Biocompatible MXene (Ti3C2Tx) Immobilized with Flavin Adenine Dinucleotide as an Electrochemical Transducer for Hydrogen Peroxide Detection in Ovarian Cancer Cell Lines

Flavin adenine dinucleotide (FAD) is a coenzyme and acts as a redox cofactor in metabolic process. Owing to such problems as poor electron transfer properties, unfavorable adsorption, and lack of stability on rigid electrodes, the bio-electrochemical applications of FAD have been limited. Herein, a novel fabrication method was developed for the immobilization process using 2D MXene (Ti3C2Tx), which enhanced the redox property of FAD and improved the electro-catalytic reduction of hydrogen peroxide (H2O2) in neutral medium. The FAD-immobilized Ti3C2Tx electrode (FAD/Ti3C2Tx) was studied by UV-Visible and Raman spectroscopies, which confirmed the successful adsorption of FAD on the Ti3C2Tx surface. The surface morphology and the elemental composition of Ti3C2Tx were investigated by high resolution transmission electron microscopy and the energy dispersive X-ray analysis. The redox property of the FAD/Ti3C2Tx modified glassy carbon electrode (FAD/Ti3C2Tx/GCE) was highly dependent on pH and exhibited a stable redox peak at −0.455 V in neutral medium. Higher amounts of FAD molecules were loaded onto the 2D MXene (Ti3C2Tx)-modified electrode, which was two times higher than the values in the reported work, and the surface coverage (ᴦFAD) was 0.8 × 10−10 mol/cm2. The FAD/Ti3C2Tx modified sensor showed the electrocatalytic reduction of H2O2 at −0.47 V, which was 130 mV lower than the bare electrode. The FAD/Ti3C2Tx/GCE sensor showed a linear detection of H2O2 from 5 nM to 2 µM. The optimization of FAD deposition, amount of Ti3C2Tx loading, effect of pH and the interference study with common biochemicals such as glucose, lactose, dopamine (DA), potassium chloride (KCl), ascorbic acid (AA), amino acids, uric acid (UA), oxalic acid (OA), sodium chloride (NaCl) and acetaminophen (PA) have been carried out. The FAD/Ti3C2Tx/GCE showed high selectivity and reproducibility. Finally, the FAD/Ti3C2Tx modified electrode was successfully applied to detect H2O2 in ovarian cancer cell lines

SPECC1L deficiency results in increased adherens junction stability and reduced cranial neural crest cell delamination

Cranial neural crest cells (CNCCs) delaminate from embryonic neural folds and migrate to pharyngeal arches, which give rise to most mid-facial structures. CNCC dysfunction plays a prominent role in the etiology of orofacial clefts, a frequent birth malformation. Heterozygous mutations in SPECC1L have been identified in patients with atypical and syndromic clefts. Here, we report that in SPECC1L-knockdown cultured cells, staining of canonical adherens junction (AJ) components, β-catenin and E-cadherin, was increased, and electron micrographs revealed an apico-basal diffusion of AJs. To understand the role of SPECC1L in craniofacial morphogenesis, we generated a mouse model of Specc1l deficiency. Homozygous mutants were embryonic lethal and showed impaired neural tube closure and CNCC delamination. Staining of AJ proteins was increased in the mutant neural folds. This AJ defect is consistent with impaired CNCC delamination, which requires AJ dissolution. Further, PI3K-AKT signaling was reduced and apoptosis was increased in Specc1l mutants. In vitro, moderate inhibition of PI3K-AKT signaling in wildtype cells was sufficient to cause AJ alterations. Importantly, AJ changes induced by SPECC1L-knockdown were rescued by activating the PI3K-AKT pathway. Together, these data indicate SPECC1L as a novel modulator of PI3K-AKT signaling and AJ biology, required for neural tube closure and CNCC delamination