Photocatalytic polypyrrole-TiO2-nanoparticles composite thin film generated at the air-water interface

Synthesis of the Ag2S/PANI@PES Composite Membrane and Its Antipollution Properties

Membrane separation technology offers a sustainable and efficient solution to wastewater management; however, membrane fouling significantly impedes its application. Photocatalytic membranes, integrating photocatalytic and membrane separation technologies, enhance membrane separation efficacy while effectively mitigating organic and biological contaminations. In this work, Ag2S/PANI@PES composite membranes were prepared via a facile in situ polymerization and successive layer adsorption technique. The modified poly(ether sulfone) (PES) membrane demonstrated improved hydrophilicity and separation performance, and its heterostructure between polyaniline (PANI), Ag0, and Ag2S effectively addressed organic fouling issues. Moreover, Ag2S/PANI@PES exhibited outstanding antimicrobial properties, as well as chemical and mechanical stability.

Multifunctional screen-printed films using polymer nanocomposite based on PPy/TiO2: conductive, photocatalytic, self-cleaning and antibacterial functionalities

In this work, two electrically conductive samples based on polypyrrole (PPy) and (PPy/TiO₂) were synthesized via mini-emulsion polymerization. Synthesized samples were used as functional fillers to formulate two different screen-printing pastes (pastes A and B) to obtain the multi-purpose printed films with excellent properties, including electrical conductivity, antibacterial, photocatalytic activity, and self-cleaning. The surface tension, pH, and conductivity measurements validated the acceptable features of the produced pastes. Because of the shear-thinning behavior and viscosity buildup properties of the produced pastes, rheological investigations confirmed their potential for screen-printing. According to I–V test results, the optimum sintering temperature was chosen as a function of electrical conductivity, and the properties of the printed patterns were investigated by varying the printing sequences as 3, 6, and 9 times and sintered at the optimum temperature (90 °C). The contact angle of water on the optimum sample printed by Paste B was ca. 127° and relatively higher than the counterpart printed by Paste A which verified the superiority of the self-cleaning properties of the printed films with latter paste over the former. The photocatalytic studies concerning the degradation of methylene blue showed that the removal percentage of ca. 63% was achieved within the first 90 min of performing the test under UV light. The photocatalytic printed film was addressed the issue of filtering the unused suspension of nanoparticles, which made it difficult to remove the particles from the treated wastewater, in terms of sustainability. The fabricated patterns using Paste B exhibited improved properties, including electrical conductivity, antibacterial and photocatalytic activity.

Conjugated Polymer Polypyrrole Nanostructures: Synthesis and Photocatalytic Applications

Conjugated polymers (CPs) have been recently widely investigated for their properties and their applications in different fields including photocatalysis. Among the family of CPs, polypyrrole (PPy) has been the most extensively studied owing to its good environmental stability, high electrical conductivity, superior redox properties and easy synthesis. Besides, nanostructured polypyrrole-based nanomaterials are a type of active organic materials for photocatalysis, which is one of their emerging applications. Nanostructuration of polypyrrole can reduce the electron-hole recombination because of short charge transfer distances and reactant adsorption, and product desorption can be enhanced owing to the high surface area offered by nanostructures. This review summarizes synthesis of different nanostructures based on π-conjugated polymer polypyrrole and the latest developments for photocatalytic applications, including degradation of organic pollutants and hydrogen generation.

Breast Cancer Inhibition by Biosynthesized Titanium Dioxide Nanoparticles Is Comparable to Free Doxorubicin but Appeared Safer in BALB/c Mice

