RESUMO
Herein, the potential of ZO3 and ZF2 aerogen-comprising molecules (where Z = Ar, Kr, and Xe) to engage in σ-, lp-, and π-hole site-based interactions was comparatively studied using various ab initio computations. For the first time, a premier in-depth elucidation of the external electric field (EEF) influence on the strength of the σ-, lp-, and π-hole site-based interactions within the ZO3/ZF2â¯NH3 and â¯NCH complexes was addressed using oriented EEF with disparate magnitude. Upon the energetic features, σ-hole site-based interactions were noticed with the most prominent preferability in comparison to lp- and π-hole analogs. This finding was ensured by the negative interaction energy values of -11.65, -3.50, and -2.74 kcal mol-1 in the case of σ-, lp-, and π-hole site-based interactions within the XeO3⯠and XeF2â¯NH3 complexes, respectively. Detailedly, the strength of the σ- and lp-hole site-based interactions directly correlated with the atomic size of the aerogen atoms and the magnitude of the positively oriented EEF. Unexpectedly, an irregular correlation was noticed for the interaction energies of the π-hole site-based interactions with the size of the π-hole. Interestingly, the π-hole site-based interactions within Kr-comprising complexes exhibited higher negative interaction energies than the Ar- and Xe-comprising counterparts. Notwithstanding, a direct proportion between the interaction energies of the π-hole site-based interactions and π-hole size was obtained by employing EEF along the positive orientation with high strength. The present outcomes would be a fundamental basis for forthcoming progress in studying the σ-, lp-, and π-hole site-based interactions within aerogen-comprising complexes and their pertinent applications in materials science and crystal engineering.
RESUMO
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 AâD 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 TMZâ¢â¢â¢Be12O12 and â¢â¢â¢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 TMZâ¢â¢â¢B12N12 and â¢â¢â¢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 TMZâ¢â¢â¢B12N12 and â¢â¢â¢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.
RESUMO
The feasibility of utilizing the mud solid waste (MSW) produced during the carbonation process of sugar refining as a cost-effective and environmentally friendly alternative for the water removal of methylene blue (MB) and Congo red (CR), being highly utilized organic dyes representing cationic and anionic species, respectively is presented. Prior to its use, the MSW was dried at 110 °C for 24 h and sieved through a 100-mesh screen. The chief constituent of the MSW utilized was CaCO3, with a point of zero charge (PZC) found at pH 8.4 and 7.96 m2 g-1 total surface area. XRD and FTIR data indicate the presence of interactions between the dyes and the MSW surface, indicating effective adsorption. Different variables, such as initial dye concentration, MSW weight, solution pH, contact time, and temperature, were all examined to determine the optimal dye removal conditions. A central composite design (CCD) approach based on response surface methodology (RSM) modeling was utilized to identify statistically significant parameters for MB and CR adsorption capacities onto the MSW adsorbent. The removal equilibrium was typically reached in 120 minutes, with the greatest removal efficiency of CR taking place at pH 2 and 328 K, while the highest MB removal efficiency was obtained at pH 12 and 296 K. Kinetic studies suggest the adsorption of both dyes on the MSW follow pseudo-second-order rates, as evident through the high correlations obtained. Linearized and non-linearized Langmuir models showed strong correlations indicating maximum adsorption capacities of 86.6 and 72.3 mg g-1 for MB and CR, respectively. High regeneration and reusability potential of the MSW was demonstrated especially for the adsorption of CR, where the removal efficiency was nearly constant throughout five adsorption cycles, ranging from 93 to 91%, while the reduction in the removal for MB was much more significantly impacted, diminishing from 95 to 79% after the five cycles.
