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At the end of May 2024, a traditional regional meeting of editors of small scientific journals in engineering disciplines was held at the Faculty of Mechanical Engineering in Belgrade. This year the meeting gathered about 20 editors who discussed novelties, good practices as well as problems in academic publishing. The primary aim of these journals was to support the local scientific community and industry by providing a platform for presenting scientific advances, connecting research and practice, and assisting young scientists in publishing their research results. However, with the widespread adoption of measuring scientific perfor­mance by publication and citation statistics, the scientists lost interest in these journals as underrated in researcher evaluation systems. Thus, low quality of received as well as revised manuscripts, low response rates of reviewers, and, consequently, long processing times and high rejection rates are some of the main problems mentioned at the meeting. All these issues are usually managed by editorial offices, which often have neither technical nor human resources for such endeavors. Still, the conclusion of the meeting was that the benefits of small independent scientific journals are significant and worth efforts particularly for providing an alternative to the profit-oriented publishing and promoting societally relevant research and value-based scientific assessments., Krajem maja 2024. godine na Mašinskom fakultetu u Beogradu održan je tradicionalni regionalni skup urednika malih naučnih časopisa iz inženjerskih disciplina. Ove godine skup je okupio oko 20 urednika koji su razgovarali o novinama, dobrim praksama, kao i problemima u akademskom izdavaštvu. Primarni cilj ovih časopisa bio je da podrže lokalnu naučnu zajednicu i industriju pružanjem platforme za predstavljanje naučnih dostignuća, povezivanje istraživanja i prakse i pomoć mladim naučnicima u objavljivanju rezultata svojih istraživanja. Međutim, sa usvajanjem široko rasprostranjenog merenja naučnog učinka putem statistike objavljivanja i broja citata, naučnici u regionu su izgubili interesovanje za ove časopise kao potcenjene u sistemima evaluacije istraživača. Dakle, loš kvalitet primljenih, kao i revidiranih rukopisa, niske stope odgovora recenzenata i, shodno tome, dugo vreme obrade i visoke stope odbijanja radova su neki od glavnih problema pomenutih na sastanku. Sve ove časopise najčešće vode redakcije koje često nemaju ni tehničke ni ljudske resurse za takve poduhvate. Ipak, na sastanku je zaključeno da su prednosti ovakvih malih nezavisnih naučnih časopisa značajne i vredne truda, posebno u pružanju alternative profitno orijentisanom izdavaštvu, kao i promovisanju društveno relevantnih istraživanja i procene naučnih doprinosa zasnovane na vrednostima.

In tissue engineering, collaboration among experts from different fields is needed to design appropriate cell scaffolds and the required 3D environment. Osteochondral tissue engineering is particularly challenging due to the necessity to provide scaffolds that imitate structural and compositional differences of two neighboring tissues, articular cartilage and bone, and the required complex biophysical environments to cultivate such scaffolds. This work focuses on two key objectives: first, to develop bilayered osteochondral scaffolds based on gellan gum and bioactive glass, and second, to create a biomimetic environment for scaffold characterization by designing and utilization of novel dual-medium cultivation bioreactor chambers. Basic chemical engineering principles were utilized to aid both aims. First, a simple heat transport model based on one-dimensional conduction was applied as a guideline for bilayered scaffold preparation, leading to the formation of the gelatinous upper part and a macroporous lower part with a thin, well-integrated interfacial zone. Second, a novel cultivation chamber was developed to be used in a dynamic compression bioreactor to provide possibilities for flow of two different media, such as chondrogenic and osteogenic. These chambers were utilized for characterization of the novel scaffolds regarding bioactivity and stability under dynamic compression and fluid perfusion during 14 days, while flow distribution under different conditions was analyzed by a tracer method and residence time distribution analysis.

Comprehensive research, particularly in evaluating drug efficacy, still heavily relies on the results obtained by the utilization of cell monolayers and animals. However, the inherent limitations of these models such as their physiological disparities from humans pose significant obstacles to acquiring reliable results thus impeding further scientific progression. To address this challenge, 3D in vitro cell culture models emerged as physiologically relevant models having the potential to enhance research and drug discovery. Our study aimed to develop a 3D in vitro cell culture model based on bone-like scaffolds in conjunction with a perfusion bioreactor (“3D Perfuse”, Innovation Center FTM, Belgrade, Serbia) for studying both physiological and pathological (i.e. tumors) bone conditions.

The slow advance in anticancer drug development can be attributed to the limitations of conventional models, predominantly monolayer cell (2D) cultures and animal models, which inadequately recapitulate the complex nature of human malignant tumors. Three-dimensional (3D) in vitro models are invaluable tools in drug screening; however, creating a universal model for all cancer types poses challenges due to the diverse nature of cancers. The aim of this work was to develop a single, versatile model using alginate microfibers to accommodate cultivation of various cancer cells.

