Molecular Interpretation of Pharmaceuticals’ Adsorption on Carbon Nanomaterials: Theory Meets Experiments

Exploring the potential of beta-cyclodextrin-based MIL-101(Cr) for pharmaceutical removal from wastewater: A combined density functional theory and molecular simulations study

Pharmaceutical contaminants pose significant risks to ecosystems and human health, necessitating effective removal strategies. This research focuses on developing advanced adsorbents for removing pharmaceutical pollutants from the environment. Metal-organic frameworks (MOFs), specifically MIL-101(Cr) functionalized with biodegradable beta-cyclodextrin (β-CDex), were investigated as potential nanocomposite adsorbents for the removal of ketorolac (KTRK), naproxen (NPXN), and tramadol (TRML). The study employed molecular simulations and density functional theory (DFT) calculations to explore the interactions between the pollutants and adsorbents. Analyses of DFT results, including electrostatic potential, ionization energy, density of states, and molecular orbital analysis, provided insights into the reactivity of pollutants and adsorbents. Additionally, the structural properties of the adsorbents, such as fractional free volume, radius of gyration, and system energies, were thoroughly examined. Molecular dynamics (MD) and Monte Carlo (MC) simulations were used to evaluate the adsorption capacities of MIL-101(Cr) for the target pharmaceutical pollutants. The results demonstrated the superior adsorption performance of the nanocomposite adsorbent, particularly for KTRK, with an adsorption energy of -1934 kcal/mol, compared to the pristine MIL-101(Cr), which had an adsorption energy of -1916 kcal/mol. This enhanced adsorption is attributed to the optimal molecular fit, guest-host solid interactions, and the selective encapsulation capabilities of β-CDex. This research highlights the potential of MOF-based nanocomposites as effective and sustainable solutions for pharmaceutical pollution. By advancing the understanding of molecular interactions through simulations, this study contributes to developing innovative adsorbents for wastewater treatment and the protection of water resources.

In-situ magnetic alginate coated chitosan core@shell beads with excellent performance in simulated and real wastewater treatment: Behavior, mechanisms, and new perspectives

Herein, a new hybrid magnetic core@shell biocomposite was prepared based on an alginate-bentonite core and a chitosan shell layer (mAB@Cs) where magnetic Fe3O4 NPs (50.7 nm) were in-situ generated on the surface via a simple non-thermal co-precipitation approach. The biocomposite has a high ability to magnetically separate and remove organic (ciprofloxacin (CPX)) and seven toxic inorganic (Cu2+, Cd2+, Co2+, Ni2+, Pb2+, Zn2+, and Hg2+) contaminants from simulated wastewater. Experimental results showed a CPX monolayer chemisorption with a Langmuir maximum adsorption capacity of 264.7 mg/g, maintained effectiveness up to the fifth cycle, and high removal rates of heavy metals ranging from 74.89 % to 99.86 % corresponding to adsorption capacities ranging from 12 to 20 mg/g. For a more accurate evaluation, the biocomposite was tested on a real urban wastewater sample (RWW) and it has manifested a noteworthy efficiency in removing a mixture of inorganic pollutants in terms of potassium K+ and orthophosphate phosphorous P-PO43-, and organic matter in terms of biological oxygen demand (BOD) and chemical oxygen demand (COD) with 46 %, 90 %, 84 %, and 64 % removal efficiencies, respectively. On top of this, a high inactivation rate of E. coli of the order of 96 % was recorded, making the prepared magnetic biocomposite adept for the simultaneous removal of emergent wastewater pollutants, from organic, inorganic, to pathogen microorganisms.

Molecular dynamics insight of interaction between the functionalized-carbon nanotube and cancerous cell membrane in doxorubicin delivery

BACKGROUND AND OBJECTIVE

Doxorubicin (DOX) is a known anticancer drug which is widely used in cancer therapy. Carbon nanotubes (CNTs) are among the most promising platforms for smart drug delivery applications. However, due to the toxicity and their low sulubility their application is limited and their functionalization with wide range of biomolecules are suggested. Therefore, the functionalized carbon nanotubes (f-CNT) with carboxyl (CNT-COO) and folic acid (CNT-COO-FA) were investigated as drug-carrier.

