Nanoscience and Nanotechnology Letters
·
2019
·Vol. 11
·期 8
·1104-1115
·
IF 0
Bhatti Huma,Jawed Rohil,Liu Hang,Ali Irshad,Zhu Libo,Liu Quanjun
Biological nanopores have been proved as impressive nano-devices capable of holding the detection sensitivity from a nanoparticle to a single macromolecule. Protein pores are efficiently reproducible with assured channel geometry and their propensity to be engineered easily make them
convenient in nanopore sensing techniques. Among various porin-proteins, MspA porin of Mycobacterium smegmatis is quite ideal for nanopore DNA sequencing. However, the traversing speed of singlestranded DNA (ssDNA) through both the mutants of MspA (M1MspA and M2MspA) is too fast to
be analyzed. Therefore, we utilized a new mutant of MspA, termed as M3MspA which was previously purified in our laboratory. We, for the first time, demonstrated that translocation of ssDNA is achieved at a minimum voltage-threshold of 40 mV at pH 8.0. This new mutant of MspA exhibits a crystal-clear
discrimination between two homopolymers, poly dA50 and poly dC50 with duration time up to few milliseconds and well-resolved signature current-amplitudes were obtained for both sides (3′ or 5′) of the polymer entered the pore, without any modification to ssDNA.
Significantly, M3MspA determines a precise length of a hetero-homopolymer, poly(dA50dC50) by producing a dwell time congruent to the sum of the time spent by their component-homopolymers, separately. On account of their specificity and sensitivity towards translocating
polynucleotides, we suggest that this new mutant of MspA would be a sophisticated bio-nanopore in further enlightening the translocation dynamics caused by diverse conformations of a same biomolecule. On top of that, it would also be helpful in nanopore DNA sequencing.
研究领域:
生物物理学
·
纳米技术
·
分子生物学
·
基因组学
✓ 已验证
DOI
Polymer Chemistry
·
2024
·Vol. 15
·期 27
·2780-2789
·
IF 4.1
Ke Wang,Zilong Wang,Meiyu Si,Xiaofang Liu,Guiyan Liu,Yongfei Zeng
Three novel temperature/pH/CO2-triple-responsive homopolymers namely P(Et-N-EO2MA), P(THP-N-EO2MA) and P(Ph-N-EO2MA) were prepared by reversible addition–fragmentation chain transfer (RAFT) polymerization. They have the same backbone structure but different types of end substituents i.e., ethyl, tetrahydropyran, and the benzene ring, respectively. Subsequently, their responsive properties were studied. P(Et-N-EO2MA) has a lower critical solution temperature (LCST)-type cloud point (CP) in aqueous solution and is affected by many factors such as the molecular structure and weight, concentration, additives, pH and CO2. P(THP-N-EO2MA) is soluble in water, but in different buffer solutions, it shows a soluble–LCST–insoluble transition, and its LCST-type CP can also be adjusted by molecular weight and concentration. P(Ph-N-EO2MA) is insoluble in water, but reversible phase transformation can be achieved by adjusting the pH of the solution or injecting CO2, and it also shows different properties in buffer solutions and an upper critical solution temperature (UCST)-type CP in n-butanol. In addition, since P(Ph-N-EO2MA) is amphiphilic, it can be self-assembled in solution, and the release of Nile Red (NR) can be achieved under the stimulation of acid. The different properties of these homopolymers show the effect of substituents on the responsiveness of multistimuli-responsive polymers, which provides ideas for the design of stimuli-responsive polymers, and have good application prospects in the fields of self-assembly and controlled release.
