scholarly journals An acetoacetate-inducible bacterial sensor

2016 ◽  
Author(s):  
David T Gonzales ◽  
Tanel Ozdemir ◽  
Geraint M Thomas ◽  
Chris P Barnes
Keyword(s):  
Biomedical Applications ◽  
Dynamic Range ◽  
Short Chain Fatty Acids ◽  
The Body ◽  
Two Component System ◽  
Gfp Expression ◽  
Bacterial Biosensor ◽  
E Coli ◽  
Spatio Temporal

Whole cell biosensors have great potential to be used as diagnostic and treatment tools in biomedical applications. Bacterial biosensors that respond to specific metabolites can help analyze spatio-temporal gradients in the body or cue expression of therapeutic agents in diseased sites. In this study, we developed an acetoacetate bacterial sensor by inserting the promoter of the atoSC two-component system (TCS) into a promoterless GFP expression plasmid and transformed it into E. coli DH5α and E. coli Nissle 1917, which both contain the atoSC TCS. This bacterial biosensor has a dynamic range of 0.01-1mM of acetoacetate, which is within the range of physiological concentrations in the blood, and exhibits up to a 100-fold change of induced GFP expression as measured by relative fluorescence. Comparing combinations among the two host strains and high/low-copy plasmid variations of the biosensor, we observed the fastest and highest response to acetoacetate with the E. coli Nissle 1917 low copy plasmid biosensor. Induction experiments on the biosensor using 50mM of the short chain fatty acids (SCFA) acetate, proprionate, and butyrate showed no response, indicating its specificity between acetoacetate and SCFAs. This acetoacetate bacterial sensor is a valuable contribution to the library of biosensors that may eventually be used for in vivo clinical applications.

scholarly journals Injectable non-leaching tissue-mimetic bottlebrush elastomers as an advanced platform for reconstructive surgery

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Erfan Dashtimoghadam ◽  
Farahnaz Fahimipour ◽  
Andrew N. Keith ◽  
Foad Vashahi ◽  
Pavel Popryadukhin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Reconstructive Surgery ◽  
Biomedical Applications ◽  
The Body ◽  
Surrounding Tissue ◽  
Curing Time ◽  
Materials Used ◽  
Significant Health

AbstractCurrent materials used in biomedical devices do not match tissue’s mechanical properties and leach various chemicals into the body. These deficiencies pose significant health risks that are further exacerbated by invasive implantation procedures. Herein, we leverage the brush-like polymer architecture to design and administer minimally invasive injectable elastomers that cure in vivo into leachable-free implants with mechanical properties matching the surrounding tissue. This strategy allows tuning curing time from minutes to hours, which empowers a broad range of biomedical applications from rapid wound sealing to time-intensive reconstructive surgery. These injectable elastomers support in vitro cell proliferation, while also demonstrating in vivo implant integrity with a mild inflammatory response and minimal fibrotic encapsulation.

scholarly journals Injectable Non-leaching Tissue-mimetic Bottlebrush Elastomers: A New Platform for Advancing Reconstructive Surgery

2020 ◽  
Author(s):  
Erfan Dashtimoghadam ◽  
Farahnaz Fahimipour ◽  
Andrew Keith ◽  
Foad Vashahi ◽  
Pavel Popryadukhin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Reconstructive Surgery ◽  
Biomedical Applications ◽  
The Body ◽  
Surrounding Tissue ◽  
Curing Time ◽  
Materials Used ◽  
Significant Health

Abstract Current materials used in biomedical devices do not match tissue’s mechanical properties and leach various chemicals into the body. These deficiencies pose significant health risks that are further exacerbated by invasive implantation procedures. Herein, we leverage the brush-like polymer architecture to design and administer minimally invasive injectable elastomers that cure in vivo into leachable-free implants with mechanical properties matching the surrounding tissue. This strategy allows tuning curing time from minutes to hours, which empowers a broad range of biomedical applications from rapid wound sealing to time-intensive reconstructive surgery. These injectable elastomers support in vitro cell proliferation, while also demonstrating in vivo implant integrity with a mild inflammatory response and minimal fibrotic encapsulation.

