Magyar Kémiai Folyóirat

Főszerkesztői levél

Lajos Szente — Fri, 18 Jul 2025 00:00:00 +0000

Gyászhír: Görög Sándor

Lajos Szente — Fri, 18 Jul 2025 00:00:00 +0000

Emlékezés Sohár Pál Professzor Úrra

Gábor Náray-Szabó — Tue, 11 Mar 2025 00:00:00 +0000

Sohár Pál 1955-ben került a Budapesti Műszaki Egyetem Vegyészmérnöki Karára. Aktívan részt vett az egyetemi életben, az 1956-os forradalom alatt egyike volt annak a három hallgatónak, akik az egyetemi diákság közösen fogalmazott proklamációját sokszorosították, a lapokat szétosztották a felvonulók között. Szerencséjére ez nem jutott az egyetemi pártvezetés tudomására, bár gyanakodtak rá. Valószínűleg ezért talált munkát a diploma megszerzése után csak a Kelenföldi Tejipari Vállalatnál. Innen került Varsányi György ajánlására a Gyógyszerkutató Intézetbe, ahol a spektroszkópiai laboratórium vezetője lett. Holly Sándorral közösen megírta az infravörös, egyedüli szerző- ként pedig az NMR-spektroszkópia magyar nyelvű, azóta is használt kézikönyvét.

In memoriam Tőke László

Gábor Blaskó — Fri, 18 Jul 2025 00:00:00 +0000

Tőke László kiváló előadó volt, többek között a „Biológiailag aktív anyagok szintézise”, illetve a „Gyógyszerkémia” tárgyakat tanította és kérte számon magas szinvonalon, nagy hallgatói érdeklődés mellett ez utóbbit egészen 75 éves koráig. Egyszerű ember volt, nem szerettte túlbonyolítani a dolgokat, mégis mindig olyan megoldásokat keresett ami mindenkinek jó volt a végén. Mindig jó kedélyű, beszédes, erős igazságérzettel bírt, soha nem rejtette véka alá a véleményét. „Létezik egy alaptehetség, de az nem elég, a szorgalom is nagyon fontos, csak így lehet messzire jutni. A munkámban érzett elégedettség az életben érzett bánatot és megpróbáltatásokat is kicsit elviselhetőbbé teszi. A legnagyobb boldogság az örömmel végzett munka, és ez a boldogság olyan, mint egy védőernyő, amely megvédi az embert az összeroppanástól” – fogalmazta meg hitvallását 80. születésnapján. Életműve munkatársai, és volt hallgatói tudmányos eredményeiben él tovább.

Emlékezés Fodor Lajosra (1950-2018)

Péter Csomós — Fri, 18 Jul 2025 00:00:00 +0000

Fodor Lajos 1950. március 4-én született Egerben. Édesapja Fodor Lajos, édesanyja Majoros Anna. Általános iskolai tanulmányait 1956-1964-ig a tiszafüredi Kiss Pál Általános Iskolában végezte. 1964-ben felvételt nyert a debreceni Vegyipari Technikumba. A középiskolai évek meghatározó, szerepet töltöttek be egész életében. „Az 1960-as évtizedben rendkívül népszerűvé vált a debreceni Vegyipari Technikum: többszörös túljelentkezés, a demográfiai viszonyokkal és a gazdaság fejlődésével (is) összefüggő tanulói létszámnö- vekedés (évfolyamonként 3 párhuzamos osztály a nappali tagozaton, a felnőttoktatás jelentős bővülése), igen magas arányú egyetemi- főiskolai továbbtanulás és biztos egzisztenciát kínáló munkaerőpiaci lehetőségek jellemezték ezt az időszakot. Az iskola országos rangú elismertségéhez az OSZTV-, majd az OKTV sikerek nagyban hozzájárultak.

