We present a method for the read-out of five serially arranged SOI ring resonator-based biosensors at a speed of 3 Hz/sensor and at a fixed wavelength of 1550 nm. The system uses the high thermo-optical coefficient of silicon by applying AC voltages to periodically heat up electrodes adjacent to each sensor. A time-division multiplex scheme allows the allocation of the measured optical output from the mutual spectrum to each specific resonator. We demonstrate our system by immobilizing two different antibodies (biotin and a hexa-His-peptide) at the surface of selected resonators and successfully showing the selective binding characteristics of analyte-probing in a microfluidics supported experiments.

Although showing impressive therapeutic potential, treatments of leukemias with T-cells expressing chimeric antigen receptors (CARs) is limited by their risk of several severe side effects [1,2]. To overcome these problem, a switchable CAR platform has been developed termed UniCAR [2-4]. Unlike conventional CAR which directed against tumor-associated antigens, UniCAR treatment involve an intermediate target module (TM) which can cross-link UniCAR T cells with tumor cells and lead to destruction [4]. The development of these novel TMs against different tumor targets require numerous repetitive tests on different synthesizing trials which is usually limited in quantity and time-consuming. Meanwhile, nano-biosensors are lately known as analytical tools which are highly sensitive, label-free, rapid and reagent-saving [5]. Among them, silicon nanowire (SiNW) sensor is extensively investigated by researchers over the past decades thanks to its compability with CMOS technology enabling mass production [6,7]. In this work, we demonstrated the application of previously published SiNW biosensor [8] on detection of the binding of UniCAR and a part of different TMs. The results underline advantage of SiNW sensor over ELISA method in term of ease of preparation, speed and sensitivity. The method is able to evaluate binding affinity of UniCAR to different TMs and open a potential to quantify the number of active UniCAR T-cells in in-vivo-sample in later stage. In the end, the application of nanosensor may speed up the R&D process of UniCAR concept and later play an important role in clinical monitoring of immunotherapy, especially, in the era of precision medicine.

Impedance cytometry represents a technique that allows the electronic characterization of colloids and living cells in a highly miniaturized way. In contrast with impedance spectroscopy, the measurements are performed at a fixed frequency, providing real-time monitoring of the species traveling over the sensor. By measuring the electrical properties of particles in suspension, the dielectric characteristics (electric conductivity and capacitance) of both cells and particles can be readily determined. During the last years, this technique has been broadly investigated; however, it is still not trivial to differentiate particles of similar size based on their dielectric characteristics. A way to increase the discrimination abilities of this technique could be the integration of nanostructures into the impedance platforms. In this work, we present the impedance cytometry study of particles using microfluidic channels aligned over interdigitated gold nanowire structures as our impedimetric sensor. The characterization of particles of different sizes and their comparison with particles of different compositions will provide an understanding of the correlation between the electrical signal and the own characteristics of each particle. This approach is an attractive element for label-free detection platforms that can be integrated into lab-on-a-chip systems, and that can be further implemented for single-cell analysis.

A development of sensors for selective detection of large (or particled) analytes, such as natural and engineered nano- and microparticles is a new challenge of analytical chemistry. Their detection is complicated by very high sensitivity requirements (in most cases in fM - aM particle concentration range), slow diffusion and non-equilibrial detection conditions, intensive adsorption to most surfaces and trend to aggregate. Recently an application of wide field surface plasmon resonance microscopy combined with computer assisted image analysis (WF-SPRM) for detection of large analytes was reported. This new technology provides a real-time detection of interaction of single nanoparticles with sensor surface. A number of the nanoparticle–surface binding events per time characterize volume concentration. A large monitored surface area of the sensor surface allows one to detect hundreds of events in each frame or totally up to a million particles on the sensor surface; this leads to very high dynamic range in the concentration scale. Linear dependence between image intensity and particle size allows one to get histograms of particle size distribution. To determine chemical composition of single nanoparticles separately, the WF-SPRM was used in combination with electrochemistry: electrochemical conversions lead to the change in the particle refractive index while the value of the applied potential of this conversion characterizes material of the particular nanoparticle. Another application field of WF-SPRM comprises surface processes leading to the formation of new nanoparticles, e.g., electrochemical nucleation. Fundamental limitations in the development of analytical techniques for large analytes will be also discussed.

