synthesis-aptamer-pei-g-peg-modified-gold-nanoparticles-loaded-with

Synthesis of Aptamer-PEI-g-PEG Modified Gold Nanoparticles Loaded with Doxorubicin for Targeted Drug Delivery

Due to drug resistance and toxicity in healthy cells, use of doxorubicin (DOX) has been limited in clinical cancer therapy. This protocol describes the ...

Xinyang Normal University

University Hospitals Leuven

The chitosan/gelatin hydrogel incorporated with biphasic calcium phosphate nanoparticles (BCP-NPs) as scaffold (CGB) for bone tissue engineering was reported in this article. Such nanocomposite hydrogels were fabricated by using cycled freeze-thawing method, of which physicochemical and biological properties were regulated by adjusting the weight ratio of chitosan/gelatin/BCP-NPs. The needle-like BCP-NPs were dispersed into composites uniformly, and physically cross-linked with chitosan and gelatin, which were identified via Scanning Electron Microscope (SEM) images and Fourier Transform Infrared Spectroscopy (FT-IR) analysis. The porosity, equilibrium swelling ratio, and compressive strength of CGB scaffolds were mainly influenced by the BCP-NPs concentration.  degradation analysis in simulated body fluids (SBF) displayed that CGB scaffolds were degraded up to at least 30 wt% in one month. Also, CCK-8 analysis confirmed that the prepared scaffolds had a good cytocompatibility through in culturing with bone marrow mesenchymal stem cells (BMSCs). Finally,  animal experiments revealed that new bone tissue was observed inside the scaffolds, and gradually increased with increasing months, when implanted CGB scaffolds into large necrotic lesions of rabbit femoral head. The above results suggested that prepared CGB nanocomposites had the potential to be applied in bone tissue engineering.

Development of chitosan/gelatin hydrogels incorporation of biphasic calcium phosphate nanoparticles for bone tissue engineering.

Proteins are the most critical executive molecules by responding to the instructions stored in the genetic materials in any form of life. More frequently, proteins do their jobs by acting as a roleplayer that interacts with other protein(s), which is more evident when the function of a protein is examined in the real context of a cell. Identifying the interactions between (or amongst) proteins is very crucial for the biochemistry investigation of an individual protein and for the attempts aiming to draw a holo-picture for the interacting members at the scale of proteomics ( or protein-protein interactions mapping). Here, we introduced the currently available reporting systems that can be used to probe the interaction between candidate protein pairs based on the fragment complementation of some particular proteins. Emphases were put on the principles and details of experimental design. These systems are dihydrofolate reductase (DHFR), β-lactamase, tobacco etch virus (TEV) protease, luciferase, β-galactosidase, GAL4, horseradish peroxidase (HRP), focal adhesion kinase (FAK), green fluorescent protein (GFP), and ubiquitin.

Detecting protein-protein interaction based on protein fragment complementation assay.

The ribosome is an essential organelle in charge of the translational processes in all kinds of cells. Currently, the scenario of its function has been significantly expanded from the classic machine for protein synthesis to a regulatory platform for quality control to maintain the protein homeostasis in a living cell. The ribosome is much more than a mechanical device with a static structure: it is inherently dynamic in structure and function, especially in response to the environmental fluctuations. Considerable effort has been made to regulate its structure and physiological function by engineering the components of a ribosome. The findings of the pioneering studies significantly deepened our understanding of a ribosome and exemplified how a ribosome could be engineered for biotechnology purposes in the era of synthetic biology. The engineering of ribosome offered highly accessible methods capable of comprehensively optimizing the performance of strains of industrial importance. In this article, the relevant recent advances were systematically reviewed.

Engineering the Translational Machinery for Biotechnology Applications.

The cellular ribosome shows a naturally evolved strong preference for the synthesis of proteins with standard amino acids. An in-depth understanding of the translation process enables scientists to go beyond this natural limitation and engineer translating systems capable of synthesizing proteins with artificially designed and synthesized non-standard amino acids (nsAA) featuring more bulky sidechains. The sidechains can be functional groups, with chosen biophysical or chemical activities, that enable the direct application of these proteins. Alternatively, the sidechains can be designed to contain highly reactive groups: enabling the ready formation of conjugates via a covalent bond between the sidechain and other chemicals or biomolecules. This co-translational incorporation of nsAAs into proteins allows for a vast number of possible applications. In this paper, we first systematically summarized the advances in the engineering of the translation system. Subsequently, we reviewed the extensive applications of these nsAA-containing proteins (after chemical modification) by discussing representative reports on how they can be utilized for different purposes. Finally, we discussed the direction of further studies which could be undertaken to improve the current technology utilized in incorporating nsAAs in order to use them to their full potential and improve accessibility across disciplines.

Incorporation of nonstandard amino acids into proteins: principles and applications.

Fabrication of reinforced scaffolds for bone regeneration remains a significant challenge. The weak mechanical properties of the chitosan (CS)-based composite scaffold hindered its further application in clinic. Here, to obtain hydroxyethyl CS (HECS), some hydrogen bonds of CS were replaced by hydroxyethyl groups. Then, HECS-reinforced polyvinyl alcohol (PVA)/biphasic calcium phosphate (BCP) nanoparticle hydrogel was fabricated via cycled freeze-thawing followed by an  biomineralization treatment using a cell culture medium. The synthesized hydrogel had an interconnected porous structure with a uniform pore distribution. Compared to the CS/PVA/BCP hydrogel, the HECS/PVA/BCP hydrogels showed a thicker pore wall and had a compressive strength of up to 5-7 MPa. The biomineralized hydrogel possessed a better compressive strength and cytocompatibility compared to the untreated hydrogel, confirmed by CCK-8 analysis and fluorescence images. The modification of CS with hydroxyethyl groups and  biomineralization were sufficient to improve the mechanical properties of the scaffold, and the HECS-reinforced PVA/BCP hydrogel was promising for bone tissue engineering applications.

Hydroxyethyl Chitosan-Reinforced Polyvinyl Alcohol/Biphasic Calcium Phosphate Hydrogels for Bone Regeneration.

Ribosome is primarily regarded as the committing organelle for the translation process. Besides the expansion of its function from a translational machine for protein synthesis to a regulatory platform for protein quality control, the activity regulation and recycling of ribosome have been deepened significantly. Recent advances have confirmed a novel mechanism in the regulation of ribosome activity when a cell encounters adverse conditions. Due to the binding of certain protein factors onto a ribosome, the structural and functional change of the ribosome inside the cell will take place, thereby leading to the formation of inactive ribosomes (70S monomer or 100S dimer), or ribosome hibernation. By ribosome hibernation, the overall protein synthesis rate of a cell could be slowed down. The resistance to adverse conditions or chemicals of the host cell will be enhanced. In this paper, we discussed the phenomenon, molecular mechanism, and physiological effect of ribosome hibernation when cells are under stresses. And then, we discussed the resuscitation of a hibernating ribosome and the role of ribosome hibernation in the treatment of antimicrobial infection.

Lei Nie

College of Life Sciences

Xinyang Normal University

Synthesis of Aptamer-PEI-g-PEG Modified Gold Nanoparticles Loaded with Doxorubicin for Targeted Drug Delivery

Lei Nie

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Xinyang Normal University

Synthesis of Aptamer-PEI-g-PEG Modified Gold Nanoparticles Loaded with Doxorubicin for Targeted Drug Delivery

College of Life Sciences