Current trends in nanomaterials-mediated biosensing platforms and signal amplification strategies for antibiotics detection in dairy products

Dairy products have become one of the most prevalent daily foods worldwide,but safety concerns are rising.In dairy farming,unscrupulous traders misuse antibiotics to treat some diseases such as mastitis in cows,leading to antibiotic residues in dairy products.Rapid,sensitive,and simple detection methods for antibiotic residues are particularly important for food safety in dairy products.Traditional detection technology can effectively detect antibiotics,but there are defects such as complicated pre-treatment and high cost.Biosensors are widely used in food safety due to fast detection speed,low detection cost,strong anti-interference ability,and suitability for the field application.Nevertheless,these sensors often fail to trigger the signal conversion output due to low target concentration.To cope with this issue,some high-efficiency signal amplification systems can be introduced to improve the detection sensitivity and linear range of biosensors.In this review,we focused on:(i)Sources and toxicity of major antibiotics in animal-derived foods.(ii)Nanomaterial-mediated biosensors for real-time detection of target antibiotics in animal-derived foods.(iii)Signal amplification techniques to increase the sensitivity of biosensors.Finally,future prospects and challenges in this research field are discussed.

In Situ Raman Monitoring of Trace Antibiotics in Different Harsh Water Environments

In situ surface-enhanced Raman scattering(SERS)is a widely used operando analytical technique,while facing numerous complex factors in applications under aqueous environment,such as low detection sensitivity,poor anti-interference capability,etc.,resulting in unreliable detectability.To address these issues,herein a new hydrophobic SERS strategy has been attempted.By comprehensively designing and researching a SERS-active structure of superhydrophobic ZnO/Ag nanowires,we demonstrate that hydrophobicity can not only draw analytes from water onto substrate,but also adjust"hottest spot"from the bottom of the nanowires to the top.As a result,the structure can simultaneously concentrate the dispersed molecules in water and the enhanced electric field in structure into a same zone,while perfecting its own anti-interference ability.The underwater in situ analytical enhancement factor of this platform is as high as 1.67×10^(11),and the operando limited of detection for metronidazole(MNZ)reaches to 10^(-9)M.Most importantly,we also successfully generalized this structure to various real in situ detection scenarios,including on-site detection of MNZ in corrosive urine,real-time warning of wrong dose of MNZ during intravenous therapy,in situ monitoring of MNZ in flowing wastewater with particulate interference,etc.,demonstrating the great application potential of this hydrophobic platform.This work realizes a synergistic promotion for in situ SERS performance under aqueous environment,and also provides a novel view for improving other in situ analytical techniques.

A new indium-based MOF as the highly stable luminescent ultra-sensitive antibiotic detector

A novel luminescent double-interpenetrated metal-organic framework(MOF),named{[In_(6)(O)_(3)(BTB)_(4)]·3H_(2)O}_(n)(1),is designed and synthesized using the tritopic linkers(1,3,5-tris(4-carboxyphenyl)benzene(H_(3)BTB))and tetranuclear clusters[In_(4)O_(2)(COO)_(8)].1 features 3,8-connected dual-wall"cage-in-cage"and exhibits excellent chemical stability owing to its high connectivity and double-interpenetrated architectures.Moreover,it could rapidly detect thiamphenicol(THI),nitrofurazone(NFZ),and nitrofurantoin(NFT)antibiotics in N,N-dime-thylformamide(DMF)with superior detection sensitivity(Ksv)and low detection limits(LOD)of 4.52×10^(3)M^(-1)and 348.6 ppm,1.43×10^(5)M^(-1)and 13.8 ppm,and 1.47×10^(5)M^(-1)and 12.1 ppm for THI,NFZ,and NFT,respectively.Additionally,compound 1 exhibits good selectivity and recyclability.It is also effectively used to detect NFT in the milk sample.Furthermore,the mechanism of luminescence quenching was revealed through the experimental results and the density functional theory calculations.The occurrence of photo-induced electron transfer(PET)affects the fluorescence quenching effect of NFT and NFZ.The design of indium-based MOFs has the potential to detect antibiotic residues in food.

Cucurbit[8]uril-mediated phosphorescent supramolecular foldamer for antibiotics sensing in water and cells

A phosphorescent supramolecular foldamer is conveniently constructed by the 1:1 host-guest complexation with cucurbit[8]uril and 1,2-diaminocyclohexane-bridged 4-(4-bromophenyl)-pyridinium salt. The tightly compact host-guest complexation in molecular foldamer can greatly suppress the fluorescence emissive channel and promote the intersystem crossing from singlet to triplet states, thus leading to the green phosphorescence at ambient temperature in aqueous solution. More intriguingly, the phosphorescence emission shows very rapid and sensitive responsiveness to different antibiotics in both inanimate milieu and living cells. Remarkably, the limit of detection of such binary inclusion complex toward sulfamethazine can reach as low as 1.86 × 10^(-7) mol/L. Thus, it is envisaged that this supramolecular nanoplatform featuring unique complexation-enhanced phosphorescence emission may hold great promise in sensing and detecting many other biological targets under physiological environment.