Cancer remains a global health burden prompting affordable, target-oriented, and safe chemotherapeutic agents to reduce its incidence rate worldwide. In this study, a rapid, cost-effective, and green synthesis of titanium dioxide (TiO₂) nanoparticles (NPs) has been carried out; Ex vivo and in vivoevaluation of their safety and anti-tumor efficacy compared to doxorubicin (DOX), a highly efficient breast anti-cancer agent but limited by severe cardiotoxicity in many patients.Thereby,TiO₂ NPs were eco-friendly synthetized using aqueous leaf extract of the tropical medicinal shrub Zanthoxylum armatum as a reducing agent. Butanol was used as a unique template. TiO₂ NPs were physically characterized by ultraviolet-visible (UV-Vis) spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscope (SEM), X-ray powder diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR) as routine state-of-the art techniques. The synthesized TiO₂ NPs were then evaluated for their cytotoxicity (by MTT, FACS, and oxidative stress assays) in 4T1 breast tumor cells, and their hemocompatibility (by hemolysis assay). In vivo anti-tumor efficacy and safety of the TiO₂ NPs were further assessed using subcutaneous 4T1 breast BALB/c mouse tumor model.The greenly prepared TiO₂ NPs were small, spherical, and crystalline in nature. Interestingly, they were hemocompatible and elicited a strong DOX-like concentration-dependent cytotoxicity-induced apoptosis both ex vivo and in vivo (with a noticeable tumor volume reduction). The underlying molecular mechanism was, at least partially, mediated through reactive oxygen species (ROS) generation (lipid peroxidation). Unlike DOX (P < 0.05), it is important to mention that no cardiotoxicity or altered body weight were observed in both the TiO₂ NPs-treated tumor-bearing mouse group and the PBS-treated mouse group (P > 0.05). Taken together, Z. armatum-derived TiO₂ NPs are cost-effective, more efficient, and safer than DOX. The present findings shall prompt clinical trials using green TiO₂ NPs, at least as a possible alternative modality to DOX for effective breast cancer therapy.

Recent Advances in Nanotechnology-Based Diagnosis and Treatments of Human Osteosarcoma

Osteosarcoma (OSA) is a type of bone cancer that begins in the cells that form bones.OSA is a rare mesenchymal bone neoplasm derived from mesenchymal stem cells. Genome disorganization, chromosomal modifications, deregulation of tumor suppressor genes, and DNA repair defects are the factors most responsible for OSA development. Despite significant advances in the diagnosing and treatment of OSA, patients' overall survival has not improved within the last twenty years. Lately, advances in modern nanotechnology have spurred development in OSA management and offered several advantages to overcome the drawbacks of conventional therapies. This technology has allowed the practical design of nanoscale devices combined with numerous functional molecules, including tumor-specific ligands, antibodies, anti-cancer drugs, and imaging probes. Thanks to their small sizes, desirable drug encapsulation efficiency, and good bioavailability, functionalized nanomaterials have found wide-spread applications for combating OSA progression. This review invokes the possible utility of engineered nanomaterials in OSA diagnosis and treatment, motivating the researchers to seek new strategies for tackling the challenges associated with it.

Enhancing the colorimetric detection of H2O2 and ascorbic acid on polypyrrole coated fluconazole-functionalized POMOFs

A new fluconazole-functionalized polyoxometalate-based metal-organic framework (POMOF) [Ag₃(FKZ)₂(H₂O)₂][H₃SiW₁₂O₄₀] (AgFKZSiW₁₂) was successfully constructed, and its polypyrrole (PPy) coated composite AgFKZSiW₁₂@PPy was also obtained via a facile 'in situ' oxidation polymerization process. The peroxidase-like activity evaluation indicates that the maximized synergistic effect from the integration of PPy, SiW₁₂ clusters, HFKZ drug molecules, and Ag ions deeply enhanced the overall performance. More importantly, AgFKZSiW₁₂@PPy exhibits the fastest response time (30 s) among all the reported peroxidase mimics to date, including the pristine AgFKZSiW₁₂ (2 min). Moreover, the AgFKZSiW₁₂@PPy-based colorimetric biosensing platform towards H₂O₂ and ascorbic acid (AA) exhibits limits of detection (LOD) as low as 0.12 μM and 2.7 μM, respectively. This work reveals a promising prospect in medical diagnosis and biotechnology for colorimetric biosensor fabrication with high performance through the introduction of PPy.

Microfluidic Production of Poly(1,6-hexanediol diacrylate)-Based Polymer Microspheres and Bifunctional Microcapsules with Embedded TiO2 Nanoparticles

Application of TiO₂ as a photocatalyst and UV protector is restricted by the difficulties in the recovery of TiO₂ nanoparticles after water treatment. In this work, TiO₂ nanoparticles (Degussa P25) were immobilised within easily recoverable poly(1,6-hexanediol diacrylate) poly(HDDA)-based polymer microspheres produced by on-the-fly photopolymerization of microfluidically generated droplets. Because of fast polymerization reaction, TiO₂ was uniformly distributed within the polymer network. The transformation of double bonds in terminal vinyl groups of HDDA monomer into single bonds during photopolymerization was confirmed by Fourier transform infrared spectroscopy. The microspheres containing 0.5 wt % TiO₂ embedded in a poly(HDDA) matrix degraded 80% of methylene blue from 1 ppm aqueous solution in 9 h under UV light irradiation of 0.9 mW/cm² at 365 nm. The microspheres could easily be separated from water and used in repeated cycles without any loss in photocatalytic activity. The inclusion of TiO₂ within a polymer matrix increased the thermal degradation temperature of the material from 364 to 389 °C. Bifunctional microcapsules consisting of aqueous or liquid paraffin core enclosed within a TiO₂/poly(HDDA) composite polymer shell were also prepared. The fluorescent dye calcein was encapsulated in the core with 100% efficiency.

