Editorial: Microenvironment-Derived Stem Cell Plasticity

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Recent advances on gradient hydrogels in biomimetic cartilage tissue engineering [version 2; referees: 2 approved]

Articular cartilage (AC) is a seemingly simple tissue that has only one type of constituting cell and no blood vessels and nerves. In the early days of tissue engineering, cartilage appeared to be an easy and promising target for reconstruction and this was especially motivating because of widespread AC pathologies such as osteoarthritis and frequent sports-induced injuries. However, AC has proven to be anything but simple. Recreating the varying properties of its zonal structure is a challenge that has not yet been fully answered. This caused the shift in tissue engineering strategies toward bioinspired or biomimetic approaches that attempt to mimic and simulate as much as possible the structure and function of the native tissues. Hydrogels, particularly gradient hydrogels, have shown great potential as components of the biomimetic engineering of the cartilaginous tissue

Stimulating Innovations from University through the Use of Digital Fabrication - Case Study of the SciFabLab at Faculty of Mechanical Engineering, University of Belgrade

Fabrication laboratory (FabLab), first created at MIT-USA, is a digital fabrication workshop equipped with tools that enable students to produce their own prototypes and engage in “learning-by-doing” process. Fablab is a do-it-yourself "DIY" workshop with open-source digital design and manufacturing CNC-machines (3D printers, laser cutters and electronics e.g. Arduino, Raspberry Pi), with a strong focus towards technology transfer options and as such is strongly connected with both the small and medium entreprizes (SMEs) and large industry in a unique ecosystem [1]. There are no such ecosystems yet in Serbia. A project started at the University of Belgrade - Faculty of Mechanical Engineering, already possessing fablab-ready infrastructure [CNC (computer-numerical controlled) machines, lab/workshop space and teaching venue] aims to establish one component of such an ecosystem –a Scientific Fab Lab (SciFabLab) as a fablab unit dedicated to scientific research using digital fabrication with special focus on possible industrial applications. SciFabLab acts as a connecting hub between scientists, entrepreneurs and SMEs/large industry enabling efficient technology transfer i.e. putting scientific findings to practice by developing unique technology products. The article will present stages of SciFabLab establishment and conclusions about the ensuing stimulation of innovations and modernization of participating faculties, research centers and universities.[http://is.fink.rs/podaci/Milan_Matijevic/50/Stimulating%20innovations%20from%20university%20through%20the%20use%20of%20digital%20fabrication%20%E2%80%93%20case%20study.pdf

Point-of-Need DNA Testing for Detection of Foodborne Pathogenic Bacteria

Foodborne pathogenic bacteria present a crucial food safety issue. Conventional diagnostic methods are time-consuming and can be only performed on previously produced food. The advancing field of point-of-need diagnostic devices integrating molecular methods, biosensors, microfluidics, and nanomaterials offers new avenues for swift, low-cost detection of pathogens with high sensitivity and specificity. These analyses and screening of food items can be performed during all phases of production. This review presents major developments achieved in recent years in point-of-need diagnostics in land-based sector and sheds light on current challenges in achieving wider acceptance of portable devices in the food industry. Particular emphasis is placed on methods for testing nucleic acids, protocols for portable nucleic acid extraction and amplification, as well as on the means for low-cost detection and read-out signal amplification

Utilization of hydrochlorate D - (6-3H) glucosamine in the process for purifying and separating the bovine Para-influenza 3 virus glycoproteic sub-units

L 'hydrochlorure de D - (6-3H) glucosamine a été utilisé comme marqueur pour purifier et séparer les sous-unités glucoprotéiques du virus Para- influenzae 3 bovin (PI3). Les résultats obtenus, en particulier avec le poly-éthylène-glycol 6 000 pour la concentration, ont été parfaitement démons tratifs. Une expérimentation sur la mise au point d’un vaccin est possible.Hydrochlorate D - (6-3H) glucosamine was used as mark-product for purifying and separating the bovine Para-influenza 3 virus glycoproteic sub-units. The results obtained, particularly with poly-ethylen-glycol 6 000 for concentration, were perfectly demonstrative. Experiment for vaccine assay is possible

Femtomolar detection of the heart failure biomarker NT-proBNP in artificial saliva using an immersible liquid-gated aptasensor with reduced graphene oxide

