Electrochemical Aptasensors for Antibiotics Detection: Recent Achievements and Applications for Monitoring Food Safety

Antibiotics are often used in human and veterinary medicine for the treatment of bacterial diseases. However, extensive use of antibiotics in agriculture can result in the contamination of common food staples such as milk. Consumption of contaminated products can cause serious illness and a rise in antibiotic resistance. Conventional methods of antibiotics detection such are microbiological assays chromatographic and mass spectroscopy methods are sensitive; however, they require qualified personnel, expensive instruments, and sample pretreatment. Biosensor technology can overcome these drawbacks. This review is focused on the recent achievements in the electrochemical biosensors based on nucleic acid aptamers for antibiotic detection. A brief explanation of conventional methods of antibiotic detection is also provided. The methods of the aptamer selection are explained, together with the approach used for the improvement of aptamer affinity by post-SELEX modification and computer modeling. The substantial focus of this review is on the explanation of the principles of the electrochemical detection of antibiotics by aptasensors and on recent achievements in the development of electrochemical aptasensors. The current trends and problems in practical applications of aptasensors are also discussed. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.1/0419/20; Horizon 2020 Framework Programme, H2020; H2020 Marie Skłodowska-Curie Actions, MSCA: 101007299; Kazan Federal University: PRIORITY-2030Acknowledgments: G.E. acknowledges the support from the Kazan Federal University Strategic Academic Leadership Program (‘PRIORITY-2030’).Funding: T.H. acknowledges funding from the Science Grant Agency VEGA, project No.: 1/0419/20. This study was also funded under European Union’s Horizon 2020 research and innovation program through the Marie Skłodowska-Curie Grant Agreement No. 101007299

Labeless Immunosensor Assay for Fluoroquinolone Antibiotics Based Upon an AC Impedance Protocol.

This paper describes the construction of a labeless immunosensor for the antibiotic ciprofloxacin and its interrogation using an AC impedance protocol. Commercial screen-printed carbon electrodes were used as the basis for the sensor. Polyaniline was electrodeposited onto the sensors and then utilized to immobilize a biotinylated antibody for ciprofloxacin using classical avidin- biotin interactions. Electrodes containing the antibodies were exposed to solutions of antigen and interrogated using an AC impedance protocol. The faradaic component of the impedance of the electrodes was found to increase with increasing concentration of antigen. Control samples containing a non-specific IgG antibody were also studied and calibration curves obtained by subtraction of the responses for specific and non-specific antibody-based sensors, thereby eliminating the effects of non-specific adsorption of antigen

Biosensor Fabrication by Direct Laser Microprinting

We report the fabrication of microbiosensors by Laser Induced Forward Transfer. Two kinds of biosensors are discussed: capacitive biosensors and polyaniline amperometric biosensors. Laser fabrication allows for low-cost, maskless patterning with the potential of miniaturization. © 2010 OSA /FiO/LS 2010

Human fall detection using mmWave radars: a cluster-assisted experimental approach

Accurate and timely human fall detection is a strong requirement either for the surveillance of critical infrastructures or for ships. Indeed, sea-faring vessels are one of the most important means for maintaining the marine economy in many countries by transporting goods or people. However, unfortunate tragic accidents on-board ships involving people, either a member of the ship’s crew or a passenger who has fallen off the ship may take place, which is known by the term “man overboard” (MOB). Accordingly, the use of radar sensors for human safety monitoring applications is vital and is of special interest since it is proven that radar sensors are less influenced by environmental conditions (e.g. fog, rain, temperature) compared to other systems like video cameras. Consequently, human fall detection from either sea or ground infrastructures is easier to be identified using radars compared to the conventional methods. This paper focuses in the description of a real experimental approach based on multiple long-range millimeter-wave band radar sensors for human fall detection. The stream(s) of information collected by the system, are processed using clustering techniques. The clustering results are evaluated in terms of the ability to detect and track real human fall scenarios. The results reveal that the measure of velocity plays a key role in the detection procedure

BIOFOS: A micro-ring resonator-based biophotonic system for food analysis - Application to olive oil contaminants

Current detection methods for contaminants in food use high-tech equipment sited in specialized laboratories. This makes online quality control along the food chain difficult. Official regulations limit pesticide and heavy-metal contamination, mainly for organic production, although their analysis is quite expensive, requires skilled personnel and is very difficult to apply to a large number of oil batches. The BIOFOS Project (ICT-FP7-GA.N.611528) aims to develop and validate a Lab-on-a-Chip (LoC) multianalyser, based on micro-biophotonic sensors, for in-situ food contaminant analysis. This device includes biosensors for milk analysis (aflatoxin M1, antibiotic and lactose), nuts (aflatoxin B1), dried fruits (ochratoxin A) and olive oil (organophosphates and metals). BIOFOS combines four high-tech platforms: (1) a photonic platform based on micro-ring resonators (MRR) for signal quantification, (2) a biological platform based on aptamers for analyte detection, (3) a nanochemical platform to immobilize aptamers onto the chip surface and (4) a microfluidic platform for sample pre-treatment and its loading into the biosensor. The project is organized in work packages in order to develop the technological platforms. End-user requirements are also considered, as well as existing fast analysis kits that will be compared against the device. Validation protocols and exploitation plans are also included. BIOFOS applications for olive oil analysis are discussed, in terms of accuracy, sensitivity, time-to-result and cost per sample.</p

BIOFOS: micro-ring resonator-based biophotonic system for food analysis. Nut mycotoxin detection

BIOFOS aims to further develop and validate a reusable and high-added value Lab-on-Chip (LoC) based, micro-biophotonic sensor platform for in situ monitoring of food contaminants. The Lab-on-Chip was tested on milk (aflatoxin M1, antibiotics and lactose), olive oil (pesticides and metals), nuts (aflatoxin B1) and dehydrated fruits (ochratoxin A). BIOFOS combines the most promising concepts from the photonic, biological, nanochemical and fluidic parts of Lab-on-Chip systems, aiming to achieve low sensitivity and high specificity, excellent reliability and compactness. Current methodologies for detection of food contamination based on heavy analytical tools cannot guarantee a safe and stable food supply. The reasons are the complexity, the long time-to-result (2-3 days) and the cost of these tools, which limit the number of samples that can be practically analyzed at food processing and storage sites. Preliminary results for almonds spiked with aflatoxin B1 are presented. First results suggest that BIOFOS has sensitivity enough for AFB1, even that the concentration is at ppb level. More data are still required, and many analyses are ongoing in the laboratory. Results are not enough to conclude about any characteristics of the device performance, even then repeatability seems very good (variation less than 3% at 25 ppb) and recovery is acceptable (78.4%), while decision limit and detection capability are still uncertain.</p