Study on screening potential allergenic proteins from infant milk powders based on human mast cell membrane chromatography and histamine release assays

Cow's milk allergy is mainly observed in infants and young children. Most allergic reactions affect the skin, followed by the gastrointestinal and respiratory systems. Conventional diagnosis is based on positive allergy studies and evaluation of parameters including IgE and IgG1 levels, acute allergic skin response and anaphylactic shock reactions. We developed a cell membrane chromatographic(CMC)method based on human mast cells(HMC-1) for screening potential allergens in infant formula milk powders(IFMP). HMC-1 cell membranes were extracted and mixed with silica to prepare cell membrane chromatography columns(10 mm ? 2 mm i.d., 5 mm). Under the conditions of 0.2 mL/min flow rate and214 nm detection wavelength, human breast milk showed no retention. However, IFMP showed clear retention. The retained fractions were collected and analyzed through matrix-assisted laser desorption/ionization time of flight mass spectrometry(MALDI-TOF-MS). Four major milk proteins, i.e., α-casein, β-casein, α-lactalbumin, and β-lactoglobulin A, were identified. Furthermore, these proteins and β-lactoglobulin B showed clear retention on HMC-1/CMC columns. To test the degranulation effects of the five proteins, histamine and β-hexosaminidase release assays were carried out. All five proteins induced HMC-1 cells to release histamine and β-hexosaminidase. Also, we established a reversed phase liquid chromatographic(RPLC) method for the determination of the five proteins in IFMP and the results showed that 90% proteins in IFMP were α-casein and β-casein. We concluded that cow's milk proteins may be potential allergens and caseins cause more β-casein allergic risk than other proteins. This conclusion was consistent with other studies.

Construction of WO_(3)/Ti-doped WO_(3)bi-layer nanopore arrays with superior electrochromic and capacitive performances

Crystalline WO_(3)/Ti-doped WO_(3)bi-layer nanopore arrays were constructed by the template synthesis of a WO_(3)nanopore layer modified by a magnetron sputtering of an amorphous Ti-doped/WO_(3)layer.The obtained bi-layer nanopore array shows a remarkable electrochromic performance with large dual-band optical modulation in both visible(VIS)and near infrared(NIR)regions(optical modulation of over 70%in the wavelength range from 600 to 1600 nm)and the fast response speed(coloring for 3.4 s and bleaching for 6.6 s).In addition,the bi-layer WO_(3)/Ti-doped WO_(3)nanopore array also present superior energy-storage properties(areal capacitance of 44.0 mF cm−2 and good rate capability),better than that of titanium-free thin films.The special bifunctional characteristics of electrochromism and pseudocapacitance can be ascribed to the large specific surface area provided by the architectural design,rich ion channels in the amorphous layer as well as proper titanium doping,which bestows the bi-layer nanopore array a great potential in clean energy applications.