PMC

Laser diffraction particle size distribution curves obtained for the reduction in anthracene particle size via ball milling in the presence of Morwet D-425 dispersant using (a) the IKA Ultra-Turrax tube drive and (b) retsch planetary ball mill.

Sample preparation method B. (1) Flash freeze the plant tissue in liquid nitrogen, (2) transfer the plant tissue to a centrifuge tube containing the pre-chilled grinding balls, (3) transfer the centrifuge tube to a pre-chilled centrifuge tube holder in a liquid nitrogen bath, (4) place the centrifuge tube holder in the mixing chamber of the ball mill and start the grinding cycle, (5) weigh out 50 mg of the plant tissue, (6) add 500 μL of 13 mM ammonium acetate solution and mix thoroughly, (7) centrifuge and transfer the supernatant to a separate centrifuge tube, (8) repeat steps 6 and 7 twice and combine the three extracts, (9) freeze, freeze dry, then reconstitute the dried extract in 100 μL acetonitrile–water (1:1, v/v)

Sodium arsenite powder was subjected to a high-energy planetary ball mill (Model PM 100) at a rotation speed of 300 rpm for 48 hrs to prepare the sodium arsenite nanoparticles. Ball milling process was implemented under atmospheric conditions (35 °C and 1 atm). Chamber and the balls were made of zirconium oxide. The mass ratio of ball to powder was chosen 30:1. Particle size analyzer (CILAS 920 [Madison, WI, USA]), equipped with a 280-µm aperture tube was used for analyzing particle size of the powder. The results revealed that the average particle size of the formed powder was <50 nm ().

Experimental flow chart for preparing cell extracts by cryogenic grinding of cells or tissues. (A) Stainless steel jars, lids, and balls for cryogenically disrupting frozen cells. The stainless steel jars and balls are used to cryogenically grind frozen cells into a powder for making whole cell protein extracts. Before use, the jars and balls are precooled in liquid nitrogen. (B) Frozen cell pellets added to a frozen steel jar. The pellets are made by dropping a cell slurry into liquid nitrogen and recovering the frozen cell pellets. The precooled steel ball is added to the jar with the cell pellets. The stainless steel cap is then screwed on to seal the chamber. (C) Steel jars inserted into the grinding mill (Retsch MM 301 Mixer Mill). For yeast, the cells are ground into a powder using 10× 3-min cycles at 25 Hz. Between each grinding cycle, the jars are removed from the holders and plunged into liquid nitrogen to keep the cells frozen. (D) Cryogenically disrupted cells. A fine powder is created from the frozen cell pellets and grinding process. The powder is kept frozen and quickly transferred to a 50-mL tube kept cool in liquid nitrogen using a cold spatula. The disrupted cells are stored at −80°C until ready to use.