Understanding the co-loading and releasing of doxorubicin and paclitaxel using chitosan functionalized single-walled carbon nanotubes by molecular dynamics simulations

Recent advances on applications of single-walled carbon nanotubes as cutting-edge optical nanosensors for biosensing technologies

Single-walled carbon nanotubes (SWCNTs) possess outstanding photophysical properties which has garnered interest towards utilizing these materials for biosensing and imaging applications. The near-infrared (NIR) fluorescence within the tissue transparent region along with their photostability and sizes in the nanoscale make SWCNTs valued candidates for the development of optical sensors. In this review, we discuss recent advances in the development and the applications of SWCNT-based nano-biosensors. An overview of SWCNT's structural and photophysical properties, sensor development, and sensing mechanisms are described. Examples of SWCNT-based optical nanosensors for detection of disease biomarkers, pathogens (bacteria and viruses), plant stressors, and environmental contaminants including heavy metals and disinfectants are provided. Molecular detection in biofluids, in vitro, and in vivo (small animal models and plants) are highlighted, and sensor integration into portable substrates for implantable and wearable sensing devices has been discussed. Recent advancements, which include high throughput assays and the use of machine learning models to predict more sensitive and robust sensing outcomes are discussed. Current limitations and future perspectives on translation of SWCNT optical probes into clinical practices have been provided.

Carbon Nanotube Loading Strategies for Peptide Drugs: Insights from Molecular Dynamics Simulations

Carbon nanotubes (CNTs) can be regarded as a potential platform for transmembrane drug delivery as many experimental works have demonstrated their capability to effectively transport bioactive molecules into living cells. Within this framework, the loading of a peptide drug onto either the interior or exterior of CNTs has gained considerable interest. This study aims to conduct a comprehensive comparison of these two loading methods. To this end, we performed molecular dynamics simulations and the umbrella sampling technique to investigate the interaction energy, conformational changes, and free energy changes of a model peptide drug containing α-helical structure interacting with the inner or outer walls of a 14.7-nm-long (20,20) CNT. Our finding reveals that, for a tube of such dimensions, it is thermodynamically more favorable for the peptide to be loaded onto the inner tube wall than the outer tube wall, primarily due to a larger free energy change for the former strategy. Conversely, unloading the drug from the tube interior poses greater challenges. Moreover, the tube's curvature plays an essential role in influencing the conformation of the adsorbed peptide. Despite the relatively weaker van der Waals interaction between the CNT exterior and the peptide, loading the peptide onto the exterior may induce significant conformational changes, particularly affecting the peptide's α-helix structure. In contrast, loading of the peptide on the CNT interior could maintain most of the α-helical content. CNTs do not typically attract specific peptide residues, with adsorbed groups primarily determined by the peptide's configurations and orientations. Finally, we offer a guideline for selecting an optimal loading strategy for CNT-based drug delivery.

Advancements in nanoscale delivery systems: optimizing intermolecular interactions for superior drug encapsulation and precision release

Nanoscale preparations, such as nanoparticles, micelles, and liposomes, are increasingly recognized in pharmaceutical technology for their high capability in tailoring the pharmacokinetics of the encapsulated drug within the body. These preparations have great potential in extending drug half-life, reducing dosing frequency, mitigating drug side effects, and enhancing drug efficacy. Consequently, nanoscale preparations offer promising prospects for the treatment of metabolic disorders, malignant tumors, and various chronic diseases. Nevertheless, the complete clinical potential of nanoscale preparations remains untapped due to the challenges associated with low drug loading degrees and insufficient control over drug release. In this review, we comprehensively summarize the vital role of intermolecular interactions in enhancing encapsulation and controlling drug release within nanoscale delivery systems. Our analysis critically evaluates the characteristics of common intermolecular interactions and elucidates the techniques employed to assess them. Moreover, we highlight the significant potential of intermolecular interactions in clinical translation, particularly in the screening and optimization of preparation prescriptions. By attaining a deeper understanding of intermolecular interaction properties and mechanisms, we can adopt a more rational approach to designing drug carriers, leading to substantial advancements in the application and clinical transformation of nanoscale preparations. Moving forward, continued research in this field offers exciting prospects for unlocking the full clinical potential of nanoscale preparations and revolutionizing the field of drug delivery.

Functionalized Carbon Nanotubes for Delivery of Ferulic Acid and Diosgenin Anticancer Natural Agents

It was investigated whether loading multi-wall carbon nanotubes (CNTs) with two natural anticancer agents: ferulic acid (FUA) and diosgenin (DGN), may enhance the anticancer effect of these drugs. The CNTs were functionalized with carboxylic acid (CNTCOOH) or amine (CNTNH2), loaded with the above pro-drugs, as well as both combined and coated with chitosan or chitosan-stearic acid. Following physicochemical characterization, the drug-loading properties and kinetics of the drug's release were investigated. Their effects on normal human skin fibroblasts and MCF-7 breast carcinoma cells, HepG2 hepatocellular carcinoma cells, and A549 non-small-cell lung cancer cells were evaluated in vitro. Their actions at the molecular level were evaluated by assessing the expression of lncRNAs (HULC, HOTAIR, CCAT-2, H19, and HOTTIP), microRNAs (mir-21, mir-92, mir-145, and mir-181a), and proteins (TGF-β and E-cadherin) in HepG2 cells. The release of both pro-drugs depended on the glutathione concentration, coating, and functionalization. Release occurred in two stages: a no-burst/zero-order release followed by a sustained release best fitted to Korsmeyer-Peppas kinetics. The combined nanoformulation cancer inhibition effect on HepG2 cancer cells was more pronounced than for A549 and MCF7 cells. The combined nanoformulations had an additive impact followed by a synergistic effect, with antagonism demonstrated at high concentrations. The nanoformulation coated with chitosan and stearic acid was particularly successful in targeting HepG2 cells and inducing apoptosis. The CNT functionalized with carboxylic acid (CNTCOOH), loaded with both FUA and DGN, and coated with chitosan-stearic acid inhibited the expression of lncRNAs and modulated both microRNAs and proteins. Thus, nanoformulations composed of functionalized CNTs dual-loaded with FUA and DGN and coated with chitosan-stearic acid are a promising drug delivery system that enhances the activity of natural pro-drugs.

