Ratiometric array of conjugated polymers–fluorescent protein provides a robust mammalian cell sensor

© 2016 American Chemical Society.Supramolecular complexes of a family of positively charged conjugated polymers (CPs) and green fluorescent protein (GFP) create a fluorescence resonance energy transfer (FRET)-based ratiometric biosensor array. Selective multivalent interactions of the CPs with mammalian cell surfaces caused differential change in FRET signals, providing a fingerprint signature for each cell type. The resulting fluorescence signatures allowed the identification of 16 different cell types and discrimination between healthy, cancerous, and metastatic cells, with the same genetic background. While the CP-GFP sensor array completely differentiated between the cell types, only partial classification was achieved for the CPs alone, validating the effectiveness of the ratiometric sensor. The utility of the biosensor was further demonstrated in the detection of blinded unknown samples, where 121 of 128 samples were correctly identified. Notably, this selectivity-based sensor stratified diverse cell types in minutes, using only 2000 cells, without requiring specific biomarkers or cell labeling

Novel hybrid organic/inorganic 2D quasiperiodic PC: from diffraction pattern to vertical light extraction

Recently, important efforts have been dedicated to the realization of a fascinating class of new photonic materials or metamaterials, known as photonic quasicrystals (PQCs), in which the lack of the translational symmetry is compensated by rotational symmetries not achievable by the conventional periodic crystals. As ever, more advanced functionality is demanded and one strategy is the introduction of non-linear and/or active functionality in photonic materials. In this view, core/shell nanorods (NRs) are a promising active material for light-emitting applications. In this article a two-dimensional (2D) hybrid a 2D octagonal PQC which consists of air rods in an organic/inorganic nanocomposite is proposed and experimentally demonstrated. The nanocomposite was prepared by incorporating CdSe/CdS core/shell NRs into a polymer matrix. The PQC was realized by electron beam lithography (EBL) technique. Scanning electron microscopy, far field diffraction and spectra measurements are used to characterize the experimental structure. The vertical extraction of the light, by the coupling of the modes guided by the PQC slab to the free radiation via Bragg scattering, consists of a narrow red emissions band at 690 nm with a full width at half-maximum (FWHM) of 21.5 nm. The original characteristics of hybrid materials based on polymers and colloidal NRs, able to combine the unique optical properties of the inorganic moiety with the processability of the host matrix, are extremely appealing in view of their technological impact on the development of new high performing optical devices such as organic light-emitting diodes, ultra-low threshold lasers, and non-linear devices

A Multichannel Biosensor for Rapid Determination of Cell Surface Glycomic Signatures.

Cell surface glycosylation serves a fundamental role in dictating cell and tissue behavior. Cell surface glycomes differ significantly, presenting viable biomarkers for identifying cell types and their states. Glycoprofiling is a challenging task, however, due to the complexity of the constituent glycans. We report here a rapid and effective sensor for surface-based cell differentiation that uses a three-channel sensor produced by noncovalent conjugation of a functionalized gold nanoparticle (AuNP) and fluorescent proteins. Wild-type and glycomutant mammalian cells were effectively stratified using fluorescence signatures obtained from a single sensor element. Blinded unknowns generated from the tested cell types were identified with high accuracy (44 out of 48 samples), validating the robustness of the multichannel sensor. Notably, this selectivity-based high-throughput sensor differentiated between cells, employing a nondestructive protocol that required only a single well of a microplate for detection

Advanced drug delivery reviews theme issue - Preface

Inorganic nanomaterials feature a wide variety of attributes that make them highly promising candidates for drug delivery. The inorganic component of these materials imparts unique properties to the resultant systems, providing access to new properties and capabilities for both delivery and imaging applications. Inorganic structures also provide scaffolds for the presentation and encapsulation of drugs, biomolecules, and imaging agents, generating delivery systems with structural and dynamic properties complementary to more conventional polymeric and lipid-based delivery vectors. The reviews in this special issue highlight both of these aspects, demonstrating the potential of these systems in biomedical applications. One of the unique aspects of nanoparticles is quantum confinement, which provides optical properties such as fluorescence that differ completely from bulk materials. The use of quantum dots (QDs) as tools for imaging and therapeutics is reviewed by Nie et al., covering issues of synthesis, functionalization, imaging, and toxicology. On the therapeutic side, the use of these systems as dual-mode imaging and delivery agents is covered. Nanomaterials can be fabricated with a wide range of magnetic properties that likewise derive from their nanoscale dimensions. McCarthy and Weissleder discuss the use of magnetic nanoparticles for MRI imaging and therapeutic applications. This review cover a number of issues in the application of magnetic materials, including functionalization, targeting, multi-modal imaging (MRI and fluorescence) and near-IR activated therapeutics. Zhang et. al provide a complementary review of nanomaterials, covering the array of core materials available, and the use of polymers, liposomes, and core-shell structures for particle functionalization. Targeting of the carriers is also covered, including magnetic targeting strategies unique to these materials. In addition to their physical properties, nanomaterials provide access to a diverse array of shapes and morphologies. Sailor et al. discuss the use of nanoporous silicon produced via etching of Si, including both silicon and silicate systems produced via oxidation of silicon precursors. In these systems the pores serves as carriers for drugs and polymers, while the microparticle ‘mothership’ can be used to target the therapeutic to disease sites. Lin et al. describes an entirely different approach to the creation of mesoporous silicates using self-assembly. A particular focus of this article is the use of ‘gatekeepers’, namely agents that cap the pores and can be triggered to release the payload. A final aspect of nanomaterials arises from our ability to control the interface between nanomaterials and their environments. While this capability is used in the preceding articles, it comes to the fore in the use of metallic nanoparticles in delivery applications. Bhattacharya and Mukherjee describe the behavior of ‘naked’ nanoparticles in vitro and in vivo, describing an array of targets. Rotello et al., in contrast, focus on the engineering of monolayer functionality on the particle. This review covers the effect of ligand design on payload release, in particular the use of the differential between extra-and intracellular glutathione levels. Additionally, the use of gold nanoparticles for photothermal therapy and the use of protein-particle conjugates as targeted therapeutics are described. Taken together, inorganic nanomaterials have much to offer in biomedical applications. While there are clearly hurdles to be overcome in implementing these systems as delivery vehicles, their unique attributes and ease of production will make these nanosystems important additions to our toolkit

Crown ether-peptide construct selectively kills cancer cells

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Hot and sticky or cold and aloof

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