Functionalized Fullerene Targeting Human Voltage-Gated Sodium Channel, hNav1.7

Molecular dynamics simulations on fullerene surfactants with different charges at the air-water interface

The interfacial activity of fullerene surfactants at the air-water interface is studied via molecular dynamics and metadynamics simulations. Fullerene surfactants with different charges show different surface activity. Meanwhile, studies show that fullerene surfactants with zero or one positive charge show interesting interface behaviour, i.e. the hydrophobic fullerene of the fullerene surfactant with zero charge orients to bulk water while the fullerene surfactant with one positive charge can be a hydrophilic and hydrophobic rotator at the air-water interface.

Proteins as supramolecular hosts for C60: a true solution of C60 in water

Hybrid systems have great potential for a wide range of applications in chemistry, physics and materials science. Conjugation of a biosystem to a molecular material can tune the properties of the components or give rise to new properties. As a workhorse, here we take a C60@lysozyme hybrid. We show that lysozyme recognizes and disperses fullerene in water. AFM, cryo-TEM and high resolution X-ray powder diffraction show that the C60 dispersion is monomolecular. The adduct is biocompatible, stable in physiological and technologically-relevant environments, and easy to store. Hybridization with lysozyme preserves the electrochemical properties of C60. EPR spin-trapping experiments show that the C60@lysozyme hybrid produces ROS following both type I and type II mechanisms. Due to the shielding effect of proteins, the adduct generates significant amounts of 1O2 also in aqueous solution. In the case of type I mechanism, the protein residues provide electrons and the hybrid does not require addition of external electron donors. The preparation process and the properties of C60@lysozyme are general and can be expected to be similar to other C60@protein systems. It is envisaged that the properties of the C60@protein hybrids will pave the way for a host of applications in nanomedicine, nanotechnology, and photocatalysis.

Computational approaches to cell-nanomaterial interactions: keeping balance between therapeutic efficiency and cytotoxicity

Owing to their unique properties, nanomaterials have been widely used in biomedicine since they have obvious inherent advantages over traditional ones. However, nanomaterials may also cause dysfunction in proteins, genes and cells, resulting in cytotoxic and genotoxic responses. Recently, more and more attention has been paid to these potential toxicities of nanomaterials, especially to the risks of nanomaterials to human health and safety. Therefore, when using nanomaterials for biomedical applications, it is of great importance to keep the balance between therapeutic efficiency and cytotoxicity (i.e., increase the therapeutic efficiency as well as decrease the potential toxicity). This requires a deeper understanding of the interactions between various types of nanomaterials and biological systems at the nano/bio interface. In this review, from the point of view of theoretical researchers, we will present the current status regarding the physical mechanism of cytotoxicity caused by nanomaterials, mainly based on recent simulation results. In addition, the strategies for minimizing the nanotoxicity naturally and artificially will also be discussed in detail. Furthermore, we should notice that toxicity is not always bad for clinical use since causing the death of specific cells is the main way of treating disease. Enhancing the targeting ability of nanomaterials to diseased cells and minimizing their side effects on normal cells will always be hugely challenging issues in nanomedicine. By combining the latest computational studies with some experimental verifications, we will provide special insights into recent advances regarding these problems, especially for the design of novel environment-responsive nanomaterials.

C60 fullerenes disrupt cellular signalling leading to TRPC4 and TRPC6 channels opening by the activation of muscarinic receptors and G-proteins in small intestinal smooth muscles

The effect of water-soluble pristine C₆₀ fullerene nanoparticles (C₆₀NPs) on receptor-operated cation channels formed by TRPC4/C6 proteins in ileal smooth muscle cells was investigated for the first time. Activation of these channels subsequent to acetylcholine binding to the expressed in these cells M₂ and M₃ muscarinic receptors represents the key event in the parasympathetic control of gastrointestinal smooth muscle motility and cholinergic excitation-contraction coupling. Experiments were performed on single collagenase-dispersed mouse ileal myocytes using patch-clamp techniques with symmetrical 125mM Cs⁺ solutions and [Ca²⁺]_i 'clamped' at 100nM in order to isolate the muscarinic cation current (mI_CAT). The current was induced by intracellular infusion of 200μM GTPγS, which activates G-proteins directly, i.e. bypassing the muscarinic receptors. C₆₀NPs applied at 10^-6M at peak response to activation of G-proteins caused mI_CAT inhibition by 47.0±3.5% (n=9). The inhibition developed rather slowly, with the time constant of 119±16s, was voltage-independent and irreversible. Thus, C₆₀NPs are unlikely to cause any direct block of TRPC4/C6 channels; rather, they may accumulate in the membrane and disrupt G-protein signalling leading to mI_CAT generation. C₆₀NPs may represent a novel class of biocompatible molecules for the treatment of disorders associated with enhanced gastrointestinal motility.