•MWCNT/PDMS flexible electrodes are prepared through a solution-based green method.•A three-electrode analytical module is developed with the MWCNT/PDMS flexible electrodes.•On-site detection of NADH, DA and UA is achieved with the analytical module-equipped cell culture plates and medical drips.•The on-site electrochemical analysis modules can be modularly adjoined into various biological and medical applications.Flexible sensors based on multi-walled carbon nanotubes (MWCNTs) and their composite materials are widely applied to develop strain sensors that generate a signal as a function of the physical or mechanical deformation. However, on-site analysis of the electrochemical active substances with the flexible electrodes during the biological or medical processes remains a great challenge for current electrochemical technologies. Herein, a universal three-electrode module, adaptable of the synchronous electrochemical analysis in practical applications has been developed with the MWCNTs and polydimethylsiloxane (PDMS) flexible film as the working and the counter electrodes and a painted silver-paste line as the pseudo-reference electrode. The MWCNT/PDMS flexible eletrodes capable of being customized into various sizes, shapes and geometries according to the detection environmental requirements, were prepared through a simple molding transfer method and endowed the on-site electrochemical analysis module with a great potential on the curved surface or in the repeatedly bending situation. Finally, in a 24-well plate and a medical drip which were equipped with the developed three-electrode module, the concentrations of dopamine (DA), uric acid (UA) and nicotinamide adenine dinucleotide (NADH) were successfully detected by Differential Pulse Voltammetry (DPV) with robust stability and repeatability. The technique developed in this study offers an accurate and cost-effective on-site electrochemical analysis system that can be modularly adjoined into various biological and medical applications.

•Conducting oil and carbon nanotube was used as medium to transfer heat from IR-LED to PCR samples.•This platform offers accurate and flexible control of temperature through the integration of PID algorithms.•The performance of this portable and inexpensive platform is a match to the conventional bench-top thermo cycler.•Lateral flow stripe was used to detect the PCR products.With the increasing need of monitoring the epidemiology of serious infectious diseases, food hygiene, food additives and pesticide residues, it is urgent to develop portable, easy-to-use, inexpensive and rapid molecular diagnostic tools. Herein, we demonstrate a prototype of IR mediated Conducting Oil and CarbOn Nanotube circUlaTing PCR (IR-COCONUT PCR) platform for nucleic acid amplification. The presented platform offers a new solution for miniaturized PCR instruments with non-contact heaters by using conducting oil and carbon nanotube as a medium in IR mediated PCR. This novel platform offers accurate and flexible control of temperature through the integration of PID (proportional–integral–derivative) algorithms to manipulate the duty cycle of the voltage signals of IR LED and a peristaltic pump. The ramping rate of the introduced platform in current study is 1.5 °C/s for heating speed and −2.0 °C/s for cooling speed. This platform fulfills 30 thermal cycles within 50 min which is a match to the conventional bench-top PCR thermo cyclers. For demonstration purpose, human papillomavirus (HPV) patient cervical swab specimens were examined. Downstream lateral flow strip (LFS) was also developed to quantity the PCR products from the IR-COCONUT PCR device within 25 min. This PCR platform together with the compatible LFS shows great potential for in-field and Point-of-Need (PoN) testing of genetic or contagious diseases.

A low-cost, convenient and precise drug combination screening microfluidic platform is developed, in which cell culture chambers designed with micropillars integrate with three laminar flow diffusion channels. This platform has several distinct features, including minimum shear stress on cells, biocompatibility, optimum concentration distribution and automatic combinatorial gradient generation, which can potentially speed up the discovery of an effective drug combination for cancer ablations. The presented device can generate two-drug combination gradients at the optimum flow rate of 90 μL/h and can be applied to identify the optimal combination of two clinically relevant chemotherapy drugs. For demonstration, paclitaxel at 0.77 × 10−3 mg/mL and cisplatin at 0.23 × 10−4 mg/mL were studied against lung cancer cells (A549). This microfluidic device has the potential to provide a precise and robust screening for anticancer combinational drugs practiced in clinics.