METHODS

Molecular dynamics (MD) simulation along with the Density Functional Theory (DFT) methods are being used to study the drug loading process on functionalized carbon nanotubes.

RESULTS

The results indicate that doxorubicin molecules interact more with CNT-COO-FA than CNT-COO. The embedded dipalmitoylphosphatidylcholine (DPPC) lipid bilayer with a folate receptor was considered a cancerous cell's representative model. Then the drug release from the f-CNTs near the lipid bilayer was simulated. The results showed that CNT-COO-FA with a pH and ligand-sensitive mechanism strongly interacts with cancerous cells, which led to higher drug release, in agreement with the experimental results. The conformational changes of the lipid bilayer and folate receptor during drug release were evaluated. The analysis showed that drug release from CNT-COO-FA has significantly changed lipid bilayer and receptor conformations. The obtained results were interpreted and justified by considering the molecular mechanisms which control the drug delivery in the studied systems.

CONCLUSIONS

Based on the obtained results, CNT-COO-FA has a better performance during the drug release compared to CNT-COO in delivering doxorubicin. Both pH and ligand sensitive mechanisms are found to be responsible for higher drug delivery efficiency of CNT-COO-FA. In contrast, CNT-COO can only enhance drug delivery efficiently with a pH-sensitive mechanism.

Evaluation of Dithiocarbamate-Modified Silica for Cisplatin Removal from Water

Despite the globally increasing use of platinum-based cytostatic drugs in the treatment of several types of cancer, only limited attention has been paid to developing a treatment for contaminated liquid samples originating from hospitals, laboratories and manufacturing facilities before and after their administration. In this work, we assess the efficiency of a low-cost adsorbent material, a dithiocarbamate-functionalized silica, in removing cisplatin from a solution containing it in the 0.5–150 mg L−1 concentration range. The advantage of having a surface-functionalized silica is that adsorption can occur by either non-covalent interaction or surface complexation. In the latter case platinum(II) is de-complexed and the original drug is no longer present. Adsorption occurs through a first rapid step, followed by a second slower process. This is likely due to the fact that in our operating conditions (0.9% w/v NaCl), only the original compound is present, for which ligand substitution is known to proceed slowly. The interesting performance, even at low metal concentration, and facile synthesis of the material mean it could be adapted for other applications where the recycling of platinum can be realized.

Advanced Polymeric Nanocomposite Membranes for Water and Wastewater Treatment: A Comprehensive Review

Nanomaterials have been extensively used in polymer nanocomposite membranes due to the inclusion of unique features that enhance water and wastewater treatment performance. Compared to the pristine membranes, the incorporation of nanomodifiers not only improves membrane performance (water permeability, salt rejection, contaminant removal, selectivity), but also the intrinsic properties (hydrophilicity, porosity, antifouling properties, antimicrobial properties, mechanical, thermal, and chemical stability) of these membranes. This review focuses on applications of different types of nanomaterials: zero-dimensional (metal/metal oxide nanoparticles), one-dimensional (carbon nanotubes), two-dimensional (graphene and associated structures), and three-dimensional (zeolites and associated frameworks) nanomaterials combined with polymers towards novel polymeric nanocomposites for water and wastewater treatment applications. This review will show that combinations of nanomaterials and polymers impart enhanced features into the pristine membrane; however, the underlying issues associated with the modification processes and environmental impact of these membranes are less obvious. This review also highlights the utility of computational methods toward understanding the structural and functional properties of the membranes. Here, we highlight the fabrication methods, advantages, challenges, environmental impact, and future scope of these advanced polymeric nanocomposite membrane based systems for water and wastewater treatment applications.

Various hydrogen bonds make different fates of pharmaceutical contaminants on oxygen-rich nanomaterials

