Regenerative medicine in lung diseases: A systematic review

Regenerative medicine has opened the door to the exploration of new therapeutic methods for the treatment of various diseases, especially those associated with local or general disregulation of the immune system. In pulmonary diseases, new therapeutic strategies have emerged that are aimed at restoring functional lung tissue rather than alleviating symptoms. These strategies focus on tissue regeneration using stem cells and/or their derivatives or replacement of dysfunctional tissue using biomedical engineering. Animal health can directly benefit from regenerative therapy strategies and also serve as a translational experimental model for human disease. Several clinical trials have been conducted to evaluate the effects of cellular treatment on inflammatory lung disease in animals. Data reported to date show several beneficial effects in ex vivo and in vivo models; however, our understanding of the mechanisms that regenerative therapies exert on diseased tissues remains incomplete

PLD growth of strontium titanate thin films on SrO-deoxidized and rGO-buffered Si(001) substrate

Epitaxy represents a process of crystal growth or material deposition in which the new created layers have a high degree of crystallographic alignment with the substrate lattice. In this research 10 nm-thick thin films of strontium titanate (STO) were grown using pulsed laser deposition (PLD) method on Si(001) whose surface was either deoxidized with strontium oxide (SrO) or buffered by reduced graphene oxide (rGO) in combination with SrO deoxidation. In addition to differently prepared Si(001) surface, the effect of deposition temperature on the crystalline structure of the STO thin films was also examined. Reflection high energy electron diffraction (RHEED), atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray reflectivity (XRR) and X-ray photoelectron spectroscopy (XPS) methods were used to examine the properties of the grown films. It was concluded that the STO thin film grown on the rGO-coated Si substrate at 515 °C shows the highest crystallinity with a smooth surface, while the film deposited on the bare silicon has amorphous structure. The STO films grown at 700 °C show textured or polycrystalline structure. Good crystallinity, epitaxial alignment, and clean interface are the major requirements for STO/Si and the STO/rGO/Si heterostructure for making an efficient and stable Si photocathode for the photoelectrochemical (PEC) water splitting. Our future work will be directed toward understanding how the obtained interfaces and crystalline structure of STO films are influencing the PEC process.Twenty-First Young Researchers’ Conference - Materials Science and Engineering: Program and the Book of Abstracts; November 29 – December 1, 2023, Belgrade, Serbi

PLD growth of strontium titanate thin films on silicon substrate for photoelectrochemical water-splitting

Epitaxial films of metal oxides deposited on silicon substrates represent a new type of material that could be used as protective (or electroactive) layer in the photoelectrochemical water splitting. To understand the influence of crystalline and interfacial properties of oxide layer on the water splitting process a ~10 nm strontium titanate (STO) films have been grown using the PLD method on bare and reduced graphene oxide (rGO) buffered silicon substrate. Our approach relied on the oxide-silicon integration using combination of SrO-assisted deoxidation and controllable coverage of silicon surface with a mono- to threelayer of spin-coated GO. The STO films have been grown at 515 and 700 °C and various experimental techniques were used to examine the surface and crystalline properties of grown films (reflection high energy electron diffraction, atomic force microscopy, scanning electron microscopy, X-ray diffraction, X-ray reflectivity and X-ray photoelectron spectroscopy). The results show that the best the crystallinity of the STO thin films was obtained on rGO/SrO deoxidized silicon surface at 515 °C. Future studies will be devoted to electrochemical characterization of the grown films, that will help to establish clearer link on how the interface and crystalline parameters affect the water splitting process.Workshop “Application-oriented material development”; September 12-14, Bucharest, 2023.Contribution: Poste

Electrochemical properties of composites of graphene oxide and cobalt ferrite doped with zink and gallium