Development of novel, effective, and safe anti-tumor drugs is still a slow and cumbersome process, which is often attributed to weaknesses of current preclinical assays and low correlation of the preclinical in vitro and in vivo data with the results obtained in clinical trials. Consequently, there is a clear need for development of more reliable in vitro three dimensional (3D) tumor models, which will capture key features of the in vivo tumor cell microenvironment and provide drug testing results relevant for human patients. The aim of the project “Biomimetic tumor engineering to enhance drug discovery – BioengineeredTumor” funded by the Science Fund of the Republic of Serbia is to develop 2 novel, simple and robust 3D models for cultures of carcinoma and osteosarcoma cells by applying systematic and integrated methodology to comprehensively define the key model components. In specific, the aim is to use different human and animal cancer cell lines in conjunction with alginate-based biomaterials as artificial extracellular matrices imitating tumor environments and to cultivate the obtained constructs in perfusion bioreactors providing enhanced transport of nutrients, gases and biochemical signals to the cells as well as adequate levels of hydrodynamic shear stresses. Thus, the strategic goal is to establish an adaptable platform suited to the use by scientists without technical expertise for long-term in vitro studies of cancer cells for applications in anti-cancer drug discovery and validation, development of personalized medical treatments, and cancer research.

Traditional cotton wound dressings, like gauze and bandages, remain popular in wound care due to their affordability. However, they have drawbacks: adhering to wounds, risking tissue damage and low absorbance of secretions, requiring multiple layers, and causing discomfort. Modern alternatives, such as alginate hydrogel dressings, target these issues. Designed for moderate to intense exudate wounds, they enhance comfort and treatment effectiveness. Yet, their higher cost limits accessibility. Moreover, neither alginate nor cotton gauze offer bioactivity, while mechanical strength of alginate hydrogel may be inadequate. This work aims to develop enhanced gauzes to overcome these challenges, offering improved functionality at affordable costs and superior wound care.

Tehničko rešenje obuhvata formulaciju i tehnologiju dobijanja unapređenih gaza za tretman rana koje su porozne, ojačane tkaninom i ne lepe se za ranu, pri tome upijaju sekret rane i regulišu njenu vlažnost, dok kontrolisano mogu da otpuštaju različite aktivne komponente, kao što su npr. joni srebra ili cinka. Prema tome, tehničko rešenje pripada oblasti materijali i hemijske tehnologije.

In the past decades, anticancer drug development brought the field of tumor engineering to a new level by the need of robust test systems. Simulating tumor microenvironment in vitro remains a challenge, and osteosarcoma—the most common primary bone cancer—is no exception. The growing evidence points to the inevitable connection between biomechanical stimuli and tumor chemosensitivity and aggressiveness, thus making this component of the microenvironment a mandatory requirement to the developed models. In this review, we addressed the question: is the “in vivo - in vitro” gap in osteosarcoma engineering bridged from the perspective of biomechanical stimuli? The most notable biomechanical cues in the tumor cell microenvironment are observed and compared in the contexts of in vivo conditions and engineered three-dimensional in vitro models.

Introduction: The NT2/D1 embryonal carcinoma cell line represents a well-established in vitro model of human neurogenesis. It’s widely used for studying neurodevelopmental processes, neurotoxicity, and neurodegenerative disorders. The utilization of alginate fibers as a 3D cell culture system offers a biocompatible and structurally supportive environment for neural differentiation and maturation of cells, making it a suitable tool for investigating neurodevelopmental processes. Methods: In thisstudy, we evaluated the alginate microfibers as a 3D modelsystem for in vitro neural differentiation of NT2/D1 cells.We described the immobilization of NT2/D1 cellsin alginate microfibers and the effect of propagation in this 3D model on morphological features, viability, and proliferation of immobilized cells. We also assessed the RA-induced initiation of neural differentiation of NT2/D1 cellsin alginate microfibers by comparison with the initiation of neural differentiation in adherent 2D cell culture. Results: Our results showed that immobilized NT2/D1 acquired morphological features characteristic of cells propagated in 3D model systems and retain viability, proliferative capacity, and ability to attach to adherent surfaces. In addition, immobilized NT2/D1 cells preserved neural differentiation capacity. Upon RA induction we detected a marked decrease in the expression of specific pluripotency-maintaining markers, SOX2, OCT4, and NANOG. Consecutively, the expression of early neural markers, SOX3, PAX6, and miR219 was significantly increased. Conclusion: Neural differentiation of NT2/D1 cellsimmobilized within alginate fibersrepresents a highly promising 3D modelsystem forstudying human neurogenesis and offers a valuable platform forscreening the effect of drugs and bioactive compounds on human neural differentiation.

