Structural analysis of potato starch transformation during high-energy ball-milling: Oxygen and humidity content effects

High Energy Ball-Milling (HEBM) modifies starchs' granule morphology, physicochemical properties, and chemical structure. However, understanding how the HEBM changes the starch chemical structure is necessary to control these modifications. Therefore, this study aimed to investigate the changes in potato starch's long- and short-range molecular order during HEBM at different environmental conditions such as oxygen (Air) and humidity content. Due to the correlation between the starch modification and the energy supplied (Esupp) by the HEBM, Burgio's equation was used to calculate this energy. The starch transformation was followed by X-ray diffraction, Fourier Transform-Infrared Spectroscopy, and Raman spectroscopy. A Principal Component Analysis (PCA) was conducted to reduce the HEBM variables. PAC analysis demonstrated that the different oxygen-humidity conditions do not affect the HEBM of potato starch. Based on the starch chemical structure transformation correlated with Esupp during HEBM, four stages were observed: orientation, modification, mechanolysis, and over-destruction. It was identified for the first time that at low milling energy (<1.5 kJ/g, orientation stage), the glycosidic rings change their orientation, and starch-water interaction increases while the starch's organization reduces. Ergo, the potato starch could be more susceptible to chemical modifications during the first two stages.

Rapid and simple isolation and detection of exosomes using CaTiO3:Eu3+@Fe3O4 multifunctional nanocomposites

Exosomes are potential biomarkers for disease diagnosis and treatment, as well as drug carriers. However, as their isolation and detection remain critical issues, convenient, rapid, low-cost, and effective methods are necessary. In this study, we present a rapid and simple method for directly capturing and analyzing exosomes from complex cell culture media using CaTiO₃:Eu³⁺@Fe₃O₄ multifunctional nanocomposites. The CaTiO₃:Eu³⁺@Fe₃O₄ nanocomposites were prepared by high-energy ball-milling and used to isolate exosomes by binding CaTiO₃:Eu³⁺@Fe₃O₄ nanocomposites and the hydrophilic phosphate head of the exosome phospholipids. Notably, the developed CaTiO₃:Eu³⁺@Fe₃O₄ multifunctional nanocomposites achieved results comparable with those of commercially available TiO₂ and were separated using a magnet within 10 min. Moreover, we report a surface-enhanced Raman scattering (SERS)-based immunoassay for detecting the exosome biomarker CD81. Gold nanorods (Au NRs) were modified with detection antibodies, and antibody-conjugated Au NRs were labeled with 3, 3, diethylthiatricarbocyanine iodide (DTTC) as the SERS tags. A method combining magnetic separation and SERS was developed to detect exosomal biomarker CD81. The results of this study demonstrate the feasibility of this new technique as a useful tool for exosome isolation and detection.