Selective extraction and sensitive determination of mercury (II) ions by flame atomic absorption spectrometry after preconcentration on an ion-imprinted polymer-coated maghemite nanoparticles

Aerosol assisted synthesis of a pH responsive curcumin anticancer drug nanocarrier using chitosan and alginate natural polymers

In recent years, several nanocarrier synthesis methods have been developed. In cancer therapy, the use of smart nanocarriers is of interest. Smart nanocarriers respond to their environment and can release their cargo in a controlled manner under the action of internal or external stimuli. In this work, we report on the development of an aerosol-assisted method for the synthesis of curcumin-loaded chitosan/alginate-based polymeric nanocarrier (CurNCs). A custom-fabricated multi-nebulizer system was utilized for the synthesis of CurNCs. The developed system comprises three main parts a sprayer, an electric heater tunnel, and a collector. Curcumin and chitosan solutions were sprayed using a pneumatic multinebulizer into the electric heater tunnel to form chitosan-curcumin assemblies. Then, the aerosol was guided into the collector solution containing sodium alginate and tri-poly phosphate aqueous solution for further cross-linkage. The synthesized CurNCs were characterized using TEM, DLS, and FTIR techniques. The TEM size of the nanoparticles was 8.62 ± 2.25 nm. The release experiments revealed that the nanocarrier is sensitive to the environment pH as more curcumin is released at acidic pH values (as is the case for cancerous tissues) compared to physiological pH. The curcumin content of the nanocarrier was 77.27 mg g-1 with a drug loading efficiency of 62%. The in-vitro cytotoxicity of the synthesized nanocarrier was evaluated against the MCF7 breast cancer cell line. The IC50 concentrations for CurNCs and curcumin were obtained as 14.86 and 16.45 mg mL-1, respectively. The results showed that while the empty nanocarrier shows non-significant cytotoxicity, the CurNCs impact the cell culture and cause prolonged cell deaths. Overall, pH-responsive curcumin polymeric nanocarrier was synthesized using a custom fabricated aerosol-based method. The method enabled fast and feasible synthesis of the nanocarrier with high efficiency.

A novel bio-solid phase extractor for preconcentrations of Hg and Sn in food samples

An ecofriendly preconcentration method was developed based on the use of Geobacillus galactosidasius sp. nov immobilized on Amberlite XAD-4 as an adsorbent for the preconcentrations of Hg and Sn. SEM-EDX performed for the investigation of surface functionality and morphology. The detailed investigations of factors such as pH of the solution, flow rate, interfering ions and sample volume have been thanks to the optimization of the pre-concentration system. The optimum pHs were found as 5.0-7.0 for Hg and Sn and also the optimum flow rates were determined as 2 mL min^-1 for recovery of Hg and Sn. Under the best experimental conditions, limits of detections (LOD) were found as 0.53 ng mL^-1 for Hg and 0.27 ng mL^-1 for Sn. RSDs were calculated as 8.2% for Hg and 6.9% for Sn. The process was validated to use certified references (fish samples). ICP-OES was used to measure the levels of Hg and Sn in various real meal patterns after the devised technique was used. Concentrations of Hg and Sn were quantitively measured on gluten-free biscuit, flour, rice, Tuna fish, meat, chicken meat, potato, chocolate, coffee, tap water, energy drink and mineral water samples with low RSD. The developed method emerges as an innovative technology that will eliminate the low cost and toxic effect.

Enhancing autophagy in Alzheimer's disease through drug repositioning

Alzheimer's disease (AD) is one of the biggest human health threats due to increases in aging of the global population. Unfortunately, drugs for treating AD have been largely ineffective. Interestingly, downregulation of macroautophagy (autophagy) plays an essential role in AD pathogenesis. Therefore, targeting autophagy has drawn considerable attention as a therapeutic approach for the treatment of AD. However, developing new therapeutics is time-consuming and requires huge investments. One of the strategies currently under consideration for many diseases is "drug repositioning" or "drug repurposing". In this comprehensive review, we have provided an overview of the impact of autophagy on AD pathophysiology, reviewed the therapeutics that upregulate autophagy and are currently used in the treatment of other diseases, including cancers, and evaluated their repurposing as a possible treatment option for AD. In addition, we discussed the potential of applying nano-drug delivery to neurodegenerative diseases, such as AD, to overcome the challenge of crossing the blood brain barrier and specifically target molecules/pathways of interest with minimal side effects.

A Novel Biosorbent for Preconcentrations of Co(II) and Hg(II) in Real Samples

A new biosorbent, composed of Amberlite XAD-4 loaded with Anoxybacillus kestanboliensis, was developed and surface morphologies were investigated by SEM and FT-IR. It was used for solid phase column preconcentrations of Co(II) and Hg(II) before their measurements by ICP-OES. LODs were calculated as 0.04 and 0.06 ng mL⁻¹ for Co(II) and Hg(II) respectively. The maximum biosorption capacities were determined as 24.3 and 27.8 mg g⁻¹ for Co(II) and Hg(II) respectively. Preconcentration factors were achieved for Co(II) and Hg(II) as 80. The method validation was performed by analyzing certified reference materials. The new process was successfully utilized for the preconcentration of these metals in various food samples. It should be highlighted that the sensitivity of ICP-OES was critically improved by applying developed method. Hence, ICP-OES could be an effective alternative for ICP-MS and/or GF-AAS.

Microfluidic array surface ion-imprinted monolithic capillary microextraction chip on-line hyphenated with ICP-MS for the high throughput analysis of gadolinium in human body fluids

A novel method by hyphenating chip-based array ion-imprinted monolithic capillary microextraction with ICP-MS was proposed for the online analysis of trace Gd in biological samples.

A modified fluorescein derivative with improved water-solubility for turn-on fluorescent determination of Hg2+ in aqueous and living cells

To improve the water-solubility of heavy-metal sensing materials, a modified fluorescein-based derivative, acryloyl fluorescein hydrazine (ACFH), was designed and developed by incorporating a non-hydrogen-bonding group into the conjugated molecule for weakening intermolecular hydrogen-bonding interactions. In neutral water environments, ACFH presented a fluorescence-enhancement performance at λ_max=512nm in the presence of Hg²⁺, which could be visualized by naked-eyes. Under the optimized conditions, the linear range of Hg²⁺ detection was 1.0-100×10^-9molL^-1 with a correlation coefficient of 0.9992 and a detection limit of 0.86×10^-9molL^-1. The recognition mechanism was confirmed to be a stable and irreversible 1:1 five-member ring complex between ACFH and Hg²⁺ with a coordination constant of 3.36×10⁹. ACFH would possess a potential application in detecting Hg²⁺ for biological assay with low cytotoxicity.

Highly sensitive and selective fluorescence detection of Hg(ii) ions based on R-phycoerythrin from Porphyra yezoensis

R-Phycoerythrin (R-PE) is a kind of natural fluorescent protein from marine Porphyra yezoensis.