Molecular dynamics investigation on synthesis of a pH- and temperature-sensitive carbon nanotube loaded with doxorubicin

The many exotic properties of carbon nanotubes (CNTs) make them a powerful attraction in the field of drug delivery systems (DDS). In this work, based on quantum chemical calculation and molecular simulation techniques, polyacrylic acid (PAA) and N-isopropyl acrylamide (NIP) are selected and acted simultaneously on the CNT to form a stable system (FCNT). As a potential DDS, FCNT captures the dispersed doxorubicin (DOX) molecules around it and maintains a stable configuration. In these processes, electrostatic and van der Waals forces act synergistically, with van der Waals forces dominating. Compared to NIP, PAA molecules exhibit stronger adhesion and encapsulation efficiency to CNT and stronger adsorption capacity to DOX. This study reveals the mechanism of action among PAA, NIP, CNT, and DOX, providing feasibility verification and prospective guidance for the experimental synthesis of PAA-NIP-CNT-type multifunctional DDS, and also broadening the idea for exploring more efficient DDS suitable for DOX.

A critical review on metal-organic frameworks (MOFs) based nanomaterials for biomedical applications: Designing, recent trends, challenges, and prospects

Nanomaterials (NMs) have garnered significant attention in recent decades due to their versatile applications in a wide range of fields. Thanks to their tiny size, enhanced surface modifications, impressive volume-to-surface area ratio, magnetic properties, and customized optical dispersion. NMs experienced an incredible upsurge in biomedical applications including diagnostics, therapeutics, and drug delivery. This minireview will focus on notable examples of NMs that tackle important issues, demonstrating various aspects such as their design, synthesis, morphology, classification, and use in cutting-edge applications. Furthermore, we have classified and outlined the distinctive characteristics of the advanced NMs as nanoscale particles and hybrid NMs. Meanwhile, we emphasize the incredible potential of metal-organic frameworks (MOFs), a highly versatile group of NMs. These MOFs have gained recognition as promising candidates for a wide range of bio-applications, including bioimaging, biosensing, antiviral therapy, anticancer therapy, nanomedicines, theranostics, immunotherapy, photodynamic therapy, photothermal therapy, gene therapy, and drug delivery. Although advanced NMs have shown great potential in the biomedical field, their use in clinical applications is still limited by issues such as stability, cytotoxicity, biocompatibility, and health concerns. This review article provides a thorough analysis offering valuable insights for researchers investigating to explore new design, development, and expansion opportunities. Remarkably, we ponder the prospects of NMs and nanocomposites in conjunction with current technology.

Theoretical studies of phosphorene as a drug delivery nanocarrier for fluorouracil

The interactions between phosphorene nanosheets (PNSs) and 5-fluorouracil (FLU) were explored using the density functional theory (DFT) method and molecular dynamics (MD) simulations. DFT calculations were performed utilizing M06-2X functional and the 6-31G(d,p) basis set in both gas and solvent phases. Results showed that the FLU molecule is adsorbed horizontally on the PNS surface with an adsorption energy (Eads) of -18.64 kcal mol-1. The energy gap (Eg) between the highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO, respectively) of PNS remains constant after the adsorption process. The adsorption behavior of PNS is not affected by carbon and nitrogen doping. The dynamical behavior of PNS-FLU was studied at T = 298, 310, and 326 K reminiscent of room temperature, body temperature, and temperature of the tumor after exposure to 808 nm laser radiation, respectively. The D value decreases significantly after the equilibration of all systems so that the equilibrated value of D is about 1.1 × 10-6, 4.0 × 10-8, and 5.0 × 10-9 cm2 s-1 at T = 298, 310, and 326 K, respectively. About 60 FLU molecules can be adsorbed on both sides of each PNS, indicating its high loading capacity. PMF calculations demonstrated that the release of FLU from PNS is not spontaneous, which is favorable from a sustained drug delivery point of view.

Discovery of novel S6K1 inhibitors by an ensemble-based virtual screening method and molecular dynamics simulation

Ribosomal protein S6 kinase beta-1 (S6K1) is considered a potential target for the treatment of various diseases, such as obesity, type II diabetes, and cancer. Development of novel S6K1 inhibitors is an urgent and important task for the medicinal chemists. In this research, an effective ensemble-based virtual screening method, including common feature pharmacophore model, 3D-QSAR pharmacophore model, naïve Bayes classifier model, and molecular docking, was applied to discover potential S6K1 inhibitors from BioDiversity database with 29,158 compounds. Finally, 7 hits displayed considerable properties and considered as potential inhibitors against S6K1. Further, carefully analyzing the interactions between these 7 hits and key residues in the S6K1 active site, and comparing them with the reference compound PF-4708671, it was found that 2 hits exhibited better binding patterns. In order to further investigate the mechanism of the interactions between 2 hits and S6K1 at simulated physiological conditions, the molecular dynamics simulation was performed. The ΔG_bind energies for S6K1-Hit1 and S6K1-Hit2 were - 111.47 ± 1.29 and - 54.29 ± 1.19 kJ mol^-1, respectively. Furthermore, deep analysis of these results revealed that Hit1 was the most stable complex, which can stably bind to S6K1 active site, interact with all of the key residues, and induce H1, H2, and M-loop regions changes. Therefore, the identified Hit1 may be a promising lead compound for developing new S6K1 inhibitor for various metabolic diseases treatment.

