pH-responsive Photinia glabra-zinc oxide-protoporphyrin IX nanoconjugates with enhanced cellular uptake for photodynamic therapy towards cancer cells.

Background: Photodynamic therapy (PDT) of cancer has been limited by the poor solubility of most photosensitizers, use of high drug dosages, and the pH difference between the tumor tissue microenvironment (slightly acidic) and the bloodstream. These affect cellular uptake, selectivity and singlet oxygen generation. Materials & methods: We formulated Photinia glabra-green synthesized zinc oxide-protoporphyrin IX (PG-ZnO-PP) nanoconjugates by conjugating the ZnO nanoparticles enriched with amino groups and PP. Results: PG-ZnO-PP nanoconjugates showed higher rate of reactive oxygen species generation, improved cellular uptake in the acidic pH and lower IC50 toward Eca-109 cells for PDT. Conclusion: PG-ZnO-PP nanoconjugates are a potential solution to reducing drug dosage of PP through improved drug uptake, for enhanced targetability and reduced skin photosensitivity with improved PDT efficacy.

The progress of treating cancer using light-sensitive drugs and laser light of known wavelength has been limited by the poor solubility of most light-sensitive drugs, the use of high drug dosages and the slightly acidic environment within the cancerous tissues compared with normal blood in the body. These affect the ability of drugs to accumulate in cancerous cells, and not the normal cells, and the ability to produce the oxygen species that are toxic to the cancerous cells. In this paper, we prepared nanoparticles from zinc acetate using Photinia glabra (PG) fruit extract which were then used to chemically react with a light-sensitive drug called protoporphyrin IX (PP) to formulate small particles known as PG­zinc oxide (ZnO)­PP nanoconjugates. Our results showed that PG­ZnO­PP nanoconjugates had the ability to produce the toxic oxygen particles at a high rate and in good quantity. They also had a higher capability to accumulate in the cancerous cells at a pH below 7 with lower values of the drug needed to cause 50% of cell death toward the cancerous cells which affect the tube that connects from the throat to the stomach when projected with laser light. We could consider PG­ZnO­PP nanoconjugates to serve as a potential solution for reducing the dosage of PP needed to treat cancer in the presence of laser light, and at the same time they can help to reduce the skin-related side effects for patients after treatment when exposed to light.

In-Vitro Ibuprofen Release Monitoring Using Carbon Quantum Dots.

In this study, nitrogen-doped carbon quantum dots CQDs, synthesized from malic acid and EDTA, were encapsulated using sodium alginate. Different parameters affecting loading capacity (such as capsules' sizes, complexation solution's concentration and encapsulation method) were investigated. After that, ibuprofen (Ibu), taken as a model drug, was tagged by CQDs to form Ibu-CQDs adduct, and then encapsulated using sodium alginate. The results showed high values of loading capacity of CQDs, ibu and Ibu-CQDs capsules; 86.3%, 92% and 67%, respectively. It was proved that Ibu-CQDs release could be tracked using spectrofluorometry and UV-vis spectroscopy. The maximum release of Ibu-CQDs was 42% after 24 h. Temperature's effect on drug release was also studied and it was found that the best release was achieved at higher temperatures (40 °C), which corresponds to the illness state. Release medium's pH was also varied to simulate the pH of different parts of the gastrointestinal tract, and it was found that the best drug release can occur in the duodenum instead of the stomach. The current Ibu-CQDs capsules hold great promise for further studies in drug release and bioimaging applications.

Adsorption of methylene blue onto electrospun nanofibrous membranes of polylactic acid and polyacrylonitrile coated with chloride doped polyaniline.

This study presents the preparation of membranes of polylactic acid (PLLA), polyacrylonitrile (PAN) and their corresponding membranes coated with polyaniline (PANI) for the adsorption of methylene blue (MB). Scanning electron microscopy micrographs reveal that all the membranes exhibit nanofibrous morphology. The adsorption capacity and the removal efficiency of the membranes are studied as a function of (initial adsorbate concentration, pH of the medium, temperature, contact time and adsorbent dosage). Coated membranes with PANI showed better adsorption performance and their DC conductivities were correlated to MB concentrations. Adsorption isotherms have also been performed and the adsorption process has been tested according to Langmuir and Freundlich models. The regeneration and reuse of the prepared membranes to re-adsorb MB were also investigated. The enhancement in adsorption performance and reusability of PANI-coated membranes in comparison with non-coated ones are fully discussed.

Novel nitrogen-doped carbon dots prepared under microwave-irradiation for highly sensitive detection of mercury ions.

In this paper, new nitrogen doped carbon dots with a high quantum yield and novel optical properties were synthesized by a simple and fast one step microwave-assisted synthesis. Citric acid monohydrate was used as a carbon source and 2,2-dimethyl-1,3-propanediamine as nitrogen source. The prepared N-CDs were characterized by Fourier transform infrared, Raman, UV-visible and photoluminescence spectroscopies. Transmission electron microscope (TEM) images revealed that the N-CDs have distinctive flake-shape morphology. The N-CDs exhibit bright blue luminescence and quenching response towards Hg2+ ions. The quenching sensitivity was investigated. The results indicate a limit of detection as low as 7.63 nM and a linear relationship over the range 0-4.2 µM. In addition, the prepared N-CDs were tested as sensor for pH in the range from 1 to 7.

Adsorption of methyl orange onto electrospun nanofiber membranes of PLLA coated with pTSA-PANI.

This work evaluates the performance of electrospun nanofiber membranes of PLLA coated with p-toluenesulfonic acid doped polyaniline (pTSA-PANI). The adsorption on the prepared membranes of methyl orange (MO), taken as an example of anionic organic dye pollutants, was studied. The effects of different parameters on the adsorption capacity and removal efficiency, such as MO concentration, temperature, adsorbent dosage, pH, and ionic strength of the solution, were investigated. The results indicate the beneficial effect of coating PLLA membranes with pTSA-PANI in promoting the adsorption performance of the membranes. The grounds behind this enhancement are discussed. The adsorption kinetics and adsorption isotherms were performed. DC conductivity and AC impedance measurements of the studied membranes were conducted. The values were correlated to MO concentrations, suggesting the potential capacity of the current membrane to be used as a sensor of MO concentration. Graphical abstract.