Responsive core-shell DNA particles trigger lipid-membrane disruption and bacteria entrapment

Biology has evolved a variety of agents capable of permeabilizing and disrupting lipid membranes, from amyloid aggregates, to antimicrobial peptides, to venom compounds. While often associated with disease or toxicity, these agents are also central to many biosensing and therapeutic technologies. Here, we introduce a class of synthetic, DNA-based particles capable of disrupting lipid membranes. The particles have finely programmable size, and self-assemble from all-DNA and cholesterol-DNA nanostructures, the latter forming a membrane-adhesive core and the former a protective hydrophilic corona. We show that the corona can be selectively displaced with a molecular cue, exposing the ‘sticky’ core. Unprotected particles adhere to synthetic lipid vesicles, which in turn enhances membrane permeability and leads to vesicle collapse. Furthermore, particle-particle coalescence leads to the formation of gel-like DNA aggregates that envelop surviving vesicles. This response is reminiscent of pathogen immobilisation through immune cells secretion of DNA networks, as we demonstrate by trapping E. coli bacteria.

Construction of Inorganic Bulks through Coalescence of Particle Precursors

Bulk inorganic materials play important roles in human society, and their construction is commonly achieved by the coalescence of inorganic nano- or micro-sized particles. Understanding the coalescence process promotes the elimination of particle interfaces, leading to continuous bulk phases with improved functions. In this review, we mainly focus on the coalescence of ceramic and metal materials for bulk construction. The basic knowledge of coalescent mechanism on inorganic materials is briefly introduced. Then, the properties of the inorganic precursors, which determine the coalescent behaviors of inorganic phases, are discussed from the views of particle interface, size, crystallinity, and orientation. The relationships between fundamental discoveries and industrial applications are emphasized. Based upon the understandings, the applications of inorganic bulk materials produced by the coalescence of their particle precursors are further presented. In conclusion, the challenges of particle coalescence for bulk material construction are presented, and the connection between recent fundamental findings and industrial applications is highlighted, aiming to provide an insightful outlook for the future development of functional inorganic materials.

Molecular dynamics simulation of sintering of Cu and Au nanoparticles

Particle coalescence has wide applications in nature and industry. In this study, molecular dynamics (MDs) simulations were employed to examine the sintering of Cu and Au nanoparticles, as well as two other systems, namely, Cu nanoparticles and Au nanoparticles. The results suggested that, the Au atoms diffused through the outer area of the sintering neck before the nanoparticles were fused into one sphere. The possible reason was that the Au atoms resembled fluid, which could be ascribed to the local thermal energy at the contact area. Typically, the change in energy per atom from 300 K to the contact temperature denoted that less energy was required for the atoms in the pure Cu system to contact with each other than those in the other two systems.

Thermoresponsive nanogels with film-forming ability

A one pot semibatch method was proposed for synthesizing poly(N-vinylcaprolactam)-based nanogels with particle coalescence ability.

Study on Processing and Characterization of Calcium Phosphate Bioceramics

The calcium phosphate bioceramics are widely used for the bone reconstruction because of their mineralogical similarities. This work aimed to obtain a biphasic calcium phosphate from hydroxyapatite nanoparticles synthesized by sonochemical technique and processed under two different conditions. The samples were uniaxially cold-pressed at 200MPa and sintered at 900°C/2h (CP900) and 1000°C/2h (CP1000) with heating rates of 2°C/min and 5°C/min, respectively. The characterizations were performed by X-ray Diffraction, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy and theoretical elastic modulus. From the geometric method, the relative density, porosity and linear shrinkage were measured. The results showed that the studied processing conditions were useful for achieving samples formed by a biphasic calcium phosphate with 80% β-tricalcium phosphate and 20% hydroxyapatite. The CP900 and CP1000 samples presented a theoretical elastic modulus of 34.7 GPa and 53.1 GPa, respectively, which are higher than that found to the compact bone. In addition, the sintering at 900oC was sufficient to promote neck formation and particle coalescence, maintaining adequate porosity (47.5%) for bone tissue ingrowth into pores.