Identification of the peptide building blocks of soy protein nanofibrils provides new clues about the determinants of protein nanofibril morphology.

Protein nanofibrils have emerged as promising building blocks in functional bio/nanomaterials as well as in food products. We here demonstrate that nanofibrils with amyloid-like properties can be produced from potato protein isolate, a major sidestream from the starch industry. Methods for solubilization of potato proteins are evaluated, and a protocol for the assembly of protein nanofibrils is presented. Characterization of the nanofibrils shows that they are rich in β-sheet structure and display the cross-β X-ray fiber diffraction pattern, which is a hallmark of amyloid-like fibrils. Atomic force microscopy shows that the fibrils are ca. 4−5 nm in diameter with a nanoscale morphology that displays a high degree of curvature. Using mass spectrometry we identify four peptides that constitute the core building blocks of the nanofibrils and show that they originate from two different classes of proteins. The structural characteristics of these peptides are distinct from previously studied plant protein nanofibrils and thereby reveal new knowledge about the formation of protein nanostructures from agricultural resources.

Background Tattoo inks have been reported to elicit allergic contact dermatitis. Objectives To investigate the labels and the contents of metals and pigments in tattoo inks, considering restrictions within the European Union. Methods Seventy‐three tattoo inks currently available on the market, either bought or donated (already used), were investigated for trace metals and pigments by inductively coupled plasma mass spectrometry and by matrix‐assisted laser desorption/ionization time of flight tandem mass spectrometry. Results Ninety‐three percent of the bought tattoo inks violated European, legal requirements on labeling. Fifty percent of the tattoo inks declared at least one pigment ingredient incorrectly. Sixty‐one percent of the inks contained pigments of concern, especially red inks. Iron, aluminium, titanium, and copper (most in green/blue inks) were the main metals detected in the inks. The level of metal impurities exceeded current restriction limits in only a few cases. Total chromium (0.35‐139 μg/g) and nickel (0.1‐41 μg/g) were found in almost all samples. The levels of iron, chromium, manganese, cobalt, nickel, zinc, lead, and arsenic were found to covary significantly. Conclusions To prevent contact allergy and toxic reactions among users it is important for tattoo ink manufacturers to follow the regulations and decrease nickel and chromium impurities.

The rapidly growing, competitive biopharmaceutical market requires tight bioprocess monitoring. An integrated, automated platform for the routine online/at-line monitoring of key factors in the cell culture medium could greatly improve process monitoring. Monoand disaccharides, as the main energy and carbon source, are one of these key factors. A CE-LIF method was developed for the analysis of several mono-and disaccharides, considering requirements and restrictions for analysis in an integrated, automated monitoring platform, such as the possibility for miniaturization to microchip electrophoresis. Analysis was performed after fluorescent derivatization with 8-aminopyrene-1,3,6-trisulfonic acid. The derivatisation reaction and the separation BGE were optimized using design of experiments. The developed method is applicable to the complex matrix of cell culture medium and proved transferable to microchip electrophoresis.

Capillary zone electrophoresis ultraviolet (CZE‐UV) has become increasingly popular for the charge heterogeneity determination of mAbs and vaccines. The ε‐aminocaproic acid (eACA) CZE‐UV method has been used as a rapid platform method. However, in the last years, several issues have been observed, for example, loss in electrophoretic resolution or baseline drifts. Evaluating the role of eACA on the reported issues, various laboratories were requested to provide their routinely used eACA CZE‐UV methods, and background electrolyte compositions. Although every laboratory claimed to use the He et al. eACA CZE‐UV method, most methods actually deviate from He's. Subsequently, a detailed interlaboratory study was designed wherein two commercially available mAbs (Waters’ Mass Check Standard mAb [pI 7] and NISTmAb [pI 9]) were provided to each laboratory, along with two detailed eACA CZE‐UV protocols for a short‐end, high‐speed, and a long‐end, high‐resolution method. Ten laboratories participated each using their own instruments, and commodities, showing excellence method performance (relative standard deviations [RSDs] of percent time‐corrected main peak areas from 0.2% to 1.9%, and RSDs of migration times from 0.7% to 1.8% [n = 50 per laboratory], analysis times in some cases as short as 2.5 min). This study clarified that eACA is not the main reason for the abovementioned variations.