Biosensors and Bioelectronics: X最新文献

The infection monitoring of chronic wounds can effectively improve the quality of wound care. However, the widely used single variable intermittent monitoring of wound provides little available information, which leads to inaccurate diagnosis and untimely warnings. In this study, a collaborative biofluid analysis based multi-channel integrated wearable detection system was constructed for the continuous detection of analytes such as pH, uric acid (UA), and C-reactive protein (CRP) in wound exudates with time division multiplexing. Based on the functionally modification with nanomaterials, integrated screen-printed electrodes (iSPE) with three working electrodes were designed for the collaboratively analyzing of wound exudates. Through the development of integrated circuits, the multi-channel wearable detection printed circuit board was constructed. With a self-designed interface, this iSPE was stably connected to the printed circuit board and realized the detection of three targets in the range of pH 3–8, UA concentrations 5–500 μmol/L, and CRP concentrations 1–1000 ng/mL at the same time. Combined with a smartphone, these results were collaborated analyzed and transferred for health management. Therefore, this integrated wearable multi-channel detection system can provide reliable and continuous evaluations for early warning of infection and further treatment of chronic wounds.

Plasmonic sensor platforms are designed for rapid, label-free, and real-time detection and they excel as the next generation biosensors. However, current methods such as Surface Plasmon Resonance require expertise and well-equipped laboratory facilities. Simpler methods such as Localized Surface Plasmon Resonance (LSPR) overcome those limitations, though they lack sensitivity. Hence, sensitivity enhancement plays a crucial role in the future of plasmonic sensor platforms. Herein, a refractive index (RI) sensitivity enhancement methodology is reported utilizing growth of gold nanoparticles (GNPs) on solid support and it is backed up with artificial neural network (ANN) analysis. Sensor platform fabrication was initiated with GNP immobilization onto solid support; immobilized GNPs were then used as seeds for chrono-spectral growth, which was carried out using NH₂OH at varied incubation times. The response to RI change of the platform was investigated with varied concentrations of sucrose and ethanol. The detection of bacteria E.coli BL21 was carried out for validation as a model microorganism and results showed that detection was possible at 10² CFU/ml. The data acquired by spectrophotometric measurements were analyzed by ANN and bacteria classification with percentage error rates near 0% was achieved. The proposed LSPR-based, label-free sensor application proved that the developed methodology promises utile sensitivity enhancement potential for similar sensor platforms.

There are limitations to monitoring modalities for chronic inflammatory conditions, including inflammatory bowel disease (IBD). Wearable devices are scalable mobile health technology that present an opportunity to monitor markers that have been linked to worsening, chronic inflammatory conditions and enable remote monitoring. In this research article, we evaluate and demonstrate a proof-of-concept wearable device to longitudinally monitor inflammatory and immune markers linked to IBD disease activity in sweat compared to expression in serum. Sixteen participants with an IBD-related hospital admission and a C-reactive protein (CRP) > 5 μg/mL were followed for up to 5 days. The sweat sensing device also known as IBD AWARE was worn to continuously measure CRP and interleukin-6 (IL-6) in the sweat of participants via electrochemical impedance spectroscopy. Serum samples were collected daily. A linear relationship between serum and sweat readings for CRP and IL-6 was demonstrated based on individual linear correlation coefficients. Pooled CRP and IL-6 serum-to-sweat ratios demonstrated improving correlation coefficients as serum cutoffs decreased. Between the first and last day of observation, significant and non-significant trends in serum CRP and IL-6 were observed in the sweat. Comparison of sweat measurements between the subjects with active IBD and 10 healthy subjects distinguished an inflamed and uninflamed state with an AUC of 0.85 (95% CI: 0.68–1.00) and a sensitivity and specificity of 82% and 70% at a CRP cutoff of 938.9 pg/mL. IBD AWARE wearable device holds promise in longitudinally monitoring individuals with IBD and other inflammatory diseases.

Herein, we report a carbon-stabilized porous silicon (pSi)-based electrochemical biosensing platform for the label- and amplification-free detection of bacterial 16S rRNA gene fragments that facilitates pan-bacterial detection. The sensing approach combines thermally carbonized pSi (THCpSi) structures as novel porous electrochemical transducers, and a highly sensitive sensing mechanism based on partial blockage of the pores caused by hybridization of 16S rRNA gene fragment to the DNA capture probe immobilized within the pores. Pore blockage upon RNA hybridization was quantified via differential pulse voltammetry as a decrease in the oxidation current of the redox pair ([Fe(CN)₆]^3/4−) added to the measuring solution. The use of carbon-stabilized pSi to build the biosensor has additional benefits: it favors high density of the immobilized bioreceptors and a large electroactive surface area, both further enhancing the overall sensitivity of the biosensor. The easily adjustable pSi morphology is key to design diagnostic tools fit-for-purpose. By tailoring the pore diameter, pore blockage upon analyte hybridization can be maximized, thus enhancing sensitivity. By tailoring film thickness, the surface area can be adjusted to optimize the amount of immobilized bioreceptors and the electroactive surface area. An excellent sensing performance was achieved by building the biosensor on THCpSi structures featuring a 27 nm pore diameter and a 1.6 μm film thickness, whose external surface was coated with a thin layer of silicon nitride (Si₃N₄), the latter contributing to maximize the pore blockage. The biosensor achieved a limit of detection of 2.3 pM when tested in 5% fetal bovine serum.