Various hydrogen bonds, especially charge-assisted hydrogen bond (CAHB), is considered as one of vital mechanisms affecting the environmental behavior and risk of pharmaceutical contaminants (PCs). Herein the sorption/desorption of three PCs including clofibric acid (CA), acetaminophen (ACT), and sulfamerazine (SMZ) on three Oxygen-rich (O-rich) nanoparticles (nano-silica: Nano-SiO₂, nano-alumina: Nano-Al₂O₃, and oxidized carbon nanotubes: O-CNTs) were investigated to explore the effect of various hydrogen bonds with different strengths on environmental behaviors of PCs. The results indicated that although solvent-assisted CAHB, solvent-uninvolved CAHB, and ordinary hydrogen bond (OHB) all played a crucial role in sorption of PCs on three O-rich nanomaterials, they showed significantly different effects on the desorption behaviors of PCs from three sorbents. Compared with OHB (hysteresis index ≤0.0766), the stronger CAHB (hysteresis index ≥0.1981) between PCs and O-rich nanoparticles having comparable pK_a with PCs, caused obvious desorption hysteresis of PCs, resulting in their better immobilization on O-rich nanomaterials. The FTIR characterization found that both solvent-assisted and solvent-uninvolved CAHB formation resulted in a new characteristic peak appeared in the high frequency (3660 cm^-1 for Nano-SiO₂, 3730 cm^-1 for Nano-Al₂O₃, and 3780 cm^-1 for O-CNTs). Also, density functional theory (DFT) calculation verified that the smaller |ΔpK_a| between PCs and O-rich sorbents, the shorter bond length, and the larger bond angle resulted in the stronger hydrogen bond formed, thereby leading to the greater immobilization of PCs. These results provide in-depth understanding of the environmental behavior and risk of PCs, and light new idea for designed materials to control PCs pollution in the environment.

Ab Initio Insight into the Interaction of Metal-Decorated Fluorinated Carbon Fullerenes with Anti-COVID Drugs

We theoretically investigated the adsorption of two common anti-COVID drugs, favipiravir and chloroquine, on fluorinated C₆₀ fullerene, decorated with metal ions Cr³⁺, Fe²⁺, Fe³⁺, Ni²⁺. We focused on the effect of fluoridation on the interaction of fullerene with metal ions and drugs in an aqueous solution. We considered three model systems, C₆₀, C₆₀F₂ and C₆₀F₄₈, and represented pristine, low-fluorinated and high-fluorinated fullerenes, respectively. Adsorption energies, deformation of fullerene and drug molecules, frontier molecular orbitals and vibrational spectra were investigated in detail. We found that different drugs and different ions interacted differently with fluorinated fullerenes. Cr³⁺ and Fe²⁺ ions lead to the defluorination of low-fluorinated fullerenes. Favipiravir also leads to their defluorination with the formation of HF molecules. Therefore, fluorinated fullerenes are not suitable for the delivery of favipiravir and similar drugs molecules. In contrast, we found that fluorine enhances the adsorption of Ni²⁺ and Fe³⁺ ions on fullerene and their activity to chloroquine. Ni²⁺-decorated fluorinated fullerenes were found to be stable and suitable carriers for the loading of chloroquine. Clear shifts of infrared, ultraviolet and visible spectra can provide control over the loading of chloroquine on Ni²⁺-doped fluorinated fullerenes.

Computational Analysis of Strain-Induced Effects on the Dynamic Properties of C60 in Fullerite

A hybrid discrete-continuous physical and mathematical model is used to study what deformation characteristics cause the rolling effect of C60 fullerene in a fullerite crystal. The interaction of fullerene atoms with surrounding molecules is described using a centrally symmetric interaction potential, in which the surrounding molecules are considered as a spherical surface of uniformly distributed carbon atoms. The rotational motion of fullerene is described by the Euler dynamic equations. The results of a numerical study of the influence of the rate, magnitude, and direction of strain on the dynamic characteristics of the rotational and translational motion of C60 fullerene in a crystalline fragment are presented.

Prospect of DFT Utilization in Polymer-Graphene Composites for Electromagnetic Interference Shielding Application: A Review

The improvement in current materials science has prompted a developing need to capture the peculiarities that determine the properties of materials and how they are processed on an atomistic level. Quantum mechanics laws control the interface among atoms and electrons; thus, exact and proficient techniques for fixing the major quantum-mechanical conditions for complex many-particle, many-electron frameworks should be created. Density functional theory (DFT) marks an unequivocal advance in these endeavours. DFT has had a rapid influence on quintessential and industrial research during the last decade. The DFT system describes periodic structural systems of 2D or 3D electronics with the utilization of Bloch’s theorem in the direction of Kohn–Sham wavefunctions for the significant facilitation of these schemes. This article introduces and discusses the infinite systems modelling approach required for graphene-based polymer composites or their hybrids. Aiming to understand electronic structure computations as per physics, the impressions of band structures and atomic structure envisioned along with orbital predicted density states are beneficial. Convergence facets coupled with the basic functions number and the k-points number are necessary to explain for every physicochemical characteristic in these materials. Proper utilization of DFT in graphene-based polymer composites for materials in EMI SE presents the potential of taking this niche to unprecedented heights within the next decades. The application of this system in graphene-based composites by researchers, along with their performance, is reviewed.

