An impedimetric biosensor for E. coli O157:H7 based on the use of self-assembled gold nanoparticles and protein G

Background: Bacterial lipases especially Pseudomonas lipases are extensively used for different biotechnological applications. Objectives: With the better understanding and progressive needs for improving its activity in accordance with the growing market demand, we aimed in this study to improve the recombinant production and biocatalytic activity of lipases via surface conjugation on gold nanoparticles. Methods: The full length coding sequences of lipase gene (lipA), lipase specific foldase gene (lipf) and dual cassette (lipAf) gene were amplified from the genomic DNA of Pseudomonas aeruginosa PA14 and cloned into the bacterial expression vector pRSET-B. Recombinant lipases were expressed in E. coli BL-21 (DE3) pLysS then purified using nickel affinity chromatography and the protein identity was confirmed using SDS-PAGE and Western blot analysis. The purified recombinant lipases were immobilized through surface conjugation with gold nanoparticles and enzymatic activity was colorimetrically quantified. Results: Here, two single expression plasmid systems pRSET-B-lipA and pRSET-B-lipf and one dual cassette expression plasmid system pRSET-B-lipAf were successfully constructed. The lipolytic activities of recombinant lipases LipA, Lipf and LipAf were 4870, 426 and 6740 IUmg-1, respectively. However, upon immobilization of these recombinant lipases on prepared gold nanoparticles (GNPs), the activities were 7417, 822 and 13035 IUmg-1, for LipA-GNPs, Lipf-GNPs and LipAf-GNPs, respectively. The activities after immobilization have been increased 1.52 and 1.93 -fold for LipA and LipAf, respectively. Conclusion: The lipolytic activity of recombinant lipases in the bioconjugate was significantly increased relative to the free recombinant enzyme where immobilization had made the enzyme attain its optimum performance.

Download Full-text

Enhanced Extracellular Synthesis of Gold Nanoparticles by Soluble Extracts from Escherichia coli Transformed with Rhizobium tropici Phytochelatin Synthase Gene

Metals ◽

10.3390/met11030472 ◽

2021 ◽

Vol 11 (3) ◽

pp. 472

Author(s):

Qunying Yuan ◽

Manjula Bomma ◽

Zhigang Xiao

Keyword(s):

Gold Nanoparticles ◽

Gold Nanoparticle ◽

Synthesis Method ◽

Nanoparticle Synthesis ◽

Morphological Properties ◽

Phytochelatin Synthase ◽

Rhizobium Tropici ◽

Whole Cells ◽

E Coli ◽

Recombinant Cells

Phytochelatins, the enzymatic products of phytochelatin synthase, play a principal role in protecting the plants from heavy metal and metalloid toxicity due to their ability to scavenge metal ions. In the present study, we investigated the capacity of soluble intracellular extracts from E. coli cells expressing R. tropici phytochelatin synthase to synthesize gold nanoparticle. We discovered that the reaction mediated by soluble extracts from the recombinant E. coli cells had a higher yield of gold nanoparticles, compared to that from the control cells. The compositional and morphological properties of the gold nanoparticles synthesized by the intracellular extracts from recombinant cells and control cells were similar. In addition, this extracellular nanoparticle synthesis method produced purer gold nanoparticles, avoiding the isolation of nanoparticles from cellular debris when whole cells are used to synthesize nanoparticles. Our results suggested that phytochelatins can improve the efficiency of gold nanoparticle synthesis mediated by bacterial soluble intracellular extracts, and the potential of extracellular nanoparticle synthesis platform for the production of nanoparticles in large quantity and pure form is worth further investigation.

Download Full-text

Multifunctional Activities of Gold Nanoparticles Biosynthesized Using Bacteria Isolated from Mining Areas

Applied Sciences ◽

10.3390/app11083670 ◽

2021 ◽

Vol 11 (8) ◽

pp. 3670

Author(s):

Chih-Yu Chen ◽

Yung-Chu Chang ◽

Teh-Hua Tsai ◽

Man-Hai Liu ◽

Ying-Chien Chung

Keyword(s):

