DFT study of the therapeutic potential of phosphorene as a new drug-delivery system to treat cancer

Bio-Nano Synergy in Therapeutic Applications: Drug-Graphene Oxide Nanocomposites for Modulated Acetylcholinesterase Inhibition and Radical Scavenging

The current study explores the synergistic application of biophysical chemistry and nanotechnology in therapeutic treatments, focusing specifically on the development of advanced biomaterials to repurpose FDA-approved Alzheimer's disease (AD) drugs as potent antioxidants. By integration of AD drugs into graphene oxide (GO) nanocomposites, an attempt to enhance the acetylcholinesterase (AChE) inhibition and increase radical scavenging activity is proposed. This bionano synergy is designed to leverage the unique properties of both the nanomaterial surface and the bioactive compounds, improving treatment effectiveness. The nanocomposites also promise targeted drug delivery, as GO can traverse the blood-brain barrier to inhibit AChE more effectively in AD patients. Furthermore, the drug-GO nanocomposite exhibits enhanced radical scavenging capabilities, offering additional therapeutic benefits. This study also elucidates a molecular level understanding on how the properties of the drugs are modified when integrated into nanocomposites with GO, enabling the development of more effective materials. The interdisciplinary approach presented in this study exploits the potential of nanotechnology to enhance drug delivery systems and achieve superior therapeutic outcomes through bionano synergy.

A Comparative DFT Investigation of the Adsorption of Temozolomide Anticancer Drug over Beryllium Oxide and Boron Nitride Nanocarriers

Herein, attempts were made to explore the adsorption prospective of beryllium oxide (Be12O12) and boron nitride (B12N12) nanocarriers toward the temozolomide (TMZ) anticancer drug. A systematic investigation of the TMZ adsorption over nanocarriers was performed by using quantum chemical density functional theory (DFT). The favorability of Be12O12 and B12N12 nanocarriers toward loading TMZ was investigated through A↔D configurations. Substantial energetic features of the proposed configurations were confirmed by negative adsorption (E ads) energy values of up to -30.47 and -26.94 kcal/mol for TMZ•••Be12O12 and •••B12N12 complexes within configuration A, respectively. As per SAPT results, the dominant contribution beyond the studied adsorptions was found for the electrostatic forces (E elst = -100.21 and -63.60 kcal/mol for TMZ•••B12N12 and •••Be12O12 complexes within configuration A, respectively). As a result of TMZ adsorption, changes in the energy of molecular orbitals followed by alterations in global reactivity descriptors were observed. Various intermolecular interactions within the studied complexes were assessed by QTAIM analysis. Notably, a favorable adsorption process was also observed under the effect of water with adsorption energy ( reaching -28.05 and -22.26 kcal/mol for TMZ•••B12N12 and •••Be12O12 complexes within configuration A, respectively. The drug adsorption efficiency of the studied nanocarriers was further examined by analyzing the IR and Raman spectra. From a sustained drug delivery point of view, the release pattern of TMZ from the nanocarrier surface was investigated by recovery time calculations. Additionally, the significant role of doping by heavy atoms (i.e., MgBe11O12 and AlB11N12) on the favorability of TMZ adsorption was investigated and compared to pure analogs (i.e., Be12O12 and B12N12). The obtained data from thermodynamic calculations highlighted that the adsorption process over pure and doped nanocarriers was spontaneous and exothermic. The emerging findings provide a theoretical base for future works related to nanocarrier applications in the drug delivery process, especially for the TMZ anticancer drug.

First-principles study of a SiC nanosheet as an effective material for nitrosourea and carmustine anti-cancer drug delivery

The development of novel nanosheet-based drug delivery systems requires a systematic understanding of the interactions between the drug and the nanosheet carrier under various physiological environments. In this work, we investigated electronic and quantum molecular descriptors of a SiC monolayer adsorbed with the anticancer drugs nitrosourea (NU) and carmustine (BCNU) using density functional theory (DFT). Our calculations revealed negative adsorption energies for both drugs, indicating a spontaneous and energetically favorable adsorption process. Density of states and orbital population analysis studies revealed that both drugs are capable of significantly (>30%) narrowing the gap between HOMO and LUMO, depending on the configuration of the adsorption complex. Furthermore, the electronic and quantum molecular descriptors were investigated in gas and water mediums to explore the effect of the solvent on the adsorption process. Our calculations predict a higher narrowing of the HOMO-LUMO gap in the water phase compared to the gas phase. Besides, a modest reduction in global hardness and a marked increase in the global electrophilicity index were observed after the adsorption of the drug molecules by the SiC nanosheet, indicating its high reactivity towards both NU and BCNU. Changing the medium to water showed a maximum 2× increase in the global electrophilicity index of the nanosheet for NU and a maximum 7× increase for BCNU. Additionally, the thermodynamic study of the adsorption process indicates that the formation energies at high temperatures are smaller than those at low temperatures, unfolding the potential of SiC nanosheet for application in the phototherapy of these drugs.