Megemlékezés Than Károlyról, a 130 éves Magyar Chemiai Folyóirat alapító főszerkesztőjéről

György Inzelt — Fri, 18 Jul 2025 00:00:00 +0000

A Magyar Kémiai Folyóirat a létrejöttét a magyarországi kémiai oktatás és kutatás meghatározó személyiségének Than Károlynak köszönheti. Ő kezdeményezte 1894-ben, amikor az Gyógyszerészeti Közlönyben, a Gyógyszerészi Hetilapban, és a Természettudományi Közlönyben felhívást tett közzé. Ennek lényeges elemeit idézzük:

„A chemia pártolóihoz! Mióta a K. M. Természettudományi Társulat a magyar művelt közönség tudományos kívánalmait helyes érzékkel felismerte, általános természettudományi irodalmunk örvendetes lendületnek indult. A Társulat e közérdekű működésén kívül törekedett tagjainak szűkebb köreiben a szorosabb értelemben vett szaktudomány fejlődését és irodalmát is előmozdítani. E végből rendezte kezdetben a szaküléseket, melyek később a szakértekezletekké alakultak. E szakértekezletek ma már általában oly eleven munkásságot fejtenek ki, hogy nemsokára egy-egy külön szakosztály alakulhat belőlök. Részünkről máris elérkezettnek látjuk az időt arra, hogy a chemiai szakértekezlet chemiai szakosztállyá alakuljon s munkássága főképen a hazai szakirodalom szempontjából ne csak mint eddig szűkebb üléseken, hanem szélesebb körben, folyóirat kiadásával is fejlesztessék.”

Characterizing the glycosylation profiles of extracellular vesicles isolated from cell lines

Lilla Turiák — Fri, 18 Jul 2025 00:00:00 +0000

Extracellular vesicles (EVs) are nanometer-sized membrane-bound particles released by cells into the extracellular space. They participate in intercellular signaling and EVs released by tumor cells have been found to play profund roles in the tumor microenvironment. Small EVs have a diameter smaller than 200 nm. Post-translational modifications (PTMs) of proteins present in EVs are challenging to analyze due to the relatively small sample amount available. Glycosylation is one the most frequent PTMs and involves the attachment of diverse glycan chains to proteins or lipids. It is known to be heavily involved in various signaling events. During N-glycosylation the glycans are attached to asparagine residues within the consensus sequence (NXS/T, where X= any amino acid except proline). Mammalian N-glycans share a common pentasaccharide core, and based on further elongation can be divided ito three classes: oligomannose, complex and hybrid. Proteglycans, a class of glycoproteins contain long linear polysaccharides, glycosaminoglycans (GAGs) composed of repeating disaccharides. The chondroitin sulfate (CS) GAG class consists of glucuronic acid and N-acetylgalactosamine units, with variable levels of sulfation influencing binding of signaling molecules. Aberrant glycosylation has been described in several diseases inlcuding cancer. Although there is ample examples in the literature describing alterations occuring at the proteomic level in small EVs in cancer, their glycosylation profiles are still underexplored. Our long term goal is to explore the glycosylation profiles of tumor-derived EVs isolated from the plasma of lung cancer pateints as predictive biomarkers. As a first step we performed the in-depth characterization of N-glycosylation and CS profiles of small EVs isolated from the A549 lung adenocarcinoma and the BEAS-2B non-tumorigenic cell line. We used nanoflow ultra-high performance liquid chromatography tandem mass spectrometry for the structural analysis of these glycosylation features. The tumor-cell derived and non-tumor cell-derived small EVs could be differentiated from each other based on their proteomic, N-glycosylation and CS GAG profiles using principal component analysis. This highlights the utility of monitoring alterations at the glycosylation level e.g. in the case of diagnostic applications.

Synthesis of carbohydrate-based crown ethers and their applications in asymmetric reactions

