| A biosensor can be defined as a compact analytical device or unit incorporating a biological or biologically derived sensitive recognition element integrated or associated with a physio-chemical transducer.The progress on novel methods in biosensor has promoted the development of analytical chemistry and life science.Meanwhile,they play a vital role in interdisciplinary field of analytical chemistry and life science.Great progress has recently been made in applying nanomaterials to sensor and biosensor development.Owing to the properties afforded by the small size of nanomaterials-theirlarge surface to-volume ratios;their physicochemical properties,composition,and shape;and their unusual target binding characteristics-these sensors can markedly improve the sensitivity and specificity of analyte detection.Metal-organic frameworks(MOFs),also known as coordination polymers,have recently emerged as an intriguing class of porous materials,which are constructed from organic linkers and inorganic cationic node through coordination bond.In recent decades,MOFs have received tremendous attention due to their powerful attributes on structural and chemical versatility and tailorffability.The purpose of this article is to synthesize a two-dimensional H2dtoaCu and apply in detection of adenosine triphosphate and bacteria.The article includes three parts:Part one:IntroductionAt first,the basic concept of biosensor brief introduction including the characteristics and classification of biosensor,direction of its research and application fields are given.Then we introduce the application of enzymes and nucleic acid in biosensor.Furthermore,mainly introduced applications of MOFs including catalysis,gas storage,drug delivery and sensing.Finally,the contents and significance of the research were proposed.Part two:A fluorescence aptasensor based on two-dimensional sheet metal-organic frameworks for the sensitive detection of adenosine triphosphate.Adenosine 5’-triphosphate(ATP)is one of the most important multifunctional nucleoside triphosphates.It is also a critical signal molecule,and plays a key role in the regulation of cellular metabolism and biochemical pathways.The fluorescence aptasensor of this chapter were constructed with two-dimensional H2dtoaCu for assaying ATP.This study found that two-dimensional H2dtoaCu has an excellent adsorption FAM-labeled aptamer and can quench the fluorescence of the FAM.However,the aptamer specifically interact with the ATP and form ATP-binding aptamer complexes,which exhibit weak adsorption onto the H2dtoaCu surface,and therefore retain the most fluorescence of the FAM-labeled ATP aptamer.The fluorescence intensity can be applied to quantitatively analyze the target ATP.Additionally,the specific recognition of ATP by the aptamer allowed a low detection limitation of 8.19 nM,indicating high sensitivity.The method was also highly selective for the analysis of the target ATP,and avoided interference from GTP,UTP,and CTP.This promising strategy might prove feasible as an ATP assay for real samples.This promising strategy might prove feasible as an ATP assay for real samples.Finally,urine was selected as the actual sample to verify the feasibility of the method.Part three:Two-dimensional H2dtoaCu as the sensing platform to visual detect bacteriaPathogenic contamination and resistant bacterial infections remain critical concerns in both developed and developing nations,due to extremely low minimum infective doses for many bacteria and the lack of inexpensive and portable methods to detect at these limits.Therefore,the rapid and sensitive detection of bacteria is a key requirement in food safety,environmental monitoring,clinical diagnosis and treatment.Escherichia coli are the most important bacteria in human and animal.Most of Escherichia coli can cause diseases such as diarrhea,Colitis and uremia.Escherichia coli are often used as a hygienic standard for drinking,food and medicine.Therefore,it is important to develop a sensitivity method detection Escherichia coli.In this chapter,we have developed a simple and cost effective colorimetric approach for Escherichia coli detection based on a two-dimensional H2dtoaCu and enzyme complex.Theβ-galactosidase(β-Gal)is a very important anionic enzyme.The activity of β-Gal is used to detect with a chromogenic substrate,o-nitrophenyl-β-D-galactopyranoside(ONPG),to provide color readout.In our system,positively charged H2dtoaCu sheets bind with P-Gal at the negatively charged residues around its active site through electrostatic interactions,resulting in the inhibition of enzymatic activity.Under these conditions,the inhibited does not hydrolyze the chromogenic substrate.Furthermore,the addition of bacteria,competitive binding of the anionic surface of the bacteria to the positively charged H2dtoaCu sheets releases the β-Gal,with concomitant restoration ofβ-Gal activity.The o-nitrophenyl,hydrolysis product of the β-Gal reaction,could provide an amplified colorimetric reaction and then the colorless substrate into the yellow product.The approach uses only a UV-Vis spectrophotometer,which is relatively inexpensive.This method provided a potential tool for field applications with a visual detection of bacteria. |