Exploring the Therapeutic Potential of Petiveria alliacea L. Phytochemicals: A Computational Study on Inhibiting SARS-CoV-2's Main Protease (Mpro)

The outbreak of SARS-CoV-2, also known as the COVID-19 pandemic, is still a critical risk factor for both human life and the global economy. Although, several promising therapies have been introduced in the literature to inhibit SARS-CoV-2, most of them are synthetic drugs that may have some adverse effects on the human body. Therefore, the main objective of this study was to carry out an in-silico investigation into the medicinal properties of Petiveria alliacea L. (P. alliacea L.)-mediated phytocompounds for the treatment of SARS-CoV-2 infections since phytochemicals have fewer adverse effects compared to synthetic drugs. To explore potential phytocompounds from P. alliacea L. as candidate drug molecules, we selected the infection-causing main protease (Mpro) of SARS-CoV-2 as the receptor protein. The molecular docking analysis of these receptor proteins with the different phytocompounds of P. alliacea L. was performed using AutoDock Vina. Then, we selected the three top-ranked phytocompounds (myricitrin, engeletin, and astilbin) as the candidate drug molecules based on their highest binding affinity scores of -8.9, -8.7 and -8.3 (Kcal/mol), respectively. Then, a 100 ns molecular dynamics (MD) simulation study was performed for their complexes with Mpro using YASARA software, computed RMSD, RMSF, PCA, DCCM, MM/PBSA, and free energy landscape (FEL), and found their almost stable binding performance. In addition, biological activity, ADME/T, DFT, and drug-likeness analyses exhibited the suitable pharmacokinetics properties of the selected phytocompounds. Therefore, the results of this study might be a useful resource for formulating a safe treatment plan for SARS-CoV-2 infections after experimental validation in wet-lab and clinical trials.

A DFT approach for finding therapeutic potential of graphyne as a nanocarrier in the doxorubicin drug delivery to treat cancer

In the present work, the drug-loading efficacy of graphyne (GYN) for doxorubicin (DOX) drug is investigated for the first time by using density functional theory (DFT). Doxorubicin drug is effective in the cure of numerous types of cancer including bone cancer, gastric, thyroid, bladder, ovarian, breast, and soft tissue cancer. Doxorubicin drug prevents the cell division process by intercalating in the double-helix of DNA and stopping its replication. The optimized, geometrical, energetic, and excited-state characteristics of graphyne (GYN), doxorubicin drug (DOX), and doxorubicin-graphyne complex (DOX@GYN complex) are calculated to see how effective it is as a carrier. The DOX drug interacted with GYN with an adsorption-energy of -1.57 eV (gas-phase). The interaction of GYN with DOX drug is investigated using NCI (non-covalent interaction) analysis. The findings of this analysis showed that the DOX@GYN complex has weak forces of interaction. Charge transfer from doxorubicin drug to GYN during DOX@GYN complex formation is described by charge-decomposition analysis and HOMO-LUMO analysis. The increased dipole-moment (8.41 D) of the DOX@GYN in contrast with therapeutic agent DOX and GYN indicated that the drug will move easily in the biochemical system. Furthermore, the photo-induced electron-transfer process is explored for excited states, and it reveals that upon interaction, fluorescence-quenching will occur in the complex DOX@GYN. In addition, the influence of the positive and negative charge states on the GYN and DOX@GYN is also considered. Overall, the findings indicated that the GYN could be exploited as an effective drug-transporter for the delivery of doxorubicin drug. Investigators will be inspired to look at another 2D nanomaterials for drug transport applications as a result of this theoretical work.

