Progress on sensors based on nanomaterials for rapid detection of heavy metal ions

The heavy metal ions,especially Cd^(2+),Pb^(2+) and Hg^(2+),show extremely hazard to the environment and human being.The measurement of heavy metal ions using sensors is catching more and more attention for its advantages of high sensitivity and selectivity,low-cost,convenience to handle and rapid detection.In recent years,nanomaterials such as gold nanoparticles(NPs),magnetic nanoparticles,graphene and nanocomposite materials are applied in sensors for improving sensitivity and selectivity,making the research on electrochemical(EC) sensors,spectrometric biosensors and colorimetric biosensors become a hot spot in the application to investigate heavy metal ions,in particular,Cd^(2+),Pb^(2+) and Hg^(2+).In this short review,the research of advanced detection of Cd^(2+),Pb^(2+) and Hg^(2+) and its progress based on nanomaterial sensors in recent years is reviewed.

Nutritional evaluation of whole soybean curd made from different soybean materials based on amino acid profiles

Objectives:Amino acid profiles of whole soybean curds(WSCs)and conventional soybean curds(CSCs)were comparatively studied to 1.,evaluate their nutritional value and 2.,study the suitable soybean material to fabricate WSCs.Materials and Methods:Nine types of soybean materials were selected to make WSCs and CSCs.Protein digestibility-corrected amino acid score(PDCAAS)and principal component analysis were selected to perform the comparative analysis of amino acid profiles of the products.Results:Total contents of amino acids in WSCs and CSCs were 41.24-54.87 mg/g and 27.77-36.82 mg/g.Content ranges of essential amino acids were 13.59-19.38 mg/g and 8.46-11.76 mg/g for WSCs and CSCs.The essential amino acid pattern of WSCs was basically close to amino acid pattern spectrum requirements except valine and sulfur amino acids.As a limiting amino acid,methionine represented less than 0.4 for PDCAAS in all soybean curds except WSCs made from relay-cropping Nandou12 and Nandou25.Conclusions:The overall quality of amino acids in WSCs was higher than that in CSCs,indicating that WSCs indeed exhibited higher nutritional value than CSCs from the viewpoint of amino acid profile.WSCs with the high nutritional value could be made using Nandou25 and relay-cropping Nandou12 as materials.

Rapid identification of diarrheagenic Escherichia coli based on barcoded magnetic bead hybridization

Diarrhea,as a global public health problem,causes a large number of infections and deaths every year.Although Escherichia coli(E.coli)is one of the normal flo ra microorganisms in the human intestinal tract,it has five pathogenic bacteria types that can cause human diarrhea,known as diarrheagenic E.coli.When people are infected,rapid and accurate diagnosis,along with timely treatment,are especially important.Here,we introduce a new method to identify and analyze a large number of pathogenic strains in E.coli by multiplex PCR and barcoded magnetic bead hybridization.Results show that the detection sensitivities of enterohemorrhagic E.coli,enterotoxigenic E.coli,enteropathogenic E.coli,enteroinvasive E.coli and enteroaggregative E.coli were 1.3×10^3 CFU/mL,2×10^4 CFU/mL,4×10^4 CFU/mL,7.2×10^4 CFU/mL and 1.7 CFU/mL respectively.This method has strong specificity and high sensitivity and detects multiple target sequences in one experiment.Compared with other methods,BMB array has great application potential.