-assembled SiO2 colloidal particle array, which exhibited satisfactory mechanical stability and provided a platform for PSs deposition. Subsequently, the PS of rose bengal (RB) was deposited on the surface of PCFs, and their capabilities for producing ROS and killing bacteria under white light irradiation were investigated. We show that PCFs can effectively improve the production of ROS and antibacterial capability compared with amorphous composite films (ACFs) and polymer films (PFs) due to the unique characteristics of PCs, that is, the slow photon phenomenon and multiple scattering effects. This study presents a breakthrough in enhanced PDAT via an innovative combination of PCs and PDT and provides insights into the design of high-performance PDAT systems. Experimental Methods Materials PEGPEA (MW 324 Da) and RB (purity > 95%) were obtained from Sigma-Aldrich (Saint Louis, MO, United States). 2-Hydroxy-2-methylpropiophenone (Darocur 1173, purity > 97%) and Chlorin e6 (Ce6, purity > 90%) were purchased from Beijing InnoChem Science & Technology Co., Ltd. (Beijing, China). Tetraethyl orthosilicate (TEOS, purity > 98%), aqueous ammonia (purity > 28%), alcohol, and N-hexane were purchased from Sinopharm (Shanghai, China). Singlet oxygen sensor green (SOSG) was purchased from Invitrogen (Shanghai, China). Escherichia coli (CCTCC AB 93154) and Staphylococcus aureus (CCTCC AB 91093) were obtained from the China Center for Type Culture Collection. Deionized (DI) water was obtained with a water purification system (NW30VF, Heal Force). All chemicals were used as received without further purification. Preparation of the PCFs and deposition of PSs on the surface of the films SiO2 colloidal particles were initially prepared by using a modified Stöber method with different sizes by adjusting the amount of TEOS and ammonia, and dispersing them in ethanol (100 mg/mL).43 To prepare PCFs, a precursor containing SiO2 colloidal particle suspension, PEGPEA, and Darocur 1173 at a mass ratio of 40:60:1 was prepared. The precursor was heated in an oven at 70 °C for 12 h to obtain the assembled precursor with brilliant structural color and then infused into a gap between two glass slides. UV light irradiation (365 nm, 2 W/cm2, MXL001A, DUVTek) was conducted on the precursor for 1 min to obtain the PCFs. For comparison, ACFs with the randomly arranged SiO2 colloidal particles and PFs without SiO2 colloidal particles were also prepared through a similar process. To deposit RB on the surface of the films, the three types of films (PCFs, ACFs, and PFs) were initially cut into small pieces (1 cm × 1 cm). Subsequently, for each piece, 8 μL of RB solution (in the mixed solvent of ethanol and N-hexane at the ratio of 1:3, v/v) with the concentration of 250 μg/mL was dripped on the surface, and the solvent was allowed to evaporate at room temperature in dark conditions. Similarly, the films deposited with Ce6 or Ag3PO4 were obtained through the above procedure. Therein, Ag3PO4 was prepared in advance according to a previously reported method.44 Detection of ROS ROS generation was determined by using the SOSG probe. In detail, the SOSG powder was initially dissolved in methanol to obtain a stock solution with a concentration of 5 mM, which was diluted to 2 μM with DI water immediately before use. Then, the films deposited with PSs were placed in a 24-well plate, followed by the addition of 500 μL of SOSG solution into each well. Subsequently, the solution was exposed to white light with a light intensity of 10 W/m2 for 3 min. Then, the fluorescence spectra of the solutions were recorded by using a fluorescence spectrometer (FP-6500, Jasco, Japan) with an excitation of 494 nm. Photodynamic inactivation of bacteria S. aureus and E. coli were chosen as the model bacteria, which were cultivated in nutrient broth (NB, pH 7.4) at 37 °C with shaking. The initial optical densities of the two bacterial suspensions were determined at 600 nm by using a UV–vis spectrophotometer (UV 1800, Shimadzu, Japan) and fixed at 0.2 (OD600 nm = 0.2). Then, the films deposited with RB were placed in a 24-well plate, followed by the addition of 500 μL of the bacterial suspensions into each well. Subsequently, the suspension of S. aureus was irradiated by a white light (10 W/m2) for 2, 5, and 10 