Circular dichroism assessment of an imidazole antifungal drug with plant based silver nanoparticles: Quantitative and DFT analysis

Circular dichroism (CD) methods have been developed for the analysis of luliconazole (LUC) using plant based silver nanoparticles (P-AgNPs). Cleaner and natural approach have found significant attention in recent times owing to their exceptional physicochemical characteristics. Utilizing FTIR, SEM, and XRD, the produced nanoparticles were analyzed. The produced P-AgNPs were then used to assay LUC in formulation drugs. Four CD methods are developed as zero order and second order derivative methods. Methods I and II are based on a normal CD scan (zero order) that produced calibration range from 2 - 16 μgmL^-1 at 232 nm (positive band) and 299 nm (negative band), respectively. Methods III and IV are the second order derivative methods that are developed at 232 nm (negative band) and at 251 nm (positive band). Density functional theory study was done to comprehend the feasibility of the developed methods and to optimize the structure and energy gap that validated the experimental procedure. The LUC assay methods using the proposed CD approach are simple, sensitive and precise with a limit of detection for methods I, II, III and IV of 0.527, 0.428, 0.250 and 0.30 μgmL^-1 and limit of quantification of 1.75, 1.42, 0.833 and 1.0 μgmL^-1, respectively. For intra- and inter-day precision, the recovery data ranged from 99.48 to 101% and 99.37 to 101%, respectively. The methods were used in dosage forms that produced a relative standard deviation of less than 2% and the true bias (θ_L and θ_U) within ±2%, demonstrating the potential use of the developed methods.

Elucidating the adsorption of 2-Mercaptopyridine drug on the aluminum phosphide (Al12P12) nanocage: A DFT study

Adsorption amplitude of the aluminum phosphide (Al12P12) nanocage toward the 2-Mercaptopyridine (MCP) drug was herein monitored based on density functional theory (DFT) calculations. The adsorption process through MCP⋅⋅⋅Al12P12 complex in various configurations was elucidated by means of adsorption (Eads) energies. According to the energetic affirmations, the Al12P12 nanocage demonstrated potential versatility toward adsorbing the MCP drug within the investigated configurations and exhibited significant negative adsorption energies up to -27.71 kcal/mol. Upon the results of SAPT analysis, the electrostatic forces showed the highest contributions to the overall adsorption process with energetic values up to -74.36 kcal/mol. Concurrently, variations of molecular orbitals distribution along with alterations in the energy gap (Egap) and Fermi level (EFL) of the studied nanocage were denoted after adsorbing the MCP drug. The favorable impact of water solvent within the MCP⋅⋅⋅Al12P12 complexes was unveiled and confirmed by negative solvation energy (ΔEsolv) values up to -17.75 kcal/mol. According to thermodynamic parameters, the spontaneous and exothermic natures of the considered adsorption process were proclaimed by negative values of ΔG and ΔH parameters. Significant changes in the IR and Raman peaks, along with the appearance of new peaks, were noticed, confirming the occurrence of the targeted adsorption process. Furthermore, the adsorption features of the MCP drug on the Al12N12 nanocage were elucidated and compared to the Al12P12 analog. The obtained results demonstrated the higher preferability of Al12P12 nanocage than the Al12N12 candidate towards adsorbing the MCP drug without structural distortion.

DFT study of sertraline hydrochloride antidepressant drug

CONTEXT

The global reactivity and molecular stability of sertraline hydrochloride (SHCl) are predicted for chemical and photo-biological applications. SHCl has a wide indirect HOMO-LUMO gap of about 4.77 eV. The p orbital states of nitrogen and chlorine atoms play the main role in HOMO and LUMO energy levels. Maximum optical transitions are observed at the energy range of 4.96 to 5.64 eV. The main reflectivity occurs at the ultraviolet energy range of 5.51 to 6.16 eV. Obtained high absorption in the ultraviolet region is in good agreement with experiments. It is found that SHCl can be used in new antidepressant drugs.

METHODS

Optoelectronic properties of SHCl was performed using density functional theory (DFT) calculations as implemented in WIEN2k package. The generalized gradient approximation (GGA) and the Modified Becke and Johnson (mBJ) potential are used for calculation of the exchange-correlation potentials.