RESUMO
The efficacy of aluminium phosphide (Al12P12) nanocage toward sensing methanol (MeOH) and ethanol (EtOH) volatile organic compounds (VOCs) was herein thoroughly elucidated utilizing various density functional theory (DFT) computations. In this perspective, MeOH⯠and EtOHâ¯Al12P12 complexes were investigated within all plausible configurations. According to the energetic features, the EtOHâ¯Al12P12 complexes exhibited larger negative values of adsorption and interaction energies with values up to -27.23 and -32.84 kcal mol-1, respectively, in comparison to the MeOHâ¯Al12P12 complexes. Based on the symmetry-adapted perturbation theory (SAPT) results, the electrostatic forces were pinpointed as the predominant component beyond the adsorption process within the preferable MeOH⯠and EtOHâ¯Al12P12 complexes. The findings of the noncovalent interaction (NCI) index and quantum theory of atoms in molecules (QTAIM) outlined the closed-shell nature of the interactions within the studied complexes. Substantial variations were found in the molecular orbitals distribution patterns of MeOH/EtOH molecules and Al12P12 nanocage, outlining the occurrence of the adsorption process within the complexes under investigation. Thermodynamic parameters were denoted with negative values, demonstrating the spontaneous exothermic nature of the most favorable complexes. New energy states were observed within the extracted density of states plots, confirming the impact of adsorbing MeOH and EtOH molecules on the electronic properties of the Al12P12 nanocage. The appearance of additional peaks in Infrared Radiation (IR) and Raman spectra revealed the apparent effect of the adsorption process on the features of the utilized sensor. The emerging results declared the potential uses of Al12P12 nanocage as a promising candidate for sensing VOCs, particularly MeOH and EtOH.
RESUMO
σ-Hole site-based interactions in the trigonal bipyramidal geometrical structure of hypervalent pnicogen, halogen, and aerogen-bearing molecules with pyridine and NCH Lewis bases (LBs) were comparatively examined. In this respect, the ZF5···, XF3O2···, and AeF2O3···LB complexes (where Z = As, Sb; X = Br, I; Ae = Kr, Xe; and LB = pyridine and NCH) were investigated. The electrostatic potential (EP) analysis affirmations outlined the occurrence of σ-holes on the systems under consideration with disparate magnitudes that increased according to the following order: AeF2O3 < XF3O2 < ZF5. In line with EP outcomes, the proficiency of σ-hole site-based interactions increased as the atomic size of the central atom increased with a higher favorability for the pyridine-based complexes over NCH-based ones. The interaction energy showed the most favorable negative values of -35.97, -44.53, and -56.06 kcal/mol for the XeF2O3···, IF3O2···, and SbF5···pyridine complexes, respectively. The preferentiality pattern of the studied interactions could be explained as a consequence of (i) the dramatic rearrangement of ZF5 molecules from the trigonal bipyramid geometry to the square pyramidal one, (ii) the significant and tiny deformation energy in the case of the interaction of XF3O2 molecules with pyridine and NCH, respectively, and (iii) the absence of geometrical deformation within the AeF2O3···pyridine and ···NCH complexes other than the XeF2O3···pyridine one. Quantum theory of atoms in molecules and noncovalent interaction index findings reveal the partially covalent nature of most of the investigated interactions. Symmetry-adapted perturbation theory affirmations declared that the electrostatic component was the driving force beyond the occurrence of the considered interactions. The obtained findings will help in improving our understanding of the effect of geometrical deformation on intermolecular interactions.
RESUMO
The oxazaphosphorine cyclophosphamide (CP) is a DNA-alkylating agent commonly used in cancer chemotherapy. This anticancer agent is administered as a prodrug activated by a liver cytochrome P450-catalyzed 4-hydroxylation reaction that yields the active, cytotoxic metabolite. The primary metabolite, 4-hydroxycyclophosphamide, equilibrates with the ring-open aldophosphamide that undergoes ß-elimination to yield the therapeutically active DNA cross-linking phosphoramide mustard and the byproduct acrolein. The present paper presents a DFT investigation of the different metabolic phases and an insight into the mechanism by which CP exerts its cytotoxic action. A detailed computational analysis of the energy profiles describing all the involved transformations and the mechanism of DNA alkylation is given with the aim to contribute to an increase of knowledge that, after more than 60 years of unsuccessful attempts, can lead to the design and development of a new generation of oxazaphosphorines.
