Detection of Tn-antigen in breast and prostate cancer models by VVL-labeled red dye-doped nanoparticles.

Fluorescence detection of breast and prostate cancer cells expressing Tn-antigen, a tumor marker, with lectin (VVL)-labeled nanoparticles. Breast and prostate cancer cells engineered to express high levels of Tn-antigen and non-engineered controls were incubated with VVL-labeled or unlabeled red dye-doped silica-coated polystyrene nanoparticles. The binding to cells was studied with flow cytometry, confocal microscopy, and electron microscopy.

Ratiometric Molecularly Imprinted Particle Probes for Reliable Fluorescence Signaling of Carboxylate-Containing Molecules.

In addition to sensitivity, selectivity, and portability, chemical sensing systems must generate reliable signals and offer modular configurability to address various small molecule targets, particularly in environmental applications. We present a versatile, modular strategy utilizing ratiometric molecularly imprinted particle probes based on BODIPY indicators and dyes for recognition and internal referencing. Our approach employs polystyrene core particles doped with a red fluorescent BODIPY as an internal standard, providing built-in reference for environmental influences.

Towards molecularly imprinted polymers that respond to and capture phosphorylated tyrosine epitopes using fluorescent bis-urea and bis-imidazolium receptors.

Early detection of cancer is essential for successful treatment and improvement in patient prognosis. Deregulation of post-translational modifications (PTMs) of proteins, especially phosphorylation, is present in many types of cancer. Therefore, the development of materials for the rapid sensing of low abundant phosphorylated peptides in biological samples can be of great therapeutic value.

Sialyl-Tn Antigen-Imprinted Dual Fluorescent Core-Shell Nanoparticles for Ratiometric Sialyl-Tn Antigen Detection and Dual-Color Labeling of Cancer Cells.

Sialyl-Tn (STn or sialyl-Thomsen-nouveau) is a carbohydrate antigen expressed by more than 80% of human carcinomas. We here report a strategy for ratiometric STn detection and dual-color cancer cell labeling, particularly, by molecularly imprinted polymers (MIPs). Imprinting was based on spectroscopic studies of a urea-containing green-fluorescent monomer and STn-Thr-Na (sodium salt of Neu5Acα2-6GalNAcα--Thr).

Fluorescent molecularly imprinted polymer particles for glyphosate detection using phase transfer agents.

In this work, molecular imprinting was combined with direct fluorescence detection of the pesticide Glyphosate (GPS). Firstly, the solubility of highly polar GPS in organic solvents was improved by using lipophilic tetrabutylammonium (TBA) and tetrahexylammonium (THA) counterions. Secondly, to achieve fluorescence detection, a fluorescent crosslinker containing urea-binding motifs was used as a probe for GPS-TBA and GPS-THA salts in chloroform, generating stable complexes through hydrogen bond formation.

Fluorescent Molecularly Imprinted Polymer Layers against Sialic Acid on Silica-Coated Polystyrene Cores-Assessment of the Binding Behavior to Cancer Cells.

Sialic acid (SA) is a monosaccharide usually linked to the terminus of glycan chains on the cell surface. It plays a crucial role in many biological processes, and hypersialylation is a common feature in cancer. Lectins are widely used to analyze the cell surface expression of SA.

Thiourea- and Amino-Substituted Benzoxadiazole Dyes with Large Stokes Shifts as Red-Emitting Probe Monomers for Imprinted Polymer Layers Targeting Carboxylate-Containing Antibiotics.

Bifunctional fluorescent molecular oxoanion probes based on the benzoxadiazole (BD) chromophore are described which integrate a thiourea binding motif and a polymerizable 2-aminoethyl methacrylate unit in the 4,7-positions of the BD core. Concerted charge transfer in this electron donor-acceptor-donor architecture endows the dyes with strongly Stokes shifted (up to >250 nm) absorption and fluorescence. Binding of electron-rich carboxylate guests at the thiourea receptor leads to further analyte-induced red-shifts of the emission, shifting the fluorescence maximum of the complexes to ≥700 nm.

Dual-Fluorescent Nanoparticle Probes Consisting of a Carbon Nanodot Core and a Molecularly Imprinted Polymer Shell.

Dual-fluorescent molecularly imprinted nanoparticles with a red-emissive carbon nanodot-doped silica core and a chlorogenic acid-imprinted fluorescent polymer layer are prepared and their use in ratiometric fluorometric analysis is described. Nanoparticle probes consisting of a shielded and stably emitting core and a shell with embedded binding sites that indicates the presence of an analyte with a change in emission allow for internally referenced measurements potentially accounting for detrimental influences from instrument drifts, light source fluctuations or sensor materials-related inhomogeneities.