A green method based on electro-assisted and photo-assisted regeneration for removal of chromium(VI) from aqueous solution

In general, spent adsorbent is regenerated using high-concentration chemicals. Although chemical regeneration is efficient, it often leads to adsorbent damage and secondary waste. To overcome these problems, electro-assisted and photo-assisted regeneration were proposed in this study for the remediation of hexavalent chromium (Cr(VI)). Filter paper was decorated with polyethylene glycol (PEG) and polypyrrole (PPy) to fabricate a FP/PEG/PPy nanocomposite, which could be used as an adsorbent for Cr(VI) with a high adsorption capacity. Moreover, it could be regenerated by electro-assisted or photo-assisted regeneration to reduce eluent use. As a result, secondary waste could be greatly reduced.

Synthesis of bare and surface modified TiO2 nanoparticles via a single source precursor and insights into their interactions with serum albumin

Choice of an apt surface modifier to design a more efficient TiO₂ NP based photosensitizer for PDT applications.

Highlights in nanocarriers for the treatment against cervical cancer

Cervical cancer is the second most common malignant tumor in women worldwide and has a high mortality rate, especially when it is associated with human papillomavirus (HPV). In US, an estimated 12,820 cases of invasive cervical cancer and an estimated 4210 deaths from this cancer will occur in 2017. With rare and very aggressive conventional treatments, one sees in the real need of new alternatives of therapy as the delivery of chemotherapeutic agents by nanocarriers using nanotechnology. This review covers different drug delivery systems applied in the treatment of cervical cancer, such as solid lipid nanoparticles (SNLs), liposomes, nanoemulsions and polymeric nanoparticles (PNPs). The main advantages of drug delivery thus improving pharmacological activity, improving solubility, bioavailability to bioavailability reducing toxicity in the target tissue by targeting of ligands, thus facilitating new innovative therapeutic technologies in a too much needed area. Among the main disadvantage is the still high cost of production of these nanocarriers. Therefore, the aim this paper is review the nanotechnology based drug delivery systems in the treatment of cervical cancer.

Beads-on-String Structured Nanofibers for Smart and Reversible Oil/Water Separation with Outstanding Antifouling Property

It is challenging to explore a unified solution for the treatment of oily wastewater from complex sources. Thus, membrane materials with flexible separation schemes are highly desired. Herein, we fabricated a smart membrane by electrospinning TiO2 doped polyvinylidene fluoride (PVDF) nanofibers. The as-formed beads-on-string structure and hierarchical roughness of the nanofibers contribute to its superwetting/resisting property to liquids, which is desirable in oil/water separation. Switched simply by UV (or sunlight) irradiation and heating treatment, the smart membrane can realize reversible separation of oil/water mixtures by selectively allowing water or oil to pass through alone. Most importantly, the as-prepared nanofiber membrane possesses outstanding antifouling and self-cleaning performance resulting from the photocatalytic property of TiO2, which has practical significance in saving solvents and recycling materials. This work provides a route for fabricating cost-effective, easily scaled up, and recyclable membranes for on-demand oil/water separation in versatile situations, which can be of great usage in the new green separation technology.

In Vitro Therapeutic Potential of Tio2 Nanoparticles Against Human Cervical Carcinoma Cells

Cellular and physiological responses to the degradation products of titanium implants are key indicators to determine the quality of biocompatibility of implant devices. The present study investigated titanium dioxide (TiO2) nanoparticle-induced cytotoxicity, apoptotic morphological modification, and apoptotic-related gene expressions in the human cervical carcinoma cells. TiO2 nanoparticle-induced cytotoxicity on cancer cells was determined by the sulphorhodamine-B assay. Apoptotic morphological modification such as nuclear fragmentation, rounding, cytoplasm shrinkage, loss of adhesion, and reduced cell volume were observed by an inverted, fluorescence, and confocal laser scanning microscope (CLSM). The DNA fragmentation study showed the occurrence of necrosis and apoptosis in nanoparticle-treated cells. The qPCR study showed the increased p53 and bax mRNA expression in the nanoparticle-treated cells compared to control. In addition, caspase 3 activity was increased in nanoparticle-treated cells, which indicates the increased auto-catalysis. Taking all these data together, it may suggest that TiO2 nanoparticle could inhibit the growth of HeLa cells.