Assuntos
Acroleína , DNA , Ciclofosfamida/farmacologia , HidroxilaçãoRESUMO
In this work, a novel double-network composite hydrogel (SA/TA), composed of sodium alginate (SA) and tannic acid (TA), was designed and fabricated by a successive cross-linking method using Ti(IV) and Ca(II) as crosslinkers. SA/TA exhibited reinforced mechanical strength and anti-swelling properties because of the double-network structure. SA/TA was used as an adsorbent for removal of a popular antiviral drug, chloroquine phosphate (CQ), in water. The adsorption performance of SA/TA was systematically investigated, to study various effects including those of TA mass content, solution pH, adsorption time, and initial CQ concentration. Adsorption was also examined in presence of inorganic and organic coexisting substances commonly found in wastewater, and under different actual water samples. Batch experimental results indicated that SA/TA could maintain higher and more stable CQ uptakes within a wide solution pH range from 3.0 to 10.0, compared to its precursor, SA hydrogel, owing to the addition of TA-Ti(IV) coordination network. The maximum experimental CQ uptake exhibited by the 1:1 (by wt) SA/TA (SA/TA2) was as high as 0.699 mmol/g at the initial pH of 9.0. A high concentration of coexisting NaCl evidently reduced the CQ uptakes of SA/TA2 due to the electrostatic shielding effect, moreover, divalent cations including Ca(II) and Mg(II) also inhibited the adsorption of CQ due to competitive adsorption. However, humic acid had little effect on this adsorption. Considering the apparent adsorption performance, the aforementioned effects of various factors and the spectroscopic characterizations, multi-interactions are suggested for adsorption including chelation, electrostatic interactions, π-π electron donor-acceptor interaction and hydrogen bonding. SA/TA showed a slight loss in adsorption capacity toward CQ and sustained physicochemical structural stability, even after six adsorption-desorption cycles. In addition to CQ, SA/TA could be efficiently used for adsorption of two other antivirus drugs, namely, hydroxychloroquine sulfate and oseltamivir phosphate. This work provides an effective strategy for the design and fabrication of novel adsorbents that can effectively adsorb antiviral drugs over a wide pH range.
Assuntos
Cloroquina/análogos & derivados , Hidrogéis , Polifenóis , Poluentes Químicos da Água , Hidrogéis/química , Adsorção , Alginatos/química , Água , Concentração de Íons de Hidrogênio , Cinética , Poluentes Químicos da Água/análiseRESUMO
σ-Hole and lone-pair (lp)-hole interactions of aerogen oxides with Lewis bases (LB) were comparatively inspected in terms of quantum mechanics calculations. The ZOn ⯠LB complexes (where Z = Kr and Xe, n = 1, 2, 3 and 4, and LB = NH3 and NCH) showed favourable negative interaction energies. The complexation features were explained in light of σ-hole and lp-hole interactions within optimum distances lower than the sum of the respective van der Waals radii. The emerging findings outlined that σ-hole interaction energies generally enhanced according to the following order: KrO4 ⯠< KrO⯠< KrO3⯠< KrO2â¯LB and XeO4⯠< XeO⯠< XeO2⯠< XeO3â¯LB complexes with values ranging from -2.23 to -12.84 kcal mol-1. Lp-hole interactions with values up to -5.91 kcal mol-1 were shown. Symmetry-adapted perturbation theory findings revealed the significant contributions of electrostatic forces accounting for 50-65% of the total attractive forces within most of the ZOnâ¯LB complexes. The obtained observations would be useful for the understanding of hole interactions, particularly for the aerogen oxides, with application in supramolecular chemistry and crystal engineering.
