Posts by Shiqi Wang published at ITN SNAL - Marie Curie Initial Training Network

Influence of a pH-sensitive polymer on the structure of monoolein cubosomes

Shiqi Wang — Fri, 05 Jan 2018 11:53:33 +0000

Soft Matter, 13, 7571-7577 (2017) Monika Kluzek, Arwen I. I. Tyler, Shiqi Wang, Rongjun Chen, Carlos M. Marques, Fabrice Thalmann, John M. Seddon, Marc Schmutz Cubosomes consist in submicron size particles of lipid bicontinuous cubic phases stabilized by surfactant polymers. They provide an appealing road towards the practical use of lipid cubic phases for pharmaceutical and cosmetic applications, and efforts are currently being made to control the encapsulation and release properties of these colloidal objects. We overcome in this work the lack of sensitivity of monoolein cubosomes to pH conditions by using a pH sensitive polymer designed to strongly interact

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pH-Responsive, Lysine-Based, Hyperbranched Polymers Mimicking Endosomolytic Cell-Penetrating Peptides for Efficient Intracellular Delivery

Shiqi Wang — Tue, 09 May 2017 14:20:12 +0000

Chem. Mater., DOI: 10.1021/acs.chemmater.7b00054 (2017). Shiqi Wang and Rongjun Chen The insufficient delivery of biomacromolecular therapeutic agents into the cytoplasm of mammalian cells remains a major barrier to their pharmaceutical applications. Cell-penetrating peptides (CPPs) are considered as potential carriers for cytoplasmic delivery of macromolecular drugs. However, due to the positive charge of most CPPs, strong non-specific cell membrane bindings may lead to relatively high toxicity. In this study, we report a series of anionic, CPP-mimicking, lysine-based hyperbranched polymers, which caused complete membrane disruption at late endosomal pH while remained non-lytic at physiological pH. The pH-responsive conformational alterations and the multivalency

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Membrane-Anchoring, Comb-Like Pseudopeptides for Efficient, pH-Mediated Membrane Destabilization and Intracellular Delivery

Shiqi Wang — Mon, 27 Feb 2017 10:46:44 +0000

ACS Appl. Mater. Interfaces, Article ASAP (2017) Siyuan Chen, Shiqi Wang, Michal Kopytynski, Marie Bachelet, and Rongjun Chen Endosomal release has been identified as a rate-limiting step for intracellular delivery of therapeutic agents, in particular macromolecular drugs. Herein, we report a series of synthetic pH-responsive, membrane-anchoring polymers exhibiting dramatic endosomolytic activity for efficient intracellular delivery. The comb-like pseudopeptidic polymers were synthesized by grafting different amounts of decylamine (NDA), which act as hydrophobic membrane anchors, onto the pendant carboxylic acid groups of a pseudopeptide, poly(l-lysine iso-phthalamide). The effects of the hydrophobic relatively long alkyl side chains on aqueous solution properties, cell

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Amino Acid Based Hydrogels with Dual Responsiveness for Oral Drug Delivery

Shiqi Wang — Wed, 18 May 2016 15:20:54 +0000

Macromol. Biosci. (2016) Shiqi Wang, Xiaoxue Liu, Ignacio J. Villar-Garcia and Rongjun Chen This study reports a series of novel amino acid based dual-responsive hydrogels. Prepared by a facile one-pot 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) coupling reaction, the solid content, structure, and mechanical behavior of hydrogels could be easily adjusted by changing the concentrations of the polymers and the crosslinkers. With pH-responsive anionic pseudo-peptides as backbones and disulfide-containing l-cystine dimethyl ester as crosslinkers, these hydrogels are able to collapse and form relatively compact structure at an acidic pH, while swelled and partly dissociated at a neutral pH. Further addition of dithiothreitol (DTT) facilitated complete degradation of hydrogels.

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Imperial College London: Fundamentals and Applications of Lipid Membrane Biophysics

Shiqi Wang — Tue, 31 Mar 2015 15:19:45 +0000

Dates: 22nd-24th September 2015 Location: Horsley Park (Ockham Road South, East Horsley, KT24 6DT) SCOPE Lipid membranes are the basic building blocks for almost all living organisms. For years numerous reports have been focused on this area to establish a comprehensive understanding of membrane structures. More recently, the development of modern experimental techniques, such as small-angle X-ray scattering, small-angle neutron scattering and cyro-TEM, provides more powerful tools for this study. In addition to experimental study, theoretical models and computational simulations also contribute to broadening the scope of this field. The fundamental study of lipid membranes facilitates technical applications, for instance, designing drug carriers which can be transferred

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Gel permeation chromatography/ Size exclusion chromatography

Shiqi Wang — Wed, 05 Nov 2014 14:02:51 +0000

Gel permeation chromatography (GPC)/ Size exclusion chromatography (SEC) is a widely used technique for measuring the molecular weight and molecular weight distribution of natural and synthetic polymers. It is based on liquid chromatographic techniques that separate individual polymer chains on the basis of their size in solution and not on their chemical properties. The separation mechanism is shown in Figure 1: Diluted polymer solution passes through GPC column which is filled with porous beads. During the elution process, molecules with small hydrodynamic volume could enter into the pores of beads, thus taking relatively long time to pass through the column.

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Nuclear magnetic resonance spectroscopy (NMR spectroscopy)

Shiqi Wang — Tue, 28 Oct 2014 18:17:22 +0000

Nuclear magnetic resonance spectroscopy (NMR spectroscopy) is one of the most widely used techniques by chemists and biologists to identify molecular structures. It relies on the phenomenon of nuclear magnetic resonance, which means the intramolecular magnetic around an atom in a specific molecular changes the resonance frequency. Thus, different atoms within one molecule could have different resonance signals and could be detected by the equipment. For NMR study, samples should first dissolve in deuterated solvent and prepared in a thin-wall glass tube (NMR tube). Then the NMR tubes should be installed with a spinner and put into the NMR spectrometer. Typical high resolution NMR spectrometers are

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Summary of the Meeting in Cambridge 1 October 2014

Shiqi Wang — Sun, 12 Oct 2014 06:45:57 +0000

1-2 October 2014 – Cambridge, Department of Chemical Engineering at the University of Cambridge. After months of discussions and proposals conducted by supervisors from each host institution and the program director, Dr. Vladimir Baulin, the management meeting in Cambridge sets the beginning of a great adventure! In an atmosphere both earnest and casual, many topics have been discussed. Some, such as schedules for jointed events, everyone’s expectation, objectives of Early Stage Researchers (ESRs), potential collaborations, and network outreach activities. Each ESR, through 10-minutes presentation, has gotten the opportunity to (1) demonstrate available infrastructure of the host institution (2) present available

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ESR5-L: Synthesis and characterization of functional biomimetic polymers for intracellular delivery

Shiqi Wang — Thu, 05 Dec 2013 14:56:50 +0000

Chemical synthesis, characterisation of polymers and nano-objects Objectives This project is focused on development of functional biomimetic polymers which can traverse across cellular membranes to deliver payloads into the cell interior. Synthesis and characterization of pH-responsive, membrane-active polymers. Preparation of therapeutic nanoparticles incorporating chemotherapeutic agents or biological molecules. Understanding and controlling of the trafficking of polymers into a model cellular system. Demonstration and optimization of delivery of payload into the cell interior. Tasks and methodology Characterization of polymer structure and composition by FTIR and NMR; measurement of polymer molecular weight and polydispersity by GPC. Appropriate method (e.g. cleavable conjugation, physical

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