Dual-responsive biohybrid neutrobots for active target delivery

2021 ◽  
Vol 6 (52) ◽  
pp. eaaz9519 ◽  
Author(s):  
Hongyue Zhang ◽  
Zesheng Li ◽  
Changyong Gao ◽  
Xinjian Fan ◽  
Yuxin Pang ◽  
...  
Keyword(s):  
Drug Delivery ◽  
The Body ◽  
Rotating Magnetic Field ◽  
Inflammatory Factors ◽  
Exciting Field ◽  
E Coli ◽  
Dual Responsive ◽  
Current Cell ◽  
Traditional Drug

Swimming biohybrid microsized robots (e.g., bacteria- or sperm-driven microrobots) with self-propelling and navigating capabilities have become an exciting field of research, thanks to their controllable locomotion in hard-to-reach areas of the body for noninvasive drug delivery and treatment. However, current cell-based microrobots are susceptible to immune attack and clearance upon entering the body. Here, we report a neutrophil-based microrobot (“neutrobot”) that can actively deliver cargo to malignant glioma in vivo. The neutrobots are constructed through the phagocytosis of Escherichia coli membrane-enveloped, drug-loaded magnetic nanogels by natural neutrophils, where the E. coli membrane camouflaging enhances the efficiency of phagocytosis and also prevents drug leakage inside the neutrophils. With controllable intravascular movement upon exposure to a rotating magnetic field, the neutrobots could autonomously aggregate in the brain and subsequently cross the blood-brain barrier through the positive chemotactic motion of neutrobots along the gradient of inflammatory factors. The use of such dual-responsive neutrobots for targeted drug delivery substantially inhibits the proliferation of tumor cells compared with traditional drug injection. Inheriting the biological characteristics and functions of natural neutrophils that current artificial microrobots cannot match, the neutrobots developed in this study provide a promising pathway to precision biomedicine in the future.

scholarly journals Diamond thin films: giving biomedical applications a new shine

2017 ◽  
Vol 14 (134) ◽  
pp. 20170382 ◽  
Author(s):  
P. A. Nistor ◽  
P. W. May
Keyword(s):  
Thin Films ◽  
Biomedical Applications ◽  
Large Body ◽  
Chemical Vapour ◽  
The Body ◽  
First Century ◽  
Diamond Thin Films ◽  
Deposition Technology

Progress made in the last two decades in chemical vapour deposition technology has enabled the production of inexpensive, high-quality coatings made from diamond to become a scientific and commercial reality. Two properties of diamond make it a highly desirable candidate material for biomedical applications: first, it is bioinert, meaning that there is minimal immune response when diamond is implanted into the body, and second, its electrical conductivity can be altered in a controlled manner, from insulating to near-metallic. In vitro, diamond can be used as a substrate upon which a range of biological cells can be cultured. In vivo , diamond thin films have been proposed as coatings for implants and prostheses. Here, we review a large body of data regarding the use of diamond substrates for in vitro cell culture. We also detail more recent work exploring diamond-coated implants with the main targets being bone and neural tissue. We conclude that diamond emerges as one of the major new biomaterials of the twenty-first century that could shape the way medical treatment will be performed, especially when invasive procedures are required.

Pyruvate kinase from the earthworm Allolobophora calliginosa: modification of the enzyme during anaerobiosis

1991 ◽  
Vol 69 (1) ◽  
pp. 251-254
Author(s):  
Athanasios I. Papadopoulos ◽  
Basile Michaelidis ◽  
Isidoros Beis
Keyword(s):  
Pyruvate Kinase ◽  
Deae Cellulose ◽  
Relative Activity ◽  
The Body ◽  
E Coli ◽  
In Vitro Incubation ◽  
Sigmoidal Kinetics ◽  
Independent Protein

The relative activity of pyruvate kinase from the body-wall muscle of the earthworm Allolobophora calliginosa was found to drop dramatically within 6 h of exposure to N2, whereas the opposite was observed during recovery. Two forms of pyruvate kinase (designated as peak I and peak II) were separated chromatographically on DEAE-cellulose and eluted at 50 and 150 mM of KCl, respectively. They displayed different kinetic behaviour with respect to substrate phosphoenolpyruvate; peak I exhibited Michaelis–Menten kinetics whereas peak II showed sigmoidal kinetics. The ratio of the enzyme units (peak I/peak II) decreased from 3.38 under normoxic conditions to 0.09 under anoxic conditions. In vitro incubation of the aerobic form of pyruvate kinase in the presence of ATP and Mg++ resulted in a reduction of the enzyme activity by 64%, suggesting the presence of an endogenous cyclic-nucleotide-independent protein kinase capable of phosphorylating pyruvate kinase. After in vitro incubation, alkaline phosphatase from E. coli increased the depressed activity of anaerobic pyruvate kinase, indicating that the enzyme molecule is phosphorylated in vivo during exposure to anoxia.

