Van der Waals forces in free and wetting liquid films

Supramolecular Nanostructures for the Delivery of Peptides in Cancer Therapy

Supramolecular nanostructured based delivery systems are emerging as a meaningful approach in the treatment of cancer, offering controlled drug release and improved therapeutic efficacy. The self-assembled structures can be small molecules, polymers, peptides, or proteins, which can be used and functionalized to achieve tailored release and target specific cells, tissues, or organs. These structures can improve the solubility and stability of drugs having low aqueous solubility by encapsulating and protecting them from degradation. Alongside, peptides as natural biomolecules have gained increasing attention as potential candidates in cancer treatment because of their biocompatibility, low cytotoxicity, and high specificity toward tumor cells. The amino acid sequences in peptide molecules are tunable, efficiently controlling the morphology of peptide-based self-assembled nanosystems and offering flexibility to form supramolecular nanostructures (SNs). It is evident from the current literature that the supramolecular nanostructures based delivery of peptide for cancer treatment hold great promise for future cancer therapy, offering potential strategies for personalized medicine with improved patient outcomes. SIGNIFICANCE STATEMENT: This review focuses on fundamentals and various drug delivery mechanisms based on SNs. Different SN approaches and recent literature reviews on peptide delivery are also presented to the readers.

Cell Membrane Coated pH-Responsive Intelligent Bionic Delivery Nanoplatform for Active Targeting in Photothermal Therapy

Aim

To produce pH-responsive bionic high photothermal conversion nanoparticles actively targeting tumors for sensitizing photothermal therapy (PTT).

Materials and Methods

The bionic nanoparticles (ICG-PEI@HM NPs) were prepared by electrostatic adsorption of indocyanine green (ICG) coupled to polyethyleneimine (PEI) and modified with tumor cell membranes. In vitro and in vivo experiments were conducted to investigate the efficacy of ICG-PEI@HM-mediated PTT.

Results

The intelligent responsiveness of ICG-PEI@HM to pH promoted the accumulation of ICG and enhanced the PTT performance of ICG-PEI@HM NPs. Compared with free ICG, NPs exhibited great photothermal stability, cellular uptake, and active tumor targeting for PTT.

Conclusion

ICG-PEI@HM NPs can enhance the efficacy of PTT and can be used as a new strategy for the construction of photothermal agents.

Disjoining pressure analysis of the lubricant nanofilm stability of liquid-infused surface upon lubricant depletion

HYPOTHESIS

The structure of the slippery layer and the evolution of functional properties of a lubricant infused substrate (LIS) is determined by the isotherm of disjoining pressure in the lubricant film.

METHODS

The macroscopic theory of van der Waals forces was applied to the layered system used to model the structure and properties of LIS. For a lubricant layer sandwiched between the flat substrate and air or water, the isotherms of disjoining pressure were calculated and their analysis was used to conclude about stability of LIS.

FINDINGS

The results obtained for silicone oil and perfluorodecalin on smooth and porous hydrophilic and hydrophobic solids allow selecting the LIS components corresponding to stability of lubricant films in air and water. It was found that for hydrophilic substrates in conditions of lubricant depletion, silicone oil and perfluorodecalin show lubricant film stability in both air and water. On flat or post microtexture hydrophobic substrate with flat tops, the perfluorodecalin lubricating layer is typically stable in air and unstable in water. In contrast, silicone oil lubricating layer demonstrates the stability in a wide range of lubricant film thicknesses for the hydrophobic substrate with flat-top textures in water, however, it can be unstable in air.

Review of low salinity waterflooding in carbonate rocks: mechanisms, investigation techniques, and future directions

This review analyses the fundamental thermodynamic theory of the crude oil-brine-rock (COBR) interface and the underlying rock-brine and oil-brine interactions. The available data are then reviewed to outline potential mechanisms responsible for increased oil recovery from low salinity waterflooding (LSWF). We propose an approach to studying LSWF and identify the key missing links that are needed to explain observations at multiple length scales. The synergistic effect of LSWF on other chemical enhanced oil recovery methods such as surfactant, alkaline, nanoparticle and polymer flooding are also outlined. We specifically highlight key uncertainties that must be overcome to fully implement the technique in the field.

Thermodynamic Stability of Volatile Droplets and Thin Films Governed by Disjoining Pressure in Open and Closed Containers

Distributed thin films of water and their coexistence with droplets are investigated using a capillary description based on a thermodynamic fundamental relation for the film Helmholtz energy, derived from disjoining pressure isotherms and an accurate equation of state. Gas-film and film-solid interfacial tensions are derived, and the latter has a dependence on film thickness. The resulting energy functionals from the capillary description are discretized, and stationary states are identified. The thermodynamic stability of configurations with thin films in systems that are closed (canonical ensemble) or connected to a particle reservoir (grand canonical ensemble) is evaluated by considering the eigenvalues of the corresponding Hessian matrices. The conventional stability criterion from the literature states that thin flat films are stable when the derivative of the disjoining pressure with respect to the film thickness is negative. This criterion is found to apply only in open systems. A closer inspection of the eigenvectors of the negative eigenvalues shows that condensation/evaporation destabilizes the film in an open system. In closed systems, thin films can be stable even though the disjoining pressure derivative is positive, and their stability is governed by mechanical instabilities of a similar kind to those responsible for spinodal dewetting in nonvolatile systems. The films are stabilized when their thickness and disjoining pressure derivative are such that the minimum unstable wavelength is larger than the container diameter. Droplets in coexistence with thin films are found to be unstable for all considered examples in open systems. In closed systems, they are found to be stable under certain conditions. The unstable droplets in both open and closed systems are saddle points in their respective energy landscapes. In the closed system, they represent the activation barrier for the transition between a stable film and a stable droplet. In the open system, the unstable droplets represent the activation barrier for the transition from a film into a bulk liquid phase. Thin films are found to be the equilibrium configuration up to a certain value of the total density in a closed system. Beyond this value, there is a morphological phase transition to stable droplet configurations.