Smartphone-Based Electrochemical System for Biosensors and Biodetection

A smartphone-based portable electrochemical sensor enabled ultrasensitive detection of paclitaxel in serum and injection samples

A point-of-care testing platform, consisting of smartphone, miniature electrochemical workstation, and screen-printed carbon electrode (SPCE) modified by gold nanoparticle (AuNPs) and multi-walled carbon nanotubes (MWCNTs), is fabricated for the ultrasensitive detection of paclitaxel (PTX) in human serum and injection solution. To enhance conductivity of the sensing system, MWCNTs concentration and AuNPs electrodeposition time were optimized. The AuNPs/MWCNTs effectively increase the working electrode area of SPCE by a factor of 1.46, contributing to improved electrochemical performance. The steps of electrode surface modification and the characterization of AuNPs/MWCNTs/SPCE were investigated by differential pulse voltammetry, impedance spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy. The sensor shows good linearity between current response and PTX concentration in 0.2 M phosphate buffer at pH = 7.4 (0.05-10 μM, with a limit of detection (LOD) of 1.7 nM) and human serum (0.5-30 μM and a LOD of 3.6 nM). The recoveries range from 89.91 to 103.36% and 91.42 to 103.73% in human serum and injection solution, respectively, with satisfactory relative standard deviation. Moreover, the sensor has excellent stability during 8 weeks and exhibits outstanding specificity and reproducibility towards PTX detection, providing a possible option for PTX determination in practical application such as therapeutic drug monitoring and drug quality control.

A microfluidic ratiometric electrochemical aptasensor for highly sensitive and selective detection of 3,3',4,4'-tetrachlorobiphenyl

This study proposes a strategy using a microfluidic ratiometric electrochemical aptasensor to detect PCB77 with excellent sensitivity and specificity. This sensing platform combines a microfluidic chip, a wireless integrated circuit system for aptamer-based electrochemical detection, and a mobile phone control terminal for parameter configuration, identification, observation, and wireless data transfer. The sensing method utilizes a cDNA (MB-COOH-cDNA-SH) that is labelled with the redox probe Methylene Blue (MB) at the 5' end and has a thiol group at the 3' end. Additionally, it utilizes a single strand PCB aptamer that has been modified with ferrocenes at the 3' end (aptamer-Fc). Through gold-thiol binding, the labelled probe of MB-COOH-cDNA-SH was self-assembled onto the surface of an Au/Nb2CTx/GO modified electrode. On exposure to aptamer-Fc, it will hybridize with MB-COOH-cDNA-SH to form a stable double-stranded structure on the electrode surface. When PCB77 is present, aptamer-Fc binds specifically to the target, enabling the double-stranded DNA to unwind. Such variation caused changes in the differential pulse voltammetry (DPV) peak currents of both MB and Fc. A substantial improvement is observed in the ratio between the two DPV peaks. Under the optimum experimental conditions, this assay has a response that covers the 0.0001 to 1000 ng mL-1 PCB77 concentration range, and the detection limit is 1.56 × 10-5 ng mL-1. The integration of a ratiometric electrochemical aptasensor with designed microfluidic and integrated devices in this work is an innovative and promising approach that offers an efficient platform for on-site applications.

Sample-to-answer sensing technologies for nucleic acid preparation and detection in the field

Efficient sample preparation and accurate disease diagnosis under field conditions are of great importance for the early intervention of diseases in humans, animals, and plants. However, in-field preparation of high-quality nucleic acids from various specimens for downstream analyses, such as amplification and sequencing, is challenging. Thus, developing and adapting sample lysis and nucleic acid extraction protocols suitable for portable formats have drawn significant attention. Similarly, various nucleic acid amplification techniques and detection methods have also been explored. Combining these functions in an integrated platform has resulted in emergent sample-to-answer sensing systems that allow effective disease detection and analyses outside a laboratory. Such devices have a vast potential to improve healthcare in resource-limited settings, low-cost and distributed surveillance of diseases in food and agriculture industries, environmental monitoring, and defense against biological warfare and terrorism. This paper reviews recent advances in portable sample preparation technologies and facile detection methods that have been / or could be adopted into novel sample-to-answer devices. In addition, recent developments and challenges of commercial kits and devices targeting on-site diagnosis of various plant diseases are discussed.