Polystyrene Microparticles with Convergently Grown Mesoporous Silica Shells as a Promising Tool for Multiplexed Bioanalytical Assays.

Functional core/shell particles are highly sought after in analytical chemistry, especially in methods suitable for single-particle analysis such as flow cytometry because they allow for facile multiplexed detection of several analytes in a single run. Aiming to develop a powerful bead platform of which the core particle can be doped in a straightforward manner while the shell offers the highest possible sensitivity when functionalized with (bio)chemical binders, polystyrene particles were coated with different kinds of mesoporous silica shells in a convergent growth approach. Mesoporous shells allow us to obtain distinctly higher surface areas in comparison with conventional nonporous shells.

Optimization of analytical assay performance of antibody-gated indicator-releasing mesoporous silica particles.

Antibody-gated indicator delivery (gAID) systems based on mesoporous silica nano- and microparticle scaffolds are a promising class of materials for the sensitive chemical detection of small-molecule analytes in simple test formats such as lateral flow assays (LFAs) or microfluidic chips. Their architecture is reminiscent of drug delivery systems, only that reporter molecules instead of drugs are stored in the voids of a porous host particle. In addition, the pores are closed with macromolecular "caps" through a tailored "gatekeeping" recognition chemistry so that the caps are opened when an analyte has reacted with a "gatekeeper".

Mix-&-Read Determination of Mercury(II) at Trace Levels with Hybrid Mesoporous Silica Materials Incorporating Fluorescent Probes by a Simple Mix-&-Load Technique.

https://doi.org/10.1002/open.

Mix-&-Read Determination of Mercury(II) at Trace Levels with Hybrid Mesoporous Silica Materials Incorporating Fluorescent Probes by a Simple Mix-&-Load Technique.

The synthesis, characterization, and application of mesoporous materials containing boron-dipyrromethene (BODIPY) moieties that allow the sensitive and selective detection of Hg in aqueous environments by fluorescence enhancement is reported. For this purpose, BODIPY dye containing a thia-aza crown ether receptor as the fluorescent probe for the detection of Hg in aqueous environments is encapsulated into mesoporous materials to avoid self-quenching or aggregation in water. Determination of Hg is accomplished within a few seconds with high selectivity and sensitivity, reaching a limit of detection of 12 ppt.

Mix-&-Read Determination of Mercury(II) at Trace Levels with Hybrid Mesoporous Silica Materials Incorporating Fluorescent Probes by a Simple Mix-&-Load Technique.

The synthesis, characterization, and application of mesoporous materials containing boron-dipyrromethene (BODIPY) moieties that allow the sensitive and selective detection of Hg in aqueous environments by fluorescence enhancement is reported. For this purpose, BODIPY dye containing a thia-aza crown ether receptor as the fluorescent probe for the detection of Hg in aqueous environments is encapsulated into mesoporous materials to avoid self-quenching or aggregation in water. Determination of Hg is accomplished within a few seconds with high selectivity and sensitivity, reaching a limit of detection of 12 ppt.

Role of Counterions in Molecularly Imprinted Polymers for Anionic Species.

Small-molecule oxoanions are often imprinted noncovalently as carboxylates into molecularly imprinted polymers (MIPs), requiring the use of an organic counterion. Popular species are either pentamethylpiperidine (PMP) as a protonatable cation or tetraalkylammonium (TXA) ions as permanent cations. The present work explores the influence of the TXA as a function of their alkyl chain length, from methyl to octyl, using UV/vis absorption, fluorescence titrations, and HPLC as well as MD simulations.

Integrating fluorescent molecularly imprinted polymer (MIP) sensor particles with a modular microfluidic platform for nanomolar small-molecule detection directly in aqueous samples.

Fluorescent sensory MIP (molecularly imprinted polymer) particles were combined with a droplet-based 3D microfluidic system for the selective determination of a prototype small-molecule analyte of environmental concern, 2,4-dichlorophenoxyacetic acid or 2,4-D, at nanomolar concentration directly in water samples. A tailor-made fluorescent indicator cross-linker was thus designed that translates the binding event directly into an enhanced fluorescence signal. The phenoxazinone-type cross-linker was co-polymerized into a thin MIP layer grafted from the surface of silica microparticles following a RAFT (reversible addition-fragmentation chain transfer) polymerization protocol.

Novel and easy access to highly luminescent Eu and Tb doped ultra-small CaF, SrF and BaF nanoparticles - structure and luminescence.

