Magnetic hydrogel applications in articular cartilage tissue engineering

Articular cartilage defects afflict millions of individuals worldwide, presenting a significant challenge due to the tissue's limited self-repair capability and anisotropic nature. Hydrogel-based biomaterials have emerged as promising candidates for scaffold production in artificial cartilage construction, owing to their water-rich composition, biocompatibility, and tunable properties. Nevertheless, conventional hydrogels typically lack the anisotropic structure inherent to natural cartilage, impeding their clinical and preclinical applications. Recent advancements in tissue engineering (TE) have introduced magnetically responsive hydrogels, a type of intelligent hydrogel that can be remotely controlled using an external magnetic field. These innovative materials offer a means to create the desired anisotropic architecture required for successful cartilage TE. In this review, we first explore conventional techniques employed for cartilage repair and subsequently delve into recent breakthroughs in the application and utilization of magnetic hydrogels across various aspects of articular cartilage TE.

Escherichia coli cytosine deaminase: Structural and biotechnological aspects

Suicide gene therapy involves introducing viral or bacterial genes into tumor cells, which enables the conversion of a nontoxic prodrug into a toxic-lethal drug. The application of the bacterial cytosine deaminase (bCD)/5-fluorocytosine (5-FC) approach has been beneficial and progressive within the current field of cancer therapy because of the enhanced bystander effect. The basis of this method is the preferential deamination of 5-FC to 5-fluorouracil by cancer cells expressing cytosine deaminase (CD), which strongly inhibits DNA synthesis and RNA function, effectively targeting tumor cells. However, the poor binding affinity of toward 5-FC compared to the natural substrate cytosine and/or inappropriate thermostability limits the clinical applications of this gene therapy approach. Nowadays, many genetic engineering studies have been carried out to solve and improve the activity of this enzyme. In the current review, we intend to discuss the biotechnological aspects of Escherichia coli CD, including its structure, functions, molecular cloning, and protein engineering. We will also explore its relevance in cancer clinical trials. By examining these aspects, we hope to provide a thorough understanding of E. coli CD and its potential applications in cancer therapy.

Gold Nanobiosensor Based on the Localized Surface Plasmon Resonance is Able to Diagnose Human Brucellosis, Introducing a Rapid and Affordable Method

Brucellosis is considered as the most common bacterial zoonosis in the world. Although the laboratory findings are the most reliable diagnosis today, the current laboratory methods have many limitations. This research aimed to design and evaluate the performance of a novel technique based on the localized surface plasmon resonance (LSPR) to eliminate or reduce existing shortcomings. For this purpose, smooth lipopolysaccharides were extracted from Brucella melitensis and Brucella abortus and fixed on the surface of the gold nanoparticles through covalent interactions. After some optimizing processes, dynamic light scattering was used to characterize the probe. The detection of captured anti-Brucella antibody was performed by measuring the redshift on LSPR peak followed by the determination of cutoff value, which indicated a significant difference between controls and true positive patients (P value < 0.01). Furthermore, 40 sera from true negative samples and positive patients were used to evaluate the performance of this method by comparing its outcomes with the gold standard (culture), standard tube agglutination test, and anti-brucellosis IgM and IgG levels (ELISA). The sensitivity, specificity, positive predictive value, and negative predictive value showed an appropriate performance of the LSPR-based method (85%, 100%, 100%, and 86%, respectively). The current research results provide a promising fast, convenient, and inexpensive method for detecting the anti-Brucella antibodies in human sera, which can be widely used in medical laboratories to diagnose brucellosis quickly and effectively.

Caspase-3: Structure, function, and biotechnological aspects

Caspase-3, a cysteine-aspartic acid protease, has recently attracted much attention because of its incredible roles in tissue differentiation, regeneration, and neural development. This enzyme is a key zymogen in cell apoptosis and is not activated until it is cleaved by initiator caspases during apoptotic flux. Since caspase-3 has represented valuable capabilities in the field of medical research, biotechnological aspects of this enzyme, including the production of recombinant type, protein engineering, and designing delivery systems, have been considered as emerging therapeutic strategies in treating the apoptosis-related disorders. To date, several advances have been made in the therapeutic use of caspase-3 in the management of some diseases such as cancers, heart failure, and neurodegenerative disorders. In the current review, we intend to discuss the caspase-3's structure, functions, therapeutic applications, as well as its molecular cloning, protein engineering, and relevant delivery systems.