Biodegradable porous polymeric drug as a drug delivery system: alleviation of doxorubicin-induced cardiotoxicity via passive targeted release

Doxorubicin (DOX) is an effective chemotherapeutic drug developed against a broad range of cancers, and its clinical applications are greatly restricted by the side effects of severe cardiotoxicity during tumour treatment. Herein, the DOX-loaded biodegradable porous polymeric drug, namely, Fc-Ma-DOX, which was stable in the circulation, but easy to compose in the acidic medium, was used as the drug delivery system avoiding the indiscriminate release of DOX. Fc-Ma was constructed via the copolymerization of 1,1'-ferrocenecarbaldehyde with d-mannitol (Ma) through the pH-sensitive acetal bonds. Echocardiography, biochemical parameters, pathological examination, and western blot results showed that DOX treatment caused increased myocardial injury and oxidative stress damage. In contrast, treatment with Fc-Ma-DOX significantly reduced myocardial injury and oxidative stress by DOX treatment. Notably, in the Fc-Ma-DOX treatment group, we observed a significant decrease in the uptake of DOX by H9C2 cells and a significant decrease in reactive oxygen species (ROS) production.

Microwave-Assisted Functionalization of Multi-Walled Carbon Nanotubes for Biosensor and Drug Delivery Applications

Microwave-assisted synthetic methods have emerged as a popular technique for surface modification and the functionalization of multi-walled carbon nanotubes (MWCNTs) for diverse drug delivery applications. Microwave-induced functionalization of MWCNTs provides a high functionalization and requires less time than conventional techniques. Microwave methods are simple, fast, and effective for the covalent and noncovalent conjugation of MWCNTs with various biomolecules and polymers. The present review focuses on the synthetic and drug delivery applications of microwave irradiation techniques (MITs) for the functionalization of MWCNTs, using amino acids and other molecular frameworks containing amino groups, vitamins, proteins, epoxy moieties, metal nanoparticles, and polymers.

The evolution mechanism of an FeMo alloy catalyst for growth of single-walled carbon nanotubes

Adding small fractions of Mo to Fe nanoparticles (NPs) can reduce the melting point of FeMo NPs to lower than that of Fe NPs to prolong the lifetime of the alloy catalyst which in turn promotes the quality of catalytically synthesized single-walled carbon nanotubes (SWCNTs). In this study, we reveal the mechanism of the above-mentioned abnormal melting behavior by employing molecular dynamics simulations. Our results indicate that the bond length between the Fe atoms and the number of bonds between the Mo atoms play an important role in reducing the melting point of the FeMo NPs. This study provides useful insight into the evolution mechanism of the alloy catalyst for the growth of SWCNTs.

Chitosan-based nanoscale systems for doxorubicin delivery: Exploring biomedical application in cancer therapy

Green chemistry has been a growing multidisciplinary field in recent years showing great promise in biomedical applications, especially for cancer therapy. Chitosan (CS) is an abundant biopolymer derived from chitin and is present in insects and fungi. This polysaccharide has favorable characteristics, including biocompatibility, biodegradability, and ease of modification by enzymes and chemicals. CS-based nanoparticles (CS-NPs) have shown potential in the treatment of cancer and other diseases, affording targeted delivery and overcoming drug resistance. The current review emphasizes on the application of CS-NPs for the delivery of a chemotherapeutic agent, doxorubicin (DOX), in cancer therapy as they promote internalization of DOX in cancer cells and prevent the activity of P-glycoprotein (P-gp) to reverse drug resistance. These nanoarchitectures can provide co-delivery of DOX with antitumor agents such as curcumin and cisplatin to induce synergistic cancer therapy. Furthermore, co-loading of DOX with siRNA, shRNA, and miRNA can suppress tumor progression and provide chemosensitivity. Various nanostructures, including lipid-, carbon-, polymeric- and metal-based nanoparticles, are modifiable with CS for DOX delivery, while functionalization of CS-NPs with ligands such as hyaluronic acid promotes selectivity toward tumor cells and prevents DOX resistance. The CS-NPs demonstrate high encapsulation efficiency and due to protonation of amine groups of CS, pH-sensitive release of DOX can occur. Furthermore, redox- and light-responsive CS-NPs have been prepared for DOX delivery in cancer treatment. Leveraging these characteristics and in view of the biocompatibility of CS-NPs, we expect to soon see significant progress towards clinical translation.

Fullerene Derivatives (CN-[OH]β) and Single-Walled Carbon Nanotubes Modelled as Transporters for Doxorubicin Drug in Cancer Therapy

Carbon nanomaterials have received increasing attention in drug-delivery applications because of their distinct properties and structures, including large surface areas, high conductivity, low solubility in aqueous media, unique chemical functionalities, and stability at the nano-scale size. Particularly, they have been used as nano-carriers and mediators for anticancer drugs such as Cisplatin, Camptothecin, and Doxorubicin. Cancer has become the most challenging disease because it requires sophisticated therapy, and it is classified as one of the top killers according to the World Health Organization records. The aim of the current work is to study and investigate the mechanism of combination between single-walled carbon nanotubes (SWCNTs) and fullerene derivatives (CN-[OH]β) as mediators, and anticancer agents for photodynamic therapy directly to destroy the infected cells without damaging the normal ones. Here, we obtain a bio-medical model to determine the efficiency of the usefulness of Doxorubicin (DOX) as an antitumor agent conjugated with SWCNTs with variant radii r and fullerene derivative (CN-[OH]β). The two sub-models are obtained mathematically to evaluate the potential energy arising from the DOX–SWCNT and DOX-(CN-[OH]β) interactions. DOX modelled as two-connected spheres, small and large, each interacting with different SWCNTs (variant radii r) and fullerene derivatives CN-[OH]β, formed based on the number of carbon atoms (N) and the number of hydroxide molecules (OH) (β), respectively. Based on our obtained results, we find that the most favorable carbon nanomaterial is the SWCNT (r = 15.27 Å), followed by fullerene derivatives CN-(OH)22, CN-(OH)20, and CN-(OH)24, with minimum energies of −38.27, −33.72, −32.95, and −29.11 kcal/mol.

