BioChip Journal最新文献

Fv-antibodies against the nucleocapsid protein (NP) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were screened from an Fv-antibody library, and a one-step immunoassay was performed to detect SARS-CoV-2 using real viral samples. The Fv-antibody library was prepared using site-directed mutagenesis of the CDR3 region, which was composed of 11 amino acids. To screen the target Escherichia coli from the Fv-antibody library, the expressed probes [N-terminal domain (NTD) labeled with GFP and C-terminal domain (CTD) labeled with GFP] were reacted separately with the Fv-antibody library. After oligonucleotide sequencing, two clones for each probe were selected as the final clones. The screened Fv-antibodies with the binding affinity to NTD (or CTD) were expressed as soluble proteins, and the affinity constant (K_D) was calculated to be 25.4 nM for NTD and 26.9 nM for CTD. The expressed Fv-antibodies were used for the one-step immunoassay based on switching-peptides, which were bound to the expressed Fv-antibodies. The one-step immunoassay based on Fv-antibodies could be used for the linear detection of SARS-CoV-2 NP, and the limit of detection (LOD) was estimated to be 9.6 nM (438 ng/mL) for Anti-NTD and 14.1 nM (639 ng/mL) for Anti-CTD. For the demonstration of one-step immunoassay for SARS-CoV-2, NATtrol™ SARS-CoV-2 real sample was used, and the LOD was estimated to be 29.7 copies/mL (Ct = 39.5) using Anti-NTD and 117.8 copies/mL (Ct = 38.0) using Anti-CTD. The measured LOD for the detection of SARS-CoV-2 using a one-step immunoassay based on the switching-peptide was considered feasible for the medical diagnosis of COVID-19. Finally, the interaction between the screened Fv-antibodies and SARS-CoV-2 NP was investigated using docking simulation.

Abstract

Microbioreactors have been widely utilized as an alternative to conventional benchtop reactors, since the miniaturized platforms offer advantages including reduced sample volume and homogeneous microenvironments. Here, we proposed an acoustofluidic microbioreactor based on surface acoustic wave (SAW)-induced acoustic streaming flow (ASF). The SAW-induced ASF, which originates from the wave attenuation in a fluid, allows rapid mixing and heat transfer for enhanced mass and heat transfer within the sample fluid. We conducted thorough numerical and experimental investigations on the acousto-hydrodynamics and heat transfer phenomena to find an optimal frequency in the prescribed cylindrical microwell. We found that the homogenous chemical concentration and temperature distributions within the fluid were rapidly achieved by the SAW-induced ASF in the proposed device. For proof-of-concept demonstration of practical applicability, we cultured Escherichia coli as a model cell using the proposed acoustofluidic microbioreactor. From comparative evaluation with conventional platforms including a shaker incubator and a microplate shaker, we confirmed that the bacteria growth rate was enhanced in the proposed acoustofluidic microbioreactor due to the high homogeneity in the chemical concentration and temperature by the acoustic agitation, without any moving mechanical components. We expect that the proposed ASF-based microbioreactor can be broadly utilized for various biological applications that require homogeneous mixing and temperature gradient within a reaction medium.

Humidity sensors are used in various applications to provide suitable environmental conditions. High-performance humidity sensors require highly sensitive active sites to detect water molecules. In this study, a nanopillar-array-based electrode (NAE) was developed, which has a large specific surface area and is applicable to various humidity-sensing materials. The NAE, which was fabricated via photo-lithography and soft lithography, exhibited superior electrochemical capacitance and diffusion behavior compared to flat electrodes. The NAE-based humidity sensor exhibited a high sensitivity and linearity, low hysteresis error, and long-term stability for a duration of 25 days. Moreover, the humidity sensor maintained a consistent impedance signal in a mechanically bent state. Furthermore, the real-time monitoring performance of the humidity sensor was demonstrated by measuring humidity changes during plant transpiration.