min, respectively, and the suspension of E. coli was irradiated by a white light (600 W/m2) for 5, 10, and 20 min, respectively. After irradiation, the bacterial suspensions were collected and placed in the dark for another 20 min. The bacteria treated without RB and light acted as a control, and the viability of the bacteria treated solely with RB or light was also studied. Then, the bacterial suspensions were diluted 22,500 times with sterilized phosphate-buffered saline (PBS) solution and inoculated 50 μL of the diluted bacterial suspensions on NB agar plates. Finally, photographs were taken after the incubation of the plates at 37 °C for 24 h. The antibacterial ratio was calculated by using the following equation: Antibacterial ratio = ( C 0 − C ) / C 0 × 100 % , (1)where C0 and C represent the number of colony-forming units in the control group and experimental group, respectively. Characterizations Scanning electron microscopy (SEM, SU8010, HITACHI, Japan) was used to observe the morphology of the SiO2 colloidal particles and the PCFs. UV–vis reflection spectra were measured with a USB4000 fiber optic spectrometer (Ocean Optics, United States). Optical photographs were recorded by using a digital camera (IXUS 105, Canon, Japan). Cross-sectional confocal laser scanning microscopy (CLSM) investigation (FV1000, Olympus, Japan) was carried out to measure the penetration depth of RB. The tensile test was performed on an IBTC-300SH machine (CARE Measurement & Control Co. Ltd., Tianjin, China) with a loading rate of 6 mm/min at room temperature. Results and Discussion Preparation of the PCFs and deposition of RB PCs can slow the group velocity of the photons at the edge of PBG, which in turn intensifies the interaction between photons and matter, further improving the light-harvesting efficiency.40,45–48 In this study, we rationally designed and fabricated PCFs with PSs deposition for enhanced PDAT. Figure 1 shows the structural design of the PCFs with the PSs deposited on the surface. The PCFs were prepared through the UV light-initiated polymerization of PEGPEA in the presence of the ordered SiO2 colloidal particle array.49 Because of the photonic structures from the ordered SiO2 colloidal particles arrangement, the PCFs exhibited sharp PBG (i.e., reflection peaks) with brilliant structural colors. The PBG of the PCFs were easily adjusted by varying the size of SiO2 colloidal particles. As shown in Figure 2a and Supporting Information Figure S1, by using SiO2 colloidal particles with sizes of 156, 174, and 218 nm, respectively, three different PCFs with their PBGs at ∼400–445 nm, ∼500–590 nm, and ∼615–710 nm, exhibiting blue, green, and red appearance, were obtained (denoted as PCF-blue, PCF-green, and PCF-red, respectively). Taking the PCF-green as an example, SEM measurements were used to characterize its microstructure. As shown in Figures 2b–2d, the thickness of the obtained PCF was ∼104 μm, and a well-ordered and non-close hexagonal packed arrangement of the SiO2 colloidal particles were observed on the surface and cross-sectional views, which was essential for generating a sharp PBG.50 Meanwhile, we found that the PCFs had good mechanical properties with an elongation at the break of 137% and tensile strength of 407 KPa ( Supporting Information Figure S2). Moreover, the PCFs also exhibited good stability as evidenced by the unchanged reflection spectra after 6 months of storage, ensuring their application as a platform for PDAT ( Supporting Information Figure S3). Figure 1 | Schematic illustration showing the preparation of PCFs deposited with PSs and their capability in enhancing ROS generation and enhanced PDAT. Download figure Download PowerPoint The PCF-green has an obvious reflection in the PBG between ∼500 and 590 nm, implying that it can prevent the propagation of light in this band, and the light will be back-reflected to the surface of the film. Hence, PSs with matched absorption wavelengths deposited on the surface of the PCF-green will absorb the reflected light, further leading to enhanced ROS generation efficiency. To this end, RB with a high absorption between 480 and 580 nm was chosen as a model PS, which approximately overlapped with the reflection wavelengths of the as-obtained PCF-green (Figure 2e). CLSM images were collected