Exploration of phosphorene as doxorubicin nanocarrier: An atomistic view from DFT calculations and MD simulations

Potential capability of phosphorene nanosheet (PNS) as doxorubicin (DOX) nanocarrier was investigated using density functional theory (DFT) method and molecular dynamics (MD) simulations. Both DFT calculations and MD simulations revealed that the DOX molecule is adsorbed horizontally onto the PNS surface with the nearest interaction distance of 2.5 Å. The binding energy of DOX is predicted to be about - 49.5 kcal.mol^-1, based on the DFT calculations. After DOX adsorption, the E_g value of PNS remains almost constant in both gas and solvent phases. The dynamical behavior of PNS-DOX was studied at T = 298, 310, and 326 K that reminiscent of room temperature, body temperature, and temperature of tumor after exposure to 808 nm laser radiation, respectively. The diffusion coefficient values of DOX molecule are proportional to temperature. We found that PNS can hold a high amount of DOX on both sides of its surface (66% in weight). MD simulations showed that the dynamical behavior of simulated systems are not affected by pH variances.

A doxorubicin-peptide-gold nanoparticle conjugate as a functionalized drug delivery system: exploring the limits

Efficient transport of pharmaceuticals to malignant cells in the human body often requires the application of drug-delivery systems (DDSs) consisting of several building blocks, each of them bearing a specific function. While nanoparticles are promising as potential carrier moieties, biomolecules may add to the efficient delivery by binding several drug molecules simultaneously. In this contribution, we apply a combination of atomistic molecular dynamics simulations and density functional theory calculations to characterize a multi-component DDS for the transport of the anthracycline antibiotic doxorubicin (DOX), comprising a gold nanoparticle (NP) and a drug-binding peptide (DBP) grafted on the NP surface. We have shown previously that the DDS can stabilize one DOX per DBP. However, by increasing the drug load to a 2 : 1 DOX : DBP ratio the two drug molecules compete for the available adsorption sites, which may cause spontaneous dissociation of one DOX molecule. We identify the chain length of the DBP as a limiting factor for the drug-loading capacity and provide important guidelines for further optimization of multi-component functionalized DDSs.

Molecular dynamics simulation study of doxorubicin adsorption on functionalized carbon nanotubes with folic acid and tryptophan

In this work, molecular dynamics (MD) simulation is used to study the adsorption of the anticancer drug, doxorubicin (DOX), on the wall or surface of pristine and functionalized carbon nanotubes (FCNTs) in an aqueous solution. Initially, the CNTs were functionalized by tryptophan (Trp) and folic acid (FA), and then the DOX molecules were added to the system. The simulation results showed that the drug molecules can intensely interact with the FCNTs at physiological pH. Furthermore, it was found that as a result of functionalization, the solubility of FCNTs in an aqueous solution increases significantly. The effect of pH variation on drug release from both pristine and FCNTs was also investigated. The obtained results indicated that in acidic environments due to protonation of functional groups (Trp) and as a result of repulsive interaction between the DOX molecule and functional groups, the release of DOX molecules from FCNT’s surface is facilitated. The drug release is also strongly dependent on the pH and protonated state of DOX and FCNT.

Thermoresponsive Chitosan-Grafted-Poly(N-vinylcaprolactam) Microgels via Ionotropic Gelation for Oncological Applications

Microgels can be considered soft, porous and deformable particles with an internal gel structure swollen by a solvent and an average size between 100 and 1000 nm. Due to their biocompatibility, colloidal stability, their unique dynamicity and the permeability of their architecture, they are emerging as important candidates for drug delivery systems, sensing and biocatalysis. In clinical applications, the research on responsive microgels is aimed at the development of "smart" delivery systems that undergo a critical change in conformation and size in reaction to a change in environmental conditions (temperature, magnetic fields, pH, concentration gradient). Recent achievements in biodegradable polymer fabrication have resulted in new appealing strategies, including the combination of synthetic and natural-origin polymers with inorganic nanoparticles, as well as the possibility of controlling drug release remotely. In this review, we provide a literature review on the use of dual and multi-responsive chitosan-grafted-poly-(N-vinylcaprolactam) (CP) microgels in drug delivery and oncological applications.

Loading and release of cancer chemotherapy drugs utilizing simultaneous temperature and pH-responsive nanohybrid

BACKGROUND

Recently, the development of nanocarriers and the improvement of their biochemical properties have became of great importance. Single-walled carbon nanotubes (SWCNT) have many applications in drug delivery systems (DDS) as a common carbon-based structure. In the current work, the penetration, co-loading, and co-release of Doxorubicin (DOX) and Paclitaxel (PAX), as two cancer chemotherapy agents, were investigated using a novel modified copolymer with functionalized SWCNT.

RESULTS

This study proposes a dual-responsive smart carrier that is sensitive to pH and temperature. The carrier consists of functionalized SWNT and Dimethyl acrylamide-trimethyl chitosan (DMAA-TMC) grafting on SWCNT. This suggested carrier was investigated by utilizing molecular simulations. Interaction energies between DOX, PAX, and carrier as well as the affinity of drugs to the nanocarrier were studied. The energy analysis of drug release and adsorption presented that DOX and PAX delivery using this carrier is selective and sensitive at healthy and cancerous conditions. The attraction of DMAA-TMC, as a biodegradable and biocompatible copolymer, with SWCNT showed that degradation mechanism in acidic environment deformed the copolymer. This leads to a smart release mechanism in an acidic cancerous tissue. Additionally, it improves hydrophilicity, optimum nano-particle size, and cell cytotoxicity concerns.

CONCLUSIONS

The simulation results manifested a significant contribution of DMAA-TMC in the adsorption and release of cancer chemotherapy drugs in normal and neoplastic tissues. The interaction of copolymer also improves the biocompatibility and biodegradability of the SWCNT. Smart drug delivery carrier can be a valuable nanohybrid for loading, transporting, and releasing of cancer chemotherapy drugs.