研究领域:
高分子化学
·
材料科学
✓ 已验证
DOI
高影响因子
MACROMOLECULES
·
2012
·
IF 5.167
Yunqing Zhu,Lin Liu,Jianzhong Du
Self-assembly of amphiphilic homopolymers composed of both hydrophilic and hydrophobic components in each repeating unit is burgeoning in recent years due to their facile synthesis compared to block copolymers. However, ordered homopolymer nanostructures are very limited, and solid TEM evidence for the formation of vesicles and other complex morphologies is necessary to address the mechanistic insights of homopolymer self-assembly. Presented in this article are the studies on the morphological transition, the structure analysis, and the formation mechanism of homopolymer self-assembly. First, a series of amphiphilic homopolymers, poly(2-hydroxy-3-phenoxypropyl acrylate) (PHPPA) with various molecular weights (MWs) have been designed and synthesized by the reversible addition–fragmentation chain transfer (RAFT) process. Second, upon simply changing the homopolymer’s chain length or cosolvents during self-assembly, a wide range of new homopolymer-based nanostructures can be obtained, such as large compound micelles (LCMs), simple vesicles, large compound vesicles (LCVs), and hydrated large compound micelles (HLCMs) as a result of different intensity of inter/intra-polymer hydrogen bonding in the homopolymer self-assemblies. Moreover, micrometer-sized branched cylinders are formed by premixing PHPPA36 and PHPPA103 homopolymers, which is not observed by self-assembly of PHPPA36 and PHPPA103 individually. Third, we claim that the structures of homopolymer self-assemblies are much different from their block copolymer analogues due to homopolymer’s fuzzy hydrophobic and hydrophilic domains compared to block copolymer’s distinct ones. We confirm that the structure of micelle core or vesicle membrane (alike to each other in nature) consists of both hydrophilic and hydrophobic moieties, which is different from block copolymer micelles or vesicles with hydrophobic cores or membranes. Also, a dye encapsulation experiment is employed to identify and distinguish a new nanostructure, HLCMs, from LCMs. Our study has provided a new perspective on homopolymer self-assembly.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2017
·
IF 7.504
Hui Sun,Jinhui Jiang,Yufen Xiao,Jianzhong Du
It is an important challenge to effectively remove environmental pollutants such as polycyclic aromatic hydrocarbons (PAHs), dyes, and heavy metal ions at a low cost. Herein, we present a multifunctional homopolymer vesicle self-assembled from a scalable homopolymer, poly(amic acid) (PAA), at room temperature. The vesicle can efficiently eliminate PAHs, cationic dyes, and heavy metal ions from water based on π–π stacking, hydrophobic effect, and electrostatic interactions with the pollutants. The residual concentrations of PAHs, cationic dyes, and heavy metal ions (such as Ni2+) in water are lower than 0.60 and 0.30 parts per billion (ppb) and 0.095 parts per million (ppm), respectively, representing a promising adsorbent for water remediation. Furthermore, precious metal ions such as Ag+ can be recovered into silver nanoparticles by in situ reduction on the membrane of PAA vesicles to form a silver nanoparticle/vesicle composite (Ag@vesicle) that can effectively catalyze the reduction of toxic pollutants such as aromatic nitro-compounds and be recycled for more than ten times.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Nano
·
2014
·
IF 12.033
Yunqing Zhu,Lang Fan,Bo Yang,Jianzhong Du
Homopolymers have been considered as a nonideal building block for creating well-defined nanostructures due to their fuzzy boundary between hydrophobic and hydrophilic moieties. However, this unique fuzzy boundary may provide some opportunities for fabricating functional nanomaterials. Presented in this paper is a pH-responsive multifunctional homopolymer vesicle based on poly[2-hydroxy-3-(naphthalen-1-ylamino)propyl methacrylate] (PHNA). This vesicle is confirmed to be an excellent supporter for gold nanoparticles (AuNPs) to facilitate the reduction reaction of 4-nitrophenol (4-NP). The pH-responsive vesicle membrane favors the effective embedding and full immobilization of AuNPs because it is kinetically frozen under neutral and basic environments, preventing AuNPs from aggregation. Meanwhile, there is a synergistic effect between the AuNPs and the supporter (PHNA vesicle). Due to the π–π interaction between the naphthalene pendants in every repeat unit of PHNA and the extra aromatic compounds, a substrate-rich (high concentration of 4-NP) microenvironment can be created around AuNPs, which can dramatically accelerate the AuNPs-catalyzed reactions. In addition, we proposed a method for more accurately determining the membrane thickness of rigid polymer vesicles from TEM images based on “stack-up” vesicles, which may overturn the measuring method commonly used by far. Moreover, proof-of-concept studies showed that those homopolymer vesicles may be used as a powerful adsorbent for effective water remediation to remove trace carcinogenic organic pollutants such as polycyclic aromatic hydrocarbons to below parts per billion (ppb) level at a very fast rate based on the π–π interaction between the naphthalene pendants in PHNA vesicle and polycyclic aromatic hydrocarbons. Overall, this multifunctional homopolymer vesicle provides an alternative insight on preparing effective recyclable AuNPs-decorated nanoreactor and powerful water remediation adsorbent.
研究领域:
材料科学
·
环境科学
·
纳米技术
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）