to observe the distribution of RB on the film.50 As shown in Figures 2f–2h, we can find that the RB molecules are homogeneously deposited on the surface of the PCF-green, and its distribution depth was ∼17 μm. Figure 2 | Preparation and characterization of the PCFs. (a) Normalized reflection spectra recorded by a fiber optic spectrometer with a white light source and corresponding photographs of PCFs with different PBGs prepared from SiO2 colloidal particles of different sizes. Scale bar in (a) is 5 mm. (b) The cross-sectional, (c) magnified surface, and (d) magnified cross-sectional SEM images of PCF-green. (e) The reflection spectrum of PCF-green and the absorption spectrum of RB. (f–h) Cross-sectional CLSM images of PCF-green deposited with RB. The red fluorescence signal originated from RB excited with the incident laser of 543 nm. Download figure Download PowerPoint Enhanced generation of ROS Having obtained the RB-deposited PCFs, we then verified their capability in enhancing ROS generation during the photodynamic process. Considering that both the slow photon effect of PCs and multiple scattering effects of SiO2 colloidal particles in the polymer matrix might contribute to the enhanced light-harvesting efficiency of RB, we also prepared PFs ( Supporting Information Figure S4) and ACFs ( Supporting Information Figure S5) with the randomly arranged SiO2 colloidal particles in the polymeric matrix for comparison. Meanwhile, PCF with PBG that is out of the absorption range of RB was also employed. To this end, SOSG, which emits fluorescence between ∼525 and 536 nm after oxidation, was employed to measure the ROS levels.31,51 Figure 3a reveals that under the irradiation of white light, which is commonly used to excite RB, for 3 min, maximum fluorescent intensity was observed in the PCF-green group and minimum fluorescent intensity in the PF group, indicating that RB on the PCF-green can generate the most ROS, while ROS generated in the PF generated the least. To intuitively demonstrate the influence of films on the production of ROS, we used PF as the control and defined the ratio of fluorescent intensity in different groups and that in the control group as an enhancement factor. According to the calculation, the enhancement factors were 1.70 ± 0.03, 2.21 ± 0.07, and 2.73 ± 0.17 for the ACF, PCF-red, and PCF-green groups, respectively (Figure 3b). The highest enhancement factor occurred in the PCF-green group. Because the PBG of PCF-green almost overlapped with the absorption spectrum of RB, the reflected light was sufficiently absorbed by RB. The slow photon phenomenon of PCs plays an important role in ROS enhancement. At the edge of PBG, the group velocity of light propagation was reduced, thereby intensifying the interaction of photons and PS, further leading to more ROS being generated. In addition, the multiple scattering effects of SiO2 colloidal particles in the polymer matrix also improved the absorption of light by RB. In contrast, the ACF and PCF-red exhibited a relatively lower enhancement of ROS production, which may solely be the result from the multiple scattering effects of SiO2 colloidal particles in the films.50 Figure 3 | PCF-green enhanced ROS production from RB under white light irradiation by using SOSG as a probe. (a) The fluorescent emission spectra of SOSG in different groups. (b) The corresponding enhancement factors in different groups. (c) Reflection spectra of PCF-green with different thicknesses. (d) The fluorescence emission spectra of SOSG in the PCF-green group with different thicknesses. Download figure Download PowerPoint Moreover, the effect of the thickness of the PCF on ROS generation was also investigated. From the reflection spectra, we found that the reflectivity of PCF-green increased with the thickness while their PBGs remained unchanged (Figure 3c). Subsequently, SOSG was also employed to demonstrate the capability of the PCF-green with different thicknesses in enhancing ROS production. As revealed in Figure 3d, stronger fluorescence was observed in the thicker (e.g., 100 and 200 μm) PCF-green groups, indicating that more ROS was generated, while relatively weaker fluorescent intensity was observed in the PCF-green group with the thickness of 50 μm. Considering that the greater influence of multiple