A long-length (hundred micrometers) carbon nanotube is successfully dispersed in aqueous solution with surfactant cellulose while maintaining its length. An electrochemical study of the synthetic pathway of dopamine (DA), dopamine-o-quinone (DAQ), leucodopaminechrome (LDAC), and dopaminechrome (DAC) at the electrode fabricated by the long-length carbon nanotube dispersed solution is presented. The sequence DA ⇌ DAQ ⇀ LDAC ⇌ DAC for the reaction is electron transfer-chemical reaction-electron transfer (ECE)-type, which is a chemical reaction (DAQ ⇀ LDAC, C) interposed between two electron transfer reactions (DA ⇌ DAQ and LDAC ⇌ DAC, E). The salient electrochemical signals due to both DA ⇌ DAQ and LDAC ⇌ DAC can be obtained at the long-length carbon nanotube electrode, unlike other carbon electrodes such as carbon paste, graphene, fullerene, nanofiber, and graphite. The overall reaction is dominated by step DAQ ⇀ LDAC and is sensitive to pH. With cyclic voltammetry in acidic media, the peak current due to LDAC ⇀ DAC disappeared at a higher scan rate because the reaction rate for DAQ ⇀ LDAC was so slow that DAQ was completely consumed in the electron transfer of DAQ ⇀ DA before the chemical reaction of DAQ ⇀ LDAC could go forward. In alkaline media, the peak height due to DAC ⇀ LDAC became as high as that due to DA ⇀ DAQ because the DAQ ⇀ LDAC rate became fast enough that a sufficient amount of LDAC was generated for the subsequent reaction of LDAC ⇀ DAC. Concomitantly, the reaction DAQ + LDAC ⇌ DA + DAC was generated. Quantitative and selective detection of dopamine based on the signal due to LDAC ⇀ DAC is possible just as in the conventional strategy of direct oxidation of dopamine (DA ⇀ DAQ).

The threat of biological and chemical terror acts remains a growing worldwide concern. There is therefore a need to develop appropriate technology for the detection of chemical and biological warfare agents, with early identification intended for use by first responders. Here, we disclose the developed autonomous air sampling and detection system for evaluation of the presence of chemical and biological warfare agents that can be harmful to the population. The current device utilizes the designed mist generator-assisted air collection system (338 l min − 1 ) and biosensing chip technologies, such as electrochemical measurement, Au nanoparticle-based localized surface plasmon resonance, and rapid microfluidic chip PCR for detection of minute concentrations lower than the mean lethal dose (LD 50 ) of nerve gases (sarin and VX), toxic proteins (BTX/A/Hc and ricin), and pathogens (anthrax simulant). An operation time of only 5-15 min is needed for the collection and detection; sample preparation is already integrated into the system without the need for direct human intervention. In addition to the system's sensitivity and ease of use, its portability makes it highly beneficial for first responders, which could aid in immediate risk assessment and mitigation of on-site events.

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General anesthetics are indispensable for effective clinical care. Although, the mechanism of action of general anesthetics remains controversial, lipid bilayers and proteins have been discussed as their targets. In this study, we focused on the relationship between cellular ATP levels and general anesthetics. The ATP levels of nematodes and cultured mammalian cells were decreased by exposure to three general anesthetics: isoflurane, pentobarbital, and 1-phenoxy-2-propanol. Furthermore, these general anesthetics abolished mitochondrial membrane potential, resulting in the inhibition of mitochondrial ATP synthesis. These results suggest that the observed decrease of cellular ATP level is a common phenomenon of general anesthetics.

Monitoring of blood glucose content is vital for diabetes patients. The conventional widely used method involves an invasive procedure for blood sampling. In addition, blood glucose measured by this way is affected by immediate food consumption and it does not show accurate baseline blood glucose measurement. Thus, monitoring blood glucose by a noninvasive method that accurately reflects baseline blood glucose content is important. Glycated albumin (GA), a biomarker for diabetes indicating the average blood glucose over 2 weeks, can be used for semilong-term blood glucose monitoring. Detection of GA in saliva is a noninvasive method that alleviates the use of needles for diabetic patients; however, its content in saliva is in the nanomolar range. Therefore, the GA enzymatic detection method was combined with the ECL method for a highly sensitive detection of GA in human serum albumin and in the saliva sample. Here, the standard curve was constructed using model substrate, FZK, between 0.1 and 2 μM, and GA in human serum albumin was measured in this range. Also, we successfully demonstrated the detection limit of 0.1 μM GA in human serum albumin sample using ECL, which has seen improvement of about 70 times more than the colorimetric methods. The detection of GA in real saliva sample suggested that sample dilution of 5 times may be necessary to suppress the ECL quenching effect by impurities.

A decrease in the levels of osmotic solutes is a main cause of underwater growth suppression in azuki bean epicotyls. This may be brought about by suppression of solute uptake via breakdown of the H(+) gradient across the plasma membrane due to a decrease in ATP. The involvement of cell wall properties in underwater growth suppression remains to be fully elucidated.

This study evaluates on the possibility of using gold nanoparticles functionalized with the luminol derivative N‐(aminobutyl)‐N‐(ethylisoluminol) (ABEI) and hybridized with graphene oxide nanoribbons on a carbon based screen‐printed electrode (ABEI‐AuNP‐GONR/SPE) as an enzymatic electrochemiluminescence (ECL) urea sensor. The electrocatalytic activity and ECL intensity of ABEI‐AuNP‐GONR/SPE were found to increase proportionally with the concentration of urea in the analyte sample, owing to the rise in pH value. These phenomena are attributed to increased formation of luminol monoanion precursors for further electrochemical oxidation, which in turn produce either luminol radicals or excited 3‐amino‐phthalate molecules. The luminescence is most likely caused by the interaction of luminol radicals with superoxide radicals formed from dissolved oxygen. The sensitivity of our sensor was determined to be 170.58 mM−1 and 16.23 mM−1 for urea concentrations from 2 to 5.82 mM and from 5.82 to 30 mM, respectively, covering the normal urea level in human blood.

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