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The progress of additive manufacturing (AM), known as 3D‐printing, has initiated a revolution in the new generation of biosensors and bioanalytical devices in recent years. The advancement in the resolution of AM has enabled the microfabrication of the architectures of electrodes and sensing layers for high‐performance sensing. Diversiform printable materials, including biocompatible materials, polymers, various gels and metals, have enormously broadened the horizon in sensors and analytical devices for both research and commercial purposes. The considerable shortening of time and cost in sensor prototyping and fabrication has been reported and various highly customizable biosensing platforms and devices are under development. Herein, the most recent studies on the applications of AM in biosensors and bioanalytical devices are summarized with the aim to provide a panorama of emerging 3D‐printing strategies for sensor design and bioanalytical device fabrication. [ABSTRACT FROM AUTHOR]

It has been challenging to measure responses of unlabeled, live whole cells. In this work, we designed a graphene-based optical biosensor with a detection depth of greater than 2 mm, a high sensitivity of 1.2 × 10 8  mV/RIU, and a fast response time of 260 ns. This novel biosensor enables fast and highly accurate label-free detection of drug responses in live cells at the cell height level, and can even sense cancer cell responses to anti-cancer drugs. Unexpected early responses to paclitaxel were observed in cancer cells using this biosensor. Two colorectal cancer cell lines, HCT116 and LoVo, were used for measurement. By combining the results from conventional biological assays, including MTT, western blot and immunofluorescence assays, these novel responses were examined in detail. This facile biosensor shows promise to be widely used as a sensor of unlabeled live cell responses for cancer therapy, anti-cancer drug screening and other cell-based research. [ABSTRACT FROM AUTHOR]

MicroRNA 21 (MIR21) has garnered much attention in recent years as an important disease biomarker. The detection of it in human system shows great significance for the healthy evaluation and major diseases early detection. Herein, a novel approach tactfully manipulates the in-situ precise preparation of copper nanoclusters on overlapping Y-shaped ds-DNA for MIR21 analysis were developed in the proposed integrated aptasensor. In the presence of target MIR21, overlapping Y-shaped ds-DNA was constructed on electrode. Copper nanoclusters were in-situ prepared on this effective template for target detection. Taking advantage of exonuclease T7 triggered targets recycling, hybridization chain reaction (HCR) and copper nanoclusters triple amplification strategy, linear detection of MIR21 was achieved from 10 pM to 0.1 fM with a detection limit down to 10 aM (S/N > 3). This approach provides a good model for integrating both synthesis and detection into one electrochemistry component. It showed promising potential for applications in aptamer related target detection in human serum analysis. [ABSTRACT FROM AUTHOR]

The real-time and label free detection abilities of surface plasmon resonance (SPR) biosensors provide a way of evaluating the influence of some genes’ expression on anti-tumor drug cytotoxicity. However, studies in this field are lacking. Connexin 43 is a tumor suppressor gene and the mechanism of its effect in cisplatin cytotoxicity is still unclear. A phase SPR biosensor was used to determine the influence of connexin 43 expression on cisplatin cytotoxicity in three cancer cell lines. The results showed that the SPR signal curves have two stages. In the first hour, the SPR signal shows dramatic changes which are related to connexin 43 expression. In the subsequent stage, the SPR signal slowly declines and is related to apoptosis. Comparison of SPR measurements from several conventional biological assays showed that connexin 43 expression can affect cellular response to cisplatin in the period of oxidative stress, and results in the cells being more sensitive to cisplatin. The conclusion is further confirmed by long-term SPR measurement results and cellular morphological changes. [ABSTRACT FROM AUTHOR]

We investigate an application case study of a phase sensitive surface plasmon resonance (SPR) biosensor based on Mach–Zehnder configuration for efficient targeted drug screening, where calculating reaction kinetic constants, inhibition effect and cytotoxicity analysis are three key factors in the evaluation. As a typical targeted drug, cetuximab is selected in the measurements assisted by the phase SPR biosensor with a sensitivity of 10 −6 in terms of refractive index unit (RIU) and stability of 6 × 10 −7 RIU in 80 min. The reaction kinetic constants of cetuximab binding to epidermal growth factor receptor (EGFR) are found as: k d (dissociation constant) = 1.75 ± 0.29 × 10 −3 S −1 , k D (equilibrium dissociation constant) = 4.19 ± 0.58 nM. The results of inhibition effect analysis show that cetuximab can block EGFR binding to its two ligands, epidermal growth factor (EGF) and EGFR-transforming growth factor α (TGF-α). This effect has been tested in three cell lines of lung adenocarcinoma, colon cancer and breast cancer. Comparing to other conventional methods, we find that the phase SPR biosensor can determine the cell sensitivity to cetuximab in just 4 h. As a label-free, real-time, high sensitivity and stability biosensor, the phase SPR biosensor is a potential optical technique for targeted drug screening and analysis of cell resistance to drugs with comparative advantages. [ABSTRACT FROM AUTHOR]

A dynamic optical tweezers system is employed for generation of an optical trap in continuous rotation for manipulating a biological cell in an aqueous solution. When the rotating speed is increased, the trapped cell experiences an augmented viscous drag force, and eventually it escapes from the trap at the critical rotating speed: when the drag force is greater than the trapping force. With experimental verifications, the method can easily be employed to differentiate cells in terms of trapping forces due to different refractive indices. The proposed method is a simple, robust, accurate and noninvasive label-free technique for cell detection. [ABSTRACT FROM AUTHOR]

Abstract Flexible electrochemical sensors for measurement and quantification of biomarkers are attracting a great deal of attention in non-invasive medical applications, due to their high mechanical compatibility and conformability with the human body. Realization of the full potential of such novel systems relies heavily on their effective manufacturing. Particularly, there is a need for manufacturing techniques that can realize complex designs, consisting of multiple functional materials which are required for sensor functionality. Among emerging additive manufacturing techniques, Direct-Ink-Writing (DIW), where polymer nanocomposite inks are dispensed through nozzles and deposited with high spatial control, carries a great potential to address this need. Here, we introduce a 3D printed flexible electrochemical biosensor for glucose detection. We show that our biosensor works linearly in glucose solution with a concentration range between 100 and 1000 μM. The sensitivity of glucose biosensor is estimated to be 17.5 nA μM−1, and the calculated value of the detection limit (S/N = 3) is 6.9 μM. The demonstrated electrochemical performance and surface properties of the printed sensors show the promising advantages of using this technique over the conventional screen printing method. These advantages include higher sensitivity and specificity and, reduced material consumption. Graphical abstract Image 1 Highlights • The first 3D printed flexible electrochemical biosensor for glucose detection. • 17.5 nA μM−1 sensitivity, 6.9 μM detection range (S/N = 3), 100–1000 μM linear range achieved with the printed sensor. • Improved surface morphology, electrochemical performance and material economy compared to screen printing. [ABSTRACT FROM AUTHOR]

In this paper, boron doped diamond (BDD) with different thickness were prepared by hot filament chemical vapor deposition. The performance of BDD electrodes for detecting dopamine (DA) and ascorbic acid (AA) were investigated. Scanning electron microscopy and Raman spectra reveal the grain size increases and the film quality improves with the increase of film thickness. Electrochemical test show that the transfer coefficient in [Fe 3 (CN) 6 ] 3−/4− redox system increases with the increase of the film thickness. The results of selectivity and sensitivity for DA mixed with AA detection show that 8h-BDD and 12h-BDD electrodes possess well selective separated oxidation peaks of DA and AA, and the 12h-BDD electrode exhibits optimal sensitivity until the DA concentration drops to 1 μ M. [ABSTRACT FROM AUTHOR]