RESUMO
The potentiality of the 6-mercaptopurine (MP) and 6-thioguanine (TG) expired drugs toward the corrosion inhibition of the aluminium (Al) (111) surface was widely investigated using a series of density functional theory (DFT) calculations. A competition between the anti-corrosive features of the studied drugs in the gas and aqueous phases was conducted on both neutral and protonated forms by means of quantum mechanical descriptors. The results of the electrostatic potential analysis demonstrated the prominent nucleophilic nature of the sulfur and nitrogen atoms over the structures of the examined drugs. The frontier molecular orbital theory findings outlined the higher preferability of TG over MP as a corrosion inhibitor. Upon determining the most beneficial configurations of the MP/TGâ¯Al (111) complexes, first-principles molecular dynamics simulations were executed. Interestingly, the competence of the TG drug in the corrosion inhibition process of Al (111) was more extensive than that of the MP one, which was confirmed by the interaction energy values of -1.79 and -1.64 eV, respectively. Upon obtaining the relaxed complexes, the effect of the presence of water solvent on the adsorption process was studied. These findings provide a foundation for developing green anti-corrosive inhibitors for the aluminium surface.
RESUMO
For the first time, sigma (σ)- and lone-pair (lp)-hole site-based interactions of SF4 and SeF4 molecules in seesaw geometry with NH3 and FH Lewis bases were herein comparatively investigated. The obtained findings from the electrostatic potential analysis outlined the emergence of sundry holes on the molecular entity of the SF4 and SeF4 molecules, dubbed the σ- and lp-holes. The energetic viewpoint announced splendid negative binding energy values for σ-hole site-based interactions succeeded by lp-hole analogues, which were found to be -9.21 and -0.50 kcal/mol, respectively, for SeF4···NH3 complex as a case study. Conspicuously, a proper concurrence between the strength of chalcogen σ-hole site-based interactions and the chalcogen's atomic size was obtained, whereas a reverse pattern was proclaimed for the lp-hole counterparts. Further, a higher preference for the YF4···NH3 complexes with elevated negative binding energy was promulgated over the YF4···FH ones, indicating the eminent role of Lewis basicity. The indications of the quantum theory of atoms in molecules generally asserted the closed-shell nature of all the considered interactions. The observation of symmetry-adapted perturbation theory revealed the substantial contributing role of the electrostatic forces beyond the occurrence of σ-hole site-based interactions. In comparison, the dispersion forces were specified to govern the lp-hole counterparts. Such emerging findings would be a gate for the fruitful forthcoming applications of chalcogen bonding interactions in crystal engineering and biological systems.
RESUMO
Structural aspects of molnupiravir complexed with the RNA of the SARS-CoV-2 virus have been recently resolved inside the RNA-dependent RNA polymerase (RdRp), demonstrating the interactions of molnupiravir with purine nucleosides. However, the preference of molnupiravir to interact with one purine nucleoside over another has not been clearly investigated. Herein, the complexation of molnupiravir in its active form with guanosine and adenosine was compared, using sundry density functional theory calculations. The plausible tautomeric structures of the molnupiravir drug in complex with guanosine/adenosine were minutely scrutinized. The relative energy findings outlined the favorability of amino-molnupiravir···keto-amino-guanosine and imino-molnupiravir···amino-adenosine optimized complexes. According to the interaction (Eint) and binding (Ebind) energy values, higher preferential base-pairing of molnupiravir with guanosine over the adenosine one was recognized with Eint/Ebind values of -31.16/-21.81 and -13.93/-12.83 kcal/mol, respectively. This could be interpreted by the presence of three and two hydrogen bonds within the former and latter complexes, respectively. Observable changes in the electronic properties and global indices of reactivity of the studied complexes also confirmed the preferential binding within the studied complexes. The findings from the quantum theory of atoms in molecules and the noncovalent interaction index also support the partially covalent nature of the investigated interactions. For both complexes, changes in thermodynamic parameters outlined the spontaneous, exothermic, and nonrandom states of the inspected interactions. Inspecting the solvent effect on the studied interactions outlined more observable amelioration within the water medium compared with the gas one. These results would be a durable ground for the forthcoming studies concerned with the interactions of the molnupiravir drug with purine nucleosides.
RESUMO
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 MCPâ â â 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 MCPâ â â 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.
