Bioconjugated fluorescent zeolite L nanocrystals as labels in protein microarrays

Tip‐mould microcontact printing for functionalisation of optical microring resonator

We present an approach to functionalise optical microring resonators as hybridisation platforms, using tip‐mould reactive microcontact printing process. Derived from reactive microcontact printing using an ad hoc mould of polydimethylsiloxane (PDMS), the method functionalises single microring resonator with a target‐specific capture agent. The authors report the functionalisation of silicon nitride (SiN) 200 μ m diameter microring resonator with single‐strand DNA and the hybridisation detection of 100 nM target analyte, while concurrently monitoring not‐functionalised microring as a control sensor. Results show that the functionalisation approach permits to address single microring resonators with mutual distance lower than 100 μ m with high precision, enabling a better integration of multiple spotting zones on the chip concerning traditional functionalisation procedures.

The spatial distribution of the photostability of thionine in zeolite L nanochannels investigated by Photobleaching Lifetime Imaging Microscopy

PbLIM is used to investigate the photostability of thionine in zeolite L. The gradient in the spatial distribution of the photostability is ascribed to a non-homogeneous distribution of active oxygen in the channels after irradiation.

Nanoparticle Detection of Urinary Markers for Point-of-Care Diagnosis of Kidney Injury

The high incidence of acute and chronic kidney injury due to various environmental factors such as heavy metals or chemicals has been a major problem in developing countries. However, the diagnosis of kidney injury in these areas can be more challenging due to the lack of highly sensitive and specific techniques that can be applied in point-of-care settings. To address this, we have developed a technique called ‘micro-urine nanoparticle detection (μUNPD)’, that allows the detection of trace amounts of molecular markers in urine. Specifically, this technique utilizes an automated on-chip assay followed by detection with a hand-held device for the read-out. Using the μUNPD technology, the kidney injury markers KIM-1 and Cystatin C were detected down to concentrations of 0.1 ng/ml and 20 ng/ml respectively, which meets the cut-off range required to identify patients with acute or chronic kidney injury. Thus, we show that the μUNPD technology enables point of care and non-invasive detection of kidney injury, and has potential for applications in diagnosing kidney injury with high sensitivity in resource-limited settings.

Multi-component assembly and luminescence tuning of lanthanide hybrids through the inside–outside double modification of zeolite A/L

A novel inside–outside double modification path is used to functionalize ZA/L to construct multi-component hybrids presenting multi-color luminescence.

Multi-component lanthanide hybrids based on zeolite A/L and zeolite A/L-polymers for tunable luminescence

Multi-component hybrids based on zeolite L/A are assembled by an inside–outside double modification route for ZA/L with lanthanide complexes. Some of them display white or near-white light emission. Furthermore, selected above-mentioned hybrids are incorporated into polymer to prepare the luminescent films.

Internalization pathways of anisotropic disc-shaped zeolite L nanocrystals with different surface properties in HeLa cancer cells

Information about the mechanisms underlying the interactions of nanoparticles with living cells is crucial for their medical application and also provides indications of the putative toxicity of such materials. Here the uptake and intracellular delivery of disc-shaped zeolite L nanocrystals as porous aminosilicates with well-defined crystal structure, uncoated as well as with COOH-, NH2 -, polyethyleneglycol (PEG)- and polyallylamine hydrochloride (PAH) surface coatings are reported. HeLa cells are used as a model system to demonstrate the relation between these particles and cancer cells. Interactions are studied in terms of their fates under diverse in vitro cell culture conditions. Differently charged coatings demonstrated dissimilar behavior in terms of agglomeration in media, serum protein adsorption, nanoparticle cytotoxicity and cell internalization. It is also found that functionalized disc-shaped zeolite L particles enter the cancer cells via different, partly not yet characterized, pathways. These in vitro results provide additional insight about low-aspect ratio anisotropic nanoparticle interactions with cancer cells and demonstrate the possibility to manipulate the interactions of nanoparticles and cells by surface coating for the use of nanoparticles in medical applications.

A facile strategy to design zeolite L crystals with tunable morphology and surface architecture

Tailoring the anisotropic growth rates of materials to achieve desired structural outcomes is a pervasive challenge in synthetic crystallization. Here we discuss a method to selectively control the growth of zeolite crystals, which are used extensively in a wide range of industrial applications. This facile method cooperatively tunes crystal properties, such as morphology and surface architecture, through the use of inexpensive, commercially available chemicals with specificity for binding to crystallographic surfaces and mediating anisotropic growth. We examined over 30 molecules as potential zeolite growth modifiers (ZGMs) of zeolite L (LTL type) crystallization. ZGM efficacy was quantified through a combination of macroscopic (bulk) and microscopic (surface) investigations that identified modifiers capable of dramatically altering the cylindrical morphology of LTL crystals. We demonstrate an ability to tailor properties critical to zeolite performance, such as external porous surface area, crystal shape, and pore length, which can enhance sorbate accessibility to LTL pores, tune the supramolecular organization of guest-host composites, and minimize the diffusion path length, respectively. We report that a synergistic combination of ZGMs and the judicious adjustment of synthesis parameters produce LTL crystals with unique surface features, and a range of length-to-diameter aspect ratios spanning 3 orders of magnitude. A systematic examination of different ZGM structures and molecular compositions (i.e., hydrophobicity and binding moieties) reveal interesting physicochemical properties governing their efficacy and specificity. Results of this study suggest this versatile strategy may prove applicable for a host of framework types to produce unrivaled materials that have eluded more conventional techniques.

Nanochannels: hosts for the supramolecular organization of molecules and complexes

Nanochannels have been used as hosts for supramolecular organization for a large variety of guests. The possibilities for building complex structures based on 2D and especially 3D nanochannel hosts are larger than those based on 1D nanochannel hosts. The latter are, however, easier to understand and to control. They still give rise to a rich world of fascinating objects with very distinguished properties. Important changes are observed if the channel diameter becomes smaller than 10 nm. The most advanced guest-nanochannel composites have been synthesized with nanochannels bearing a diameter of about 1 nm. Impressive complexity has been achieved by interfacing these composites with other objects and by assembling them into specific structures. This is explained in detail. Guest-nanochannel composites that absorb all light in the right wavelength range and transfer the electronic excitation energy via FRET to well-positioned acceptors offer a unique potential for developing FRET-sensitized solar cells, luminescent solar concentrators, color-changing media, and devices for sensing in analytical chemistry, biology, and diagnostics. Successful 1D nanochannel hosts for synthesizing guest-host composites have been zeolite-based. Among them the largest variety of guest-zeolite composites with appealing photochemical, photophysical, and optical properties has been prepared by using zeolite L (ZL) as a host. The reasons are the various possibilities for fine tuning the size and morphology of the particles, for inserting neutral molecules and cations, and for preparing rare earth complexes inside by means of the ship-in-a-bottle procedure. An important fact is that the channel entrances of ZL-based composites can be functonalized and completely blocked, if desired, and furthermore that targeted functionalization of the coat is possible. Different degrees of organizational levels and prospects for applications are discussed, with special emphasis on solar energy conversion devices.