On-chip rapid drug screening of leukemia cells by acoustic streaming.

Rapid and personalized single-cell drug screening testing plays an essential role in acute myeloid leukemia drug combination chemotherapy. Conventional chemotherapeutic drug screening is a time-consuming process because of the natural resistance of cell membranes to drugs, and there are still great challenges related to using technologies that change membrane permeability such as sonoporation in high-throughput and precise single-cell drug screening with minimal damage. In this study, we proposed an acoustic streaming-based non-invasive single-cell drug screening acceleration method, using high-frequency acoustic waves (>10 MHz) in a concentration gradient microfluidic device. High-frequency acoustics leads to increased difficulties in inducing cavitation and generates acoustic streaming around each single cell. Therefore, single-cell membrane permeability is non-invasively increased by the acoustic pressure and acoustic streaming-induced shear force, which significantly improves the drug uptake process. In the experiment, single human myeloid leukemia mononuclear (THP-1) cells were trapped by triangle cell traps in concentration gradient chips with different cytarabine (Ara-C) drug concentrations. Due to this dual acoustic effect, the drugs affect cell viability in less than 30 min, which is faster than traditional methods (usually more than 24 h). This dual acoustic effect-based drug delivery strategy has the potential to save time and reduce the cost of drug screening, when combined with microfluidic technology for multi-concentration drug screening. This strategy offers enormous potential for use in multiple drug screening or efficient drug combination screening in individualized/personalized treatments, which can greatly improve efficiency and reduce costs.

[Bioavailability of nickel and its complexes during anaerobic digestion].

The biouptake of nickel and its complexes for methanogenic enrichment in the presence of different chelators during batch methane fermentation were investigated in this paper. The results showed that the chelators had obvious effects on anaerobic digestion. At sodium acetate concentration of 85 mmol/L, sulfides concentration of 1 mmol/L, nickel concentration of 200 micromol/L and temperature was 35 degrees C, methane production in the NTA added system were 15% and 9% which was higher than that in CA and EDTA amended ones. While nickel concentration was 100 micromol/L, methane production in NTA added system were 43% and 57% which was higher than that in CA and EDTA amended ones. The biouptake of nickel for methanogenic enrichment related to the species of nickel complexes. NTA was the best chelator for stimulating nickel biouptake in the anaerobic reactors, and EDTA was the better one. The biouptake of Ni-CA complexes was the minimum for the methanogenic enrichment.

[Effect of metal chelating agent on anaerobic digestion under different substrates].

Aided by GC analysis, the effect of metal chelating agent on anaerobic digestion under different substrates was investigated. The results showed that the addition of chelating agent A could greatly promote the methane production under different substrates and speed the conversion of organic acid to methane, especially for propionic acid. When the dosage of chelating agent A was 10 micromol/L, the methane production was, respectively, 19.8%, 133.0% and 45.2% for butyric acid, propionic acid and acetic acid. Also, the arrearage time of methane production was shortened and the production rate increased by 4-fold. During 4-8 d operation, the degradation rate of butyric acid reached 56%. The accumulation of acetic acid was not detected by GC analysis, which demonstrated acetic acid converted from butyric acid was quickly utilized by methane producing bacteria. The increase in methane production due to the addition of chelating agent A could be supported by enzymology. Taking acetic acid as an example, the content of coenzyme F420 in sludge increased to 1.52 micromol/g from 1.20 micromol/g due to the addition of 10 micromol/L chelating agent A.