Sensitive detection of Nampt(PBEF/Visfatin)in human serum for point-of-care applications using aptamer based capacitive biosensor

NAMPT is a multifunctional protein, also known as visfatin or pre-B cell colony-enhancing factor, which exists as the rate-limiting intracellular enzyme for nicotinamide adenine dinucleotide (NAD) synthesis starting from nicotinamide [1]. The plasma Nampt levels are reported to have correlation with obesity and obese related metabolic disease, such as Type 2 diabetes mellitus (T2DM), cardiovascular diseases [2] and hyperlipidemia [3] due to association with lipoprotein and cholesterol. Therefore, sensitive detection of Nampt potentially enable accurate diagnosis of T2DM, cardiovascular and hyperlipidemia diseases. In this study, for the first time, we developed an ssDNA aptamer that specifically bind Nampt (Kd=72.52 nM) in human serum by systematic evolution of ligands by exponential enrichment (SELEX) process. Nampt-specific ssDNA aptamers were then applied as the recognition molecules for the development of a capacitive biosensor using non-Faradaic impedance spectroscopy (nFIES), which converts the biological binding event into a quantifiable signal for sensitive and efficient detection of the Nampt (Fig. 1). The interaction of aptamer-Nampt induced the change in dielectric properties, charge distribution, and conductivity. The limit of detection was 1 ng/ml with a dynamic range of upto 50 ng/ml in serum and this range is under the clinical requirements both in the normal Nampt levels, which is 15.8 ng/ml, and in the T2DM patients level, which is 31.9 ng/ml. This assay system for Nampt detection using aptamers is a potential alternative approach for applications in clinical studies and Point-Of-Care health technologies

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Multi-messenger Observations of a Binary Neutron Star Merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ∼ 1.7 {{s}} with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of {40}-8+8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 {M}ȯ . An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ∼ 40 {{Mpc}}) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ∼ 9 and ∼ 16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.</p

Editorial note - Professor Turner's retirement

On behalf of the new editorial team of Biosensors and Bioelectronics, Co-Editors in chief.Peer reviewe

Chemical-specific continuous biomonitoring using a recombinant bioluminescent bacterium DNT5 (nagR-nagAa :: luxCDABE)

The recombinant bioluminescent bacterium, DNT5, containing a nagR-nagAa::luxCDABE fusion, was tested in a multi-channel continuous monitoring system to evaluate its ability to detect benzoic acid derivatives. Seven chemicals, benzoic acid, salicylic acid, 2,5-dihydroxy benzoic acid, 3,5-dihydroxy benzoic acid, benzene, naphthalene and phenol, were used to characterize the responses of DNT5. This strain responded uniquely to each chemical, and these responses were then evaluated based upon the structures of each chemical. The greatest bioluminescent responses were to salicylic acid and benzoic acid, followed by 2,5-dihydroxy benzoic acid and 3,5-dihydroxy benzoic acid, but DNT5 was unresponsive when exposed to benzene, phenol and naphthalene, suggesting it has a strong preference for benzoic acid derivatives with few or no ring-substituted groups.close3

The continuous monitoring of field water samples with a novel multi-channel two-stage mini-bioreactor system

Toxicity monitoring of field water samples was performed using a novel multi-channel two-stage mini-bioreactor system and genetically engineered bioluminescent bacteria for the continuous monitoring and classification of the toxicity present in the samples. The toxicity of various samples spiked with known endocrine disrupting chemicals and phenol was also investigated for system characterization. The field samples used in this study were obtained from two different sites on a monthly basis - from a drinking water treatment plant, referred to as site N, and from a stream near a dam which is currently being constructed, referred to as site T. These samples were either pumped or injected into the second mini-bioreactors to initiate the toxicity test. Most of the samples did not show any specific toxicity. However, one sample showed to have, based upon the detection results, and was deemed toxic. The samples spiked with phenol showed possible responses in the DPD2540 and TV1061 channels, indicating the occurrence of both membrane and protein damage due to phenol. In the tests using an endocrine disrupting chemical, bisphenol A, DNA damage was detected in the DPD2794 channel with a concentration of 2 ppm. Finally, a simple but novel early warning protocol that can be used in a drinking water reservoir and a suspected place where effluents of toxic materials enter the water sourse was suggested with a schematic diagram. In conclusion, this system showed good feasibility for use as a toxicity monitoring system in the field and as an early warning system, indicating if effluents are toxicopen192

Biosensors for healthcare: current and future perspectives

Biosensors are utilized in several different fields, including medicine, food, and the environment; in this review, we examine recent developments in biosensors for healthcare. These involve three distinct types of biosensor: biosensors for in vitro diagnosis with blood, saliva, or urine samples; continuous monitoring biosensors (CMBs); and wearable biosensors. Biosensors for in vitro diagnosis have seen a significant expansion recently, with newly reported clustered regularly interspaced short palindromic repeats (CRISPR)/Cas methodologies and improvements to many established integrated biosensor devices, including lateral flow assays (LFAs) and microfluidic/electrochemical paper-based analytical devices (??PADs/ePADs). We conclude with a discussion of two novel groups of biosensors that have drawn great attention recently, continuous monitoring and wearable biosensors, as well as with perspectives on the commercialization and future of biosensors