The Dark Side of Platinum Based Cytostatic Drugs: From Detection to Removal

The uncontrolled release of pharmaceutical drugs into the environment raised serious concerns in the last decades as they can potentially exert adverse effects on living organisms even at the low concentrations at which they are typically found. Among them, platinum based cytostatic drugs (Pt CDs) are among the most used drugs in cancer treatments which are administered via intravenous infusion and released partially intact or as transformation products. In this review, the studies on environmental occurrence, transformation, potential ecotoxicity, and possible treatment for the removal of platinum cytostatic compounds are revised. The analysis of the literature highlighted the generally low total platinum concentration values (from a few tens of ng L−1 to a few hundred μg L−1) found in hospital effluents. Additionally, several studies highlighted how hospitals are sources of a minor fraction of the total Pt CDs found in the environment due to the slow excretion rate which is longer than the usual treatment durations. Only some data about the impact of the exposure to low levels of Pt CDs on the health of flora and fauna are present in literature. In some cases, adverse effects have been shown to occur in living organisms, even at low concentrations. Further ecotoxicity data are needed to support or exclude their chronic effects on the ecosystem. Finally, fundamental understanding is required on the platinum drugs removal by MBR, AOPs, technologies, and adsorption.

Graphene and its derivatives: understanding the main chemical and medicinal chemistry roles for biomedical applications

Over the past few years, there has been a growing potential use of graphene and its derivatives in several biomedical areas, such as drug delivery systems, biosensors, and imaging systems, especially for having excellent optical, electronic, thermal, and mechanical properties. Therefore, nanomaterials in the graphene family have shown promising results in several areas of science. The different physicochemical properties of graphene and its derivatives guide its biocompatibility and toxicity. Hence, further studies to explain the interactions of these nanomaterials with biological systems are fundamental. This review has shown the applicability of the graphene family in several biomedical modalities, with particular attention for cancer therapy and diagnosis, as a potent theranostic. This ability is derivative from the considerable number of forms that the graphene family can assume. The graphene-based materials biodistribution profile, clearance, toxicity, and cytotoxicity, interacting with biological systems, are discussed here, focusing on its synthesis methodology, physicochemical properties, and production quality. Despite the growing increase in the bioavailability and toxicity studies of graphene and its derivatives, there is still much to be unveiled to develop safe and effective formulations.

Graphic abstract

Carbon nanohorns as nanocontainers for cisplatin: insight into their interaction with the plasma membranes of normal and breast cancer cells

Cisplatin (cddp)-based chemotherapy is one of the most effective therapeutic alternatives for breast cancer treatment, the most common form of cancer, despite the severe side effects related to the high toxicity and low selectivity of cddp. To circumvent these drawbacks, the encapsulation of cddp into oxidized carbon nanohorns (CNHoxs) has been shown as a promising formulation with biocompatibility and low toxicity. However, there is still a lack of studies regarding the behavior of this cddp@CNHox nanovector on the cell membranes. This study presents an in silico description of the interactions between cddp@CNHox and membrane models of cancer (C_memb) and normal (N_memb) cells referring to a typical human breast. The results revealed the interaction mechanism of the inclusion complex 3cddp@CNHox (three cddp molecules are included in the CNHox cavity) with these biomembranes, which is a multistep process including approach, landing, insertion, and penetration. The 3cddp@CNHox stability was monitored over time, and demonstrated the trapping of cddp molecules inside the CNHox cavity over all simulations. The van der Waals contribution played a primary role (∼74%) for the complex stability. Moreover, the binding free energy calculations indicated that the interaction of the 3cddp@CNHox complex with the C_memb model was slightly more favorable, on average, than with the N_memb model. Analysis of the hydrogen bonds (HBs) formed over simulations of 800 ns explains the selectivity for the C_memb model, since the total number of HBs established between the inclusion complex and the C_memb model was about three times greater than that with the N_memb model. By reinforcing the potentiality of oxidized CNHox as a nanovector of cddp, the results presented in this study may assist and drive new experimental studies with this nanomaterial, focusing on the development of less aggressive formulations for breast cancer treatment.