Facile Synthesis of SrCO₃-Sr(OH)₂/PPy Nanocomposite with Enhanced Photocatalytic Activity under Visible Light

Pyrrole monomer was chemically polymerized onto SrCO₃-Sr(OH)₂ powders to obtain SrCO₃-Sr(OH)₂/polypyrrole nanocomposite to be used as a candidate for photocatalytic degradation of methylene blue dye (MB). The material was characterized by Fourier transform infrared (FTIR) spectroscopy, UV/Vis spectroscopy, and X-ray diffraction (XRD). It was observed from transmission electronic microscopy (TEM) analysis that the reported synthesis route allows the production of SrCO₃-Sr(OH)₂ nanoparticles with particle size below 100 nm which were embedded within a semiconducting polypyrrole matrix (PPy). The SrCO₃-Sr(OH)₂ and SrCO₃-Sr(OH)₂/PPy nanocomposites were tested in the photodegradation of MB dye under visible light irradiation. Also, the effects of MB dye initial concentration and the catalyst load on photodegradation efficiency were studied and discussed. Under the same conditions, the efficiency of photodegradation of MB employing the SrCO₃-Sr(OH)₂/PPy nanocomposite increases as compared with that obtained employing the SrCO₃-Sr(OH)₂ nanocomposite.

Organically modified titania nanoparticles for sustained drug release applications

In this paper, we report the synthesis, characterization of drug-doped organically modified titania nanoparticles, and their applications in sustained drug release. The drug-doped nanoparticles were synthesized in the hydrophobic core of oil-in-water microemulsion medium. Structural aspects obtained through TEM and FESEM depicted that organically modified titania nanoparticles are monodispersed with spherical morphology, with an average size of around 200 nm. Their polymorphic forms and porosity were determined using powder XRD and BET, respectively, which showed that they are present in the anatase form, with a surface area of 136.5 m(2)/g and pore-diameter of 5.23 nm. After synthesis and basic structural characterizations, optical properties were studied for both fluorophore and drug encapsulated nanoparticles. The results showed that though the optical properties of the fluorophore are partially diminished upon nanoencapsulation, it became more stable against chemical quenching. The nanoparticles showed pH-dependent drug release pattern. In vitro studies showed that the nanoparticles were efficiently uptaken by cells. Cell viability assay results showed that though the placebo nanoparticles are non-cytotoxic, the drug-doped nanoparticles show drug-induced toxicity. Therefore, such porous nanoparticles can be used in non-toxic drug delivery applications.

A new strategy for TiO2 whiskers mediated multi-mode cancer treatment

Traditional Chinese medicine (TCM) which functions as chemotherapeutic or adjuvantly chemotherapeutic agents has been drawing a great many eyeballs for its easy obtain and significant antitumor effects accompanied with less toxic and side effects. PDT (photodynamic therapy) utilizes the fact that certain compounds coined as photosensitizers, when exposed to light of a specific wavelength, are capable of generating cytotoxic reactive oxygen species (ROS) such as hydroxyl radical, hydrogen peroxide, and superoxide to kill cancer cells. Combinations of cancer therapeutic modalities are studied to improve the efficacy of treatment. This study aimed to explore a new strategy of coupling of titanium dioxide whiskers (TiO2 Ws) with the anticancer drug gambogic acid (GA) in photodynamic therapy. The nanocomposites were coined as GA-TiO2. The combination of TiO2 Ws with GA induced a remarkable enhancement in antitumor activity estimated by MTT assay, nuclear DAPI staining, and flow cytometry. Furthermore, the possible signaling pathway was explored by reverse transcription polymerase chain reaction (RT-PCR) and Western blot assay. These results identify TiO2 Ws of good biocompatibility and photocatalytic activity. In human leukemia cells (K562 cells), TiO2 Ws could obviously increase the intracellular concentration of GA and enhance its potential antitumor efficiency, suggesting that TiO2 Ws could act as an efficient drug delivery carrier targeting GA to carcinoma cells. Moreover, photodynamic GA-TiO2 nanocomposites could induce an evident reinforcement in antitumor activity with UV illumination. These results reveal that such modality combinations put forward a promising proposal in cancer therapy.

