Publications by authors named "Shaolu Li"

4 Publications

  • Page 1 of 1

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

Quantitative analysis of zeptomole microRNAs based on isothermal ramification amplification.

RNA 2009 Sep 20;15(9):1787-94. Epub 2009 Jul 20.

Department of Biomedical Engineering, College of Engineering, Peking University, Beijing 100871, China.

To date, approximately 700 microRNA (miRNA) molecules have been identified in humans. Accurate and sensitive quantification of miRNA levels will help unveil their biological functions. Here, we extend the isothermal ramification amplification (RAM) approach to a sensitive and specific real-time assay for quantitative analysis of miRNA. This RAM miRNA assay is based on the threshold cycle (C(T)) principle similar to that of real-time PCR. It has a dynamic range of at least seven orders of magnitude, allowing for the quantification of miRNA input from 10(3) to 10(10) copies per reaction (10 nM to 1 fM). The capabilities of discriminating single-base mismatch and distinguishing mature miRNAs from their precursors are achieved by coupling the reverse-transcription of miRNA to the generation of a closed C-probe, rather than using expensive detection probes like in real-time PCR. Quantitative measurement of 5 miRNAs (mir-1, miR-122, mir-150, mir-143, and let-7a) across 12 mouse tissues is validated in total RNA samples without further purification. U6 snRNA, snoRNA 135, and miRNA-191 could be simultaneously quantified as endogenous controls. These results suggest that our RAM miRNA assay might provide a universal tool for miRNA detection and functional studies to meet the needs for bench examination, clinical diagnosis, and on-site detection.
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http://dx.doi.org/10.1261/rna.1555209DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2743063PMC
September 2009

Real-time polymerase chain reaction microRNA detection based on enzymatic stem-loop probes ligation.

Anal Chem 2009 Jul;81(13):5446-51

School of Electronic and Information Engineering, Beihang University, Beijing, China, 100191.

MiRNAs (microRNAs) are a group of endogenous, small noncoding RNA with the length of 18-25 nucleotides, which have recently been demonstrated to play important roles in a wide range of biological processes. In this work, we developed a simple, sensitive, specific, and inexpensive assay through the combination of enzymatic probe ligation and real-time PCR amplification for the measurement of mature miRNAs. A couple of novel DNA probes with a stem-loop structure were implemented to reduce nonspecific ligation by at least 100-fold. The assay has several remarkable features including wide dynamic range, low total RNA input (0.02-0.2 ng), distinct anti-interference from precursor miRNAs (signal-to-noise ratio > 500), and single-base mismatch discrimination among miRNA sequences. In addition, a one-tube assay could be accomplished by designing a couple of universal probes, which makes it feasible to examine the expression of a whole family of miRNA (such as let-7) at one time. Finally, we validated the method for quantifying the expression of four mature miRNAs including miR-122, miR-1, miR-34a, and let-7a across 10 mouse tissues, where U6 snRNA could be simultaneously examined as an endogenous control. Thus, this method revealed a great potential for miRNA quantitation in ordinary laboratory studies and clinical diagnoses.
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http://dx.doi.org/10.1021/ac900598dDOI Listing
July 2009

A triphenylamine-containing donor-acceptor molecule for stable, reversible, ultrahigh density data storage.

J Am Chem Soc 2007 Sep 29;129(38):11674-5. Epub 2007 Aug 29.

Key Laboratory of Organic Solids, Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China.

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http://dx.doi.org/10.1021/ja074226eDOI Listing
September 2007
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