Green synthesis of iron-based nanoparticles using Chlorophytum comosum leaf extract: methyl orange dye degradation and antimicrobial properties

Nowadays, green synthesis methods have gained growing attention in nanotechnology owning to their versatile features including high efficiency, cost-effectiveness, and eco-friendliness. Here, the aqueous extract of Chlorophytum comosum leaf was applied for the preparation of iron nanoparticles (INPs) to obtain spherical and amorphous INPs with a particle size below 100 nm as confirmed by TEM. The synthesized INPs managed to eliminate methyl orange (MO) from the aqueous solution. The concentration of MO can be easily checked via ultraviolet-visible (UV-Vis) spectroscopy throughout the usage of INPs at the presence of H2O2. The synthesized INPs exhibited MO degradation efficiency of 77% after 6 h. Furthermore, the synthesized INPs exhibited antibacterial activity against both Gram-negative and Gram-positive bacteria. The prepared INPs have an impressive effect on Staphylococcus aureus at concentrations below 6 μg/ml. Overall, the synthesized INPs could considerably contribute to our combat against organic dyes and bacteria.

High rate of contamination with Staphylococcus aureus in traditional Koozeh cheeses. A molecular typing approach

BACKGROUND

Koozeh cheese is an Iranian dairy product in rural areas, it is necessary to consider the microbial contamination in this supply.

OBJECTIVE

This study evaluates microbial contamination in Koozeh cheese by molecular tools.

MAATERIAL AND METHODS

S. aureus and its enterotoxins including type A and type B were identified by biochemical and polymerase chain reaction (PCR) and molecular typing was done by RAPD (Random Amplification of Polymorphic DNA) method. A total of 42 sheeps and cows Koozeh cheese samples were collected from random market in the cities and the surrounding villages.

RESULTS

71.42% of samples were contaminated with Staphylococcus spp. and in 50% of isolates, S. aureus specific coagulase gene "coa" was detected. High-level contamination was observed in 7.14% of samples. The SEA or SEB enterotoxins were produced in 42.84% of isolates. No clonal relationship was observed by molecular approach.

CONCLUSION

The obtained results indicate a high level of microbial contamination in Koozeh cheese. Half of isolates were enterotoxin producer and had high diversity and no clonal relationship. Long processing and manipulation are involved in contamination. Improvement in hygiene, training local manufactures of Koozeh cheese, control of products for possible contamination and developing new protocols is needed to decrement of S. aureus contamination in Koozeh Cheese products.

Emerging frontiers in drug release control by core-shell nanofibers: a review

In recent years, core-shell (CS) nanofiber has widely been used as a carrier for controlled drug release. This outstanding attention toward CS nanofiber is mainly due to its tremendous significance in controllable drug release in specific locations. The major advantage of CS nanofibers is forming a highly porous mesh, boosting its performance for many applications, due to its large surface-to-volume ratio. This inherently high ratio has prompted electrospun fibers to be considered one of the best drug-delivery-systems available, with the capacity to enhance properties such as cell attachment, drug loading, and mass transfer. Using electrospun fibers as CS nanofibers to incorporate different cargos such as antibiotics, anticancer agents, proteins, DNA, RNA, living cells, and diverse growth factors would considerably satisfy the need for a universal carrier in the field of nanotechnology. In addition to their high surface area, other benefit included in these nanofibers is the ability to trap drugs, easily controlled morphology, and their biomimetic characteristics. In this review, by taking the best advantages of the preparation and uses of CS nanofibers, a novel work in the domain of the controlled drug delivery by nanofiber-based scaffolds is presented.

Green synthesized nanoclusters of ultra-small zero valent iron nanoparticles as a novel dye removing material

Iron based nanoparticles have gained much attention in recent years due to their unique physicochemical properties especially in the environmental remediation practices. There has been an increasing demand for new sustainable techniques for production of these nanoparticles. In the present work, a novel iron nanostructure was successfully fabricated by a facile and green approach using the aqueous extract of Mediterranean cypress (Cupressus sempervirens). In fact, nanoclusters of highly reactive ultra-small (~1.5nm in diameter) iron nanoparticles were constructed. Diameters of iron nanoclusters were measured to be from 9 to 31nm with mean diameter of 19nm. Appearance of the characteristic X-ray diffraction peak of zero valent iron at 2θ=43.5° indicates the great potential of Mediterranean cypress leaf extract for complete reduction of ferric ions. The presence of phytochemicals as organic capping agent was confirmed by IR radiation absorption at 1020cm^-1 and 1623cm^-1 corresponding to the presence of CO and carbonyl groups, respectively. The fabricated nanoclusters also showed a great potential for dye removal from aqueous solution in a time dependent manner. Decolourization efficiency was calculated to be 95% in a 6h process for methyl orange removal. The results of this study suggest the possibility of using iron nanoclusters for future pollutants removal applications from aqueous environments.