Blockchain-enabled secure and efficient data sharing scheme for trust management in healthcare smartphone network

The Internet of Medical Things (IoMT) is an extended genre of the Internet of Things (IoT) where the Things collaborate to provide remote patient health monitoring, also known as the Internet of Health (IoH). Smartphones and IoMTs are expected to maintain secure and trusted confidential patient record exchange while managing the patient remotely. Healthcare organizations deploy Healthcare Smartphone Networks (HSN) for personal patient data collection and sharing among smartphone users and IoMT nodes. However, attackers gain access to confidential patient data via infected IoMT nodes on the HSN. Additionally, attackers can compromise the entire network via malicious nodes. This article proposes a Hyperledger blockchain-based technique to identify compromised IoMT nodes and safeguard sensitive patient records. Furthermore, the paper presents a Clustered Hierarchical Trust Management System (CHTMS) to block malicious nodes. In addition, the proposal employs Elliptic Curve Cryptography (ECC) to protect sensitive health records and is resilient against Denial-Of-Service (DOS) attacks. Finally, the evaluation results show that integrating blockchains into the HSN system improved detection performance compared to the existing state of the art. Therefore, the simulation results indicate better security and reliability when compared to conventional databases.

Nanomedical approaches in the realm of rheumatoid arthritis

Rheumatoid arthritis (RA) is a heterogeneous autoimmune inflammatory disorder defined by the damage to the bone and cartilage in the synovium, which causes joint impairment and an increase in the mortality rate. It is associated with an incompletely elucidated pathophysiological mechanism. Even though disease-modifying antirheumatic drugs have contributed to recent improvements in the standard of care for RA, only a small fraction of patients is able to attain and maintain clinical remission without the necessity for ongoing immunosuppressive drugs. The evolution of tolerance over time as well as patients' inability to respond to currently available therapy can alter the overall management of RA. A significant increase in the research of RA nano therapies due to the possible improvements they may provide over traditional systemic treatments has been observed. New approaches to getting beyond the drawbacks of existing treatments are presented by advancements in the research of nanotherapeutic techniques, particularly drug delivery nano systems. Via passive or active targeting of systemic delivery, therapeutic drugs can be precisely transported to and concentrated in the affected sites. As a result, nanoscale drug delivery systems improve the solubility and bioavailability of certain drugs and reduce dose escalation. In the present paper, we provide a thorough overview of the possible biomedical applications of various nanostructures in the diagnostic and therapeutic management of RA, derived from the shortcomings of conventional therapies. Moreover, the paper suggests the need for improvement on the basis of research directions and properly designed clinical studies.

Portable Multi-Channel Electrochemical Device with Good Interaction and Wireless Connection for On-Site Testing

It is very important to rapidly test the key indicators of water in the field to fully evaluate the quality of the regional water environment. However, a high-resolution measuring device that can generate small currents for low-concentration analytes in water samples is often bulky, complex to operate, and difficult for data sharing. This work introduces a portable multi-channel electrochemical device with a small volume, good interaction, and data-sharing capabilities called PMCED. The PMCED provides an easy-to-operate graphical interactive interface to conveniently set the parameters for cyclic voltammetry or a differential pulse method performed by the four electrode channels. At the same time, the device, with a current sensitivity of 100 nA V^-1, was applied to the detection of water samples with high background current and achieved a high-resolution measurement at low current levels. The PMCED uses the Narrow Band Internet of Things (NB-IoT) to meet the needs for uploading data to the cloud in remote areas. The electrochemical signal preprocessing and chemometrics models run in the cloud, and the final results are visualized on a web page, providing a remote access channel for on-site testing results.