Robust Prediction of Personalized Cell Recognition from a Cancer Population by a Dual Targeting Nanoparticle Library

Nanomaterials are used increasingly in diagnostics and therapeutics, particularly for malignancies. Efficient targeting of nanoparticles to specific cells is an important requirement for the development of successful nanoparticle‐based theranostics and personalized medicines. Gold nanoparticles are surface modified using a library of small organic molecules, and optionally folate, to investigate their ability to target four cell lines from common cancers, three having high levels of folate receptors expression. Uptake of these nanoparticles varies widely with surface chemistriy and cell lines. Sparse machine learning methods are used to computationally model surface chemistry–uptake relationships, to make quantitative predictions of uptake for new nanoparticle surface chemistries, and to elucidate molecular aspects of the interactions. The combination of combinatorial surface chemistry modification and machine learning models will facilitate the rapid development of targeted theranostics.     

Using SERS Tags to Image the Three‐Dimensional Structure of Complex Cell Models

Methods to image complex 3D cell cultures are limited by issues such as fluorophore photobleaching and decomposition, poor excitation light penetration, and lack of complementary techniques to verify the 3D structure. Although it remains insufficiently demonstrated, surface‐enhanced Raman scattering (SERS) imaging is a promising tool for the characterization of biological complex systems. To this aim, a controllable 3D cell culture model which spans nearly 1 cm² in surface footprint is designed. This structure is composed of fibroblasts containing SERS‐encoded nanoparticles (i.e., SERS tags), arranged in an alternating layered structure. This “sandwich” type structure allows monitoring of the SERS signals in the z‐axis and with mm dimensions in the xy‐axis. Taking advantage of correlative microscopy techniques such as electron microscopy, it is possible to corroborate nanoparticle positioning and distances in z‐depths of up to 150 µm. This study reveals a proof‐of‐concept method for detailed 3D SERS imaging of a complex, dense 3D cell culture model.     

Cell Adhesion and Cellular Patterning on a Self‐Assembled Monolayer of Zeolite L Crystals

Chemically functionalized self‐assembled monolayers made by disk‐shaped zeolite L nanocrystals are used as models for biocompatible surfaces to study cell‐adhesion behavior. Different chemical groups lead to different cellular behavior and fluorescent‐molecule‐loaded zeolites allow the position of the cells to be determined. Furthermore, a patterned monolayer of asymmetrically functionalized zeolite L obtained by microcontact chemistry is used to grow cells. A spatial recognition of the cells, which proliferate only on the bioactive‐molecule‐functionalized stripes, is possible.     

Self‐Limiting Galvanic Growth of MnO2 Monolayers on a Liquid Metal—Applied to Photocatalysis

Liquid metals offer unprecedented chemistry. Here it is shown that they can facilitate self‐limiting oxidation processes on their surfaces, which enables the growth of metal oxides that are atomically thin. This claim is exemplified by creating atomically thin hydrated MnO₂ using a Galvanic replacement reaction between permanganate ions and a liquid gallium–indium alloy (EGaIn). The “liquid solution”–“liquid metal” process leads to the reduction of the permanganate ions, resulting in the formation of the oxide monolayer at the interface. It is presented that under mechanical agitation liquid metal droplets are established, and simultaneously, hydrated gallium oxides and manganese oxide sheets delaminate themselves from the interfacial boundaries. The produced nanosheets encapsulate a metallic core, which is found to consist of solid indium only, with the full migration of gallium out of the droplets. This process produces core/shell structures, where the shells are made of stacked atomically thin nanosheets. The obtained core/shell structures are found to be an efficient photocatalyst for the degradation of an organic dye under simulated solar irradiation. This study presents a new research direction toward the modification and functionalization of liquid metals through spontaneous interfacial redox reactions, which has implications for many applications beyond photocatalysis.     

Growth of CdTe Films on Amorphous Substrates Using CaF<Subscript>2</Subscript> Nanorods as a Buffer Layer

Continuous biaxially textured CdTe films were grown on biaxial CaF₂ buffer layers. The CaF₂ nanorods were grown by oblique angle vapor deposition and possessed a {111} 〈121〉 biaxial texture. The CdTe film was deposited by metal organic chemical vapor deposition (MOCVD). Film morphology and the CdTe/CaF₂ interface were studied by scanning electron microscopy and transmission electron microscopy. Characterization showed that small CdTe grains formed initially from the CaF₂ surfaces. These small grains then merged into large columnar grains during growth. Analysis revealed that the crystalline orientation of the CdTe film followed the biaxial texture of the CaF₂ nanorods.