The possibility of surface functionalization and formation of stable aqueous suspensions make graphene oxide (GO) suitable as base for composite materials, especially with nanoparticles. Cobalt ferrite (CFO) has attracted attention due to its unique properties such as large magnetic anisotropy, high coercivity, moderate saturation magnetization, excellent chemical stability, mechanical hardness, etc. This study presents the electrochemical properties of GO and CFO composites, as well as CFO doped with zinc (CFO_Zn) and gallium (CFO_Ga). Magnetic nanoparticles were synthesized using the solvothermal method, after which the oleic acid was exchanged with dihydrocaffeic acid to obtain the hydrophilic material. GO was synthesized using a modified Hummer's method. Composites of GO and magnetic nanoparticles were synthesized by the hydrothermal method (T = 120 °C, t = 3 h), with nominal fractions of 5 and 15 wt.% of magnetic nanoparticles. X-ray structural diffraction, as well as FTIR analysis, confirmed the complete oxidation of graphene layers. SEM and TEM images showed deposition of magnetic nanoparticles on GO layer with the different distribution density between 5 wt.% and 15 wt.% composites. Also, shape and size of magnetic nanoparticles remained unchanged. Based on FTIR analysis of hydrothermally treated GO and composites a partial reduction of epoxy groups was found along with hydrogen bond established between the components of the composite. The electrochemical charge storage of composites is mainly of pseudocapacitive nature, which originates from the oxidoreduction reactions of H+ ions from electrolytes and surface functional groups of GO. The best electrochemical properties, in terms of the highest specific capacity, were shown by the composite which contains 15 wt.% CFO, which value is 36.86 F g-1 at a polarization rate of 5 mV s-

Electrochemical properties of composites of graphene-oxide and cobalt-ferrite doped with zink and gallium

U ovom radu prikazana su elektrohemijska svojstva kompozita grafen-oksida i nanočestica kobalt-ferita, kao i kobalt-ferita dopiranog sa cinkom i galijumom. Grafen-oksid (GO) sintetisan je modifikovanom Hamerovom metodom. Magnetne nanočestice sintetisane su solvotermalnom metodom, nakon čega je izvršena izmena oleinske kiseline dihidrokofeinskom kiselinom sa ciljem dobijanja hidrofilnog materijala. Kompoziti grafen-oksida i magnetnih nanočestica sintetisani su hidrotermalnom metodom, prilikom čega je udeo magnetnih čestica bio 5 i 15 težinskih % u odnosu na grafen-oksid. Rezultati rendgeno-strukturne i FTIR analize potvrdili su potpunu oksidaciju grafenskih slojeva. SEM i TEM analize pokazale su depoziciju magnetnih nanočestica na sloju grafen-oksida, bez promene veličine ili oblika nanočestica. FTIR analiza hidrotemalno tretiranog grafen-oksida i kompozita pokazala je da dolazi do delimične redukcije epoksi grupa, kao i da se uspostavlja vodonična veza između komponenti kompozita. Ciklovoltamogrami pokazuju da su kompoziti stabilni pri brzinama polarizacije od 5 do 400 mV s-1, kao i da je njihov kapacitet pretežno pseudokapacitivne prirode. Pseudokapacitivnost potiče od oksidoredukcionih reakcija H+ jona iz elektrolita i površinskih funkcionalnih grupa grafen oksida. Na osnovu ciklovoltamograma izračunati su specifični kapaciteti svih kompozita, pri čemu je najveću vrednost pokazao kompozit CFO_GO_15% koja iznosi 36,86 F g-1 pri brzini polarizacije od 5 mV s-1.This paper presents the electrochemical properties of graphene-oxide composites and nanoparticles of cobalt-ferrite, as well as cobalt-ferrite doped with zinc and gallium. Graphene-oxide (GO) was synthesized by a modified Hummer's method. The magnetic nanoparticles were synthesized by the solvothermal method, after which the oleic acid was exchanged with dihydrocaffeic acid to obtain the hydrophilic material. Composites of graphene-oxide and magnetic nanoparticles were synthesized by the hydrothermal method, where the share of magnetic particles was 5 and 15 wt.% on graphene-oxide. The results of X-ray structural and FTIR analysis confirmed the complete oxidation of graphene layers. SEM and TEM analyzes showed deposition of magnetic nanoparticles on the graphene-oxide layer, without changing the size or shape of the nanoparticles. FTIR analysis of hydrothermally treated graphene oxide and composites showed that there is a partial reduction of epoxy groups, also a hydrogen bond is established between the components of the composite. Cyclic voltammograms show that the composites are stable at polarization rates of 5-400 mV s-1, and that their capacity is predominantly pseudocapacitive in nature. Pseudocapacitance originates from the oxidoreduction reactions of H+ ions from electrolytes and surface functional groups of graphene-oxide. Based on the cyclic voltammograms, the specific capacities of all composites were calculated and the highest value being shown by the CFO_GO_15% composite, which is 36.86 F g-1 at a polarization rate of 5 mV s-1