Exploring pH dependent delivery of 5-fluorouracil from functionalized multi-walled carbon nanotubes

Multi-walled carbon nanotubes (MWCNTs) can be applied for pH-sensitive delivery of anticancer drugs. Due to the importance of 5-fluorouracil (5-FU) in different tumor therapy regimens, it has been widely used in different pH dependent drug delivery systems. To investigate the pH effects on loading (and release) of 5-FU on (and from) the functionalized MWCNTs and propose the optimum condition for drug delivery, both macroscopic and microscopic studies were carried out using chromatography and molecular dynamic simulation at different conditions. For both levels of studies, different analytical approaches were performed to assess the validity of the methods. The experimental results revealed that 5-FU has more binding affinity to the surface of the nanocarrier at physiological pH (pH = 7.4) and showed more release at acidic conditions (pH = 5.0). Meanwhile it has been observed that basic pH (pH = 9.0) can lead to a dramatic decrease effect on loading of the drug. The results of this study can be used to suggest the optimum pH levels for nanocarbon based formulations of 5-FU in cancer therapy.

Assessment of the effect of external and internal triggers on adsorption and release of paclitaxel from the PEI functionalized silicene nanosheet: A molecular dynamic simulation

In order to examine the adsorption mechanisms of paclitaxel (PTX) on silicene nanosheet (SNS) molecular dynamics (MD) simulations are carried out. The MD outcomes show that the adsorption of PTX on the pristine SNS is exothermic and spontaneous. The interaction between the PTX molecule and the pristine SNS is mainly due to the formation of π-π interactions through their aromatic rings, which are supplemented by X-π (X = N-H, C-H, and CO) interactions. Upon functionalization of SNS by Polyethylenimine (PEI), drug molecules prefer to bind to the nanocarrier instead of the polymer. In the functionalized SNS (f-SNS), the binding energy of the drug with the nanocarrier becomes stronger in comparison to the SNS case (E_ads: -2468.91 vs -840.95 kJ/mol). At the acidic condition, protonation of drug and PEI cause that the interaction between PTX and the nanocarrier become weaker and drug molecules could release from the nanocarrier surface. Finally, two f-SNS and protonated f-SNS (f-pSNS) systems are induced by the electric field (EF). Evaluation of the dynamic properties of these systems (with strengths 0.5 and 1 V/nm) shows that the electric field could be acted as a stimulus for drug release from nanocarriers. The obtained results from this study provide valuable information about the loading/release mechanisms of PTX on/from the SNS surface.

Lignin, lipid, protein, hyaluronic acid, starch, cellulose, gum, pectin, alginate and chitosan-based nanomaterials for cancer nanotherapy: Challenges and opportunities

Although nanotechnology-driven drug delivery systems are relatively new, they are rapidly evolving since the nanomaterials are deployed as effective means of diagnosis and delivery of assorted therapeutic agents to targeted intracellular sites in a controlled release manner. Nanomedicine and nanoparticulate drug delivery systems are rapidly developing as they play crucial roles in the development of therapeutic strategies for various types of cancer and malignancy. Nevertheless, high costs, associated toxicity and production of complexities are some of the critical barriers for their applications. Green nanomedicines have continually been improved as one of the viable approaches towards tumor drug delivery, thus making a notable impact on which considerably affect cancer treatment. In this regard, the utilization of natural and renewable feedstocks as a starting point for the fabrication of nanosystems can considerably contribute to the development of green nanomedicines. Nanostructures and biopolymers derived from natural and biorenewable resources such as proteins, lipids, lignin, hyaluronic acid, starch, cellulose, gum, pectin, alginate, and chitosan play vital roles in the development of cancer nanotherapy, imaging and management. This review uncovers recent investigations on diverse nanoarchitectures fabricated from natural and renewable feedstocks for the controlled/sustained and targeted drug/gene delivery systems against cancers including an outlook on some of the scientific challenges and opportunities in this field. Various important natural biopolymers and nanomaterials for cancer nanotherapy are covered and the scientific challenges and opportunities in this field are reviewed.

Design of new drug delivery platform based on surface functionalization of black phosphorus nanosheet with a smart polymer for enhancing the efficiency of doxorubicin in the treatment of cancer

The development of drug delivery systems (DDSs) has raised hopes for targeted cancer therapy. Smart polymers can be conjugated with several nanoparticles and increase their efficiency in biomedical applications. In this work, the classical molecular dynamics and well-tempered metadynamics simulations are performed to study the behavior of black phosphorus (BPH) nanosheet functionalized with polyethylenimine (PEI) in adsorption, diffusion, and release of doxorubicin (DOX) anticancer drug. Adsorption of the drug on PEI-BPH surface is mainly due to the formation of strong pi-pi interaction between the drug and BPH. The drug-binding to the nanosheet is enhanced by the intermolecular hydrogen bond that formed between DOX and PEI. The energy values for the interaction of DOX with BPH and PEI are calculated to be about - 180 and - 50 kJ/mol, respectively. The obtained results indicated that the adsorption of the drug molecules on the nanosheet destroyed the hydration layer around the BPH-PEI surface. The free energy calculation for DDS shows a global minimum in which the distances of DOX from BPH surface and PEI are about 1.0 and 0.5 nm, respectively. Furthermore, the diffusion of DDS into the membrane has a macropinocytosis pathway that is in line with experimental observations. Moreover, it is found that, unlike the isolated DOX, the drug in complex with BPH-PEI can be easily penetrated membrane cells. The study of the pH-responsive release of the drug shows the high solubility of the polymer in the water environment plays the main role in swelling of DDS and the release of the DOX molecules.

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.

