Controlled encapsulation of colloidal semiconductor quantum dots in a microdroplet.

Precise deposition of materials on surfaces is one of the crucial steps in a broad range of applications and functional device fabrication at both the micro- and nanoscale. Semiconductor quantum dots (QDs), with their unique optical and physical properties, have frequently been a focus of attempts for micro- or nano-positioning. Here, we present a method for reproducible, repetitive, and precise deposition of QD-containing microdroplets using hydrophobic micropipettes without any need to apply an actuation voltage.

Expression of concern: An impedimetric immunosensor based on diamond nanowires decorated with nickel nanoparticles.

Expression of concern for 'An impedimetric immunosensor based on diamond nanowires decorated with nickel nanoparticles' by Palaniappan Subramanian , , 2014, , 1726-1731, https://doi.org/10.1039/C3AN02045B.

Thin-film-based optical fiber interferometric sensor on the fiber tip for endovascular surgical procedures.

Objective: Endovascular surgery requires accurate measurement of parameters such as pressure, temperature, and biomarkers within vessels for real-time tissue response monitoring and ensuring targeted therapeutic interventions. However, the availability of small tip-based sensors capable of precise application, for example, navigating an aneurysm's lumen, is limited. With their capabilities for real-time analysis, flexibility, and biocompatibility, optical fiber sensors (OFS) hold promise in addressing this need.

Double-layer optical fiber interferometer with bio-layer-modified reflector for label-free biosensing of inflammatory proteins.

This work discusses label-free biosensing application of a double-layer optical fiber interferometer where the second layer tailors the reflection conditions at the external plain and supports changes in reflected optical spectrum when a bio-layer binds to it. The double-layer nanostructure consists of precisely tailored thin films, i.e.

NFC Smartphone-Based Electrochemical Microfluidic Device Integrated with Nanobody Recognition for C-Reactive Protein.

Point-of-care testing (POCT) devices play a crucial role as tools for disease diagnostics, and the integration of biorecognition elements with electronic components into these devices widens their functionalities and facilitates the development of complex quantitative assays. Unfortunately, biosensors that exploit large conventional IgG antibodies to capture relevant biomarkers are often limited in terms of sensitivity, selectivity, and storage stability, considerably restricting the use of POCT in real-world applications. Therefore, we used nanobodies as they are more suitable for fabricating electrochemical biosensors with near-field communication (NFC) technology.

Investigation of Peptides for Molecular Recognition of C-Reactive Protein-Theoretical and Experimental Studies.

We investigate the interactions between C-reactive protein (CRP) and new CRP-binding peptide materials using experimental (biological and physicochemical) methods with the support of theoretical simulations (computational modeling analysis). Three specific CRP-binding peptides (P2, P3, and P9) derived from an M13 bacteriophage have been identified using phage-display technology. The binding efficiency of the peptides exposed on phages toward the CRP protein was demonstrated via biological methods.

Determination of the Dissociation Constant for Polyvalent Receptors Using ELISA: A Case of M13 Phages Displaying Troponin T-Specific Peptides.

Phage-derived affinity peptides have become widespread thanks to their easy selection via phage display. Interactions between a target protein and its specific peptide are similar to those between antibodies and antigens. The strength of these non-covalent complexes may be described by the dissociation constant ().

Aligned silver nanowires for plasmonically-enhanced fluorescence detection of photoactive proteins in wet and dry environment.

We developed a method of aligning silver nanowires in a microchannel and fixing them to glass substrates via appropriate functionalization. The attachment of nanowires to the substrate is robust with no variation of their angles over minutes. Specific conjugation with photoactive proteins is observed using wide-field fluorescence imaging in real-time for highly concentrated protein solution, both in a microchannel and in a chip geometry.

Native llama Nanobody Library Panning Performed by Phage and Yeast Display Provides Binders Suitable for C-Reactive Protein Detection.