RESUMO
BRD4 (bromodomain-containing protein 4) is an epigenetic reader that realizes histone proteins and promotes the transcription of genes linked to cancer progression and non-cancer diseases such as acute heart failure and severe inflammation. The highly conserved N-terminal bromodomain (BD1) recognizes acylated lysine residues to organize the expression of genes. As such, BD1 is essential for disrupting BRD4 interactions and is a promising target for cancer treatment. To identify new BD1 inhibitors, a SuperDRUG2 database that contains more than 4600 pharmaceutical compounds was screened using in silico techniques. The efficiency of the AutoDock Vina1.1.2 software to anticipate inhibitor-BRD4-BD1 binding poses was first evaluated based on the co-crystallized R6S ligand in complex with BRD4-BD1. From database screening, the most promising BRD4-BD1 inhibitors were subsequently submitted to molecular dynamics (MD) simulations integrated with an MM-GBSA approach. MM-GBSA computations indicated promising BD1 binding with a benzonaphthyridine derivative, pyronaridine (SD003509), with an energy prediction (ΔGbinding) of -42.7 kcal/mol in comparison with -41.5 kcal/mol for a positive control inhibitor (R6S). Pharmacokinetic properties predicted oral bioavailability for both ligands, while post-dynamic analyses of the BRD4-BD1 binding pocket demonstrated greater stability for pyronaridine. These results confirm that in silico studies can provide insight into novel protein-ligand regulators, specifically that pyronaridine is a potential cancer drug candidate.
Assuntos
Simulação de Dinâmica Molecular , Proteínas Nucleares , Simulação de Acoplamento Molecular , Proteínas Nucleares/metabolismo , Proteínas que Contêm Bromodomínio , Fatores de Transcrição/metabolismo , Ligantes , Proteínas de Ciclo Celular/metabolismoRESUMO
An in-line smartphone connected to a screen-printed selective electrode hand-held device was used to determine the concentration of distigmine bromide (DB) in its pure and dosage forms as well as its degradation kinetics by continuously measuring the change in the produced emf over time. The main objective, supported by the data presented, is to produce a highly reliable smartphone integrated selective sensor as a portable analyzer with potential high cloud connectivity combining a wide linear dynamic range, the fastest response time with the lowest limits of detection and quantitation while best integrating green analytical chemistry principles. The choice of ionophore used in this approach was guided by computation and the data obtained was compared with traditional analytical techniques. DB, for which there are no previously reported stability-indicating methods and for which four novel such methods are proposed here, was selected as a model drug for this work. At-line UV-spectrophotometry DB assay was obtained by measuring the difference between the spectra of the degradation product and the same concentration of intact drug. The degradation kinetics were studied by this method through tracking the decrease of DB absorbance and/or the increase of a generated degradation product signal over time. Off-line separation based HPLC and TLC stability-indicating methods for DB were also presented. All methods employed in this work were validated for accuracy, precision, specificity, repeatability, linearity, range, detection and quantification limits according to the ICH guidelines and were applied to the analysis of laboratory prepared mixtures as well as commercial products. While all methods proposed were shown to be highly reliable, the smartphone integrated selective sensor is highlighted as a portable analyzer with potential high cloud connectivity and was shown to combine a wide linear dynamic range, the fastest response time with the lowest limits of detection and quantitation while best integrating green analytical chemistry principles.
Assuntos
Bioensaio , Química Analítica , Cinética , Eletrodos , Preparações FarmacêuticasRESUMO
Multidrug resistance (MDR) is one of the most problematic issues in chemotherapeutic carcinoma therapy. The ABCB1 transporter, a drug efflux pump overexpressed in cancer cells, has been thoroughly investigated for its association with MDR. Thus, discovering ABCB1 inhibitors can reverse the MDR in cancer cells. In the current work, a molecular docking technique was utilized for hunting the most prospective ABCB1 inhibitors from the Toxin and Toxin-Target Database (T3DB). Based on the docking computations, the most promising T3DB compounds complexed with the ABCB1 transporter were subjected to molecular dynamics (MD) simulations over 100 ns. Utilizing the MM-GBSA approach, the corresponding binding affinities were computed. Compared to ZQU (calc. -49.8 kcal/mol), Emamectin B1a (T3D1043), Emamectin B1b (T3D1044), Vincristine (T3D4016), Vinblastine (T3D4017), and Vindesine (T3D2479) complexed with ABCB1 transporter demonstrated outstanding binding affinities with ΔGbinding values of -93.0, -92.6, -93.8, -92.2, and -90.8 kcal/mol, respectively. The structural and energetic investigations confirmed the constancy of the identified T3DB compounds complexed with the ABCB1 transporter during the 100 ns MD course. To mimic the physiological conditions, MD simulations were conducted for those identified inhibitors complexed with ABCB1 transporter in the presence of a POPC membrane. These findings revealed that Emamectin B1a, Emamectin B1b, Vincristine, Vinblastine, and Vindesine are promising ABCB1 inhibitors that can reverse the MDR. Therefore, subjecting those compounds to further in-vitro and in-vivo investigations is worthwhile.