Everyday struggle of humanity with novel diseases and present once, urge researchers to find novel and improve existing therapies to enhance their efficiency and safety. One of the promising approaches to overcome these challenges is controlled release of drugs. Biomaterials based on poly(methacrylic acid) (PMAA) are excellent drug delivery systems because they can control release rate and released amount of drug. Also, due to their pH sensitivity the PMAA hydrogels can release drug at the site of action. Namely, these nontoxic and biocompatible hydrogels swell in the environment with pH value higher than pKa of PMAA (4.6) and release encapsulated drug during the process. In present study, PMAA hydrogels are synthetized under ambient conditions by simple, cost effective and eco-friendly synthesis. Novel initiation system based on hydrogen peroxide, potato peel peroxidase and vitamin C (VC) is used for the first time for free radical polymerization of PMAA hydrogel. In accordance with the principles of circular economy, peroxidase was isolated from potato peel waste by water extraction for 12 h at 4 ℃. Four PMAA hydrogels were prepared by using potato peel peroxidase with various enzyme activity (0.4; 0.8; 1.2 and 1.8 IU), whereas the amounts of H2O2 (30 mL) and VC (10 mg) have been kept constant. The composition of the PMAA hydrogels was confirmed by FTIR analysis, whereas their porous structure was revealed by SEM. The swelling of the PMAA hydrogels was monitored in two media: 0.1M HCl (as simulation of human stomach) and phosphate buffer with pH 7.4 (as simulation of human intestines). In order to encapsulate anti-inflammatory drug – dexamethasone into the PMAA hydrogels, the hydrogels were immersed into the dexamethasone aqueous solution (5 mg/ml) and left to swell to the equilibrium, after which they were dried at room temperature. Dexamethasone release from the PMAA hydrogels was monitored in the same environments as was the PMAA swelling. The results showed th

Development of novel biomaterials for potential biomedical applications requires comprehensive preclinical studies. Traditional methods for biomaterial evaluation are based on in vitro testing routinely performed in monolayer cell cultures followed by in vivo animal studies. However, these methods have numerous limitations. Although studies in cell monolayers allow rapid evaluation of biomaterials by standardized protocols, quantitative and comparable results, cell metabolism and morphology is changed in the 2-dimensional environment often leading to unreliable results. On other hand, animal studies are complex, time-consuming, expensive and raise ethical concerns. One of the approaches to address this problem and obtain reliable results in a more efficient way is utilization of biomimetic bioreactors. These bioreactors are primarily developed as an essential component in tissue engineering mimicking physiological in vivo conditions in particular tissue or organ by providing all necessary biochemical (e.g. pH, nutrients, gases, growth factors) and biophysical signals (e.g., shear stress, hydrostatic pressure, mechanical strains) for cell differentiation and metabolic activity. Some examples include perfusion bioreactors, bioreactors with shear stresses and/or dynamic compression, and bioreactor with stretch and shear stresses imitating conditions in vascularized tissues, articular cartilage, and vascular grafts, respectively. Such physiologically relevant, while strictly controlled environment is also beneficial for biomaterial assessment, investigation of cell-biomaterial interactions, and prediction of biomaterial behaviour upon application. The present review provides readers with up-to-date studies and results regarding utilization of biomimetic bioreactors as tools for comprehensive and efficient evaluation of novel biomaterials, such as determination of mechanical characteristics, release of bioactive substances, cell-biomaterial interactions and cytotoxicity.

Biomaterials engineering is one of the strongest research areas at the Faculty of Technology and Metallurgy (FTM), University of Belgrade including development of novel biomaterials for orthopaedic and dental applications. Especially, synthesis and physico-chemical characterization methods are well established resulting in variety of novel inorganic, polymer and composite biomaterials produced in different forms with controlled compositions and structures. Still, expertise in further advancement of the research results towards utilization in medical devices is lacking. The ExcellMater Horizon 2020 project aims to further advance the scientific and technological capacity of the Faculty in this area by twinning the knowledge from the three European partners, internationally leading institutions, with recognized expertise in biological characterization methods, intellectual property protection and utilization, evaluation of health technologies and regulatory aspects of medical devices. The aim of the project is also to increase visibility of scientific research and enhance collaboration of engineers at FTM with life scientists, medical doctors and pharmacists as well as with industry. Here, we will present some of the novel bioceramic and composite biomaterials developed at FTM aimed for potential applications in orthopaedics, dentistry, bone tissue engineering, and cancer research.

A multidisciplinary approach based on experiments and mathematical modeling was used in biomimetic system development for three-dimensional (3D) cultures of cancer cells. Specifically, two cancer cell lines, human embryonic teratocarcinoma NT2/D1 and rat glioma C6, were immobilized in alginate microbeads and microfibers, respectively, and cultured under static and flow conditions in perfusion bioreactors. At the same time, chemical engineering methods were applied to explain the obtained results. The superficial medium velocity of 80 mu m s(-1) induced lower viability of NT2/D1 cells in superficial microbead zones, implying adverse effects of fluid shear stresses estimated as similar to 67 mPa. On the contrary, similar velocity (100 mu m s(-1)) enhanced the proliferation of C6 glioma cells within microfibers compared to static controls. An additional study of silver release from nanocomposite Ag/honey/alginate microfibers under perfusion indicated that the medium partially flows through the hydrogel (interstitial velocity of similar to 10 nm s(-1)). Thus, a diffusion-advection-reaction model described the mass transport to immobilized cells within microfibers. Substances with diffusion coefficients of similar to 10(-)(19)-10(-11) m(2) s(-)(1) are sufficiently supplied by diffusion only, while those with significantly lower diffusivities (similar to 10(-1)(9) m(2) s(-1)) require additional convective transport. The present study demonstrates the selection and contribution of chemical engineering methods in tumor model system development.