Selective Detection of Folic Acid Using 3D Polymeric Structures of 3-Carboxylic Polypyrrole.

The detection of folic acid in biological samples or pharmaceutical products is of great importance due to its implications in the biological functions of the human body, along with the development and growth of the fetus. The deficiency of folic acid can be reversed by the intake of different pharmaceutical formulations or alimentary products fortified with this molecule. The elaboration of sensing platforms represents a continuous work in progress, a task in which the use of conductive polymers modified with different functionalities represents one of the outcoming strategies. The possibility of manipulating their morphology with the use of templates or surfactants represents another advantage. A sensing platform based on carboxylic functionalized polypyrrole was synthesized via the electrochemical approach in the presence of a polymeric surfactant on a graphite-based surface. The sensor was able to detect the folic acid from 2.5 µM to 200 µM with a calculated limited of detection of 0.8 µM. It was employed for the detection of the analyte from commercial human serum and pharmaceutical products with excellent recovery rates. The results were double checked using an optimized spectrophotometric procedure that confirmed furthermore the performances of the sensor related to real samples assessment.

Electrochemical Fingerprint of Arsenic (III) by Using Hybrid Nanocomposite-Based Platforms.

Arsenic, one of the most abundant mineral and also one to the most toxic compounds. Due to its high toxicity sensitive analytical methods are highly important, taking into account that the admitted level is in the range of µg L-1. A novel and easy to use platform for As(III) detection from water samples is proposed, based on gold and platinum bi metallic nanoparticles and a conductive polymer (polyaniline). The electrochemical detection was achieved after optimization of cathodic pre-concentration and stripping parameters by square wave anodic stripping voltammetry at modified screen-printed carbon-based electrochemical cells, proving its applicability for disposable and cost-effective in situ analysis of arsenic.

Ara H1 peanut allergen detection using a labelled electrochemical aptasensor based on GO-COOH@bimetallic composite platform.

Allergies are defined as a hypersensitivity reaction, immunologically mediated, as a result to an external stimulus. Peanuts induced allergies are considered one of the most severe, life-threatening food sensitivities since they trigger the highest frequency of severe and fatal reactions, even in trace amounts. Therefore, it is imperative to develop fast, accurate and easy-to-use analytical methods to determine Ara h1, is a seed storage protein from Arachis hypogea and the main peanut derived allergen. In this work, two strategies were applied to develop an electrochemical aptasensor based on GO-COOH and metallic nanoparticles immobilised on screen-printed carbon electrodes (SPCEs). The analytical performances of the aptasensor showed a linear range of 5-150 nM, and a limit of detection of 1.66 nM. The method was applied in peanut-free food samples with very good recoveries proving to be a promising tool for peanut allergy prevention.

Recent Progress of Electrochemical Aptasensors toward AFB1 Detection (2018-2023).

Food contaminants represent possible threats to humans and animals as severe food safety hazards. Prolonged exposure to contaminated food often leads to chronic diseases such as cancer, kidney or liver failure, immunosuppression, or genotoxicity. Aflatoxins are naturally produced by strains of the fungi species Aspergillus, which is one of the most critical and poisonous food contaminants worldwide. Given the high percentage of contaminated food products, traditional detection methods often prove inadequate. Thus, it becomes imperative to develop fast, accurate, and easy-to-use analytical methods to enable safe food products and good practices policies. Focusing on the recent progress (2018-2023) of electrochemical aptasensors for aflatoxin B1 (AFB1) detection in food and beverage samples, without pretending to be exhaustive, we present an overview of the most important label-free and labeled sensing strategies. Simultaneous and competitive aptamer-based strategies are also discussed. The aptasensors are summarized in tabular format according to the detection mode. Sample treatments performed prior analysis are discussed. Emphasis was placed on the nanomaterials used in the aptasensors' design for aptamer-tailored immobilization and/or signal amplification. The advantages and limitations of AFB1 electrochemical aptasensors for field detection are presented.

Characterization and In Vitro Biocompatibility of Two New Bioglasses for Application in Dental Medicine-A Preliminary Study.

Bioactive glasses (BGs), also known as bioglasses, are very attractive and versatile materials that are increasingly being used in dentistry. For this study, two new bioglasses-one with boron (BG1) and another with boron and vanadium (BG2)-were synthesized, characterized, and tested on human dysplastic keratinocytes. The in vitro biological properties were evaluated through pH and zeta potential measurement, weight loss, Ca2+ ions released after immersion in phosphate-buffered saline (PBS), and scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS) analysis. Furthermore, biocompatibility was evaluated through quantification of lactate dehydrogenase activity, oxidative stress, transcription factors, and DNA lesions. The results indicate that both BGs presented the same behavior in simulated fluids, characterized by high degradation, fast release of calcium and boron in the environment (especially from BG1), and increased pH and zeta potential. Both BGs reacted with the fluid, particularly BG2, with irregular deposits covering the glass surface. In vitro studies demonstrated that normal doses of the BGs were not cytotoxic to DOK, while high doses reduced cell viability. Both BGs induced oxidative stress and cell membrane damage and enhanced NFkB activation, especially BG1. The BGs down-regulated the expression of NFkB and diminished the DNA damage, suggesting the protective effects of the BGs on cell death and efficacy of DNA repair mechanisms.

