Au@Ag-labeled SERS lateral flow assay for highly sensitive detection of allergens in milk

Casein andα-lactalbumin(α-LA)are the main allergens in cow's milk,which can affect the skin,respiratory system,and gastrointestinal tract,even cause anaphylactic shock.Developing a rapid and sensitive detection method of casein andα-LA is still pursued.Herein,a surface-enhanced Raman scattering based lateral flow assay(SERS-LFA)method for rapid and highly sensitive detection of milk allergens in food was established for effectively preventing allergic symptoms.Gold@silver nanoparticles(Au@Ag NPs)were synthesized as SERS active substrate to prepare the antibody-modified SERS Probe and SERS-LFA strips toward casein andα-LA were assembled according to the sandwich mode.The detection results were calculated according to colorimetric and Raman signal.The introduction of SRES signal significantly increased the sensitivity of detection with the limit of detection(LOD)of 0.19 ng/mL and 1.74 pg/mL,and exhibited an excellent linear relationship within the range of 0.55-791.50 ng/mL and 0.1 pg/mL-100.0 ng/mL for casein andα-LA,respectively.Furthermore,SERS-LFA strips was highly specific with the recovery rates for corresponding80.36%-105.12%and 85.73%-118.22%for casein andα-LA,respectively.Therefore,the SERS-LFA could be in great potential to develop a unique allergen detection method.

High-performance supercapacitor based on ultralight and elastic three-dimensional carbon foam/reduced graphene/polyaniline nanocomposites

A novel supercapacitor based on ultralight and elastic three-dimensional (3D) porous melamine foam (MF)-derived macroporous carbon (3DPMFDMC)/reduced graphene oxide (rGO)/polyaniline (PANI) nanocomposites (denoted as 3DPMFDMC/rGO/PANI) were fabricated. By high temperature carboniza-tion, the commercial MF soaked in GO solution was prepared into ultralight and elastic 3DPMFDMC, the rGO were uniformly distributed into 3DPMFDMC to obtain 3DPMFDMC/rGO, and finally PANI was grown on the 3DPMFDMC/rGO by using in situ chemical oxidation polymerization method. The obtained 3DPMFDMC/rGO/PANI nanocomposites were characterized by SEM, FT-IR and Raman. The results showed the uniform distribution of rGO connected the broken fibers of 3DPMFDMC produced in the high temperature carbonization to improve the electrical conductivity and also enlarged the specific surface area of nanocomposites greatly. Lots of PANI were vertically arrayed on the surface of 3DPMFDMC/rGO. 3DPMFDMC/rGO/PANI exhibited a rapid electron/mass transport. Owing to its special structures and nanocomposites, the supercapacitor showed good electrical performance with a specific capacitance of 1870 F/g at the current density of 1 A/g. Moreover, the specific capacitance remained 95.4%after 1000 charging/discharging cycles at a current density of 5 A/g.