C-reactive protein (CRP) is an inflammation biomarker that should be quantified accurately during infections and healing processes. Nanobodies are good candidates to replace conventional antibodies in immunodiagnostics due to their inexpensive production, simple engineering, and the possibility to obtain higher binder density on capture surfaces. Starting from the same pre-immune library, we compared the selection output resulting from two independent panning strategies, one exclusively exploiting the phage display and another in which a first round of phage display was followed by a second round of yeast display.

Fingermark detection using upconverting nanoparticles and comparison with cyanoacrylate fuming.

This paper reports the synthesis of high-quality upconverting nanoparticles (UCNPs) - sodium yttrium tetrafluoride doped with ytterbium and erbium (NaYF:Yb,Er) with a silica shell and capped with phenyl functional groups. The main goal of this research was to design tailor-made UCNPs for fingermark detection, to test and validate a nanoparticle-based detection technique and to compare their performance against a benchmark method to assess potential implementation in routine practice by law enforcement agencies. The water-based UCNPs solution was applied to natural fingermarks on a number of substrates.

Controlling plasmon propagation and enhancement via reducing agent in wet chemistry synthesized silver nanowires.

Silver nanowires with varying diameters and submillimeter lengths were obtained by changing a reducing agent used during hydrothermal synthesis. The control over the nanowire diameter turns out to play a critical role in determining their plasmonic properties, including fluorescence enhancement and surface plasmon polariton propagation. Advanced fluorescence imaging of hybrid nanostructures assembled of silver nanowires and photoactive proteins indicates longer propagation lengths for nanowires featuring larger diameters.

Adsorption of bacteriophages on polypropylene labware affects the reproducibility of phage research.

Hydrophobicity is one of the most critical factors governing the adsorption of molecules and objects, such as virions, on surfaces. Even moderate change of wetting angle of plastic surfaces causes a drastic decrease ranging from 2 to 5 logs of the viruses (e.g.

Interactions of Eu(TTA)(HO) with Latent Fingermark Components-A Time-Gated Visualization of Latent Fingermarks on Paper.

We introduce a new latent fingermark (LFM) development method, where compounds showing long lifetime luminescence are generated in situ by the reactions of Eu(TTA)(HO) with LFM components. Until now, time-gated imaging could not be used to develop LFM on porous surfaces due to the difficulties with selective binding of the developing agents to the fingermark ridges. The nature of the interactions of Eu(TTA)(HO) with the LFM material has been investigated for three model compounds commonly found in the LFM composition-oleic acid, l-serine, and squalene.

Real-time fluorescence sensing of single photoactive proteins using silver nanowires.

We demonstrate that single functionalized silver nanowires form a geometric platform suitable for efficient real-time detection of single photoactive proteins. By collecting series of images using wide-field fluorescence microscopy, events of single protein attachment can be distinguished with the signal to noise ratio further improved by fluorescence enhancement due to plasmon excitations in the nanowires. The enhancement is evidenced by strong shortening of the fluorescence decay of single photoactive proteins conjugated to the silver nanowires.

CRP-binding bacteriophage as a new element of layer-by-layer assembly carbon nanofiber modified electrodes.

Recently, bacteriophage particles have started to be applied as a new biomaterial for developing sensing platforms. They can be used as both a recognition element or/and as building blocks, template/scaffold. In this paper, we studied a bacteriophage selected through phage-display technology.

Silver Island Film for Enhancing Light Harvesting in Natural Photosynthetic Proteins.

The effects of combining naturally evolved photosynthetic pigment-protein complexes with inorganic functional materials, especially plasmonically active metallic nanostructures, have been a widely studied topic in the last few decades. Besides other applications, it seems to be reasonable using such hybrid systems for designing future biomimetic solar cells. In this paper, we describe selected results that point out to various aspects of the interactions between photosynthetic complexes and plasmonic excitations in Silver Island Films (SIFs).

Photochemical Printing of Plasmonically Active Silver Nanostructures.

