Implications of Nanobiosensors in Agriculture

Nanotechnology has emerged as a boon to the society with immense potential in varied area of research and our day-to-day life. The application of nanotechnology for the advancement of biosensor leads to an efficient nanobiosensor with miniature structure as compared to conventional biosensors. Nanobiosensors can be effectively used for sensing a wide variety of fertilizers, herbicide, pesticide, insecticide, pathogens, moisture, and soil pH. Taken together, proper and controlled use of nanobiosensor can support sustainable agriculture for enhancing crop productivity.

FET-based nanobiosensors for the detection of smell and taste

Various nanobiosensors composed of biomaterials and nanomaterials have been developed,due to their demonstrated advantage of showing high performance.Among various biomaterials for biological recognition elements of the nanobiosensor,sensory receptors,such as olfactory and taste receptors,are promising biomaterials for developing nanobiosensors,because of their high selectivity to target molecules.Field-effect transistors(FET)with nanomaterials such as carbon nanotube(CNT),graphene,and conducting polymer nanotube(CPNT),can be combined with the biomaterials to enhance the sensitivity of nanobiosensors.Recently,many efforts have been made to develop nanobiosensors using biomaterials,such as olfactory receptors and taste receptors for detecting various smells and tastes.This review focuses on the biomaterials and nanomaterials used in nanobiosensor systems and studies of various types of nanobiosensor platforms that utilize olfactory receptors and taste receptors which could be applied to a wide range of industrial fields,including the food and beverage industry,environmental monitoring,the biomedical field,and anti-terrorism.

Self-assembling bacterial pores as components of nanobiosensors for the detection of single peptide molecules

Nano-sized bacterial pores were inserted into a lipid membrane as a nanobiosensor for the detection of single peptide molecules. Due to the intrinsic properties of single-channel conductance, the transit of individual molecules through the pore can be studied. The analysis of both the blockage current and duration is able to provide specific structural information and allows the detection of specific peptides in bulk mixtures.

Nano-Sized Elements in Electrochemical Biosensors

The emerging nanotechnology has opened novel opportunities to explore analytical applications of the fabricated nano-sized materials. Recent advances in nano-biotechnology have made it possible to realize a variety of enzyme electrodes suitable for sensing application. In coating miniaturized electrodes with biocatalysts, undoubtedly the most of the potential deposition processes suffer from the difficulty in depositing process and reproducible coatings of the active enzyme on the miniature transducer element. The promising prospects can concern to the obtaining of thin protein layers by using, i.e. electrochemical deposition, electrophoretic deposition as well as monolayer methods (Langmuir-Blodgett procedure, Layer-by-Layer—LbL). Many aspects dealing with deposition of enzyme by techniques employing electric field are considered, including surface charge of enzyme, and its migration under applied electric filed. The using of nanoscale materials (i.e. nanoparticles, nanowires, nanorods) for electrochemical biosensing has seen also explosive increase in recent years following the discovery of nanotubes. These structures offer a promise in the development of biosensing, facilitating the great improvement of the selectivity and sensitivity of the current methods. Finally, the perspectives in the further exploration of nanoscaled sensors are discussed.

Bacteriorhodopsin and SWCNT Scaffold for Optical Nanobiosensor

This paper describes theoretical steps to develop an optical nanobiosensor using bacteriorhodopsin （BR） as the biomembrane and Single-Walled Carbon NanoTube （SWCNT） as the scaffold. Bacteriorhodopsin is a retinal protein used by archaea that come under the family of halobacteria. This retinal protein acts as a proton pump and resulting proton gradient is used to change the voltage that pass across the drain and source. The biosensor contains nano ISFET where the channel is made of a carbon nanotube for the conduction of current. The gate is replaced by bacteriorhodopsin biomembrane. Bacteriorhodopsin can be used as a molecular-level ultra fast bi-stable red / green photo switch for making 3D optical molecular memories that reliably store data with 10,000 molecules/bit. The molecules switch in femtoseconds. Biomembrane will sense 510 nm and 650 nm wavelength of light and the sensing voltage can be used to convert the data into digital signals. This molecular level memory device can be used for ‘Read-Write＇ operations. The sensor performance will also be ultra fast since it uses photons for the data storage, which are much faster than electrons used in normal memory devices, and the 3D storage capacity is much higher maximum of 10^13/cm^2.

Advancement of noble metallic nanoparticles in agriculture: A promising future

Since the last decades,nanotechnology has gained the attention of researchers in the field of plant sciences.The characteristics of nanoparticles are reliant on their shape and size.Formulations involving noble metallic nanoparticles(NMNPs)offer novel technologies to boost agricultural productivity and minimize conventional pesticide use.The application of nanoparticles as nanofertilizer improves plant growth and enhances nutrient uptake efficiency.Noble metallic nanoparticles act as antimicrobial agents against multidrug-resistant pathogens and provide protection to plants.Nanobiosensors and nanodevices are utilized in diverse agro-based areas such as plant disease diagnosis and nanoparticle-based material delivery.Several studies have focused on negative impacts such as toxicity and environmental threats posed by NMNPs.Understanding the effects of NMNPs on agriculture is critical for the assessment of their safety and the impending environmental risks to biodiversity and human health.Here,we summarize the advances of NMNPs towards revolutionizing modern agricultural applications and the recent trends in sustainable precision agriculture.

Wavelength-dependent three-dimensional single-molecule superlocalization imaging for yoctomole detection of thyroid-stimulating hormone on a quantum dot nanobiosensor

A wavelength-dependent three-dimensional(3D)superlocalization imaging method on gold nanoislands(GNIs)chip was developed as a supersensitive single-molecule thyroid-stimulating hormone(TSH)nanobiosensor.Scattered and fluorescent signals from gold nanoislands on the substrate and quantum dots(QDs)nanoprobes were simultaneously isolated and acquired within an evanescent field layer generated by total internal reflection(TIR)of incident light using a dual-view device.The 3D TIR fluorescence images of TSH-bound QDs on the GNIs were obtained using z-axis optical sectioning at 10nm intervals before/after immunoreaction to identify the optimal conditions for detection.The localized centroid position of QD nanoprobes and GNI were distinguished at a subdiffraction limit resolution using 3D Gaussian fitting to the point spread function.The QD TSH nanobiosensor using wavelength-dependent 3D TIR fluorescence-based single-molecule localization microscopy(3D TIRF-SLM)imaging technique showed an excellent detection limit of 90 yoctomoles(~54 molecules)and a wide linear dynamic range of 1.14 zmol/L-100 pmol/L for TSH.The detection sensitivity was about 4.4×10^(9)times higher than conventional enzyme-linked immunosorbent assay and could successfully quantify TSH in human serum.The wavelength-dependent 3D TIRF-SLM technique may emerge as a reliable platform for ultrahigh-sensitive nanobiosensors at the single-molecule level and early diagnosis with quantification of disease-related ultra-tracebiomolecules.