Insulating and semiconducting polymeric free-standing nanomembranes with biomedical applications

Free-standing nanomembranes, which are emerging as versatile elements in biomedical applications, are evolving from being composed of insulating (bio)polymers to electroactive conducting polymers.

Surface imprinting of a g-C3N4 photocatalyst for enhanced photocatalytic activity and selectivity towards photodegradation of 2-mercaptobenzothiazole

Based on Fe₃O₄/g-C₃N₄ as the support, 2-mercaptobenzothiazole (MBT) as the template molecule, and pyrrole as the functional monomer, we synthesized magnetic conductive imprinted photocatalysts (MCIPs) that were significantly efficient and stable.

Conjugated polymer/nanocrystal nanocomposites for renewable energy applications in photovoltaics and photocatalysis

Conjugated polymer/nanocrystal composites have attracted much attention for use in renewable energy applications because of their versatile and synergistic optical and electronic properties. Upon absorbing photons, charge separation occurs in the nanocrystals, generating electrons and holes for photocurrent flow or reduction/oxidation (redox) reactions under proper conditions. Incorporating these nanocrystals into conjugated polymers can complement the visible light absorption range of the polymers for photovoltaics applications or allow the polymers to sensitize or immobilize the nanocrystals for photocatalysis. Here, the current developments of conjugated polymer/nanocrystal nanocomposites for bulk heterojunction-type photovoltaics incorporating Cd- and Pb-based nanocrystals or quantum dots are reviewed. The effects of manipulating the organic ligands and the concentration of the nanocrystal precursor, critical factors that affect the shape and aggregation of the nanocrystals, are also discussed. In the conclusion, the mechanisms through which conjugated polymers can sensitize semiconductor nanocrystals (TiO2 , ZnO) to ensure efficient charge separation, as well as how they can support immobilized nanocrystals for use in photocatalysis, are addressed.

In vitro and in vivo anticancer activity of surface modified paclitaxel attached hydroxyapatite and titanium dioxide nanoparticles

Targeted drug delivery using nanocrystalline materials delivers the drug at the diseased site. This increases the efficacy of the drug in killing the cancer cells. Surface modifications were done to target the drug to a particular receptor on the cell surface. This paper reports synthesis of hydroxyapatite and titanium dioxide nanoparticles and modification of their surface with polyethylene glycol (PEG) followed by folic acid (FA). Paclitaxel, an anticancer drug, is attached to functionalized hydroxyapatite and titanium dioxide nanoparticles. The pure and functionalised nanoparticles are characterised with XRD, TEM and UV spectroscopy. Anticancer analysis was carried out in DEN induced hepatocarcinoma animals. Biochemical, hematological and histopathological analysis show that the surface modified paclitaxel attached nanoparticles have an higher anticancer activity than the pure paclitaxel and surface modified nanoparticles without paclitaxel. This is due to the targeting of the drug to the folate receptor in the cancer cells.

Principles and mechanisms of photocatalytic dye degradation on TiO2based photocatalysts: a comparative overview

Pictorial representation of all possible dye degradation reaction in UV light initiated indirect dye degradation mechanism. This mechanism is practically more important over visible light initiated direct mechanism.

Loading of PPy on the surface of transition metal coordination polymer modified polyoxometalate (TMCP/POM): a feasible strategy to obtain visible light active and high quantum yields POM based photocatalyst

PPy loaded TMCP/POM composite materials were fabricated successfully and display better photocatalytic activity than TMCP/POM under visible light irradiation.

Polypyrrole-decorated Ag-TiO2 nanofibers exhibiting enhanced photocatalytic activity under visible-light illumination

In this work, a novel photocatalyst, polypyrrole (PPy)-decorated Ag-TiO2 nanofibers (PPy-Ag-TiO2) with core-shell structure, was successfully synthesized using an electrospinning technique, followed by a surfactant-directed in situ chemical polymerization method. The results show that a PPy layer was formed on the surface of Ag-TiO2 nanofiber, which is beneficial for protecting Ag nanoparticles from being oxidized. Meanwhile, the PPy-Ag-TiO2 system exhibits remarkable light absorption in the visible region and high photocurrent. Among them, the 1%-PPy-Ag-TiO2 sample shows the highest photoactivity, which is far exceeds that of the single- and two-component systems. This result may be due to the synergistic effect of Ag, PPy, and TiO2 nanostructures in the ternary system.