Controlled supramolecular interactions for targeted release of Amiodarone drug through Graphyne to treat cardiovascular diseases: An in silico study

In the current study, the drug loading ability of graphyne (GY) for the amiodarone (AMD) drug is investigated for the first time. The efficacy of GY as a carrier for amiodarone (a cardiovascular drug) is evaluated by calculating its electronic, energetic, optimized, and excited state properties with help of the density functional theory (DFT). The AMD drug interacted with the GY molecule with an adsorption energy of about -0.19 eV (gas-phase) and -1.92 eV (aqueous phase), suggesting that the AMD@GY complex is stable in water-phase. The HOMO (highest-occupied molecular-orbital) of the AMD@GY complex is concentrated on the AMD drug while the LUMO (lowest-unoccupied molecular-orbital) is centralized on GY with absolute charge separation, indicating charge transfer will occur between AMD and GY. The charge-transfer process is further studied with the aid of charge-decomposition analysis (CDA). The non-covalent interaction analysis (NCI) exposed that non-covalent forces exist between the GY carrier and AMD drug. These non-covalent forces between AMD drug and GY carrier play a significant role in drug unloading at the targeted or diseased site. Likewise, the calculations at excited-state, charge-state (+1 and -1) influence on GY and AMD@GY complex structures, and photo-induced electron transfer analysis (PET) are also studied for the graphyne-based drug-delivery system. According to PET and electron-hole analysis, fluorescence-quenching will occur upon interaction. Overall, it is concluded that graphyne can be exploited as a drug carrier for amiodarone drug delivery. Researchers will be fascinated to look at alternative 2D nanomaterials for drug delivery applications as a result of this theoretical work.

Molecular Modelling of Optical Biosensor Phosphorene-Thioguanine for Optimal Drug Delivery in Leukemia Treatment

Simple Summary

Nanocarriers have been used to solve the problems associated with conventional antitumor drug delivery systems, including no specificity, severe side effects, burst release and damaging the normal cells. It improves the bioavailability and therapeutic efficiency of antitumor drugs, while providing preferential accumulation at the target site. Various 2D nanomaterials such as graphene, MoS2, and WSe2 have been used as nanocarrier. The recent discovery of phosphorene has introduced new possibilities in designing a sensible drug delivery system, due to low cytotoxicity, biocompatibility, high surface to volume ratio, which can increase its drug loading capacity. The biodegradation of phosphorene inside the human body produces non-toxic intermediates, like phosphate. Phosphate is necessary for the formation of bone and teeth. Phosphate is also used by the cell for energy, cell membranes, and DNA (deoxyribonucleic acid). Therefore, phosphorene nanocarrier is not harmful, especially for the treatment of cancer in vivo applications.

Abstract

Thioguanine is an anti-cancer drug used for the treatment of leukemia. However, thioguanine has weak aqueous solubility and low biocompatibility, which limits its performance in the treatment of cancer. In the present work, these inadequacies were targeted using density functional theory-based simulations. Three stable configurations were obtained for the adsorption of thioguanine molecules on the phosphorene surface, with adsorption energies in the range of −76.99 to −38.69 kJ/mol, indicating physisorption of the drug on the phosphorene surface. The calculated bandgap energies of the individual and combined geometries of phosphorene and thioguanine were 0.97 eV, 2.81 eV and 0.91 eV, respectively. Owing to the physisorption of the drug molecule on the phosphorene surface, the bandgap energy of the material had a direct impact on optical conductivity, which was significantly altered. All parameters that determine the potential ability for drug delivery were calculated, such as the dipole moment, chemical hardness, chemical softness, chemical potential, and electrophilicity index. The higher dipole moment (1.74 D) of the phosphorene–thioguanine complex reflects its higher biodegradability, with no adverse physiological effects.

Two-dimensionalcovalent triazine frameworks as superior nanocarriers for the delivery of thioguanine anti-cancer drugs: a periodic DFT study

This work aims to introduce a superior nanocarrier for thioguanine (TG) anti-cancer drug delivery, drug release, and cancer therapy through computational chemistry.

Surface adsorption of nitrosourea on pristine and doped (Al, Ga and In) boron nitride nanosheets as anticancer drug carriers: the DFT and COSMO insights

