Publications by authors named "Dongxiao Yin"

3 Publications

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Fission and Internal Fusion of Protocell with Membraneless "Organelles" Formed by Liquid-Liquid Phase Separation.

Langmuir 2020 07 3;36(27):8017-8026. Epub 2020 Jul 3.

Beijing National Laboratory for Molecular Sciences, MOE Key Laboratory of Polymer Chemistry and Physics, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.

Construction of protocells with hierarchical structures and living functions is still a great challenge. Growing evidence demonstrates that the membraneless organelles, which facilitate many essential cellular processes, are formed by RNA, protein, and other biopolymers via liquid-liquid phase separation (LLPS). The formation of the protocell in the early days of Earth could follow the same principle. In this work, we develop a novel coacervate-based protocell containing membraneless subcompartments via spontaneous liquid-liquid phase separation by simply mixing single-stranded oligonucleotides (ss-oligo), quaternized dextran (Q-dextran), and poly(l-lysine) (PLL) together. The resulting biphasic droplet, with PLL/ss-oligo phase being the internal subcompartments and Q-dextran/ss-oligo phase as the surrounding medium, is capable of sequestering and partitioning biomolecules into distinct regions. When the droplet is exposed to salt or Dextranase, the surrounding Q-dextran/ss-oligo phase will be gradually dissociated, resulting in the chaotic movement and fusion of internal subcompartments. Besides, the external electric field at a lower strength can drive the biphasic droplet to undergo a deviated circulation concomitant with the fusion of localized subcompartments, while a high-strength electric field can polarize the whole droplet, resulting in the release of daughter droplets in a controllable manner. Our study highlights that liquid-liquid phase separation of biopolymers is a powerful strategy to construct hierarchically structured protocells resembling the morphology and functions of living cells and provides a step toward a better understanding of the transition mechanism from nonliving to living matter under prebiotic conditions.
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http://dx.doi.org/10.1021/acs.langmuir.0c01864DOI Listing
July 2020

PEGylated gene carriers in serum under shear flow.

Soft Matter 2020 Mar;16(9):2301-2310

Beijing National Laboratory for Molecular Sciences and the Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.

The behaviour of drug/gene carriers in the blood stream under shear is still a puzzle. In this work, using the complexes formed by 21 bp DNA and poly(ethylene glycol)-b-poly(l-lysine) (PEG-PLL) of varying PEG lengths, we studied the dynamic behaviour of the complexes in the presence of fetal bovine serum (FBS) and under flow at different shear rates, a condition mimicking the internal physical environment of blood vessels. The PEG5k-PLL/DNA complex possesses a dense DNA/PLL core and a loose PEG5k protecting layer. The PEGylated DNA complexes exhibit multiple responses to external shear in the presence of FBS. The loose PEG5k layer is firstly disturbed at a shear rate below 30 s-1. The exposure of the charged core to the environment results in a secondary aggregation of the complex with FBS. The size of the aggregate is limited to a certain range as the shear rate increases to 50 s-1. The dense DNA/PLL core starts to withstand the shear force as the shear rate reaches 500 s-1. The reorganization of the core to accommodate more serum molecules leads to tertiary aggregation of the complexes. If PEG cannot form a valid layer around the complex, as in PEG2k-PLL/DNA, the complex forms an aggregate even without shear, and the first shear dependent region is missing. If the PEG layer is too stable around the complex, as in PEG10k-PLL/DNA, no tertiary aggregation occurs. The mechanism of shear on the behaviour of delivery particles in serum helps to design gene carriers with high efficacy.
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http://dx.doi.org/10.1039/c9sm02397fDOI Listing
March 2020

Distributions and contamination assessment of heavy metals in the surface sediments of western Laizhou Bay: Implications for the sources and influencing factors.

Mar Pollut Bull 2017 Jun 29;119(1):429-438. Epub 2017 Mar 29.

College of Marine Geoscience, Ocean University of China, Qingdao 266100, PR China; Key Lab of Submarine Geosciences and Prospecting Techniques, Ministry of Education, Ocean University of China, Qingdao 266100, PR China.

Heavy metals (Cu, Pb, Cr, Cd and As) contents in surface sediments from western Laizhou Bay were analysed to evaluate the spatial distribution pattern and their contamination level. As was mainly concentrated in the coastal area near the estuaries and the other metals were mainly concentrated in the central part of the study area. The heavy metals were present at unpolluted levels overall evaluated by the sediment quality guidelines and geoaccumulation index. Principal component analysis suggest that Cu, Pb and Cd were mainly sourced from natural processes and As was mainly derived from anthropogenic inputs. Meanwhile, Cr originated from both natural processes and anthropogenic contributions. Tidal currents, sediments and human activities were important factors affecting the distribution of heavy metals. The heavy metal environment was divided into four subareas to provide a reference for understanding the distribution and pollution of heavy metals in the estuary-bay system.
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http://dx.doi.org/10.1016/j.marpolbul.2017.03.046DOI Listing
June 2017
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