scattering effects may be brought from the thicker film, the PCF-green with an optimized thickness of 100 μm was used in the following studies. To verify the generality of the enhanced ROS production by the PCs, we prepared Ce6 deposited PCF-blue ( Supporting Information Figure S6) and Ag3PO4 nanoparticles deposited PCF-green ( Supporting Information Figures S7 and S8), whose PBGs were roughly matched with the corresponding PSs and photocatalysts, respectively. Similarly, the ROS generation was also measured by adopting the SOSG probe. As expected, maximum fluorescent intensity was observed in the two PCF groups, indicating that Ce6 and Ag3PO4 on the PCFs generated the most ROS ( Supporting Information Figures S9 and S10). The above results demonstrated that PCFs are universal in enhancing the production of ROS by PSs or photocatalysts, and the improvement can be attributed to the increment of light-harvesting efficiency by PSs based on the slow photon effect of PCs and multiple scattering effects of SiO2 colloidal particles. In vitro antibacterial study Having demonstrated that PCs can enhance the capability of PSs or photocatalysts to produce ROS, we reasonably speculate that PCs can enhance the antibacterial effect of PDAT. To this end, we took S. aureus and E. coli as examples to demonstrate the enhanced PDAT based on RB, which was deposited on the surface of three different films (i.e., PCF-green, ACF, and PF). As shown in Figures 4a and 4b, when S. aureus was treated solely with RB or light (10 W/m2), all three different groups did not show any obvious effects on bacteria. In contrast, when being treated with RB and upon light irradiation for 2 min, the antibacterial ratio of the PCF group was 77.9% ± 2.3%, which was increased by ∼15.3% and ∼38.7% over those of the ACF group (62.6% ± 3.1%) and the PF group (39.2% ± 2.2%). The above results indicate that PCF can improve the PDAT effect of RB, which resulted from the enhancement of the light-harvesting efficiency of RB and further increased the production of ROS. However, further extending the irradiation time to 10 min, the antibacterial ratio of the PF group reached 98.2% ± 0.5%, which was almost the same with the ACF group (99.6% ± 0.3%) and the PCF group (99.7% ± 0.2%). These results indicate that the PCF can assist the PSs to utilize limited excitation light, thereby effectively producing ROS and displaying a higher antibacterial ratio. Figure 4 | Antibacterial activities of RB on the surface of different films under white light irradiation. Photographs of bacterial colonies formed by (a) S. aureus and (c) E. coli after being incubated in Petri dishes for 24 h at 37 °C. The scale bars in the last image in (a) and (c) apply to the other images. The antibacterial ratio against (b) S. aureus and (d) E. coli. The error bars represent the standard deviation. Download figure Download PowerPoint Compared with S. aureus, the PDAT effect of RB to E. coli was relatively weak, which is probably due to the obvious structural difference of their cell envelope. In other words, Gram-negative bacteria (e.g., E. coli) have a bilayer membrane structure with a dense outer layer, which may reduce the killing effect of PDAT.21,52,53 Hence, relatively long periods and harsh conditions were adopted for irradiation. We found that sole treatments of RB or light (600 W/m2) did not display any obvious effects on the bacteria. When the irradiation time was 5 min, the antibacterial ratio of the PCF group was ± which was increased by and those of the ACF group ± and PF group ± When the irradiation time was to 20 min, the antibacterial ratio of the PF group, the ACF group, and the PCF group reached ± ± and ± respectively and we can that PCs can improve the antibacterial effect of PDAT when the excitation light is which not only the requirements of excitation equipment but also damage to normal tissues by huge light which is of great significance in the field of PDAT. We have demonstrated that PCs can effectively enhance the PDAT by using PCFs. When the absorption of PSs or photocatalysts matched with the PBGs of the PCFs, the slow photon phenomenon of PCs and multiple scattering effects of SiO2 colloidal particles improved the capability of PSs or photocatalysts to light by intensifying the interaction between