Method to Construct Volcano Relations by Multiscale Modeling: Building Bridges between the Catalysis and Biosimulation Communities

Understanding the complex interactions of different building blocks within a sophisticated drug-delivery system (DDS), aimed at targeted transport of the drug to malignant cells, requires modeling techniques on different time and length scales. On the example of the anthracycline antibiotic doxorubicin (DOX), we investigate a potential DDS component, consisting of a gold nanoparticle and a short peptide sequence as carriers of DOX. The combination of atomistic molecular dynamics simulations and density functional theory calculations facilitates compiling a volcano plot, which allows deriving general conclusions on DDS constituents for chemotherapeutic agents within the class of anthracycline antibiotics: the nanoparticle and peptide carrier moieties need to be chosen in such a way that the anthracycline body of the drug is able to intercalate between both entities or between two (π-stacking) residues of the peptide. Using the popular volcano framework as a guideline, the present article connects the catalysis and biosimulation communities, thereby identifying a strategy to overcome the limiting volcano relation by tuning the coordination number of the drug in the DDS component.

Not only in silico drug discovery: Molecular modeling towards in silico drug delivery formulations

The use of methods at molecular scale for the discovery of new potential active ligands, as well as previously unknown binding sites for target proteins, is now an established reality. Literature offers many successful stories of active compounds developed starting from insights obtained in silico and approved by Food and Drug Administration (FDA). One of the most famous examples is raltegravir, a HIV integrase inhibitor, which was developed after the discovery of a previously unknown transient binding area thanks to molecular dynamics simulations. Molecular simulations have the potential to also improve the design and engineering of drug delivery devices, which are still largely based on fundamental conservation equations. Although they can highlight the dominant release mechanism and quantitatively link the release rate to design parameters (size, drug loading, et cetera), their spatial resolution does not allow to fully capture how phenomena at molecular scale influence system behavior. In this scenario, the "computational microscope" offered by simulations at atomic scale can shed light on the impact of molecular interactions on crucial parameters such as release rate and the response of the drug delivery device to external stimuli, providing insights that are difficult or impossible to obtain experimentally. Moreover, the new paradigm brought by nanomedicine further underlined the importance of such computational microscope to study the interactions between nanoparticles and biological components with an unprecedented level of detail. Such knowledge is a fundamental pillar to perform device engineering and to achieve efficient and safe formulations. After a brief theoretical background, this review aims at discussing the potential of molecular simulations for the rational design of drug delivery systems.

Carbon Nanotubes: Smart Drug/Gene Delivery Carriers

The unique properties of carbon nanotubes (CNTs) (such as their high surface to volume ratios, enhanced conductivity and strength, biocompatibility, ease of functionalization, optical properties, etc.) have led to their consideration to serve as novel drug and gene delivery carriers. CNTs are effectively taken up by many different cell types through several mechanisms. CNTs have acted as carriers of anticancer molecules (including docetaxel (DTX), doxorubicin (DOX), methotrexate (MTX), paclitaxel (PTX), and gemcitabine (GEM)), anti-inflammatory drugs, osteogenic dexamethasone (DEX) steroids, etc. In addition, the unique optical properties of CNTs have led to their use in a number of platforms for improved photo-therapy. Further, the easy surface functionalization of CNTs has prompted their use to deliver different genes, such as plasmid DNA (PDNA), micro-RNA (miRNA), and small interfering RNA (siRNA) as gene delivery vectors for various diseases such as cancers. However, despite all of these promises, the most important continuous concerns raised by scientists reside in CNT nanotoxicology and the environmental effects of CNTs, mostly because of their non-biodegradable state. Despite a lack of widespread FDA approval, CNTs have been studied for decades and plenty of in vivo and in vitro reports have been published, which are reviewed here. Lastly, this review covers the future research necessary for the field of CNT medicine to grow even further.

Advances in Drug Delivery Nanosystems Using Graphene-Based Materials and Carbon Nanotubes

Carbon is one of the most abundant elements on Earth. In addition to the well-known crystallographic modifications such as graphite and diamond, other allotropic carbon modifications such as graphene-based nanomaterials and carbon nanotubes have recently come to the fore. These carbon nanomaterials can be designed to help deliver or target drugs more efficiently and to innovate therapeutic approaches, especially for cancer treatment, but also for the development of new diagnostic agents for malignancies and are expected to help combine molecular imaging for diagnosis with therapies. This paper summarizes the latest designed drug delivery nanosystems based on graphene, graphene quantum dots, graphene oxide, reduced graphene oxide and carbon nanotubes, mainly for anticancer therapy.

Novel pH-responsive nanohybrid for simultaneous delivery of doxorubicin and paclitaxel: an in-silico insight

BACKGROUND

The distribution of drugs could not be controlled in the conventional delivery systems. This has led to the developing of a specific nanoparticle-based delivery system, called smart drug delivery systems. In cancer therapy, innovative biocompatible nanocarriers have received much attention for various ranges of anti-cancer drugs. In this work, the effect of an interesting and novel copolymer named "dimethyl acrylamide-trimethyl chitosan" was investigated on delivery of paclitaxel and doxorubicin applying carboxylated fullerene nanohybrid. The current study was run via molecular dynamics simulation and quantum calculations based on the acidic pH differences between cancerous microenvironment and normal tissues. Furthermore, hydrogen bonds, radius of gyration, and nanoparticle interaction energies were studied here. Stimulatingly, a simultaneous pH and temperature-responsive system were proposed for paclitaxel and doxorubicin for a co-polymer. A pH-responsive and thermal responsive copolymer were utilized based on trimethyl chitosan and dimethyl acrylamide, respectively. In such a dualistic approach, co-polymer makes an excellent system to possess two simultaneous properties in one bio-polymer.

RESULTS

The simulation results proposed dramatic and indisputable effects of the copolymer in the release of drugs in cancerous tissues, as well as increased biocompatibility and drug uptake in healthy tissues. Repeated simulations of a similar article performed for the validation test. The results are very close to those of the reference paper.

CONCLUSIONS

Overall, conjugated modified fullerene and dimethyl acrylamide-trimethyl chitosan (DMAA-TMC) as nanohybrid can be an appropriate proposition for drug loading, drug delivery, and drug release on dual responsive smart drug delivery system.

