Serinol-Based Versatile Disulfide-Reducing Reagent

Here, we report the synthesis of disulfide-reducing agents 2-(dibenzylamino) propane-1,3-dithiol (DPDT) and 2-(dibenzylamino)-2-methylpropane-1,3-dithiol (DMPDT) from serinol and methyl serinol, respectively. DPDT was found to show greater stability than DMPDT. Hence, the effectiveness of DPDT as a reducing agent was evaluated in both liquid and solid phases. The reducing capacity of this agent was comparable to that of DTT.

1,2-Benzenedithiol and Toluene-3,4-dithiol Arsenic(III) Complexes-Synthesis, Structure, Spectroscopic Characterization and Toxicological Studies

A new group of arsenic(III) complexes with bidentate S,S-donor ligands, 1,2-benzenedithiol (Ph(SH)₂) and toluene-3,4-dithiol (MePh(SH)₂), were synthesized. The use of arsenic(III) iodide and bromide promoted the formation of neutral complexes (1-4) with the general formula AsX(LS₂) (X = I or Br, L = MePh or Ph). The crystal structures of these compounds were determined using single-crystal X-ray diffraction (scXRD). Unlike other arsenic(III) complexes, AsBr(PhS₂) complex (2) was found to crystallize with a rare 13 molecules in the asymmetric unit. The compounds were also characterized by conventional physico-chemical techniques (Fourier transform infrared (FT-IR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, nuclear magnetic resonance (NMR), high-performance liquid chromatography (HPLC), elemental analysis (EA) and electrospray ionization-mass spectrometry (ESI-MS)). The results from structural and spectroscopic studies were supported by DFT calculations using the B3LYP/LANL2DZ and (or) 6-31+G(d,p) approaches. The cytotoxicity of these complexes was estimated for human acute promyelocytic leukemia cell line (NB4). They exhibited remarkable cytotoxicities after 48 h of treatment with IC₅₀ equal to about 10 µM and 40 µM for complexes with 1,2-benzenedithiolato and toluene-3,4-dithiolato ligand, respectively. Their toxicity was lower than that of commonly used chemotherapeutic As₂O₃ (IC₅₀ = 1.4 µM).

Highly sensitive disposable nucleic acid biosensors for direct bioelectronic detection in raw biological samples

The development of rapid, low-cost and reliable diagnostic methods is crucial for the identification and treatment of many diseases. Screen-printed gold electrodes (Au/SPEs), coated with a ternary monolayer interface, involving hexanedithiol (HDT), a specific thiolated capture probe (SHCP), and 6-mercapto-1 hexanol (MCH) (SHCP/HDT/MCH) are shown here to offer direct and sensitive detection of nucleic acid hybridization events in untreated raw biological samples (serum, urine and crude bacterial lysate solutions). The composition of the ternary monolayer was modified and tailored to the surface of the Au/SPE. The resulting SHCP/HDT/MCH monolayer has demonstrated to be extremely useful for enhancing the performance of disposable nucleic acid sensors based on screen-printed electrodes. Compared to common SHCP/MCH binary interfaces, the new ternary self-assembled monolayer (SAM) resulted in a 10-fold improvement in the signal (S)-to-noise (N) ratio (S/N) for 1 nM target DNA. The SHCP/HDT/MCH-modified Au/SPEs allowed the direct quantification of the target DNA down to 25 pM (0.25 fmol) and 100 pM (1 fmol) in undiluted/untreated serum and urine samples, respectively, and of 16S rRNA Escherichia coli (E. coli) corresponding to 3000 CFU μL(-1) in raw cell lysate samples. The new SAM-coated screen-printed electrodes also displayed favorable non-fouling properties after a 24h exposure to raw human serum and urine samples, offering great promise as cost-effective nucleic acid sensors for a wide range of decentralized genetic tests.