This study presents a novel method for detecting plant viruses by combining a personal glucose meter (PGM)-based cascade enzymatic reaction (CER) with loop-mediated isothermal amplification (LAMP). This technique exploits the consumption of deoxynucleotides (dNTPs) during the LAMP process as a substrate for CER, leading to a measurable change in glucose concentration. This change can be detected using PGM, enabling the identification of the presence or absence of the target virus. This method provide a more efficient alternative to traditional methods like ELISA and PCR. It overcomes their limitation in terms of laboratory equipment requirement, sensitivity, and on-site applicability. In addition, we also developed a portable diagnostic device that integrates a heating block with a glucose measurement module. By utilizing this device, the rapid and precise detection of various plant viruses, including horseradish latent virus (HRLV), onion yellow dwarf virus (OYDV), soybean yellow common mosaic virus (SYCMV), cnidium vein yellowing virus 1 (CnVYV-1), and perilla mosaic virus (PerMV), successfully achieved within 40 min. This advancement offers a practical and cost-effective solution for managing plant pathogen threats in agriculture.

Thermal gradients have emerged as a promising technique for manipulating and sorting biological material at the microscale, holding considerable potential in lab-on-a-chip technology. Herein, we propose a non-invasive thermohydrodynamic approach for fast cell manipulation using a microfluidic open-to-air device. Cell discrimination is achieved by simply changing the temperature gradient toward the control of the convective effect on their displacement. First, the size and morphology/roughness-based motion capabilities were modeled using polystyrene (PS) microparticles with different sizes (5 and 20 μm) and polycaprolactone (PCL) microspheres, respectively. Computational fluid dynamics simulations of the generated flow were also carried out to demonstrate the influence of both the thermohydrodynamic and Marangoni effects in the PS particle displacement, where the thermally induced convective effect was not enough to move the microparticles inside the channel, but the combination of thermally induced convection together with the Marangoni effect. Indeed, small particles (5 μm) followed a full convective path, whereas the bigger ones (20 μm) exhibited a rolling motion on the substrate from the cold side to the hot side. Also, the relationship between in-flow speed and PCL (≈ 20 μm) surface roughness confirmed the driving force of this convection-based approach. Then, the microfluidic device was successfully used to separate Henrietta Lacks cancer cells (HeLa) from red blood (RBCs) and fibroblast (HFF-1) cells. To this end, thermal gradients were tailored to achieve the desired thermohydrodynamic effect, showing a highly versatile performance. Both cell models (HeLa-RBCs and HeLa-HFF-1), due to rationale tweaking of the imposed temperature gradients (ΔT = 10 K, 303–293 K, and ΔT = 5 K, 303–298 K), were efficiently separated in less than 5 and 60 s, respectively; with excellent cell viabilities. The proposed microfluidic approach holds considerable promise for thermohydrodynamic sorting and manipulation of biological material by non-invasive methods using portable instrumentation. The potential parallelization of the thermal-convective approach opens new avenues for early disease diagnosis (liquid biopsies) or the study of biological systems, even at physiological temperatures with a potential impact in cell (organ)-on-a-chip technologies.

DNA has emerged as an attractive medium for storing large amounts of data due to its high information density, long-term stability, and low energy consumption. However, in contrast to commercially available storage media, DNA-based data storage currently falls behind in terms of writing and reading speeds, waste as well as cost. To harness the full potential of DNA as a data storage medium, it is imperative to advance high-throughput DNA synthesis without compromising cost and pollution. Industry-standard phosphoramidite DNA synthesis has reached its limitation because of its short nucleotide length (< 200), overconsumption of organic solvents leading to the production of toxic wastes, and slow writing speed. Enzymatic DNA synthesis shows promise as a replacement with long nucleotides, an environmentally friendly process, and fast writing speed. In this review, we overview enzymatic DNA synthesis methods, evaluate current methods that utilize high-throughput and parallel synthesis, and conclude with comments on how enzymatic DNA synthesis can be the answer to DNA data storage.