The combination of DNA origami nanostructures and aptamers provides a powerful technology for diagnostic assays. Here, we functionalized a DNA origami nanostructure with a Protein-A binding aptamer to target Staphylococcus aureus bacterial cells. Using an enzyme-linked oligonucleotide assay (ELONA), we semi-quantitatively analyzed and compared the interaction of the aptamer and aptamer-modified DNA origamis with Staphylococcus aureus bacterial isolates. The results showed that aptamer-functionalized DNA nanostructures bind with five times higher affinity (K_D: 34 ± 5 nM) compared to the aptamer alone (K_D: 160 ± 9 nM). Visualising the interaction of bacterial cells and nanostructures with electron cryotomography further confirmed the aptamer-mediated specific interaction of DNA nanostructures with bacterial cells.

Mechanical stresses are an environmental challenge virtually all tissues in the body are exposed to and thus, are of fundamental interest to study cell reactions in mechanobiology. Yet, unlike acute short-term mechanical cell stimulations, long-term or cyclic mechano-stimulation as experienced in the body is difficult to reproduce. Bioreactors are designed to control cell culture conditions, but still, there are yet no technical solutions available to merge bioreactor and opto-biomechatronics technologies for cyclic stretch-applications and simultaneous live cell imaging. To close this gap, we have engineered an opto-biomechatronics module, consisting of our in-house developed IsoStretcher technology and customised epifluorescence optics, into an automated bioreactor platform. For this, redesigned polydimethylsiloxane (PDMS) chambers with closed geometry ($\backsim$700 $\mu$L internal volume) to warrant sterile operation were developed. Those chambers could be flushed with cell solution for cell seeding in a sterile manner. The epifluorescence imaging module was engineered into the reactor underneath the IsoStretcher to allow for continuous image acquisition during long-term stretch cycles (hours to days). The system was validated on human fibroblast BJ foreskin cells, and Cal-520 Ca^2＋ fluorescence was stably imaged using our in-built autofocus functionality. Cultures for 24 h within the IsoStretcher-bioreactor preserved a normal cell morphology as compared to external incubator control cultures. Isotropic stretch was reliably transferred to the cell membranes. Our system with in-built bioreactor and opto-biomechatronics functionality provides a holistic technology platform for the growing field of mechanobiology to allow long-term observations of cultured single cells and confluent cell layers that are subjected to cyclic long-term isotropic stretch protocols.

The spread of infectious diseases poses a global threat to human health and the economy. Conventional laboratory-based pathogen detection analytical techniques are reliable, but are labour and time consuming. Decentralized, rapid pathogen detection and classification devices are essential to boost biosecurity efforts and can aid in the advancement of modern medicine. Here, we describe the development of an integrated digital microfluidic (DMF) electrochemical impedimetric sensor for rapid and on-site detection of lipopolysaccharide (LPS), a molecular signature of Gram-negative bacteria. The sensor was fabricated by immobilizing toll-like receptor protein (TLR4) onto a gold sensing electrode that was fabricated on an indium tin oxide (ITO) DMF top plate. The top plate also housed lithographically patterned ITO pseudo-reference and auxiliary electrodes for a three-electrode electrochemical impedance (EIS) detection system. We exploited the unique feature of DMF to manipulate droplets consisting of samples, buffers, wash solutions and reagents to perform automated EIS measurements due to the interaction of TLR4 with LPS. The integrated sensor platform showed a detection limit of 35 ng/mL LPS and a linear range of up to 400 ng/mL. The small size and ease of operation of the integrated system holds great prospect for the development of portable, and automated generic pathogen detection and classification platform for point-of-need applications.

This article represents an analysis of the performance of multi-layer surface plasmon resonance (SPR) biosensors in detecting the transferable human SARS-CoV-2 Omicron (B.1.1.529) variant. The proposed multi-layer SPR biosensor performance is enhanced by integrating fine-tuning prisms, plasmonic metals, and two-dimensional (2D) transition metal dichalcogenides (TMDs) materials. To evaluate the performance of the multi-layer SPR sensor, the transfer matrix method (TMM) is employed. In numerical result, the proposed (CaF₂/Cu/BP/Graphene) structure demonstrates the most favorable sensitivity and detection accuracy, characterized by a 410° angle shift sensitivity/refractive index unit (RIU). Additionally, the sensor achieves a detection accuracy (DA) of 0.4713, a quality factor (QF) of 94.25 ${RIU}^{-1}$, a figure of merit (FOM) of 91.87, and a combined sensitivity factor (CSF) of 90.36. The presented sensor is also capable of detecting target biomolecule binding interactions between ligands and analytes at a range of concentrations (from 0 nM to 1000 nM), implying its potential use for detecting the omicron virus strain. The outcomes highlight the effectiveness of the presented sensor for real time, and label free detection, particularly in identifying the Omicron viral strain. Eventually, this research promises advanced biosensor technology, crucial for rapid viral variant detection and diagnostics.

The present study describes the creation of a 3D printed cassette named “3DP-PAC”, integrated to an electrochemical-aptasensor for the detection of dengue virus. It consists of an electrode cassette printed from a PLA non-conductive filament that provides a sophisticated design & support system to the delicate conductive paper-electrode. Chemically synthesized GO/ZnO-NC was used, which increases the sensor's sensitivity by accelerating the flow of electrons transferring. DENV DNA-Aptamer specifically binds to its target antigen of DENV, confirming its selectivity and demonstrating no cross reactivity with chikungunya virus antigen (CHIKV–Ag). The current study developed a 3D-based aptasensor for detecting dengue virus at a low level of detection (0.1 μg/ml). In human serum, the established platform performed well. This study paves the way for the manufacture of next-generation electrochemical biosensors utilizing 3D printing technology, with possible consequences for healthcare applications on the edge of commercialization.