RESUMO
The potentiality of the ß12 borophene (ß12) and pristine graphene (GN) nanosheets to adsorb tetrahalomethanes (CX4; X = F, Cl, and Br) were investigated using density functional theory (DFT) methods. To provide a thorough understanding of the adsorption process, tetrel (XC-X3âââß12/GN)- and halogen (X3C-Xâââß12/GN)-oriented configurations were characterized at various adsorption sites. According to the energetic manifestations, the adsorption process of the CX4âââß12/GN complexes within the tetrel-oriented configuration led to more desirable negative adsorption energy (Eads) values than that within the halogen-oriented analogs. Numerically, Eads values of the CBr4âââBr1@ß12 and T@GN complexes within tetrel-/halogen-oriented configurations were -12.33/-8.91 and -10.03/-6.00 kcal/mol, respectively. Frontier molecular orbital (FMO) results exhibited changes in the EHOMO, ELUMO, and Egap values of the pure ß12 and GN nanosheets following the adsorption of CX4 molecules. Bader charge transfer findings outlined the electron-donating property for the CX4 molecules after adsorbing on the ß12 and GN nanosheets within the two modeled configurations, except the adsorbed CBr4 molecule on the GN sheet within the tetrel-oriented configuration. Following the adsorption process, new bands and peaks were observed in the band structure and density of state (DOS) plots, respectively, with a larger number in the case of the tetrel-oriented configuration than in the halogen-oriented one. According to the solvent effect affirmations, adsorption energies of the CX4âââß12/GN complexes increased in the presence of a water medium. The results of this study will serve as a focal point for experimentalists to better comprehend the adsorption behavior of ß12 and GN nanosheets toward small toxic molecules.
RESUMO
There is an increasing need to find cost-effective and sustainable solutions for treating wastewater from contaminants of emerging concern (CECs). In this regard, cape gooseberry husk-typically an agri-food waste-is investigated for the first time as a potential biosorbent for the removal of model pharmaceutical contaminants of caffeine (CA) and salicylic acid (SA) from water. Three different preparations of husks were investigated and characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller analysis, zeta potential, and point of zero charge measurements. The activation of the husk led to an increase in the surface area, pore volume, average pore size, and adsorption favorability. The single-component adsorption of SA and CA onto the three husks was investigated at different initial concentrations and pH values to determine the optimal operating conditions. The maximal removal efficiencies of SA and CA reached up to 85 and 63%, respectively, for the optimal husk which also offers a less energy-intensive option in its activation. This husk also exhibited high rates of adsorption that exceeded other husk preparations by up to four times. It was proposed that CA interacts electrostatically with the husk, while SA binds through weak physical interactions (e.g., van der Waals and H-bonding). In binary systems, CA adsorption was highly favored over SA adsorption, owing to its electrostatic interactions. The selectivity coefficients αSACA varied with initial concentration and ranged between 61 and 627. The regeneration of husk was also successful resulting in its re-use for up to four full consecutive cycles, further demonstrating the efficiency of cape gooseberry husk use in wastewater treatment.