1,3-dimercaptopropan-2-ol, a symmetrical di-thiol, has been synthesized and applied as a new type of anchor molecule to prepare a self-assembled monolayer (SAM) on the gold surface. The formed monolayers were studied by cyclic voltammetry, impedance spectroscopy, X-ray photoelectron spectroscopy, kinetic capacitance, and contact angle measurements. The SAM structure depends on the adsorption conditions. A short incubation time of the electrode at high concentration of this di-thiol leads to the predominating binding through one thiol group of the adsorbate to the gold surface, while a long incubation at low concentration leads to the predominating binding by both thiol groups. A comparative study of the desorption and replacement of SAMs indicates a strong stability increase when the SAM molecules bond gold surface by two bonds mainly. This monolayer was used to immobilize electrochemically active p-benzoquinone moiety. The surface concentration of p-benzoquinone obtained from cyclic voltammetry is 2.5 ± 0.2 × 10⁻¹⁰ mol cm⁻² which corresponds to the functionalization of 65 ± 5% of SAM molecules. The obtained highly stable SAM with redox-active terminal group can be applied for different tasks of chemical sensing and biosensing. As an example, an application of this system for electrocatalytical oxidation of dihydronicotinamide adenosine dinucleotide (NADH) was tested.

This work describes a multisensing wearable platform for monitoring biomarkers in sweat during the practice of exercise. Five electrochemical sensors for pH, potassium, sodium, chloride, and lactate are implemented in a flexible patch approach together with a paper microfluidic component to continuously measured sweat composition. The sensors are fabricated with silicon technologies: Ion Selective field effect transistors (ISFETs) for pH and ionic species and a gold thin-film microelectrode for lactate. The latter includes a polymeric membrane based on an electropolymerized polypyrroled structure where all the biocomponents required for carrying out the lactate analyses are entrapped. The flexible patch is fabricated using hybrid integration technologies that includes printed pads defined on a polyimide (Kapton^®) substrate and wire bonding encapsulation of silicon chips. To fix and align the sensors to the flexible substrate, different laminated materials like polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS) and silicone-based adhesive are used. First results show the good performance of the sensors – ISFETS sensitivity between 54–59 mV dec^-1 for ion ranges in sweat (from 2 to 100 mM) and lactate sensor’ sensitivity of (−135 × 102 µA M⁻¹ cm^-2 for the range of 2–50 mM). The microfluidic platform has been tested in terms of adequate sensor wettability and rapid response during the time span of exercise activity (2h) showing excellent results.

Respiratory tract infections have the highest rates of antibiotic prescriptions where symptoms like fever, cough and rigors are regularly misinterpreted and bacterial infections cannot be distinguished from viral ones. Nevertheless, it has been recently suggested that C-reactive protein (CRP), a protein produced by the liver in response to infection, could serve as a potential biomarker for the precise differentiation of these two types of infections. Thus, its quick and accurate detection would potentially reduce the unnecessary antibiotic use. To this end, we present an easy and sensitive approach for the selective detection of C-reactive protein (CRP) by liquid-gated carbon nanotube field effect transistors (LG-CNTFET). Herein, CNT-networks were deposited between electrodes via controlled dielectrophoretic deposition and then functionalized with a novel specific antibody and a polyethylene glycol (PEG) layer in order to overcome the Debye screening. Successful fabrication and functionalization was confirmed by scanning electron microscopy and chemiluminescence immunoassays. The results showed a selective and reproducible detection down to picomolar concentrations in PBS buffer without complicated microfluidics. The simplicity and high sensitivity of this sensor platform make it a promising tool for the quick and precise differential diagnosis of viral and bacterial infections.

