Self-assembled monolayers of octadecylphosphonic acid and polymer films: Surface chemistry and chemical structures studied by time-of-flight secondary ion mass spectrometry

Selective Tumor Hypoxia Targeting Using M75 Antibody Conjugated Photothermally Active MoOx Nanoparticles

Photothermal therapy (PTT) mediated at the nanoscale has a unique advantage over currently used cancer treatments, by being spatially highly specific and minimally invasive. Although PTT combats traditional tumor treatment approaches, its clinical implementation has not yet been successful. The reasons for its disadvantage include an insufficient treatment efficiency or low tumor accumulation. Here, we present a promising new PTT platform combining a recently emerged two-dimensional (2D) inorganic nanomaterial, MoOx, and a tumor hypoxia targeting element, the monoclonal antibody M75. M75 specifically binds to carbonic anhydrase IX (CAIX), a hypoxia marker associated with many solid tumors with a poor prognosis. The as-prepared nanoconjugates showed highly specific binding to cancer cells expressing CAIX while being able to produce significant photothermal yield after irradiation with near-IR wavelengths. Small aminophosphonic acid linkers were recognized to be more effective over the combination of poly(ethylene glycol) chain and biotin-avidin-biotin bridge in constructing a PTT platform with high tumor-binding efficacy. The in vitro cellular uptake of nanoconjugates was visualized by high-resolution fluorescence microscopy and label-free live cell confocal Raman microscopy. The key to effective cancer treatment may be the synergistic employment of active targeting and noninvasive, tumor-selective therapeutic approaches, such as nanoscale-mediated PTT. The use of active targeting can streamline nanoparticle delivery increasing photothermal yield and therapeutic success.

Manipulating Li2S2/Li2S mixed discharge products of all-solid-state lithium sulfur batteries for improved cycle life

All-solid-state lithium-sulfur batteries offer a compelling opportunity for next-generation energy storage, due to their high theoretical energy density, low cost, and improved safety. However, their widespread adoption is hindered by an inadequate understanding of their discharge products. Using X-ray absorption spectroscopy and time-of-flight secondary ion mass spectrometry, we reveal that the discharge product of all-solid-state lithium-sulfur batteries is not solely composed of Li2S, but rather consists of a mixture of Li2S and Li2S2. Employing this insight, we propose an integrated strategy that: (1) manipulates the lower cutoff potential to promote a Li2S2-dominant discharge product and (2) incorporates a trace amount of solid-state catalyst (LiI) into the S composite electrode. This approach leads to all-solid-state cells with a Li-In alloy negative electrode that deliver a reversible capacity of 979.6 mAh g-1 for 1500 cycles at 2.0 A g-1 at 25 °C. Our findings provide crucial insights into the discharge products of all-solid-state lithium-sulfur batteries and may offer a feasible approach to enhance their overall performance.

Ab-Initio Investigations on Hydrogen Dissociation and Cross-Linking of Hydrocarbon Chains of Self-Assembled Monolayers of Alkanes

First-principles calculations were carried out to study the structural and electronic properties of hydrocarbon chains of self-assembled monolayers with hydrogen dissociation. It was found that the incoming hydrogen could lead to the formation of H2 molecules by stripping the nearby hydrogen atoms in the chains and thereby leave the neighboring carbon atoms to be free radicals. Two parallel hydrocarbon chains with dangling bonds can form a direct C-C bond, i.e., cross-linking happens between the two chains, which is ascribed to a charge accumulation in the cross-linking region. The polymerization of short molecules into long hydrocarbon chains through a different cross-linking mode is also discussed.

Superhydrophobic Self-Assembled Silane Monolayers on Hierarchical 6082 Aluminum Alloy for Anti-Corrosion Applications

In this work, a two-stage methodology to design super-hydrophobic surfaces was proposed. The first step consists of creating a rough nano/micro-structure and the second step consists of reducing the surface energy using octadecyltrimethoxysilane. The surface roughening was realized by three different short-term pretreatments: (i) Boiling water, (ii) HNO3/HCl etching, or (iii) HF/HCl etching. Then, the surface energy was reduced by dip-coating in diluted solution of octadecyltrimethoxysilane to allow the formation of self-assembled silane monolayers on a 6082-T6 aluminum alloy surface. Super-hydrophobic aluminum surfaces were investigated by SEM-EDS, FTIR, profilometry, and contact and sliding angles measurements. The resulting surface morphologies by the three approaches were structured by a dual hierarchical nano/micro-roughness. The surface wettability varied with the applied roughening pretreatment. In particular, an extremely high water contact angle (around 180°) and low sliding angle (0°) were evidenced for the HF/HCl-etched silanized surface. The results of electrochemical tests demonstrate a remarkable enhancement of the aluminum alloy corrosion resistance through the proposed superhydrophobic surface modifications. Thus, the obtained results evidenced that the anti-wetting behavior of the aluminum surface can be optimized by coupling an appropriate roughening pretreatment with a self-assembled silane monolayer deposition (to reduce surface energy) for anticorrosion application.