To minimize the side effects of chemotherapeutic drugs and enhance the effectiveness of cancer treatment, it is necessary to find a suitable drug delivery carrier for anticancer drugs. Recently nanomaterials are extensively being studied as drug vehicles and transport drugs in tumor cells. Using DFT calculations, the adsorption behavior with electronic sensitivity and reactivity of pristine and doped (Al, Ga and In)-BNNS towards the nitrosourea (NU) drug has been investigated in gas as well as water media. Our calculations showed that the NU drug is physically adsorbed on the pristine BNNS with −0.49 and −0.26 eV by transferring little amount of charge of about 0.033e and 0.046e in gas and water media in the most stable complex. But after replacing one of the central B atoms with an Al or Ga or In atom, the sensitivity of the doped BNNS remarkably enhances towards the NU drug molecules. The NU drug prefers to be chemically adsorbed on the BN(Al)NS, BN(Ga)NS and BN(In)NS by −1.28, −1.58 and −3.06 eV in the gas phase and −1.34, −1.23 and −3.65 eV in water media in the most stable complexes respectively. The large destabilization of LUMO energies after the adsorption of the NU drug on the BN(Al)NS, BN(Ga)NS and BN(In)NS significantly reduces their E_g from 4.37 to 0.69, 4.37 to 1.04 and 4.33 to 0.66 eV in the S1 complex respectively. The reduction of E_g of doped BNNS by the NU drug greatly enhances the electrical conductivity which can be converted to an electrical signal. Therefore, this doped BNNS can be used as a fascinating electronic sensor for the detection of NU drug molecules. Furthermore the work function of the doped BNNS was largely affected by the NU drug adsorption about 47.3%, 39.3% and 40.4% in the gas phase and 41.3%, 36.6% and 31.6% in water media in the S1 complex of NU/BN(Al)NS, NU/BN(Ga)NS and NU/BN(In)NS respectively. Thus, the doped BNNS may be used as a Ф type sensor for NU drug molecules.

Doped (Al, Ga and In)-BNNS can be used as fascinating drug carriers for the NU drug.

First-principles studies on two-dimensional B3O3 adsorbent as a potential drug delivery platform for TEPA anticancer drug

The remarkable properties of pristine B₃O₃ nanosheet as a nanocarrier for adsorption and desorption of TEPA anticancer drug for designing potential drug delivery platform were investigated using periodic DFT calculations. We studied the adsorption energy of all stable complexes formed between the drug molecule and B₃O₃ in gas and aqueous phases along with electronic structure analysis of complexes. Different adsorption configurations were studied for drug/B₃O₃ complexes, including the interaction of the C atom of the triangular ring, O atom in the TEPA drug with the B atom in B₃O₃, and indirect drug interaction the middle of the R1 ring cavity of the B₃O₃ nanosheet. The take-up of TEPA prompts a substantial change of 68.13% in the band gap (E_g) of the B₃O₃ nanosheet in the most stable complex. The present study results affirmed the application of B₃O₃ nanosheet as a potential vehicle for TEPA drugs in the treatment of cancerous tissues.

Computational study of therapeutic potential of phosphorene as a nano-carrier for drug delivery of nebivolol for the prohibition of cardiovascular diseases: a DFT study

Density functional theory (DFT) calculations were utilized to assess the drug delivery efficiency of phosphorene carrier for nebivolol drug to treat cardiovascular diseases. The optimized structures, excited state, and electronic properties of nebivolol, phosphorene, and nebivolol-phosphorene (nebivolol-PH) complex were considered to determine the drug delivery ability of phosphorene at the target site. The increased dipole moment (6.08 D) results in the higher solubility of the complex in polar solvents (water). Weak interactive forces between nebivolol and phosphorene were demonstrated by the non-covalent interaction (NCI) plot that facilitated the offloading of nebivolol at the targeted area. The analysis of frontier molecular orbitals (FMOs) revealed that during excitation, the charge was transferred from nebivolol as a higher occupied molecular orbital (HOMO) to phosphorene as a lower unoccupied molecular orbital (LUMO). Thus, the charge-transfer process was further studied by charge decomposition analysis (CDA). The calculated results at the excited state for the nebivolol-PH complex exhibited that the maximum wavelength (λmax) was red-shifted by 6 nm in the gas phase. The electron-hole theory and photoinduced electron transfer (PET) processes were carried out for the exploration of different excited states of the complex. Additionally, phosphorene with + 1 and - 1 charge states indicated the minor structural changes and provide the stable nebivolol-PH complex. This theoretical study also investigated that phosphorene can be exploited as an effective carrier for the delivery of a therapeutic agent as nebivolol to treat cardiovascular diseases. This work will also encourage the researchers to investigate the other 2D nanoparticles as a nano-drug delivery system (NDDS).