Veterinary drug residues in food have emerged as an urgent threat to consumer safety. Herein, we present the first square wave voltammetric method for the trace-level detection of cinnarizine residues, a recently used antischistosomal drug, in bovine food samples. The method depends on the electrochemical oxidation after modification of the carbon paste sensor with recycled Al₂O₃-NPs functionalized multi-walled carbon nanoparticles. The produced sensor (Al₂O₃-NPs/ MWCNTs/CPE) was characterized using the transmission electron microscope, scanning electron microscope, Fourier-transform infrared spectroscopy, energy-dispersive spectrometer, and X-ray diffractometer that confirm the successful incorporation of the Al₂O₃-NPs/MWCNTs composite into the modified electrode. As expected, the active surface area and electron transfer processes were accelerated by the modification, which was evidenced by cyclic voltammetry, chronoamperometric studies, scan rate studies, and electrochemical impedance spectroscopy. Compared to previous techniques, this facile sensor demonstrated enhancements across critical analytical criteria including the detection limit of 0.17 nM, linear response across 5–100 nM (r² = 0.998), accuracy ranging from 96.5 to 103.2%, precision below 0.81% relative standard deviation, reproducibility within 0.36% range, 20 s response time and applicability in spiked food matrices. In addition, five different greenness and whiteness tools quantified exceptional environmental friendliness, economic feasibility and waste reduction of 63%–93%, reaffirming alignment with sustainability paradigms. These advantages support practical adoption in quality control especially laboratories lacking expensive instrumentation. Overall, the ingenious sensor reconciles nanotechnology innovation with the circular economy ethos to tackle an urgent food safety challenge, guided holistically by sustainability metrics.

Lateral flow immunoassay (LFIA) has become a popular method for the rapid detection of biological molecules, with an emerging need for multiplex detection capabilities. A novel LFIA device capable of simultaneously detecting three different antigens on a single test line was developed, with each antigen identifiable by a unique color. Gold nanoparticles (AuNPs; red), gold nanorods (AuNRs; blue), and silver nanoparticles (AgNPs; yellow) were engineered to flow concurrently within the LFIA device and specifically react with α-fetoprotein (AFP), neuron-specific enolase (NSE), and carcinoembryonic antigen (CEA) on the test line. The device was effective for both individual and simultaneous detection of the analytes, with a limit of detection (LOD) of 50 ng/mL. Given its rapid response, ease of use, and affordability, this multiplex detection LFIA device shows great potential for a wide range of applications, including food quality management, livestock diagnosis, and health and environmental monitoring.

Abstract

The contagious respiratory illness coronavirus disease 2019 (COVID-19) has had an unprecedented impact on both global health and society, causing a global pandemic due to its rapid transmission. The emergence of numerous variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) underscores the critical importance of accurately diagnosing variants of concern (VOCs). Viruses have demonstrated a remarkable ability to evolve and adapt to their environments. Therefore, it is crucial to develop effective diagnostic methods that provide rapid, high sensitivity, and selectivity in a point-of-care (PoC) format, meeting the vital need for detecting and addressing emerging new viruses in the future. With the development of nanotechnology and biotechnology, there have been innovations in rapid, multiplexed, and portable sensors with high sensitivity and specificity. In this review, we discuss the fundamental properties of the SARS-CoV-2 virus, conventional diagnostic methods, and recent developments from the perspective of electrochemical- and nanophotonic-based SARS-CoV-2 biosensors, including our recent work.

Flow at various scales, such as perfusion flow and interstitial flow, is a critical component of the physiology of living systems. Microphysiological system (MPS), which is designed to mimic human physiology, needs to recapitulate various physiological flows to accurately reflect in vivo conditions. Most MPSs that simulate flows utilize a pump and tubing (pumped-based-flow MPS). However, these components have limitations that prevent them from recapitulating sophisticated physiological phenomena. Alternatively, passive-flow MPS can be used to recapitulate physiological flow on various scales without using pumps or tubing. This review presents recent developments in passive-flow-based MPS using various engineering approaches. To this end, engineering approaches that enable a passive-flow-based MPS to operate are summarized. Subsequently, representative examples of passive-flow-based MPS are reviewed under the criterion of whether they can recapitulate single-organ (tissue) or multi-organ (tissue) systems. It is our belief that passive-flow-based MPS will be widely used in a wide range of fields, such as human physiology research, analysis of pharmacokinetics and pharmacodynamics (PK/PD), and even space medicine research.