Measuring NT-proBNP biomarker is recommended for preliminary diagnostics of the heart failure. Recent studies suggest a possibility of early screening of biomarkers in saliva for non-invasive identification of cardiac diseases at the point-of-care. However, NT-proBNP concentrations in saliva can be thousand time lower than in blood plasma, going down to pg/mL level. To reach this level, we developed a label-free aptasensor based on a liquid-gated field effect transistor using a film of reduced graphene oxide monolayer (rGO-FET) with immobilized NT-proBNP specific aptamer. We found that, depending on ionic strength of tested solutions, there were different levels of correlation in responses of electrical parameters of the rGO-FET aptasensor, namely, the Dirac point shift and transconductance change. The correlation in response to NT-proBNP was high for 1.6 mM phosphate-buffered saline (PBS) and zero for 16 mM PBS in a wide range of analyte concentrations, varied from 1 fg/mL to 10 ng/mL. The effects of transconductance and Dirac point shift in PBS solutions of different concentrations are discussed. The biosensor exhibited a high sensitivity for both transconductance (2 uS/decade) and Dirac point shift (2.3 mV/decade) in diluted PBS with the linear range from 10 fg/mL to 1 pg/mL. The aptasensor performance has been also demonstrated in undiluted artificial saliva with the achieved limit of detection down to 41 fg/mL (~4.6 fM)

loop-mediated isothermal amplification (lamP) as a point-of-care SarS-covdetection method

Pravovremeno testiranje većeg broja ljudi na SARS-CoV-2 virus je povezano sa nižim mortalitetom od COVID-19 oboljenja. Međutim, većina zemalja nema mogućnosti za takvo masivno testiranje putem metode “PCR u realnom vremenu”, zbog visoke cene neophodne opreme i potrebe za stručnim osobljem. Zbog toga se razvijaju brze i ekonomičnije metode, koje se najčešće zasnivaju na izotermalnim metodama amplifikacije DNK. Za ove metode nije potreban ciklični termostat, zbog čega su primenljivije za terensku upotrebu. Fokus je na izotermalnoj amplifikaciji posredovanoj petljom (lamP), zbog njene visoke specifičnosti, mogućnosti za upotrebu neprečišćenih uzoraka i jednostavnosti merenja signala. Autori predstavljaju pregled najvažnijih radova o LAMP metodi za detekciju SARS-CoV-2 virusa objavljenih tokom 2020. godine, kao i opise nekoliko komercijalnih kompleta na bazi LAMP metode za COVID-19 testiranje.Massive testing for SARS-CoV-2 virus is related to lower mortality rates of COVID-19. Most countries face challenges to perform massive testing with the currently available methods (real-time PCR), due to expensive equipment and requirement of highly skilled personnel. To overcome these challenges, faster and cost-effective alternative detection methods are being developed, primarily based on isothermal methods of nucleic acid amplification (isoNAAs). PCR depends on precision instruments, high cleanliness of operating conditions and cannot be easily used on-site, while isoNAAs, which do not require thermal cyclers, are more applicable for point-of-care (PoC) use. Loop-mediated isothermal amplification (LAMP) is one of the isoNAA most in focus for COVID-19 tests due to its high specificity and possibility to use unpurified specimens in combination with simplified detection setup. The article gives a review of the most significant publications on use of LAMP for SARS-CoV-2 detection and of the several commercial LAMP-based COVID-19 testing kits.Ministarstva prosvete, nauke i tehnološkog razvoja Republike Srbije – broj ugovora 451-03-68/2020-14/ 200358 za autore M. Dj, T.K i Lj.J i broj ugovora 451-03-9/2021- 14/200125 za Ž.D.P. Autori zahvaljuju Jeleni Ognjenov na pomoći u pripremi ilustracija za rad

Role of N-type voltage-dependent calcium channels in autoimmune optic neuritis.