Aptasensors for lysozyme detection: Recent advances.

Lysozyme is an enzyme existing in multiple organisms where it plays various vital roles. The most important role is its antibacterial activity in the human body; in fact, it is also called "the body's own antibiotic". Despite its proven utility, lysozyme can potentially trigger allergic reactions in sensitive individuals, even in trace amounts. Therefore, lysozyme determination in foods is becoming of paramount importance. Traditional detection methods are expensive, time-consuming and they cannot be applied for fast in-situ quantification. Electrochemical and optical sensors have attracted an increasing attention due to their versatility and ability to reduce the disadvantages of traditional methods. Using an aptamer as the bioreceptor, the sensor selectivity is amplified due to the specific recognition of the analyte. This review is presenting the progresses made in lysozyme determination by means of electrochemical and optical aptasensors in the last five years. A critical overview on the methodologies employed for aptamer immobilization and on the strategies for signal amplification of the assays will be described. Different optical and electrochemical aptasensors will be discussed and compared in terms of analytical performances, versatility and real samples applications.

Design, in vitro bioactivity and in vivo influence on oxidative stress and matrix metalloproteinases of bioglasses in experimental skin wound.

BACKGROUND: The bioactive glasses (BGs) are very attractive materials increasingly used in healing skin lesions due to their antibacterial effect and stimulation of collagen deposition and angiogenesis. In this study, three specimens of bioactive glasses (BG1, BG2 and BG3) have been synthesized and characterized. METHODS: In order to evaluate their in vitro bioactivity, the pH measurements, zeta potential and the concentration of Ca2+ and fluor ions released after immersion in phosphate buffered saline (PBS) followed by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy, inductively coupled plasma optical emission spectrometry (ICP-OES) and for BG1 and BG3, X-ray powder diffraction analysis, were performed. X-ray photoelectron spectroscopy (XPS) was also used for detection of different ions in the solid bioglasses before immersion in PBS. The impact of BG1 and BG3 on skin healing mechanisms was evaluated by oxidative stress and matrix metalloproteases (MMP)-2 and -9 and by histopathological analysis. RESULTS: The results have shown that all the BGs tested are characterized by a very high degradation rate and a very fast Ca2+, fluor and boron releases and displayed changed surface morphology at SEM, after 7 and 14 days of immersion in PBS. In addition, BG1 and BG3 reduced in vivo the lipid peroxidation, increased the nitric oxide, especially at 14 days and improved superoxide dismutase activity, mainly in BG1 treated animals. In parallel, both BG1 and BG3, diminished MMP-9 at 14 days and increased the proportion of normal collagen in the bed of the wound, particularly BG3. CONCLUSION: These results suggested that due to the antioxidant and anti-inflammatory properties of components released from BGs and regulatory properties on MMPs activities, BGs can exert beneficial effects in wound healing.

Electrochemical Non-Enzymatic Detection of Glucose Based on 3D Electroformed Copper on Ni Foam Nanostructures.

Despite the fact that the electrochemical biosensors based on glucose oxidase represent the golden standard for the management of diabetes, the elaboration of nonenzymatic sensors became extensively studied as an out-of-the-box concept that aims to simplify the existing approach. An important point of view is represented by the low price of the sensing device that has positive effects for both end-users and healthcare systems. The enzyme-free sensors based on low-cost materials such as transition metals have similar analytical properties to the commercial ones while eliminating the issues associated with the presence of the enzyme, such as the stability issues and limited shelf-life. The development of nanoporous nanomaterials for biomedical applications and electrocatalysis was referred to as an alternative to the conventional methods due to their enlarged area, electrical properties, ease of functionalization and not least to their low cost. Herein, we report the development of an electrochemical nonenzymatic sensor for glucose based on 3D copper nanostructures with Ni foams as promotor of the enhanced nanoporous morphology. The sensors were successfully tested in the presence of the designated target, even in the presence of common interference agents found in biological samples.

Electrochemical Biosensors as Potential Diagnostic Devices for Autoimmune Diseases.

An important class of biosensors is immunosensors, affinity biosensors that are based on the specific interaction between antibodies and antigens. They are classified in four classes based on the type of employed transducer: electrochemical, optical, microgravimetric, and thermometric and depending on the type of recognition elements, antibodies, aptamers, microRNAs and recently peptides are integrating parts. Those analytical devices are able to detect peptides, antibodies and proteins in various sample matrices, without many steps of sample pretreatment. Their high sensitivity, low cost and the easy integration in point of care devices assuring portability are attracting features that justify the increasing interest in their development. The use of nanomaterials, simultaneous multianalyte detection and integration on platforms to form point-of-care devices are promising tools that can be used in clinical analysis for early diagnosis and therapy monitoring in several pathologies. Taking into account the growing incidence of autoimmune disease and the importance of early diagnosis, electrochemical biosensors could represent a viable alternative to currently used diagnosis methods. Some relevant examples of electrochemical assays for autoimmune disease diagnosis developed in the last several years based on antigens, antibodies and peptides as receptors were gathered and will be discussed further.