Seminar khoa học của TS. Đặng Văn Diễn, TS. Lê Nguyễn Minh Thông, ThS. Đỗ Anh Tuấn và TTS. Elise Y-Lan

Vào 14h00, ngày 23/05/2025 Viện IAST tổ chức buổi trao đổi học thuật tại Phòng họp B với nội dung chi tiết như sau:

1/ TS. Đặng Văn Diễn trình bày về "MoS2 nanoflowers grown on plasma-induced W-anchored graphene for efficient and stable H2 production through seawater electrolysis"
Abstract: Herein, we found that three-dimensional (3D) transition metal dichalcogenide (TMD)—MoS2 nanoflowers—grown on two-dimensional (2D) tungsten oxide-anchored graphene nanosheets (MoS2@W-G) functioned as a superior catalyst for the hydrogen evolution reaction (HER) under both acidic and alkaline conditions. The optimized weight ratio of MoS2@W-G (MoS2:W-G/1.5:1) in 0.5 M H2SO4 achieved a low overpotential of 78 mV at 10 mA cm–2, a small Tafel slope of 48 mV dec–1, and a high exchange current density (0.321 mA cm–2). Furthermore, the same MoS2@W-G composite exhibited stable HER performance when using real seawater, with Faradaic efficiencies of 96 and 94% in acidic and alkaline media, respectively. Density functional theory calculations based on the hybrid MoS2@W-G structure model confirmed that suitable hybridization of 3D MoS2 and 2D W-G nanosheets could lower the hydrogen adsorption: Gibbs free energy (∆GH*) from 1.89 eV for MoS2 to –0.13 eV for the MoS2@W-G composite. The excellent HER activity of the 3D/2D hybridized MoS2@W-G composite arose from an abundance of active heterostructure interfaces, which optimized the electrical configuration, thereby accelerating the adsorption and dissociation of H2O. Our findings suggest a new approach for the rational development of alternative 3D/2D TMD/graphene electrocatalysts for HER applications using seawater.

2/ TS. Lê Nguyễn Minh Thông trình bày về  "First-Principles insights into Stabilization of Small Organic Molecules on V2CTx MXenes"
Abstract: Molecular adsorptions on metal surfaces attract particular attention for fundamental understanding and practical regulation, concerning many urgent adsorption and detection technologies. However, due to their inert properties, organic molecules often encounter technical difficulties in adsorptive practices. MXenes, a family of two-dimensional materials, propose new adsorptive media for a variety of organic adsorbates. This work reports the interaction trends of greenhouse gases, namely, CH4, CO2, and H2O molecules with V2CTx MXenes studied by first-principles density functional theory calculations (DFT). Insight analysis of the density of states assists in determining the bonding mechanisms and electronic structure changes upon the adsorption on the studied surfaces. Engineering terminations allow us to better separate various target molecules. The dissociation processes, followed by adsorption, are the key signals showing the activity of the induced surface sites, in which the oxygen vacancies play an important role.

3/ ThS. Đỗ Anh Tuấn trình bày về "Tripeptides inhibit dual targets AChE and BACE-1: a computational study"
Abstract: Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline and memory loss, with amyloid-beta (Aβ) plaques and acetylcholine deficits being central pathological features. Inhibition of dual targets including acetylcholinesterase (AChE) and beta-site amyloid precursor protein cleaving enzyme 1 (BACE-1) represents a promising strategy to address cholinergic deficits and amyloid pathology. In this study, we used computational approaches to evaluate 8000 tripeptides as potential dual inhibitors of AChE and BACE-1. Machine learning models revealed the four top-lead tripeptides including WHM, HMW, WMH, and HWM. Molecular docking simulations indicated that WHM possessed the most favorable interactions through hydrogen bonds, π–π stacking, and salt bridges with key catalytic residues in both enzymes. Molecular dynamics simulations confirmed the stability of the protein–ligand complexes, with WHM exhibiting the most consistent conformations and significant disruption of catalytic residue geometries. Free energy perturbation analysis further supported WHM's superior stability across both targets. ADMET predictions suggested moderate oral absorption and limited brain penetration, consistent with the typical behavior of peptide-based compounds. Overall, WHM demonstrated the strongest potential as a dual inhibitor of AChE and BACE-1, offering a promising lead for future therapeutic development in AD.

4/ TTS. Elise Y-Lan Tran trình bày về "A Comparative Analysis of Prevalent GJB2 Mutations Found in the Vietnamese Deaf Population"
Abstract: Deafness and congenital hearing loss is one of the most prevalent genetic disorders in Vietnam, with over 1.2 million individuals affected. Although various sources of deafness exist, mutations in the gap junction beta-2 (GJB2) gene have arisen as one of the leading causes of deafness in Vietnam (1). Located on chromosome 13, GJB2 encodes for Connexin-26 (Cx26), a gap junction transmembrane protein responsible for communication between cells in the cochlea by regulating potassium ion flux. Mutations in GJB2 can disrupt this ion transport, leading to varying degrees of hearing loss. Past clinical studies have also found an association between different mutation types and the severity of hearing loss (2, 3). Despite this, most basic biomedical research regarding Cx26 focuses on the composition of a specific mutated protein compared to the wild-type, non-mutated protein rather than examining the variations across different mutation types (4-6). Thus, this project aims to elucidate the relationship between the mutations and the structural characteristics of three Cx26 variants identified in genetic screenings of the Vietnamese population: V37I, V27I, and E114G (7-10). The Cx26 models were constructed by Open-Source PyMOL 2.5.0 and AlphaFold 2.0, solvated with ions using Visual Molecular Dynamics, and embedded in a double cell membrane via the CHARMM-GUI Bilayer Membrane Builder and Multicomponent Assembler (11-15). GROMACS 2019.6 was employed to simulate potassium ion transport through the Cx26 channel using steered molecular dynamics, carry out umbrella sampling simulations, and compute the potential of mean force (16). Point mutations located within the transmembrane region of the protein, particularly V37I and V27I, are predicted to have a more negative impact on the permeability of potassium ion transport as compared to E114G.