A flow injection analysis coupled dual electrochemical detector for selective and simultaneous detection of guanine and adenine

Nanocellulose in biomedical and biosensing applications: A review

Cellulose is abundant in the nature and nanocellulose (NC) in particular is regarded as a credible green substrate to be used in bio nanocomposites for various applications. NC exhibits excellent mechanical reinforcement properties comparable to conventionally used materials due to its high specific surface area and tunable surface chemistry. Additionally, low toxicity, biodegradability and biocompatibility of NC deem it a promising material for use in different biomedical applications. In this review, we highlight the biomedical applications of NC based hydrogels and aerogels/nanocomposites and advancements of their employment in the areas of wound dressing, drug delivery, tissue engineering, scaffolds and biomedical implants. This review also explores the recent use of NC in making biosensors for the detection of cholesterol, various enzymes and diseases, heavy metal ions in human sweat and urine, and for general health monitoring.

Ultrasensitive Physical, Bio, and Chemical Sensors Derived from 1-, 2-, and 3-D Nanocellulosic Materials

Sensors are of increasing interest since they can be applied to daily life in different areas from various industrial sectors. As a natural nanomaterial, nanocellulose plays a vital role in the development of novel sensors, particularly in the context of constructing multidimensional architectures. This review summarizes the utilization of nanocellulose including cellulose nanofibers, cellulose nanocrystals, and bacterial cellulose for sensor design, mainly focusing on the influence of nanocellulose on the sensing performance of these sensors. Special attention is paid to nanocellulose in different forms (1D, 2D, and 3D) to highlight the impact of nanocellulose constructed structures. The aim is to provide a critical review on the most recent progress (especially after 2017) related to nanocellulose-containing sensors, since there are significantly increasing research activities in this area. Moreover, the outlook for the development of nanocellulose-containing sensors is also provided at the end of this work.

Single step grown MoS2 on pencil graphite as an electrochemical sensor for guanine and adenine: A novel and low cost electrode for DNA studies

Herein we report a simple, one-step approach to prepare a low-cost and binder free MoS₂-pencil graphite electrode (i.e., MoS₂-PGE) for the electrochemical oxidation of DNA nucleobases i.e., guanine (G) and adenine (A) in physiological pH (7.4) buffer solution. MoS₂-PGE was synthesised by hydrothermal method and the morphology of such hybrid was characterized by field emission scanning electron microscopy, X-ray diffraction, Raman and X-ray photoelectron spectroscopy. In cyclic voltammetry, MoS₂-PGE displays two well-seprated and well-defined irresversible peaks at 0.58 and 0.90 V for electrochemical oxidation of G and A respectively when compared to bare PGE. Likewise, differential pulse voltammetry of MoS₂-PGE showed well-seprated and sharp peak current responses for G and A at 0.56 V and 0.85 V respectively. Under optimized conditions, DPV was further adopted for simultaneous and separation-free determination of G and A in physiological pH. MoS₂-PGE shows good stability with linear range of 15-120 μM and 15-120 μM for G and A detection respectively. Obtained sensitivity and limit of detection (signal-to-noise = 3) are comparable with the previous literature. As an immediate practical applicability, MoS₂-PGE was used for quantification of G and A concentration in calf-thymus DNA and detected ratio of G and A (i.e., [G]/[A]) ratio is 0.85. The current approach provides a new avenue towards the development of affordable electrodes for a wide range of bioanalytical applications.

Construction and application of a new cell electrochemical detecting system based on the hyposmotic principle

A new cell electrochemical detecting system has been constructed based on the hyposmotic principle, in which the electrochemical signals have been strengthened by about 109.75% for the signal at about +0.70 V and 532.94% for the signal at about +1.03 V. The electrochemical detection limits of the cells have been improved by one order of magnitude. The individual concentrations of intracellular purines have been obtained.

Recent advances in flow injection analysis

A dynamic development of methodologies of analytical flow injection measurements during four decades since their invention has reinforced the solid position of flow analysis in the arsenal of techniques and instrumentation of contemporary chemical analysis.

Electrochemical sensor for individual and simultaneous determination of guanine and adenine in biological fluids and in DNA based on a nano-In–ceria modified glassy carbon paste electrode

A novel, simple and sensitive electrochemical method for individual and simultaneous determination of guanine and adenine was developed using an In doped ceria nanoparticle modified glassy carbon paste electrode (In–CeO₂/GCPE).

Electrochemical sensing of guanine, adenine and 8-hydroxy-2′-deoxyguanosine at glassy carbon modified with single-walled carbon nanotubes covalently functionalized with lysine

Synthesis and characterization of l-lysine covalently functionalized SWCNT and analytical application for the highly sensitive quantification of guanine, adenine and 8-hydroxy-2′-deoxyguanosine.

Functionalized solid electrodes for electrochemical biosensing of purine nucleobases and their analogues: a review

Interest in electrochemical analysis of purine nucleobases and few other important purine derivatives has been growing rapidly. Over the period of the past decade, the design of electrochemical biosensors has been focused on achieving high sensitivity and efficiency. The range of existing electrochemical methods with carbon electrode displays the highest rate in the development of biosensors. Moreover, modification of electrode surfaces based on nanomaterials is frequently used due to their extraordinary conductivity and surface to volume ratio. Different strategies for modifying electrode surfaces facilitate electron transport between the electrode surface and biomolecules, including DNA, oligonucleotides and their components. This review aims to summarize recent developments in the electrochemical analysis of purine derivatives, as well as discuss different applications.