Modeling and development of screen-printed impedance biosensor for cytotoxicity studies of lung carcinoma cells

Low-cost and cleanroom-free prototyping of microfluidic and electrochemical biosensors: Techniques in fabrication and bioconjugation

Integrated microfluidic biosensors enable powerful microscale analyses in biology, physics, and chemistry. However, conventional methods for fabrication of biosensors are dependent on cleanroom-based approaches requiring facilities that are expensive and are limited in access. This is especially prohibitive toward researchers in low- and middle-income countries. In this topical review, we introduce a selection of state-of-the-art, low-cost prototyping approaches of microfluidics devices and miniature sensor electronics for the fabrication of sensor devices, with focus on electrochemical biosensors. Approaches explored include xurography, cleanroom-free soft lithography, paper analytical devices, screen-printing, inkjet printing, and direct ink writing. Also reviewed are selected surface modification strategies for bio-conjugates, as well as examples of applications of low-cost microfabrication in biosensors. We also highlight several factors for consideration when selecting microfabrication methods appropriate for a project. Finally, we share our outlook on the impact of these low-cost prototyping strategies on research and development. Our goal for this review is to provide a starting point for researchers seeking to explore microfluidics and biosensors with lower entry barriers and smaller starting investment, especially ones from low resource settings.

In situ continuously monitoring of cancer cell invasion process based on impedance sensing

Activation of invasion and metastasis is recognized as one of the hallmarks of cancer. There are 90% of cancer-related deaths due to metastasis and given that it is worthy of note to study cancer progression and metastasis. Owing to restricted tools used to underpin the study of tumor invasion process, an on-site platform was developed to monitor this event in vitro. We used interdigital gold electrodes to monitor the dynamic process of cancer cells invading into extracellular matrix in situ continuously. Influences of collagen concentration and number of cancer cells on the measured impedance was exhibited. In addition, the parameters used to demonstrate the experiment results were optimized. The change of impedance magnitude indicated the cell-matrix interaction during invasion process. The potential further use of this platform would be complementary in cell studies when concerning metastasis.

The Measurement and Analysis of Impedance Response of HeLa Cells to Distinct Chemotherapy Drugs

Electric cell–substrate impedance sensing exhibits a real-time and label-free feature to monitor the response of cells stimulated by various biochemical and mechanical signals. Alterations in the currents passing through the cell–electrode system characterize the impedance variations of cells. The impedance responses of HeLa cells under distinct chemotherapy drugs combine the effects of cell proliferation and cell–substrate adhesion. Optimal interdigitated electrodes were selected to explore the impedance responses of HeLa cells. Measurements of impedance of cells in response to three widely used chemotherapy drugs in clinical practice, namely cisplatin, doxorubicin, 5-fluorouracil, were performed. The results demonstrated that distinct impedance responses of HeLa cells to drugs were exhibited and a decrease in measured impedance was observed after drug treatment, accompanied by alterations in the distribution and intensity of the adhesion-related protein vinculin and the rate of cell proliferation. The link between the impedance profiles of HeLa cells and their biological functions was developed based on the circuit model. This study demonstrated the weights of cell proliferation and adhesion of HeLa cells under the treatments of DDP, DOX, and 5-FU, resulted in distinct impedance responses of cells, providing an impedance-based evaluation methodology for cervical cancer treatment.

Design a prototype for automated patient diagnosis in wireless sensor networks

It is indeed necessary to design of an elderly support mobile healthcare and monitoring system on wireless sensor network (WSN) for dynamic monitoring. It comes from the need for maintenance of healthcare among patients and elderly people that leads to the demand on change in traditional monitoring approaches among chronic disease patients and alert on acute events. In this paper, we propose a new automated patient diagnosis called automated patient diagnosis (AUPA) using ATmega microcontrollers over environmental sensors. AUPA monitors and aggregates data from patients through network connected over web server and mobile network. The scheme supports variable data management and route establishment. Data transfer is established using adaptive route discovery and management approaches. AUPA supports minimizing packet loss and delay, handling erroneous data, and providing optimized decision-making for healthcare support. The performance of AUPA's QoS approach is tested using a set of health-related sensors which gather the patient's data over variable period of time and send from a source to destination AUPA node. Experimental results show that AUPA outperforms the existing schemes, namely SPIN and LEACH, with minimal signal loss rate and a better neighborhood node selection and link selection. It diminishes the jitter compared to the related algorithms. Graphical abstract Stack architecture of AUPA.