A universal fast and easy access at room temperature to transparent sols of nanoscopic Eu and Tb doped CaF, SrF and BaF particles via the fluorolytic sol-gel synthesis route is presented. Monodisperse quasi-spherical nanoparticles with sizes of 3-20 nm are obtained with up to 40% rare earth doping showing red or green luminescence. In the beginning luminescence quenching effects are only observed for the highest content, which demonstrates the unique and outstanding properties of these materials.

A Rapid and Sensitive Strip-Based Quick Test for Nerve Agents Tabun, Sarin, and Soman Using BODIPY-Modified Silica Materials.

Test strips that in combination with a portable fluorescence reader or digital camera can rapidly and selectively detect chemical warfare agents (CWAs) such as Tabun (GA), Sarin (GB), and Soman (GD) and their simulants in the gas phase have been developed. The strips contain spots of a hybrid indicator material consisting of a fluorescent BODIPY indicator covalently anchored into the channels of mesoporous SBA silica microparticles. The fluorescence quenching response allows the sensitive detection of CWAs in the μg m(-3) range in a few seconds.

Polystyrene Core-Silica Shell Particles with Defined Nanoarchitectures as a Versatile Platform for Suspension Array Technology.

The need for rapid and high-throughput screening in analytical laboratories has led to significant growth in interest in suspension array technologies (SATs), especially with regard to cytometric assays targeting a low to medium number of analytes. Such SAT or bead-based assays rely on spherical objects that constitute the analytical platform. Usually, functionalized polymer or silica (SiO2) microbeads are used which each have distinct advantages and drawbacks.

Microgels at the Water/Oil Interface: In Situ Observation of Structural Aging and Two-Dimensional Magnetic Bead Microrheology.

Stimuli-responsive microgels can be used as stabilizers for emulsions. However, the details of structure and the viscoelastic property of the microgel-laden interface are still not well-known. We synthesized fluorescently labeled microgels and used confocal microscopy to observe their arrangement at the water/oil interface.

Ethylene glycol-based microgels at solid surfaces: swelling behavior and control of particle number density.

The adsorption of ethylene glycol (EG)-based microgel particles at silicon surfaces was investigated. Monodisperse p-MeO2MA-co-OEGMA microgel particles were synthesized by precipitation polymerization. Particle size and the volume phase transition temperature (VPTT) can be tailored by changing the amount of comonomer.

Immobilization of water-soluble HRP within poly-N-isopropylacrylamide microgel particles for use in organic media.

In the present work, the immobilization of enzymes within poly-N-isopropylacrylamide (p-NIPAM) microgels using the method of solvent exchange is applied to the enzyme horseradish peroxidase (HRP). When the solvent is changed from water to isopropanol, HRP is embedded within the polymer structure. After the determination of the immobilized amount of enzyme, an enhanced specific activity of the biocatalyst in isopropanol can be observed.

Interaction of gold nanoparticles with thermoresponsive microgels: influence of the cross-linker density on optical properties.

The interaction of spherical gold nanoparticles (Au-NPs) with microgels composed of chemically cross-linked poly-(N-isopropylacrylamide) is reported. Simple mixing of the two components leads to adsorption of the gold particles onto the microgels. Different loading densities can be achieved by varying the ratio of gold particles to microgel particles.

Immobilization of lipase B within micron-sized poly-N-isopropylacrylamide hydrogel particles by solvent exchange.

The aim of the present work is the use of a water soluble enzyme in an organic solvent, still with a pronounced catalytic activity. Therefore, lipase B from Candida antarctica (CalB) is immobilized within micron-sized thermosensitive p-NIPAM hydrogel particles using a solvent exchange from polar to organic solvents. The absorbed amount of CalB is investigated at different immobilization temperatures.

Using hydrogel microparticles to transfer hydrophilic nanoparticles and enzymes to organic media via stepwise solvent exchange.

We present a simple and versatile approach of using hydrogel microparticles to transfer both inorganic hydrophilic nanoparticles (NPs) such as CdTe quantum dots and enzymes such as lipase B from Candida antarctica (CalB) to organic media and eventually encapsulate them in the gel microparticles by consecutive exchange of the water swollen in the hydrogel microparticles with water-miscible organic solvents and water-immiscible solvents. The entrapment of hydrophilic nanoparticles is due to their incompatibility with water-immiscible organic solvents soaked in the gel matrices and in the surrounding environment, so the present approach obviates the need for any chemical modification to the NP surface or to the hydrogel and furthermore does not require any size matching or chemical affinity of the NPs for the hydrogel networks. The solvent exchange process causes little change of the intrinsic properties of hydrophilic nanoparticles; CdTe quantum dots encapsulated in hydrogel microparticles, dispersed in water-immiscible organic solvents, remain strongly fluorescent, and CalB retains high catalytic activity.