RESUMO
Graphene (GN) nanosheets have been widely exploited in biomedical applications as potential nanocarriers for various drugs due to their distinct physical and chemical properties. In this regard, the adsorption behavior of cisplatin (cisPtCl2) and some of its analogs on a GN nanosheet was investigated in perpendicular and parallel configurations by using density functional theory (DFT). According to the findings, the most significant negative adsorption energies (Eads) within the cisPtX2â¯GN complexes (where X = Cl, Br, and I) were observed for the parallel configuration, with values up to -25.67 kcal/mol at the H@GN site. Within the perpendicular configuration of the cisPtX2â¯GN complexes, three orientations were investigated for the adsorption process, namely, X/X, X/NH3, and NH3/NH3. The negative Eads values of the cisPtX2â¯GN complexes increased with the increasing atomic weight of the halogen atom. The Br@GN site showed the largest negative Eads values for the cisPtX2â¯GN complexes in the perpendicular configuration. The Bader charge transfer outcomes highlighted the electron-accepting properties of cisPtI2 within the cisPtI2â¯GN complexes in both configurations. The electron-donating character of the GN nanosheet increased as the electronegativity of the halogen atom increased. The band structure and density of state plots revealed the occurrence of the physical adsorption of the cisPtX2 on the GN nanosheet, which was indicated by the appearance of new bands and peaks. Based on the solvent effect outlines, the negative Eads values generally decreased after the adsorption process in a water medium. The recovery time results were in line with the Eads findings, where the cisPtI2 in the parallel configuration took the longest time to be desorbed from the GN nanosheet with values of 61.6 × 108 ms at 298.15 K. The findings of this study provide better insights into the utilization of GN nanosheets in drug delivery applications.
RESUMO
The efficiency of pristine graphene (GN) in the delivery process of the Favipiravir (FPV) anti-COVID-19 drug was herein revealed within the FPVâ¯GN complexes in perpendicular and parallel configurations in terms of the density functional theory (DFT) method. Adsorption energy findings unveiled that the parallel configuration of FPVâ¯GN complexes showed higher desirability than the perpendicular one, giving adsorption energy up to -15.95 kcal mol-1. This favorability could be interpreted as a consequence of the contribution of π-π stacking to the overall strength of the adsorption process in the parallel configuration. Frontier molecular orbitals (FMO) findings demonstrated the ability of the GN nanosheet to adsorb the FPV drug by the alteration in the EHOMO, ELUMO, and Egap values before and after the adsorption process. Based on Bader charge results, the FPV drug and GN sheet exhibited electron-donating and -accepting characters, respectively, which was confirmed by the negative sign of the computed charge transfer (Qt) values. The FPV(R)â¯T@GN complex showed the most desirable Qt value of -0.0377e, which was in synoptic with the adsorption energy pattern. Electronic properties of GN were also altered after the adsorption of the FPV drug in both configurations, with more observable changes in the parallel one. Interestingly, the Dirac point of the GN sheet coincided with the Fermi level after the adsorption process, indicating that the adsorption process unaffected the presence of the Dirac point. The occurrence of the adsorption process was also noticed by the existence of new bands and peaks in the band structure and DOS plots, respectively. Short recovery time rendered the GN nanosheet an efficient FPV drug delivery system. The obtained findings provide new insight into the biomedical applications of the GN sheet as a promising drug delivery system.
RESUMO
The dramatic rise in cancer incidence, alongside treatment deficiencies, has elevated cancer to the second-leading cause of death globally. The increasing morbidity and mortality of this disease can be traced back to a number of causes, including treatment-related side effects, drug resistance, inadequate curative treatment and tumor relapse. Recently, anti-cancer bioactive peptides (ACPs) have emerged as a potential therapeutic choice within the pharmaceutical arsenal due to their high penetration, specificity and fewer side effects. In this contribution, we present a general overview of the literature concerning the conformational structures, modes of action and membrane interaction mechanisms of ACPs, as well as provide recent examples of their successful employment as targeting ligands in cancer treatment. The use of ACPs as a diagnostic tool is summarized, and their advantages in these applications are highlighted. This review expounds on the main approaches for peptide synthesis along with their reconstruction and modification needed to enhance their therapeutic effect. Computational approaches that could predict therapeutic efficacy and suggest ACP candidates for experimental studies are discussed. Future research prospects in this rapidly expanding area are also offered.