Oral Administration Properties Evaluation of Three Milk-derived Extracellular Vesicles Based on Ultracentrifugation Extraction Methods

Milk-derived extracellular vesicles (M-EVs) are low-cost, can be prepared in large quantities, and can cross the gastrointestinal barrier for oral administration. However, the composition of milk is complex, and M-EVs obtained by different extraction methods may affect their oral delivery. Based on this, we propose a new method for extracting M-EVs based on cryogenic freezing treatment (Cryo-M-EVs) and compare this method with the previously reported acetic acid treatment (Acid-M-EVs) method and the conventional ultracentrifugation method (Ulltr-M-EVs). The new method simplifies the pretreatment step and achieves 25-fold and 2-fold higher yields than Acid-M-EVs and Ulltr-M-EVs. And it was interesting to note that Cryo-M-EVs and Acid-M-EVs had higher cellular uptake efficiency, and Cryo-M-EVs presented the best transepithelial transport effect. After oral administration of the three M-EVs extracted by three methods in mice, Cryo-M-EVs effectively successfully crossed the gastrointestinal barrier and achieved hepatic accumulation, whereas Acid-M-EVs and Ultr-M-EVs mostly resided in the intestine. The M-EVs obtained by the three extraction methods showed a favorable safety profile at the cellular as well as animal level. Therefore, when M-EVs obtained by different extraction methods are used for oral drug delivery, we can utilize their accumulation properties at different sites to better deal with different diseases. This article is protected by copyright. All rights reserved.

Design and implementation of suspended drop crystallization

In this work, a novel crystal growth method termed suspended drop crystallization has been developed. Unlike traditional methods, this technique involves mixing protein and precipitant directly on an electron microscopy grid without any additional support layers. The grid is then suspended within a crystallization chamber designed in-house, allowing for vapor diffusion to occur from both sides of the drop. A UV-transparent window above and below the grid enables the monitoring of crystal growth via light, UV or fluorescence microscopy. Once crystals have formed, the grid can be removed and utilized for X-ray crystallography or microcrystal electron diffraction (MicroED) directly without having to manipulate the crystals. To demonstrate the efficacy of this method, crystals of the enzyme proteinase K were grown and its structure was determined by MicroED following focused ion beam/scanning electron microscopy milling to render the sample thin enough for cryoEM. Suspended drop crystallization overcomes many of the challenges associated with sample preparation, providing an alternative workflow for crystals embedded in viscous media, sensitive to mechanical stress and/or subject to preferred orientation on electron microscopy grids.

Design and implementation of suspended drop crystallization

We have developed a novel crystal growth method known as suspended drop crystallization. Unlike traditional methods, this technique involves mixing protein and precipitant directly on an electron microscopy grid without any additional support layers. The grid is then suspended within a crystallization chamber which we designed, allowing for vapor diffusion to occur from both sides of the drop. A UV transparent window above and below the grid enables the monitoring of crystal growth via light, UV, or fluorescence microscopy. Once crystals have formed, the grid can be removed and utilized for x-ray crystallography or microcrystal electron diffraction (MicroED) directly without having to manipulate the crystals. To demonstrate the efficacy of this method, we grew crystals of the enzyme proteinase K and determined its structure by MicroED following FIB/SEM milling to render the sample thin enough for cryoEM. Suspended drop crystallization overcomes many of the challenges associated with sample preparation, providing an alternative workflow for crystals embedded in viscous media, sensitive to mechanical stress, and/or suffering from preferred orientation on EM grids.

Effect of isochoric freezing on quality aspects of minimally processed potatoes

The enhanced interest in greater convenience foods has recently led to the expansion of minimally processed potato products. This study investigated the effects of isochoric freezing on pre-peeled potato cubes, including quality attributes (microstructure, texture, and color), nutritional value (ascorbic acid (AA) content, total phenolic content, and antioxidant capacity), and polyphenol oxidase activity. Isochoric freezing (-3 °C/30 MPa) was compared with isobaric freezing (-3 °C/0.1 MPa) and individual quick freezing followed by frozen storage at -20 °C for 4 weeks. The isochoric sample had lower drip loss and volume shrinkage as well as better preserved texture and microstructure than the other samples. All freezing methods caused an increase in total phenolic content and antioxidant capacity, but a decrease in AA content. Also, all freezing methods caused browning of the thawed potatoes, but isochoric freezing delayed its onset for more than 1 week. PRACTICAL APPLICATION: Results showed that isochoric freezing of pre-peeled and cut potatoes caused less freeze damage than isobaric and individual quick freezing, which might find application in the commercial preservation of minimally processed food products.

Effects of antimicrobial coatings and cryogenic freezing on survival and growth of Listeria innocua on frozen ready-to-eat shrimp during thawing

Foodborne pathogens such as Listeria monocytogenes could pose a health risk on frozen ready-to-eat (RTE) shrimp as the pathogen could grow following thawing. In this study, antimicrobial-coating treatments alone, or in combination with cryogenic freezing, were evaluated for their ability to inhibit the growth of Listeria innocua, a surrogate for L. monocytogenes, on RTE shrimp. Cooked RTE shrimp were inoculated with L. innocua at 3 population levels and treated with coating solutions consisting of chitosan, allyl isothiocyanate (AIT), or lauric arginate ester (LAE). The treated shrimp were then stored at -18 °C for 6 d before being thawed at 4, 10, or 22 °C for either 24 or 48 h. Results revealed that antimicrobial coatings achieved approximately 5.5 to 1 log CFU/g reduction of L. innocua on RTE shrimp after the treatments, depending on the inoculated population levels. The coating-treated shrimp samples had significantly (P < 0.05) less L. innocua than controls at each thawing temperature and time. Cryogenic freezing in combination with coating treatments did not achieve synergistic effects against L. innocua. Antimicrobial coatings can help to improve product safety by reducing Listeria on RTE shrimp.

Using sieving and pretreatment to separate plastics during end-of-life vehicle recycling

Plastics continue to be a challenge for recovering materials at the end-of-life for vehicles. However, it may be possible to improve the recovery of plastics by exploiting material characteristics, such as shape, or by altering their behavior, such as through temperature changes, in relation to recovery processes and handling. Samples of a 2009 Dodge Challenger front fascia were shredded in a laboratory-scale hammer mill shredder. A 2 × 2 factorial design study was performed to determine the effect of sample shape (flat versus curved) and sample temperature (room temperature versus cryogenic temperature) on the size of the particles exiting from the shredder. It was determined that sample shape does not affect the particle size; however, sample temperature does affect the particle size. At cryogenic temperatures, the distribution of particle sizes is much narrower than at room temperature. Having a more uniform particle size could make recovery of plastic particles, such as these more efficient during the recycling of end-of-life vehicles. Samples of Chrysler minivan headlights were also shredded at room temperature and at cryogenic temperatures. The size of the particles of the two different plastics in the headlights is statistically different both at room temperature and at cryogenic temperature, and the particles are distributed narrowly. The research suggests that incremental changes in end-of-life vehicle processing could be effective in aiding materials recovery.