Objective: The aim of this study was to investigate the role of voltage-dependent calcium channels (VDCCs) in axon degeneration during autoimmune optic neuritis. Methods: Calcium ion (Ca2 ) influx into the optic nerve (ON) through VDCCs was investigated in a rat model of optic neuritis using manganese-enhanced magnetic resonance imaging and in vivo calcium imaging. After having identified the most relevant channel subtype (N-type VDCCs), we correlated immunohistochemistry of channel expression with ON histopathology. In the confirmatory part of this work, we performed a treatment study using -conotoxin GVIA, an N-type specific blocker. Results: We observed that pathological Ca2 influx into ONs during optic neuritis is mediated via N-type VDCCs. By analyzing the expression of VDCCs in the inflamed ONs, we detected an upregulation of 1B, the pore-forming subunit of N-type VDCCs, in demyelinated axons. However, high expression levels were also found on macrophages/activated microglia, and lower levels were detected on astrocytes. The relevance of N-type VDCCs for inflammation-induced axonal degeneration and the severity of optic neuritis was corroborated by treatment with -conotoxin GVIA. This blocker led to decreased axon and myelin degeneration in the ONs together with a reduced number of macrophages/activated microglia. These protective effects were confirmed by analyzing the spinal cords of the same animals. Interpretation: We conclude that N-type VDCCs play an important role in inflammation-induced axon degeneration via two mechanisms: First, they directly mediate toxic Ca2 influx into the axons; and second, they contribute to macrophage/microglia function, thereby promoting secondary axonal damage

Modification of Polysaccharides with Phenols for Hydrogels Formation and Electrospinnig

Carboxymethylcellulose (CMC) and alginate (ALG) are water-soluble polysaccharides used in food and cosmetics industry. They have big potential for use in pharmaceutical products due to their high biocompatibility, biodegradibility, low immunogenicity and low price. When crosslinked they can absorb large amounts of water and swell to form hydrogels with great physical properties. The need for new biomaterials and hydrogels is growing daily, due to their use in tissue engineering, drug delivery and cell and enzyme immobilization studies. In this study we modified ALG and CMC, in order to get a cross-linkable polymer that can make hydrogels by chemical and enzymatic means. After periodate oxidation we obtained polysaccharides with different degrees of oxidation: 2.5, 5, 10, 15 and 20 mol%. Further modification using reductive amination in the presence of different phenolic compounds like tyramine, was done. This modification was confirmed by UV–VIS and FT-IR spectroscopy, while concentration of phenol and ionizable groups was determined using absorbance at 275 nm and acid–base titration. All CMC and AlG tyramines were able to form hydrogels after crosslinking with horse radish peroxidase (HRP) and hydrogen peroxide. Both derivatives have been successfully electrospun and crosslinked afterwards. Due to the introduction of amino groups and decrease in molecular weight, they were significantly more soluble in water up to 30 % (w/w) compared to native polysaccharides and their electrospinability also improved. We aim to make nanofibers using tyraminepolysaccharides that will be more stable in cell culture media after cross-linking covalently and with calcium/barium ions. Diameter of nanofibers was determined by scanning electron microscopy (SEM). Cross-linked nanofibers that we obtained will be used for tissue engineering of blood vessels

MODIFICATION OF CARBOXYMETHYLCELLULOSE WITH PHENOLS FOR PEROXIDASE INDUCED HYDROGELS FORMATION AND ELECTROSPINNING

Carboxymethylcellulose (CMC) is water-soluble cellulose ether which is used in food and cosmetics industry. It also has big potential for use in pharmaceutical products due to its high biocompatibility, biodegradibility, low immunogenicity and low price. Crosslinked CMC can absorb large amounts of water and swell to form hydrogels with great physical properties. The need for new biomaterials and hydrogels is growing daily, due to their use in tissue engineering, drug delivery and cell and enzyme immobilization studies. In this study we modified CMC, in order to get a crosslinkable polymer that can make hydrogels by chemical and enzymatic means. After periodate oxidation of CMC we obtained CMC with different degrees of oxidation: 2.5, 5, 10, 15 and 20 mol%. Further modification using reductive amination in the presence of different phenolic compounds like tyramine, was done. This modification of CMC was confirmed by UV–VIS and FT-IR spectroscopy, while concentration of phenol and ionizable groups was determined using absorbance at 275 nm and acid–base titration. All CMCtyramines were able to form hydrogels after cross-linking with horse radish peroxidase (HRP) and hydrogen peroxide. CMC derivatives have been successfully electrospun and crosslinked afterwards. Due to the introduction of amino groups and decrease in molecular weight, they were significantly more soluble in water up to 30 % (w/w) compared to native polysaccharides and their electrospinability also improved. We aim to make nanofibers using tyramine-polysaccharides that will be more stable in cell culture media after cross-linking covalently and with calcium/barium ions. Diameter of nanofibers was determined by scanning electron microscopy (SEM). Cross-linked nanofibers that we obtained will be used for tissue engineering of blood vessels