scholarly journals A novel Bursin-like peptide as a potential virus inhibitor and immunity regulator in SPF chickens infected with recombinant ALV

2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Yukun Zeng ◽  
Zuxin Gong ◽  
Binbin Wu ◽  
Wenchao Guan ◽  
Shenyi Yu ◽  
...  
Keyword(s):  
Growth Performance ◽  
Virus Titer ◽  
The Body ◽  
Bursa Of Fabricius ◽  
Virus Eradication ◽  
First Report ◽  
E Coli ◽  
Valuable Adjunct

Abstract Background Avian leukosis viruses (ALVs) are important contagious suppressive factors of chicken immunity and growth performance, resulted in enormous economic loss. Although virus eradication programs are applied in breeder flocks, ALVs are still widespread globally. Therefore, other valuable adjunct to reduce the negative effect of ALVs should be considered. Bursin-like peptide (BLP) showed remarkable immunomodulatory effects, whereas their influence on ALV-infected avian groups has not been reported. Here, a designed hybrid BLP was expressed in E. coli. The purified BLP was injected subcutaneously weekly in SPF chickens congenitally infected with a natural ALV strain. Then the influences of this BLP on the growth performance, immune response and virus titer of ALV-infected chickens were determined. Results This BLP injection significantly improved the body weights of ALV-infected birds (P < 0.05). BLP injection significantly enhanced organ index in the BF in ALV-infected birds (P < 0.05). The weekly injection of BLP significantly lengthened the maintenance time of antibodies against Newcastle disease virus (NDV) attenuated vaccine of ALV-infected birds (P < 0.05) and boosted the antibody titer against avian influenza virus (AIV) H5 inactive vaccine of mock chicken (P < 0.05). BLP injection in mock chickens enhanced the levels of serum cytokines (IL-2, IL-4 and interferon-γ) (P < 0.05). Surprisingly, the novel BLP significantly inhibited expression of the ALV gp85 gene in the thymus (P < 0.05), kidney (P < 0.05) and bursa of Fabricius (BF) (P < 0.01) of ALV-infected chickens. Both viral RNA copy number and protein level decreased significantly with BLP (50 μg/mL) inoculation before ALV infection in DF1 cells (P < 0.05). Conclusions This is the first report investigating the influence of BLP on the growth and immunity performance of chickens infected by ALV. It also is the first report about the antiviral effect of BLP in vivo and in vitro. This BLP expressed in E. coli showed potential as a vaccine adjuvant, growth regulator and antiretroviral drug in chickens to decrease the negative effects of ALV infection.

scholarly journals Phosphorene Is the New Graphene in Biomedical Applications

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2301 ◽  
Author(s):  
Marco Tatullo ◽  
Fabio Genovese ◽  
Elisabetta Aiello ◽  
Massimiliano Amantea ◽  
Irina Makeeva ◽  
...  
Keyword(s):  
Smart Materials ◽  
Biomedical Applications ◽  
Biochemical Properties ◽  
Black Phosphorus ◽  
The Body ◽  
Toxic Agents ◽  
Black Phosphorene ◽  
Similar Materials ◽  
Low Cytotoxicity

Nowadays, the research of smart materials is focusing on the allotropics, which have specific characteristics that are useful in several areas, including biomedical applications. In recent years, graphene has revealed interesting antibacterial and physical peculiarities, but it has also shown limitations. Black phosphorus has structural and biochemical properties that make it ideal for biomedical applications: 2D sheets of black phosphorus are called Black Phosphorene (BP), and it could replace graphene in the coming years. BP, similar to other 2D materials, can be used for colorimetric and fluorescent detectors, as well as for biosensing devices. BP also shows high in vivo biodegradability, producing non-toxic agents in the body. This characteristic is promising for pharmacological applications, as well as for scaffold and prosthetic coatings. BP shows low cytotoxicity, thus avoiding the induction of local inflammation or toxicity. As such, BP is a good candidate for different applications in the biomedical sector. Properties such as biocompatibility, biodegradability, and biosafety are essential for use in medicine. In this review, we have exploited all such aspects, also comparing BP with other similar materials, such as the well-known graphene.