In this paper, we demonstrate plasmonic substrates prepared on demand, using a straightforward technique, based on laser-induced photochemical reduction of silver compounds on a glass substrate. Importantly, the presented technique does not impose any restrictions regarding the shape and length of the metallic pattern. Plasmonic interactions have been probed using both Stokes and anti-Stokes types of emitters that served as photoluminescence probes.

Simultaneous optical and electrochemical label-free biosensing with ITO-coated lossy-mode resonance sensor.

In this work we discuss a new label-free biosensing device based on indium tin oxide (ITO) overlaid section of a multimode optical fiber fused silica core. The sensor has been used to optical measurements also simultaneously interrogated electrochemically (EC). Due to optimized thickness and optical properties of ITO film, a lossy-mode resonance (LMR) could be observed in the optical domain, where electrical properties of the film allowed for application of the sensor as a working electrode in an EC setup.

Immunosensor Based on Long-Period Fiber Gratings for Detection of Viruses Causing Gastroenteritis.

Since the norovirus is the main cause of acute gastroenteritis all over the world, its fast detection is crucial in medical diagnostics. In this work, a rapid, sensitive, and selective optical fiber biosensor for the detection of norovirus virus-like particles (VLPs) is reported. The sensor is based on highly sensitive long-period fiber gratings (LPFGs) coated with antibodies against the main coat protein of the norovirus.

Zinc oxide quantum dots embedded in hydrophobic silica particles for latent fingermarks visualization based on time-gated luminescence measurements.

In this work we demonstrate a composite material based on silica particles. The particles have been doped with zinc oxide quantum dots which possess long living luminescence. The surface of the particles has been functionalized with phenyl groups using sol-gel process.

Plasmonics with Metallic Nanowires.

The purpose of this review is to introduce and present the concept of metallic nanowires as building-blocks of plasmonically active structures. In addition to concise description of both the basic physical properties associated with the electron oscillations as well as energy propagation in metallic nanostructures, and methods of fabrication of metallic nanowires, we will demonstrate several key ideas that involve interactions between plasmon excitations and electronic states in surrounding molecules or other emitters. Particular emphasis will be placed on the effects that involve not only plasmonic enhancement or quenching of fluorescence, but also propagation of energy on lengths that exceed the wavelength of light.

Ultrasensitive tantalum oxide nano-coated long-period gratings for detection of various biological targets.

In this work we discussed a label-free biosensing application of long-period gratings (LPGs) optimized in refractive index (RI) sensitivity by deposition of thin tantalum oxide (TaO) overlays. Comparing to other thin film and materials already applied for maximizing the RI sensitivity, TaO offers good chemical and mechanical stability during its surface functionalization and other biosensing experiments. It was shown theoretically and experimentally that when RI of the overlay is as high as 2 in IR spectral range, for obtaining LPGs ultrasensitive to RI, the overlay's thickness must be determined with subnanometer precision.

Optical Properties of Submillimeter Silver Nanowires Synthesized Using the Hydrothermal Method.

We report on the synthesis of long silver nanowires using the hydrothermal method, with H₂O₂ as the reducing agent. Our approach yields nanowires with an average diameter and length of about 100 nm and 160 µm, respectively, reaching the maximum length of 800 µm. Scanning electron microscopy (SEM) measurements revealed the presence of a thick, inhomogeneous poly(vinylpyrrolidone) (PVP) layer covering the nanowires, which with time becomes much more uniform, leading to well-defined extinction peaks in the ultraviolet-visible (UV-Vis) spectra.

Interactions of bacteriophage T4 adhesin with selected lipopolysaccharides studied using atomic force microscopy.

The interaction between the T4 bacteriophage gp37 adhesin and the bacterial lipopolysaccharide (LPS) is a well-studied system, however, the affinity and strength of the interaction haven't been analyzed so far. Here, we use atomic force microscopy to determine the strength of the interaction between the adhesin and its receptor, namely LPS taken from a wild strain of E. coli B.