New α-Hydrazinophosphonic acid: Synthesis, characterization, DFT study and in silico prediction of its potential inhibition of SARS-CoV-2 main protease

A new α-Hydrazinophosphonic acid (HDZPA) has been synthesized and its molecular structure was determined using spectroscopic methods. The Density Functional Theory (DFT) at the B3LYP/6-31 G (d,p) level was utilized to determine the electronic properties, vibrational modes and active sites of the examined molecule. In this context, some quantum chemical parameters have been calculated in order to discuss the reactivity of the studied molecule. Also, the inhibition activity of the investigated α-Hydrazinophosphonic acid for SARS-CoV-2 main protease (M^pro) and RNA dependent RNA polymerase (RdRp) has been predicted using in silico docking.

Theoretical investigation of favipiravir antiviral drug based on fullerene and boron nitride nanocages

Smart implementation of novel advanced nanocarriers such as functionalized C₂₄ and B₁₂N₁₂ nanocages is used supplement for antiviral activity 5-Fluoro-2-hydroxypyrazine-3-carboxamide (Favipiravir; Avigan; T-705), as treatment of COVID-19. The interaction energies of Favipiravir with perfect (B₁₂N₁₂ and C₂₄) and doped (BC₂₃ and CB₁₁N₁₂) nanocages were studied at temperatures equal to 310.15 K and 298.15 K using DFT. Our results have shown that the interaction of the Favipiravir (C[bond, double bond]O group) with BC₂₃ and CB₁₁N₁₂ is more favorable than with the C₂₄ and B₁₂N₁₂ nanocages in the gas and aqueous environments. Additionally, the natural bond orbital, the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO), energy gap, chemical reactivity, molecular electrostatic potential, and thermodynamic parameters of the optimized structure have been examined. Furthermore, the UV-Vis and infrared spectroscopy have been evaluated for the investigation of the molecular orbitals Participated in the absorption spectrum of the Favipiravir before and after the interaction with the C₂₄, BC₂₃, B₁₂N_12, and CB₁₁N₁₂, sites at maximum wavelength utilizing the time-dependent density functional theory (TD-B3LYP and TD-CAM-B3LYP). The intermolecular interactions have been analyzed by non-covalent interactions (NCI) and also, the electron localization function (ELF) is discussed.

Computational and synthetic biology approaches for the biosynthesis of antiviral and anticancer terpenoids from Bacillus subtilis

Recent advancements in medicinal research have identified several antiviral and anticancer terpenoids that are usually deployed as a source of flavor, fragrances and pharmaceuticals. Under the current COVID-19 pandemic conditions, natural therapeutics with least side effects are the need of the hour to save the patients, especially, which are pre-affected with other medical complications. Although, plants are the major sources of terpenoids; however, for the environmental concerns, the global interest has shifted to the biocatalytic production of molecules from microbial sources. The gram-positive bacterium Bacillus subtilis is a suitable host in this regard due to its GRAS (generally regarded as safe) status, ease in genetic manipulations and wide industrial acceptability. The B. subtilis synthesizes its terpenoid molecules from 1-deoxy-d-xylulose-5-phosphate (DXP) pathway, a common route in almost all microbial strains. Here, we summarize the computational and synthetic biology approaches to improve the production of terpenoid-based therapeutics from B. subtilis by utilizing DXP pathway. We focus on the in-silico approaches for screening the functionally improved enzyme-variants of the two crucial enzymes namely, the DXP synthase (DXS) and farnesyl pyrophosphate synthase (FPPS). The approaches for engineering the active sites are subsequently explained. It will be helpful to construct the functionally improved enzymes for the high-yield production of terpenoid-based anticancer and antiviral metabolites, which would help to reduce the cost and improve the availability of such therapeutics for the humankind.

The supramolecularly complexes of calix[4]arene derivatives toward favipiravir antiviral drug (used to treatment of COVID-19): a DFT study on the geometry optimization, electronic structure and infrared spectroscopy of adsorption and sensing