We investigated prototype of the strain sensor based on the layers of the bionanomaterial contained bovine serum albumin (BSA - matrix), and multi-walled carbon nanotubes (MWCNT - filler). The aqueous dispersion of 25 wt.% BSA/0.3 wt.% MWCNT was applied by screen printing on flexible polyethylene terephthalate substrates. After drying layers by the laser irradiation (~ 970 nm) various parameters of layers were controlled, i.e., resistance R, bending angle q, number of cycles n, measurement time, etc. One measurement cycle corresponded to a change within the range q = ≈ ±150°. The layers of BSA/MWCNT bionanomaterial were de mentions: (15 ÷ 20) mm × (8 ÷ 10) mm × (0.5 ÷1. 5) µm. The dependences of resistance R on the bending angle q were similar for all layers: at q = ± 30, the R(q) curves represented approximately linear dependences (with an error of ≤ 10%); beyond this range, the dependences became nonlinear. The following quantitative values were obtained for the investigated strain sensor: specific conductivity ~ 1 ÷ 10 S/m, linear strain sensitivity ~ 160, bending sensitivity 1.0 ÷ 1.5%/°. These results are high. The examined layers of the bionanomaterial BSA/MWCNT as a strain sensor is of a particular interest for medical practice. In particular strain sensors can be implemented by applying a water dispersion of nanomaterials to human skin using a 3-D printer for monitoring: movements (arms, blinking) and detection of signs of pathology (dysphagia, respiratory diseases, angina, et. al.).

In Visible Light Communication (VLC) Systems, data are transmitted by modulating light from an illumination source, that could be an ordinary lamp or light-emitting diodes (LEDs). Photovoltaic cells based on massive heterojunctions of semiconductor polymers have focused the attention of researchers due to several potential advantages over their inorganic counterparts, such as simplicity, low cost and the ability to process large area devices even on flexible substrates. In this paper, we use commercial LEDs in transmission and organic photodetectors (OPD) based on poly(3-hexylthiophene) (P3HT) and a phenyl-C61-butyric acid methyl ester (PCBM) blend used as active layer in reception. We have fabricated and characterized the I-V curve and the Bit Error Rate (BER) response of the OPD using low cost processing techniques and we have used an Atmel 8‐bit microcontroller in order to control the electronics to transmit and modulate the signal. Finally, in this work, we have developed and characterized organic photodetectors in a low cost visible light communications system capable of transmitting an image file in real-time, as a proof of concept that is cost effective, since the whole system was implemented using low cost components.

This work attempts the identification of the production year, the cultivar’s region and the aging method used in the elaboration of different Spanish red wines, all from the “tempranillo” grape variety. The identification of such characteristics relies on the use of a voltammetric Electronic Tongue (ET) system formed by modified graphite‐epoxy electrodes (GEC) and metallic electrodes to collect a set of six voltammograms per sample, and different chemometric tools to accomplish the final identifications.A large sample set, that included 199 different wine samples from commercial and own elaboration origin were analysed with the electronic tongue system, using the cyclic voltammetry technique and without any sample pre-treatment. To process the extremely complex, and high dimensionality generated data, a compression strategy was used for the acquired voltammograms, using the Discrete Wavelet Transform (DWT). This treatment reduced the information to ca. 10%, preserving significant features from the voltammetric signals. Compressed data was evaluated firstly by unsupervised methods, i.e., Principal Component Analysis (PCA), without much success as it was found that such methods were unable to unravel the patterns contained within such complex data samples. Finally, the processed electrochemical information was evaluated by supervised methods to accomplish the proper identification, among those methods were Linear Discriminant Analysis (LDA), Supported Vector Machines (SVM) or Artificial Neural Networks (ANN). The best results were obtained using Artificial Neural Networks (ANNs) achieving 96.1% of correct classification for bottled year, 86.8% for elaboration region (protected designation of origin) and 98.6% for maturation type with or without use of wood barrel.