photons and matter, thereby enhancing the ROS production In addition, ROS bacteria by oxidative damage to the biomolecules, the antibacterial ratio increased by under light irradiation, effective PDAT. The excitation light is one in PDAT. the intensity of light is a direct to improve the PDAT, which, however, the of damage by huge light energy at the same Therefore, improving the efficiency of PSs or photocatalysts to excitation light can be a and effective strategy to enhance the efficiency of PDAT. that this finding provides a convenient yet strategy for enhancing the efficiency of PDAT without increasing the on equipment and damage to normal tissues by huge light energy. Supporting Information Supporting Information is and Figures and the characterization of Ag3PO4 of is of to Information This was by the Science of China The the and Center for their in the use of their S. and of Bacterial Zhang Li into with Antibacterial 2, Li Zhang Wang of and Li Wang with and Enhanced of Staphylococcus aureus Zhang Zhang Li into the by Staphylococcus aureus 2, of Zhang Li Bacterial Wang Wang Zhang Li and of a in in and and against

Cell adhesion molecules play an important role in inflammatory response, angiogenesis and tumor progression. Butein (tetrahydroxychalcone) is a small molecule from natural sources, known to be a potential therapeutic drug with anti-inflammatory, anticancer and antioxidant activities. In the present study, we investigated the inhibitory effect of butein on tumor necrosis factor (TNF)-α-induced adhesion molecule expression and its molecular mechanism of action. Butein significantly decreased TNF-α-induced monocyte (U937) cell adhesion to lung epithelial cells in a dose-dependent manner. Butein also inhibited the protein and mRNA expression of intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in TNF-α-stimulated A549 human lung epithelial cells in a dose-dependent manner. Butein inhibited TNF-α-induced reactive oxygen species (ROS) generation and nuclear factor-κB (NF-κB) activation in A549 cells; it also inhibited the phosphorylation of MAPKs and Akt, suggesting that the MAPK/Akt signaling pathway may be involved in the butein-mediated inhibition of TNF-α-induced leukocyte adhesion to A549 cells. Collectively, our results suggest that butein affects cell adhesion through the inhibition of TNF-α-induced ICAM-1 and VCAM-1 expression by inhibiting the NF-κB/MAPK/Akt signaling pathway and ROS generation, thereby, elucidating the role of butein in the anti-inflammatory response.

The eye lens is mainly composed of the highly ordered water-soluble (WS) proteins named crystallins. The aggregation and insolubilization of these proteins lead to progressive lens opacification until cataract onset. Although this is a well-known disease, the mechanism of eye lens protein aggregation is not well understood; however, one of the recognized causes of proteins modification is related to the exposure to UV light. For this reason, the spectroscopic properties of WS lens proteins and their stability to UV irradiation have been evaluated by different biophysical methods including synchrotron radiation circular dichroism, fluorescence, and circular dichroism spectroscopies. Moreover, dynamic light scattering, gel electrophoresis, transmission electron microscopy, and protein digestion followed by tandem LC–MS/MS analysis were used to study the morphological and structural changes in protein aggregates induced by exposure to UV light. Our results clearly indicated that the exposure to UV radiation modified the protein conformation, inducing a loss of ordered structure and aggregation. Furthermore, we confirmed that these changes were attributable to the generation of reactive oxygen species due to the irradiation of the protein sample. This approach, involving the photodenaturation of proteins, provides a benchmark in high-throughput screening of small molecules suitable to prevent protein denaturation and aggregation.

Phototoxicity of CdSe/ZnSe quantum dots with surface coatings of 3-mercaptopropionic acid or tri- n-octylphosphine oxide/gum arabic in Daphnia magna under environmentally relevant UV-B light

WARNING : The light-emitting molecular structures responsible for the chemiluminescence and fluorescence phenomena are not necessarily the same!