Gold Nanoparticles ◽

Mining Area ◽

Synthesis Process ◽

Average Particle ◽

Bifidobacterium Lactis ◽

E Coli ◽

Mining Areas ◽

Skin Cells ◽

Study Results ◽

Antityrosinase Activity

Research on gold nanoparticles (AuNPs) has often focused on their physical, chemical, and crystalline characteristics. Commercial AuNPs have been applied in the diverse fields of biomedicine, catalysis, photovoltaics, and sensing. In this study, we explored the various activities of AuNPs to widen their applicability. This paper presents a simple and rapid synthesis process of AuNPs with bacteria isolated from a gold mining area. We also investigated the optimization of reaction parameters for AuNP synthesis. The study results revealed that among the isolated strains, Bifidobacterium lactis and Escherichia coli demonstrated the highest capabilities of AuNP synthesis. The optimal pH values for AuNP synthesis by B. lactis (BLAuNPs) and E. coli (ECAuNPs) were 5.0 for 72 h of incubation and 8.0 for 24 h of incubation. The average particle sizes of ECAuNPs and BLAuNPs were 4.2 and 5.6 nm, respectively. Furthermore, these biogenic AuNPs were found to be stable with no aggregation after 3 months of storage. BLAuNPs and ECAuNPs exhibited high levels of antimicrobial, antioxidant, photocatalytic, and antityrosinase activity. Moreover, they were noncytotoxic to skin cells even at 100% melanin inhibitory concentrations. Considering the demonstrated multifunctional activities of AuNPs, BLAuNPs and ECAuNPs have promising potential for commercialization.

Download Full-text

Disulfide-induced self-assembled targets: A novel strategy for the label free colorimetric detection of DNAs/RNAs via unmodified gold nanoparticles

Scientific Reports ◽

10.1038/srep45837 ◽

2017 ◽

Vol 7 (1) ◽

Cited By ~ 10

Author(s):

Ehsan Shokri ◽

Morteza Hosseini ◽

Mehdi D. Davari ◽

Mohammad R. Ganjali ◽

Maikel P. Peppelenbosch ◽

...

Keyword(s):

Gold Nanoparticles ◽

Colorimetric Detection ◽

Label Free ◽

Self Assembled ◽

Novel Strategy

Download Full-text

Gold Nanoparticles Presenting Hybridized Self-Assembled Aptamers That Exhibit Enhanced Inhibition of Thrombin

Angewandte Chemie ◽

10.1002/ange.201101718 ◽

2011 ◽

Vol 123 (33) ◽

pp. 7802-7807 ◽

Cited By ~ 13

Author(s):

Yen-Chun Shiang ◽

Chia-Lun Hsu ◽

Chih-Ching Huang ◽

Huan-Tsung Chang

Keyword(s):

Gold Nanoparticles ◽

Self Assembled ◽

Inhibition Of Thrombin

Download Full-text

Innenrücktitelbild: In Situ Synthesis of Self-Assembled Gold Nanoparticles on Glass or Silicon Substrates through Reactive Inkjet Printing (Angew. Chem. 2/2014)

Angewandte Chemie ◽

10.1002/ange.201310429 ◽

2013 ◽

Vol 126 (2) ◽

pp. 611-611

Author(s):

Mutalifu Abulikemu ◽

Eman Husni Da'as ◽

Hanna Haverinen ◽

Dongkyu Cha ◽

Mohammad Azad Malik ◽

...

Keyword(s):

Gold Nanoparticles ◽

Inkjet Printing ◽

In Situ Synthesis ◽

Silicon Substrates ◽

Self Assembled

Download Full-text

Acetylcholinesterase Biosensor Based on Gold Nanoparticles and Cysteamine Self Assembled Monolayer for Determination of Monocrotophos

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2009.se24 ◽

2009 ◽

Vol 9 (4) ◽

pp. 2368-2373 ◽

Cited By ~ 14

Author(s):

Dan Du ◽

Wenjuan Chen ◽

Jie Cai ◽

Jianming Zhang ◽

Haiyang Tu ◽

...

Keyword(s):

Gold Nanoparticles ◽

Self Assembled Monolayer ◽

Self Assembled

Download Full-text

A Self-Assembled DNA Nanostructure as FRET Nanoflare for Intracellular ATP Imaging

Chemical Communications ◽

10.1039/d1cc02316k ◽

2021 ◽

Author(s):

Cai Shijun ◽

Jiaoli Wang ◽

Jing Li ◽

Bing Zhou ◽

Chunmei He ◽

...

Keyword(s):

Gold Nanoparticles ◽

Dna Nanostructure ◽

Intracellular Atp ◽

Self Assembled

Due to the incorporation of gold nanoparticles (AuNPs), the reported AuNP-based FRET nanoflares still have some problems, such as non-negligible cytotoxicity and time-consuming preparation procudure. In this communication, a novel...

Download Full-text