Molecularly imprinted polymer-based SAW sensor for label-free detection of cerebral dopamine neurotrophic factor protein

In this study we report on a surface acoustic wave (SAW) sensor modified with a molecularly imprinted polymer (MIP) film that selectively recognizes the cerebral dopamine neurotrophic factor (CDNF) protein, a potential biomarker for early-stage diagnosis and/or the follow-up of neuroprotective therapies. CDNF-MIP as a synthetic recognition element was prepared by a simple electrochemical surface imprinting approach allowing its reliable interfacing with SAW sensor. The optimal thickness of the MIP layer as well as a suitable pretreatment method were adjusted to improve the recognition capacity and selectivity of the resulting CDNF-MIP sensor. The 4.7 nm thick CDNF-MIP layers treated in 0.04 mg/ml HSA solution demonstrated the highest relative rebinding towards CDNF. The selectivity of the sensor was studied by the carefully designed competitive binding experiments, which revealed that the sensor can sense CDNF confidently in a label-free manner starting from 0.1 pg/ml. We anticipate that the findings can be a premise for fabricating the desired cost-effective research or diagnostics tools in the field of neurodegenerative diseases.Peer reviewe

STRUCTURAL PROPERTIES OF ZnO NANOPOWDERS SYNTHESIZED BY THERMAL DECOMPOSITION

Zinc oxide nanostructures attract considerable attention of researchers due to their unique properties such as electrical conductivity, piezoelectric properties, optical transparency, emission, wide forbidden zone. Zinc oxide nanopowders are obtained by various methods: hydrothermal synthesis, sol-gel method, pyrolysis, chemical precipitation from solution and others. The task of development of low-cost methods of zinc oxide synthesis with high reproducibility is actual. The thermal decomposition method is a controlled relatively inexpensive method that can enable large scale production without the use of complex equipment and expensive materials.  In this work, nanostructured ZnO samples were prepared by thermal decomposition of zinc acetate dehydrate at temperatures 400 ̊С and 700 ̊С. The influence of such synthesis parameters as duration and temperature on the morphology and structural properties of the obtained samples was investigated. It was found that the morphology of the synthesised ZnO samples significantly depends on the synthesis temperature. The obtained Raman scattering spectra show characteristic peaks of zinc oxide and carbon. An efficient, inexpensive method for the synthesis of zinc oxide nanoparticles with controlled morphology, promising for use as photocatalysts, the basis for the development of sensor devices, is presented

Gas Sensors Based on Electrospun Nanofibers

Nanofibers fabricated via electrospinning have specific surface approximately one to two orders of the magnitude larger than flat films, making them excellent candidates for potential applications in sensors. This review is an attempt to give an overview on gas sensors using electrospun nanofibers comprising polyelectrolytes, conducting polymer composites, and semiconductors based on various sensing techniques such as acoustic wave, resistive, photoelectric, and optical techniques. The results of sensing experiments indicate that the nanofiber-based sensors showed much higher sensitivity and quicker responses to target gases, compared with sensors based on flat films

Electrochemically synthesized polymers in molecular imprinting for chemical sensing

This critical review describes a class of polymers prepared by electrochemical polymerization that employs the concept of molecular imprinting for chemical sensing. The principal focus is on both conducting and nonconducting polymers prepared by electropolymerization of electroactive functional monomers, such as pristine and derivatized pyrrole, aminophenylboronic acid, thiophene, porphyrin, aniline, phenylenediamine, phenol, and thiophenol. A critical evaluation of the literature on electrosynthesized molecularly imprinted polymers (MIPs) applied as recognition elements of chemical sensors is presented. The aim of this review is to highlight recent achievements in analytical applications of these MIPs, including present strategies of determination of different analytes as well as identification and solutions for problems encountered

Electrochemically Synthesized MIP Sensors: Applications in Healthcare Diagnostics

Early-stage detection and diagnosis of diseases is essential to the prompt commencement of treatment regimens, curbing the spread of the disease, and improving human health. Thus, the accurate detection of disease biomarkers through the development of robust, sensitive, and selective diagnostic tools has remained cutting-edge scientific research for decades. Due to their merits of being selective, stable, simple, and having a low preparation cost, molecularly imprinted polymers (MIPs) are increasingly becoming artificial substitutes for natural receptors in the design of state-of-the-art sensing devices. While there are different MIP preparation approaches, electrochemical synthesis presents a unique and outstanding method for chemical sensing applications, allowing the direct formation of the polymer on the transducer as well as simplicity in tuning the film properties, thus accelerating the trend in the design of commercial MIP-based sensors. This review evaluates recent achievements in the applications of electrosynthesized MIP sensors for clinical analysis of disease biomarkers, identifying major trends and highlighting interesting perspectives on the realization of commercial MIP-endowed testing devices for rapid determination of prevailing diseases

Recombination behaviour at the ultrathin polypyrrole film silicon interface investigated by in situ pulsed photoluminescence

We investigated the change in Si surface recombination behaviour during the electrodeposition of ultrathin polypyrrole PPy films onto Si surfaces by means of in situ pulsed photoluminescence PL spectroscopy. The quenching of the band gap related PL is lower better passivation when the electrodeposition is performed in a less acidic solution by use of potential pulse sequences. In situ infrared spectroscopic ellipsometry IR SE was applied for the first time to PPy electrodeposition. IR SE and PL measurements confirm negligible formation of SiOx species at the Si PPy interface although aqueous electrolytes were use

Ultrathin polypyrrole films on silicon substrates

The electrochemical deposition of polypyrrole PPy on p Si 100 electrodes was investigated. The electrodeposition was performed in aqueous electrolyte solutions utilising cyclic voltammetry. Thin, adhesive, uniform PPy films were successfully deposited on p Si 100 electrodes. The Si PPy interface was characterised with infrared spectroscopic ellipsometry IR SE and photoluminescence PL measurements to obtain information of a possible oxidation of the Si interface and charge carrier recombination at the interface, respectively. Very small amounts of interfacial silicon oxides have been found at the Si PPy interface. PL measurements lead to the assumption that electrodeposition of PPy onto the Si electrodes generated only very few additional non radiative recombination active nr defects. Hence, polypyrrole is an excellent passivation of nr defects at the silicon surfac