Mechanistic Understanding From Molecular Dynamics Simulation in Pharmaceutical Research 1: Drug Delivery

In this review, we outline the growing role that molecular dynamics simulation is able to play as a design tool in drug delivery. We cover both the pharmaceutical and computational backgrounds, in a pedagogical fashion, as this review is designed to be equally accessible to pharmaceutical researchers interested in what this new computational tool is capable of and experts in molecular modeling who wish to pursue pharmaceutical applications as a context for their research. The field has become too broad for us to concisely describe all work that has been carried out; many comprehensive reviews on subtopics of this area are cited. We discuss the insight molecular dynamics modeling has provided in dissolution and solubility, however, the majority of the discussion is focused on nanomedicine: the development of nanoscale drug delivery vehicles. Here we focus on three areas where molecular dynamics modeling has had a particularly strong impact: (1) behavior in the bloodstream and protective polymer corona, (2) Drug loading and controlled release, and (3) Nanoparticle interaction with both model and biological membranes. We conclude with some thoughts on the role that molecular dynamics simulation can grow to play in the development of new drug delivery systems.

Elucidation of pH impacts on monosubstituted benzene derivatives using normal Raman and surface-enhanced Raman scattering

Raman spectral vibrational frequencies are used to probe the local chemical environment surrounding molecules in solution and adsorbed to gold nanostars. Herein, the impacts of functional group protonation on monosubstituted benzene derivatives with amine, carboxylic acid, or hydroxide are evaluated. Changes in binding affinity and orientation are apparent by evaluating systematic variations in vibrational frequencies. Notably, the electron donating abilities of these functional groups influence the vibrational frequency of the ring breathing mode, thus leading to improved spectral interpretation. Furthermore, gold nanostars are used to investigate the impact of molecular protonation on the adsorption of benzoic acid/benzoate to gold. The changes in molecular protonation are measured using zeta potential and the surface-sensitive technique, surface-enhanced Raman scattering. These methods reveal that pH variations induce carboxylate protonation and electron redistribution that weaken molecular affinity, thereby causing the molecule to adopt a perpendicular to parallel orientation with respect to the nanostar surface. Functional group identity influences the ring breathing mode frequency as a function of changes in electron donation from the functional group to the ring in solution as well as molecular affinity to and orientation on gold. This exploitation of vibrational frequencies facilitates the elucidation of molecule behavior in complex systems.

A Review on Chitosan's Uses as Biomaterial: Tissue Engineering, Drug Delivery Systems and Cancer Treatment

Chitosan, derived from chitin, is a biopolymer consisting of arbitrarily distributed β-(1-4)-linked D-glucosamine and N-acetyl-D-glucosamine that exhibits outstanding properties- biocompatibility, biodegradability, non-toxicity, antibacterial activity, the capacity to form films, and chelating of metal ions. Most of these peculiar properties are attributed to the presence of free protonable amino groups along the chitosan backbone, which also gives it solubility in acidic conditions. Moreover, this biopolymer can also be physically modified, thereby presenting a variety of forms to be developed. Consequently, this polysaccharide is used in various fields, such as tissue engineering, drug delivery systems, and cancer treatment. In this sense, this review aims to gather the state-of-the-art concerning this polysaccharide when used as a biomaterial, providing information about its characteristics, chemical modifications, and applications. We present the most relevant and new information about this polysaccharide-based biomaterial's applications in distinct fields and also the ability of chitosan and its various derivatives to selectively permeate through the cancer cell membranes and exhibit anticancer activity, and the possibility of adding several therapeutic metal ions as a strategy to improve the therapeutic potential of this polymer.

Synthesis, Colloidal Characterization and Targetability of Phenylboronic Acid Functionalized α-Tocopheryl Polyethylene Glycol Succinate in Cancer Cells

This study reports targetable micelles developed after covalent functionalization of α-tocopheryl polyethylene glycol succinate (TPGS) with amino phenylboronic acid (APBA). Nuclear magnetic resonance (NMR) and infrared (IR) spectroscopic results showed successful attachment of APBA to the hydrophilic segment of TPGS. Dynamic light scattering and small-angle neutron scattering studies revealed that the conjugate self-assembled in water to produce spherical core-shell micelles (14–20 nm) which remained stable against temperature (ca. 25–45 °C) and pH changes. The micelles could solubilize a high payload of paclitaxel (PLX) without exhibiting changes in the average size. However, at the saturation solubility, drug molecules migrated from the core to the shell region and engaged with APBA groups via π–π stacking interaction. Confocal microscopy and cell sorting analyses verified the effective translocation ability of TPGS-APBA micelles in sialic acid (SA) expressing MDA-MB-453 cells. At equivalent PLX dose, TPGS-APBA micelles showed about a twofold improvement in apoptotic death among the cells exposed for 2 h. Our findings indicate that the attachment of APBA can be a potential strategy for improving the intra-cellular localization of carriers among cancer cells expressing SA residues.

Molecular insight into the smart functionalized TMC-Fullerene nanocarrier in the pH-responsive adsorption and release of anti-cancer drugs

The Doxorubicin (DOX) and Paclitaxel (PAX) are widely used for cancer-therapy. Herein, in the efforts devoted to developing smart drug carriers, the loading and releasing of the DOX and PAX on the pH sensitive functionalized Fullerene carrier was investigated by molecular dynamics (MD) simulations. The effects of chitosan polymer as a functionalizing agent of the Fullerene carrier was also studied. In addition, the Fullerene carrier was functionalized with carboxyl groups in order to improve the loading and releasing properties of the DOX and PAX. The results showed the DOX is well adsorbed on Fullerene which was functionalized with carboxyl group and it was released controllably in cancerous tissues. According to the results of the electrostatic and Van der Waals interactions, it was found that the functionalized Fullerene can be a proper carrier for DOX in comparison with PAX. Adding the trimethyl chitosan (TMC) polymer to the carrier could improve the Van der Waals attractions of the PAX and Fullerene which indicates that by passing the time at acidic pH, the Van der Waals energy reaches zero that leads to promote the release of the PAX in cancerous tissues. The carboxyl group which was employed as a functionalizing agent could also increase the number of hydrogen bonds for the PAX and DOX at acidic and neutral pH, respectively. Moreover, a significant rise in the number of hydrogen bonds between the PAX and Fullerene at neutral pH was achieved by adding the TMC to the carrier. A more decrease of gyration radius was obtained for the DOX at acidic pH which confirms that the DOX with TMC-Fullerene is a more stable carrier. So, this smart nanomedicine system is introduced as an promising composition for smart cancer therapy.