While the world is in search of a vaccine that can cure COVID-19 disease, favipiravir is the most commonly used antiviral drug in the treatment of patients during the pandemic process. In this study, we investigated the host-guest interaction between the popular supramolecule calix[4]arene derivatives and the favipiravir drug by using the DFT (Density Functional Theory) method. The B3LYP hybrid method and 6-31G (d,p) basis set were utilized to determine the optimized structures of the host and guest molecules and their complexes. The negative adsorption energy (∆E) and adsorption enthalpy (∆H) calculated for the complexes formed between calix[4]arene compounds and favipiravir drug molecule mentioned that adsorption of favipiravir molecule was an exothermic process on calix[4]arene structures. On the other hand, among the calixarene derivatives in the study, Gibbs free energy change (∆G) value for the adsorption was only negative on calix[4]arene4 molecule. The infrared spectroscopy (IR) calculations were performed by examining the C=O, O-H and NH2 vibrational frequencies to see the adsorption behavior in the favipiravir-calix[4]arene complex. After adsorption of the favipiravir molecule, HOMO-LUMO gap values decreased significantly for the structures and therefore electrical conductivity increased proportionally. In addition, sensor response factors, Fermi energy levels and workfunction changes of calix[4]arene derivatives were calculated and examined. Charge transfer between the four calix[4]arene compounds and the favipiravir molecule has occurred after adsorption. This attributes that calix[4]arene derivatives can be used as a well-suited favipiravir sensor (electronic and workfunction) and adsorbent at room temperature. Based on the calculations made to see the solvent effect on the adsorption of favipiravir it was determined that it did not affect the interaction between the drug molecule and the calix[4]arene compound too much and the adsorption energy turned into a slightly less negative value.

Chloroquine and hydroxychloroquine inhibitors for COVID-19 sialic acid cellular receptor: Structure, hirshfeld atomic charge analysis and solvent effect

COVID-19, the pandemic disease recently discovered in Wuhan (China), severely spread and affected both social and economic activity all over the world. Attempts to find an effective vaccine are challenging, time-consuming though interminable. Hence, re-proposing effective drugs is reliable and effective alternative. Taking into account the genome similarity of COVID-19 with SARS-CoV, drugs with safety profiles could be fast solution. Clinical trials encouraged the use of Chloroquine and Hydroxychloroquine for COVID-19 inhibition. One of the possible inhibition pathways is the competitive binding with the angiotension-converting enzyme-2 (ACE-2), in particular with the cellular Sialic acid (Neu5Ac). Here, we investigate the possible binding mechanism of ClQ and ClQOH with sialic acid both in the gas phase and in water using density functional theory (DFT). We investigated the binding of the neutral, monoprotonated and diprotonated ClQs and ClQOHs to sialic acid to simulate the pH effect on the cellular receptor binding. DFT results reveals that monoprotonated ClQ⁺ and ClQOH⁺, which account for more than 66% in the solution, possess high reactivity and binding towards sialic acid. The Neu5Ac-ClQ and the analogues Neu5Ac-ClQOH adducts were stabilized in water than in the gas phase. The molecular complexes stabilize by strong hydrogen bonding and π - π stacking forces. In addition, proton-transfer in Neu5Ac-ClQOH⁺ provides more stabilizing power and cellular recognition binding forces. These results shed light on possible recognition mechanism and help future breakthroughs for COVID-19 inhibitors.

Toward an efficient and eco-friendly route for the synthesis of dimeric 2,4-diacetyl phloroglucinol and its potential as a SARS-CoV-2 main protease antagonist: insight from in silico studies

Dimeric 2,4-diacetyl phloroglucinol derivatives were synthesized under green chemistry protocols and found to be the potential inhibitor of 3CLpro of SARS-CoV-2.

Remarkable enhancement in sensor ability of polyaniline upon composite formation with ZnO for industrial effluents

Polyaniline emeraldine salt and Polyaniline Zinc Oxide composite are comprehensively studied to compare their sensing ability towards ammonia, acetone, methanol and ethanol. Sensing ability is evaluated through thermodynamic, geometric and electronic parameters. A number of orientations are evaluated in search for the lowest energy structure. The comparison of thermodynamic, geometric and electronic parameters of simple and composite sensors confirmed that composite sensor shows better sensing ability than simple PANI. Composite formation between polyaniline and zinc oxide is a thermodynamically feasible process with interaction energy of -42.8 kcal/mol. Both sensor shows highest interaction energy for ethanol among four analytes. Composite sensor shows almost twice the interaction with ethanol, methanol and acetone while 1.5 times the interaction energy for ammonia. The results of run simulations and subsequent calculations showed that in composite sensors, zinc oxide not only enhances the binding power of conducting polymer with analytes but also interacts directly with analytes. Strong hydrogen bonding as well as weak dispersion forces of attraction are responsible for the stability of composite and all complexes, as revealed by non-covalent interaction (NCI) studies. Acetone shows a different behaviour in composite sensor complex than other analytes.