834 CRISPR-mediated in situ editing of liver resident macrophages for treating liver cancers

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A886-A886
Author(s):  
Zhutian Zeng ◽  
Wei Liu
Keyword(s):  
Immune Responses ◽  
Genome Editing ◽  
Kupffer Cells ◽  
Coli Strain ◽  
The Body ◽  
E Coli ◽  
Liver Macrophage ◽  
Liver Cancers

BackgroundLiver cancer is one of the leading cause of cancer death worldwide with limited treatment options. The liver accommodates the largest population of tissue resident macrophages in the body, namely Kupffer cells. Immune deviation of hepatic immune responses from anti-tumor towards pro-tumor is crucial for cancer progression. This process is closely correlated with the functional polarization of these macrophages. In situ genome editing of liver resident macrophage with intention to shift macrophage function to stimulate anti-tumor immune responses is promising in treating liver cancers.MethodsWe have previously shown that Kupffer cells quickly capture and phagocytose circulating bacteria, making bacteria as a potential liver macrophage-specific deliver vector. Taking advantages of the clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 technology, we have established a bacteria mediated genome editing methods for liver resident macrophages in vivo.ResultsWe used a non-pathogenic Escherichia coli (E. coli) strain as a deliver vector for the CRISPR-Cas9 plasmids, essentially all liver resident macrophages but neither liver sinusoids endothelial cells nor hepatocytes were shown to taken up the bacteria, indicating the robustness and specificity of E. coli-mediated plasmid delivery. To test the genome editing efficiency, we chose VSIG4, Tim-4 and F4/80 that were highly expressed by Kupffer cells and validated the gene knockout/knockdown effects using intravital imaging. Expression of these receptors by Kupffer cells diminished by more than 90%. Simultaneously editing of multiple genes was also achieved with a slightly decreased efficiency when compared to single gene editing. The acute inflammatory responses and the hepatotoxity caused by bacteria were ameliorated by pre-immunization with the same E. coli strain, and can be further minimized by using a mutant E. coli strain that processed a modified LPS structure, which dramatically decreased the TLR-4 mediated inflammatory signaling and improved the safety of this method. Moreover, we have shown that not only embryonically-derived Kupffer cell but also monocyte-derived liver macrophages could be edited. The applications of this approach in treating primary liver cancers and liver metastasis are under investigation.ConclusionsTaken together, we have established a rapid, efficient and convenient method to achieve in situ genome editing of liver resident macrophages in vivo. By targeting essential genes that instruct macrophage polarization, this method could be used as immunotherapy for liver diseases, including cancers.

Biological Micro/Nanofluidics

2008 ◽  
Author(s):  
Shuichi Takayama ◽  
Yi-Chung Tung ◽  
Bor-Han Chueh
Keyword(s):  
Mammalian Cells ◽  
The Body ◽  
Biological Information ◽  
Screening Methods ◽  
Vitro Fertilization ◽  
Stem Cell Engineering ◽  
Biological Studies ◽  
Spatio Temporal

Many biological studies, drug screening methods, and cellular therapies require culture and manipulation of living cells outside of their natural environment in the body. The gap between the cellular microenvironment in vivo and in vitro, however, poses challenges for obtaining physiologically relevant responses from cells used in basic biological studies or drug screens and for drawing out the maximum functional potential from cells used therapeutically. One of the reasons for this gap is because the fluidic environment of mammalian cells in vivo is microscale and dynamic whereas typical in vitro cultures are macroscopic and static. This presentation will give an overview of efforts in our laboratory to develop programmable microfluidic systems that enable spatio-temporal control of both the chemical and fluid mechanical environment of cells. The technologies and methods close the physiology gap to provide biological information otherwise unobtainable and to enhance cellular performance in therapeutic applications. Specific biomedical topics that will be discussed include subcellular signalling in normal and cancer cells, in vitro fertilization on a chip, studies of the effect of physiological and pathological fluid mechanical stresses on endothelial and epithelial cells, and microfluidic stem cell engineering. In the nanoscale regime, tunable nanochannels that can manipulate single DNA molecules will be discussed.

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