•A “signal-on” electrochemical genosensor based on stem-loop DNA probe was proposed.•2D stem-loop DNA structure was combined with 3D DNA origami as the sensing probe.•Detection signals showed linearity with microRNA concentrations from 100 pM to 1 µM.•The developed genosensor had a detection limit of 10 pM.•The genosensor can be used in simulative cellular environment.Recent reports have indicated that aberrant expression of microRNAs is highly correlated with occurrence of lung cancer. Therefore, highly sensitive detection of lung cancer specific microRNAs provides an attractive approach in lung cancer early diagnostics. Herein, we designed 3D DNA origami structure that enables electrochemical detection of lung cancer related microRNAs. The 3D DNA origami structure is constituted of a ferrocene-tagged DNA of stem-loop structure combined with a thiolated tetrahedron DNA nanostructure at the bottom. The top portion hybridized with the lung cancer correlated microRNA, while the bottom portion was self-assembled on gold disk electrode surface, which was modified with gold nanoparticles (Au NPs) and blocked with mercaptoethanol (MCH). The preparation process and the performance of the proposed electrochemical genosensor were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under the optimal conditions, the developed genosensor had a detection limit of 10 pM and a good linearity with microRNA concentration ranging from 100 pM to 1 µM, which showed a great potential in highly sensitive clinical cancer diagnosis application.

•The graphene-DNA tetrahedron-AuNPs modified gold disk electrode was firstly constructed.•The developed biosensor successfully detected NADH from 1 fM to 10 pM at 0.28 V.•Both the regeneration and selectivity of the developed biosensor were proved to be robust.•The novel biosensor would further benefit the field of NADH related disease diagnostics.Dihydronicotinamide adenine dinucleotide (NADH) is a major biomarker correlated with lethal diseases such as cancers and bacterial infection. Herein, we report a graphene-DNA tetrahedron-gold nanoparticle modified gold disk electrode for highly sensitive NADH detection. By assembling the DNA tetrahedron/graphene composite film on the gold disk electrode surface which prior harnessed electrochemical deposition of gold nanoparticles to enhance the effective surface area, the oxidation potential of NADH was substantially decreased to 0.28 V (vs. Ag/AgCl) and surface fouling effects were successfully eliminated. Furthermore, the lower detection limit of NADH by the presented platform was reduced down to 1 fM, with an upper limit of 10 pM. Both the regeneration and selectivity of composite film-modified electrode are investigated and proved to be robust. The novel sensor developed here could serve as a highly sensitive probe for NADH detection, which would further benefit the field of NADH related disease diagnostics.

•A sequential application of two-level and orthogonal array composite design was introduced.•Optimization of 5 selected anti-prostate-cancer drugs were studied.•Doxorubicin and docetaxel were found most significant and effective combinations in the cancer survival model used in the study.•Present work illustrate for better understanding of anti-cancer drug mechanism that can facilitate clinical practice of better drug combination.Prostate cancer is one of the most common cancers among men in the United States. It is also a major leading cause of cancer death among men of all races. In order to treat prostate cancer, drug combinations are often applied. Drug combinations target at different pathways of cells can potentially lead to higher efficacy and lower toxicity due to drug synergy. In this paper, we sequentially applied a two-level design and a follow-up orthogonal array composite design (OACD) to investigate combinations of five anti-cancer drugs, namely, doxorubicin, docetaxel, paclitaxel, cis-dichlorodiamine platinum and dihydroartemisinin. Our initial screening using a two-level full factorial design identified doxorubicin and docetaxel as the most significant drugs. A follow-up experiment with an OACD revealed more complicated drug interactions among these 5 anti-cancer drugs. Quadratic effects of doxorubicin and paclitaxel appeared to be significant. A further investigation on contour plots of all the two-drug pairs indicated that combination of doxorubicin and docetaxel are the most effective companion, while the combination of cis-dichlorodiamine platinum and dihydroartemisinin showed unknown antagonistic effects which diminished the individual drug anti-cancer efficacy. These observations have significant practical implications in the understanding of anti-cancer drug mechanism that can facilitate clinical practice of better drug combinations.