Molecular simulation of diffusion of rigidity-tuned nanoparticles in biological hydrogels

The penetration capability of the drug nano-carriers (NCs) in biological hydrogels, such as mucus and tumor interstitial matrix, would typically influence the efficiency of drug delivery. Understanding the effect of the physicochemical property of the drug carriers on their diffusion capability in biological hydrogel becomes important for designing and optimizing the nano-carriers. Here, using a coarse-grained molecular dynamics model, we studied how the rigidity of NCs affected their diffusivity in biological hydrogel. The results showed that semi-elastic NCs have higher diffusivity than the hard and the soft NCs. Furthermore, the affinity between the NCs and biological hydrogels and the size ratio between the hydrogel meshes and NCs have also affected the diffusivity of the NCs. Further analysis revealed the mechanism that the deformation of the NCs dominates their diffusivity. These findings demonstrated that the rigidity of NCs is a key parameter in designing efficient NCs for deep penetration into the biological hydrogels.

Photocatalytic Carboxylation of Phenyl Halides with CO_(2) by Metal-Organic Frameworks Materials

In this work,important commercial pharmaceutical intermediates,phenylpropionic acid compounds,are successfully obtained by catalyzing the reaction of carbon dioxide with phenyl halides using MOF-5,a typical metal-organic framework(MOF)material.The influence of temperature,pressure,catalyst type and light on the reaction is investigated,and a 90.3%selectivity towards fluorophenylpropionic acid is reached.Significantly,the catalysts are effective for varied benzyl compounds containing different substituent groups.The catalysts are stable and remain active after three cycles.

Effect of defects on the electronic structure of a PbI2/MoS2 van der Waals heterostructure: A first-principles study

PbI2/MoS2,as a typical van der Waals(vdW)heterostructure,has attracted intensive attention owing to its remarkable electronic and optoelectronic properties.In this work,the effect of defects on the electronic structures of a PbI2/MoS2 heterointerface has been systematically investigated.The manner in which the defects modulate the band structure of PbI2/MoS2,including the band gap,band edge,band alignment,and defect energy-level density within the band gap is discussed herein.It is shown that sulfur defects tune the band gaps,iodine defects shift the positions of the band edge and Fermi level,and lead defects realize the conversions between the straddling-gap band alignment and valence-band-aligned gap,thus enhancing the light-absorption ability of the material.

Molecular dynamics simulation of diffusion of nanoparticles in mucus

The rapid diffusion of nanoparticles （NPs） through mucus layer is critical for efficient transportation of NPs-loaded drug delivery system. To understand how the physical and surface properties of NPs affect their diffusion in mucus, we have developed a coarse-grained molecular dynamics model to study the diffusion of NPs in modeled mucus layer. Both steric obstruction and hydrodynamic interaction are included in the model capable of capturing the key characteristics of NPs＇ diffusion in mucus. The results show that both particle size and surface properties significantly affect the diffusivities of NPs in mucus. Furthermore, we find rodlike NPs can gain a higher diffusivity than spherical NPs with the same hydrodynamic diameter. In addition, the disturbed environment can enhance the diffusivity of NPs. Our findings can be utilized to design mucus penetrating NPs for targeted drug delivery system.