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.

Doxorubicin Encapsulation in Carbon Nanotubes Having Haeckelite or Stone-Wales Defects as Drug Carriers: A Molecular Dynamics Approach

Doxorubicin (DOX), a recognized anticancer drug, forms stable associations with carbon nanotubes (CNTs). CNTs when properly functionalized have the ability to anchor directly in cancerous tumors where the release of the drug occurs thanks to the tumor slightly acidic pH. Herein, we study the armchair and zigzag CNTs with Stone-Wales (SW) defects to rank their ability to encapsulate DOX by determining the DOX-CNT binding free energies using the MM/PBSA and MM/GBSA methods implemented in AMBER16. We investigate also the chiral CNTs with haeckelite defects. Each haeckelite defect consists of a pair of square and octagonal rings. The armchair and zigzag CNT with SW defects and chiral nanotubes with haeckelite defects predict DOX-CNT interactions that depend on the length of the nanotube, the number of present defects and nitrogen doping. Chiral nanotubes having two haeckelite defects reveal a clear dependence on the nitrogen content with DOX-CNT interaction forces decreasing in the order 0N > 4N > 8N. These results contribute to a further understanding of drug-nanotube interactions and to the design of new drug delivery systems based on CNTs.

Plane Animation Simulation of the Interaction between Carbon Nanomaterials and Cell Lysosomes

With the continuous development of cell dynamics, Raman scattering has become more and more common in the application of cell imaging and dynamic changes in chemical substances. This research mainly discusses the plane animation simulation process of the interaction between carbon nanomaterials and cell lysosomes. Twenty parallel HeLa cells were seeded on 40 mm imaging scaffolds. The 15% bovine placental serum cell culture cells are placed in a thermostat for 12 hours at a CO2 concentration of 6%. After washing 4 times, 20 μL of the dual control system is added to the confocal dish, and cycle optimization culture is performed at 2, 4, 6, and 8 hours. It is incubated for 10 hours, 20 hours, and 30 hours (35°C, 6% CO2). Next, the HeLa cells were taken out and seeded on three 30 mm confocal cell culture dishes. CCl4 is added to the initial confocal Petri dish. After heating for 30 minutes, the nanoparticle system is added to the two confocal Petri dishes and circulated within an appropriate time. After washing with PBS, the SERS signal in the cells was imaged with a laser confocal Raman microscope, and the excitation channels were GFP 475 and Cy3 channels. LysoTrackerRed (2p μM) was used for local experiments of cell isotope. Deoxygen (2p μM) was used to induce cell death, and the pH changes in lysosomes in cells were imaged in real time with a confocal microscope. Two distinct peaks in the Raman spectrum were observed at 1246 cm−1 and 1543 cm−1. The research results show that the carbon nanomaterial synthesized by a simple method at room temperature has high stability and is suitable for analysis and detection of imaging with cells as the target.

Residue Char Derived from Microwave-Assisted Pyrolysis of Sludge as Adsorbent for the Removal of Methylene Blue from Aqueous Solutions

Residue char is the main by-product of the microwave-assisted pyrolysis of activated sludge and it has a high content of fixed carbon and porous structure, but little is known about its character as an absorbent. In this study, residue char of activated sludge with microwave-assisted pyrolysis was used as an adsorbent to absorb methylene blue. The effects of pyrolysis temperature, pyrolysis holding time, contact time, and adsorption temperature on the adsorption ability of residue char were investigated. Kinetics, isotherm, and thermodynamic models were also included to study the adsorption behavior. The results showed that the optimal pyrolysis condition was 15 min and 603 °C, and the adsorption capacity reached up to 80.01 mg/g. The kinetics analyses indicated the adsorption behavior followed the pseudo-second-order kinetics model and the adsorption process was mainly due to chemical interaction. The adsorption isotherm was described by Freundlich model and thus, its process was multimolecular layer adsorption. Furthermore, the thermodynamics parameters (ΔG0, ΔH0, and ΔS0) at different temperatures indicated that the nature of the adsorption process was endothermic and spontaneous.