Current Progress in Biomedical Applications of Chitosan-Carbon Nanotube Nanocomposites: A Review

The currently observed development of medical science results from the constant search for innovative solutions to improve the health and quality of life of patients. Particular attention is focused on the design of a new generation of materials with a high degree of biocompatibility and tolerance towards the immune system. In addition, apart from biotolerance, it is important to ensure appropriate mechanical and technological properties of materials intended for intra-body applications. Knowledge of the above parameters becomes the basis for considerations related to the possibilities of choosing the appropriate polymer materials. The researchers' interest, as evidenced by the number of available publications, is attracted by nanobiocomposites based on chitosan and carbon nanotubes, which, due to their properties, enable integration with the tissues of the human body. Nanosystems can be used in many areas of medicine. They constitute an excellent base for use as dressing materials, as they exhibit antimicrobial properties. In addition, they can be carriers of drugs and biological macromolecules and can be used in gene therapy, tissue engineering, and construction of biosensors. For this reason, potential application areas of chitosan-carbon nanotube nanocomposites in medical sciences are presented in this publication, considering the characteristics of the system components.

Modified gaphene oxide (GO) particles in peptide hydrogels: a hybrid system enabling scheduled delivery of synergistic combinations of chemotherapeutics

The scheduled delivery of synergistic drug combinations is increasingly recognized as highly effective against advanced solid tumors. Of particular interest are composite systems that release a sequence of drugs with defined kinetics and molar ratios to enhance therapeutic effect, while minimizing the dose to patients. In this work, we developed a homogeneous composite comprising modified graphene oxide (GO) nanoparticles embedded in a Max8 peptide hydrogel, which provides controlled kinetics and molar ratios of release of doxorubicin (DOX) and gemcitabine (GEM). First, modified GO nanoparticles (tGO) were designed to afford high DOX loading and sustained release (18.9% over 72 h and 31.4% over 4 weeks). Molecular dynamics simulations were utilized to model the mechanism of DOX loading as a function of surface modification. In parallel, a Max8 hydrogel was developed to release GEM with faster kinetics and achieve a 10-fold molar ratio to DOX. The selected DOX/tGO nanoparticles were suspended in a GEM/Max8 hydrogel matrix, and the resulting composite was tested against a triple negative breast cancer cell line, MDA-MB-231. Notably, the composite formulation afforded a combination index of 0.093 ± 0.001, indicating a much stronger synergism compared to the DOX-GEM combination co-administered in solution (CI = 0.396 ± 0.034).

Application of Nanotechnology in Cancer Diagnosis and Therapy - A Mini-Review

Cancer is a leading cause of death and poor quality of life globally. Even though several strategies are devised to reduce deaths, reduce chronic pain and improve the quality of life, there remains a shortfall in the adequacies of these cancer therapies. Among the cardinal steps towards ensuring optimal cancer treatment are early detection of cancer cells and drug application with high specificity to reduce toxicities. Due to increased systemic toxicities and refractoriness with conventional cancer diagnostic and therapeutic tools, other strategies including nanotechnology are being employed to improve diagnosis and mitigate disease severity. Over the years, immunotherapeutic agents based on nanotechnology have been used for several cancer types to reduce the invasiveness of cancerous cells while sparing healthy cells at the target site. Nanomaterials including carbon nanotubes, polymeric micelles and liposomes have been used in cancer drug design where they have shown considerable pharmacokinetic and pharmacodynamic benefits in cancer diagnosis and treatment. In this review, we outline the commonly used nanomaterials which are employed in cancer diagnosis and therapy. We have highlighted the suitability of these nanomaterials for cancer management based on their physicochemical and biological properties. We further reviewed the challenges that are associated with the various nanomaterials which limit their uses and hamper their translatability into the clinical setting in certain cancer types.

Development and evaluation of a pH-responsive and water-soluble drug delivery system based on smart polymer coating of graphene nanosheets: an in silico study

The objective of this study is to develop a controlled and water-soluble delivery system for doxorubicin (DOX) based on the coating of graphene (G) with a smart polymer. A combination of polyethyleneimine (PEI) and G–DOX is investigated by performing density functional theory (DFT) calculations and molecular dynamics (MD) simulations. Several parameters have been employed to evaluate the effect of PEI on the adsorption and release mechanisms of DOX. The obtained results indicated that the binding energy of the drug molecule on G in the presence of PEI is enhanced by about 20% under neutral conditions, whereas the drug absorption becomes weaker in an acidic environment so that DOX could be separated from the carrier surface using near-infrared radiation (NIR). Based on the atom in molecule (AIM) theory, two hydrogen bonds with strengths of about −12.59 and −39.99 kJ mol⁻¹ have been established. Furthermore, evaluating the dynamic behavior of the designed systems in water solution shows that the polymer in physiological pH rapidly adsorbed on the drug–carrier complex. However, at acidic pH, it is quickly desorbed from the carrier surface and the G–DOX complex can be exposed to cancer cells. The obtained results of the present research may be used in future experimental work to design smart DDSs.

The objective of this study is to develop a controlled and water-soluble delivery system for doxorubicin (DOX) based on the coating of graphene (G) with a smart polymer.