Anticancer Potential of Pyridoxine-Based Doxorubicin Derivatives: An In Vitro Study.

Doxorubicin (DOX) is a prevalent anticancer agent; however, it is unfortunately characterized by high cardiotoxicity, myelosuppression, and multiple other side effects. To overcome DOX limitations, two novel pyridoxine-derived doxorubicin derivatives were synthesized (DOX-1 and DOX-2). In the present study, their antitumor activity and mechanism of action were investigated.

Inert-Atmosphere Microfabrication Technology for 2D Materials and Heterostructures.

Most 2D materials are unstable under ambient conditions. Assembly of van der Waals heterostructures in the inert atmosphere of the glove box with ex situ lithography partially solves the problem of device fabrication out of unstable materials. In our paper, we demonstrate an approach to the next-generation inert-atmosphere (nitrogen, <20 ppm oxygen content) fabrication setup, including optical contact mask lithography with a 2 μm resolution, metal evaporation, lift-off and placement of the sample to the cryostat for electric measurements in the same inert atmosphere environment.

Cost-Effective Laboratory Matrix Projection Micro-Lithography System.

This paper presents a home-built projection lithographer designed to transfer the image from a DLP (digital light processing) projector MEMS matrix onto the microscope objective's field of view, where a photoresist-covered substrate is placed. The photoresist is exposed using blue light with a wavelength of 450 nm. To calibrate the device and adjust focal lengths, we utilize a red light that does not affect the photoresist.

Synthesis and biological evaluation of fluoroquinolones containing a pyridoxine derivatives moiety.

We report herein the design, synthesis and biological evaluation of series of 7-substituted fluoroquinolones with pyridoxine derivatives. In vitro screening of antibacterial activity and toxicity of 39 synthesized fluoroquinolones defined compounds 7 and 28 as lead compounds for further investigations. On various clinical isolates lead compounds 7 and 28 exhibited antibacterial activity comparable with reference fluoroqinolones.

Photodynamics of Bright Subnanosecond Emission from Pure Single-Photon Sources in Hexagonal Boron Nitride.

Bright and stable emitters of single indistinguishable photons are crucial for quantum technologies. The origin of the promising bright emitters recently observed in hexagonal boron nitride (hBN) still remains unclear. This study reports pure single-photon sources in multi-layered hBN at room temperature that demonstrate high emission rates.

Micromask Lithography for Cheap and Fast 2D Materials Microstructures Fabrication.

The fast and precise fabrication of micro-devices based on single flakes of novel 2D materials and stacked heterostructures is vital for exploration of novel functionalities. In this paper, we demonstrate a fast high-resolution contact mask lithography through a simple upgrade of metallographic optical microscope. Suggested kit for the micromask lithography is compact and easily compatible with a glove box, thus being suitable for a wide range of air-unstable materials.

Synthesis, antitumor activity and structure-activity studies of novel pyridoxine-based bioisosteric analogs of estradiol.

A new efficient approach to the synthesis of 6-alkenyl substituted pyridoxine derivatives has been developed. A series of 31 novel alkenyl pyridoxine derivatives, stilbene-based bioisosteric analogs of estradiol, were synthesized. In vitro cytotoxicity of the obtained compounds against MCF-7 (ER+) breast cancer tumor cells was studied using the MTT assay.

Making van der Waals Heterostructures Assembly Accessible to Everyone.

Van-der Waals heterostructures assembled from one or few atomic layer thickness crystals are becoming increasingly more popular in condensed matter physics. These structures are assembled using transfer machines, those are based on mask aligners, probe stations or are home-made. For many laboratories it is vital to build a simple, convenient and universal transfer machine.

Novel Bis-Ammonium Salts of Pyridoxine: Synthesis and Antimicrobial Properties.

A series of 108 novel quaternary bis-ammonium pyridoxine derivatives carrying various substituents at the quaternary nitrogen's and acetal carbon was synthesized. Thirteen compounds exhibited antibacterial and antifungal activity (minimum inhibitory concentration (MIC) 0.25-16 µg/mL) comparable or superior than miramistin, benzalkonium chloride, and chlorhexidine.

Synthesis and in vitro antitumor activity of novel alkenyl derivatives of pyridoxine, bioisosteric analogs of feruloyl methane.

Two series of novel pyridoxine-based azaheterocyclic analogs of feruloyl methane (Dehydrozingerone, DZG) were synthesized, and their biological activity against a panel of tumor and normal cell lines was evaluated in vitro. The most active compounds possessed expressed cytotoxic activity, which was comparable to cytotoxic activity of doxorubicin and significantly higher than that of DZG, and a remarkable selectivity for the studied cancer cell lines as compared to the normal cells. The leading compound and DZG initiated arrest of the cell cycle in the G2/M phase, preventing normal division and further transition of daughter cells to the G0/G1 phase.

New Derivatives of Pyridoxine Exhibit High Antibacterial Activity against Biofilm-Embedded Staphylococcus Cells.

Opportunistic bacteria Staphylococcus aureus and Staphylococcus epidermidis often form rigid biofilms on tissues and inorganic surfaces. In the biofilm bacterial cells are embedded in a self-produced polysaccharide matrix and thereby are inaccessible to biocides, antibiotics, or host immune system. Here we show the antibacterial activity of newly synthesized cationic biocides, the quaternary ammonium, and bisphosphonium salts of pyridoxine (vitamin B6) against biofilm-embedded Staphylococci.

Antibacterial effects of quaternary bis-phosphonium and ammonium salts of pyridoxine on Staphylococcus aureus cells: A single base hitting two distinct targets?

We studied the effects of quaternary bis-phosphonium and bis-ammonium salts of pyridoxine with lipophilic substituents on the survival and morphology of Staphylococcus aureus cells. We found that, while originating from the same base, they exhibit considerably different antimicrobial mechanisms. In the presence of Ca(2+) ions the MIC and MBC values of ammonium salt increased 100-fold, suggesting that Ca(2+) ions can successfully impede the membrane Ca(2+) ions exchange required for ammonium salt incorporation.

Synthesis of a new quaternary phosphonium salt: NMR study of the conformational structure and dynamics.

A novel phosphonium salt based on pyridoxine was synthesized. Conformational analysis of the compound in solution was performed using dynamic NMR experiments and calculations. The obtained results revealed some differences in the conformational transitions and the energy parameters of the conformational exchange of the studied compound in comparison to previously reported data for other phosphorus-containing pyridoxine derivatives.

Bis-phosphonium salts of pyridoxine: the relationship between structure and antibacterial activity.

A series of 23 novel bis-phosphonium salts based on pyridoxine were synthesized and their antibacterial activities were evaluated in vitro. All compounds were inactive against gram-negative bacteria and exhibited the structure-dependent activity against gram-positive bacteria. The antibacterial activity enhanced with the increase in chain length at acetal carbon atom in the order n-Pr>Et>Me.

Synthesis and antibacterial activity of novel phosphonium salts on the basis of pyridoxine.

A series of 13 phosphonium salts on the basis of pyridoxine derivatives were synthesized and their antibacterial activity against clinically relevant strains was tested in vitro. All compounds were almost inactive against gram-negative bacteria and exhibited structure-dependent activity against gram-positive bacteria. A crucial role of ketal protection group in phosphonium salts for their antibacterial properties was demonstrated.