István Orbán — Fri, 18 Jul 2025 00:00:00 +0000

The aim of my PhD research was to synthesize new chiral monoaza-crown ethers and to apply them as enantioselective catalysts in asymmetric phase-transfer reactions. Additionally, I aimed to investigate the complexation properties of previously synthesized carbohydrate-based azacrown ethers. During the research, I synthesized a total of 19 new chiral crown ethers, most of which are carbohydrate-based macrocycles. In one case, I used an amino acid as the starting material. Starting from D-glucose, 13 new macrocycles were synthesized. Four of these contain ethyl groups at the positions 4 and 6 of the glucose moiety, while possessing different side arms. The other nine compounds are lariat ethers whose side chains contain one or two heteroatoms in the form of a heterocycle. These were prepared by reacting the appropriate primary amines with diiodo podants, in a macrocyclization reaction. Most of the primary amines required for ring closure were prepared by myself, using two different methods. The macrocycles with diethyl groups were tested in five different asymmetric phase-transfer reactions, and they were compared with structurally similar crown ethers with different protective groups at the 4th and 6th positions. In the presence of the new crown ethers, the enantiomeric excess (ee) produced was generally lower, but in the two-phase solid-liquid cyclopropanation of 2-benzylidenemalononitrile, 99% ee was achieved with one of the new crown ethers. This was better than the result obtained with the reference macrocycle (70% ee). In addition, I conducted experiments in the field of a previously unknown MIRC-type reaction in our research group. This reaction involved the cyclopropanation between 2-cyano-3-phenylacrylic acid ethyl ester and diethyl bromomalonate. During these experiments, the effects of ten different catalysts previously synthesized by our group were examined, as well as the solvent dependence of the enantioselectivity and the reaction’s robustness, using derivatives with various substitutions on the aromatic ring. The highest enantiomeric excess achieved during these reactions was 89%, in the synthesis of one of the new cyclopropane derivatives. Six different macrocycles from the glucose-based crown ethers with heterocyclic side chains were tested in a total of five different twophase asymmetric reactions. The results were varied, with several factors – the length of the side chain and the type of heteroatom – influencing the yield and selectivity obtained. The best result was measured in the reaction of 2-cyano-3-phenylacrylic acid ethyl ester and diethyl bromomalonate (84% ee). Starting from L-valine, a chiral crown ether containing only one center of asymmetry was synthesized. With this crown ether, I investigated the relationship between the number of centers of asymmetry in the catalyst and the degree of induced asymmetric induction. The macrocycle was tested in five model reactions, and the best result was obtained in the epoxidation of trans-chalcone, yielding 62%. During my research, 5 new D-idose-based lariat ethers were also synthesized, which differed in the spatial arrangement of the substituent at the anomeric position and in their side chains. I tested the new idose-based macrocycles in seven different phase-transfer reactions. Among these, the highest enantiomeric excess was measured in the epoxidation of trans-chalcone, yielding 81%. Previously in our research group, carbohydrate-based monoaza-crown ethers have primarily been used for complexing inorganic alkali metal salts to facilitate enantioselective syntheses. To further explore their complexation properties, I investigated the reactions of ten glucose-based lariat ethers and four anhydrous transition metal salts – cobalt(II), copper(II), palladium(II), and nickel(II) chloride – in dichloromethane. The experiments revealed that the macrocycles tested were most suitable for complexing copper(II) chloride.

In Situ Formation of BOC Protecting Groups on Silicon Carbide Nanoparticles

Szabolcs Czene — Fri, 18 Jul 2025 00:00:00 +0000

After successfully forming amino groups directly on the surface of SiC nanoparticles, our research interest turned to addressing the instability of free –NH2 groups in air. From our previous work, we were convinced that peptide coupling remains stable even after more than one year of storage in solution and in a refrigerator. The formation of a protecting group served several purposes. First, storing the material in solid-state form at room temperature is easier than maintaining it in a solution in a refrigerator. Second, the resulting amide bond system confirms that the recovery of the PL signal in the peptide–SiC conjugate can be attributed to the transformation of the amino-terminated SiC. Third, the preparation using N-bromosuccinimide offers milder conditions compared to the original Hofmann degradation. Since the BOC group can be easily removed by acid, the method is also suitable for generating the –NH2 group. This is confirmed by the fact that, after acidification to pH = 6, we observed a fraction after chromatography where the pH of the mixture was 8. We examined these fractions using UV–VIS spectroscopy, and no signal corresponding to N-bromosuccinimide was observed in the spectra. Combining the contents of these fractions, we recorded ¹H and ¹³C NMR spectra of the reaction product C. Precise NMR and IR analysis relies on proper knowledge of the positions of the functional groups. Based on the proton NMR, methyl groups are evident (1.8 ppm), which also correspond to a signal in the carbon spectrum (62.6 ppm). In the IR spectrum, the BOC derivative shows Amide I and II bands (1672 and 1550 cm⁻¹), which disappear after acid treatment, as well as bands characteristic of isocyanates (2251 cm⁻¹) and protonated amino groups (2500–3200 cm⁻¹), confirming both the formation of the protecting group and the presence of intermediates involved in Hofmann degradation following its removal. Indirect confirmation comes from the PL spectrum, which shows that a clearly measurable signal is obtained again in the amide-bonded system. This provides additional evidence for the potential use of SiC as a fluorescent biomarker when coupled to biomolecules. Compared to dye molecules, nanocrystals offer the advantage of having stable fluorescence, making them suitable for such applications.

Synthesis of new potentially biologically active sulfur- and selenium-containing carbohydrate derivatives

Fanni Hőgye — Fri, 18 Jul 2025 00:00:00 +0000

Lectins, as carbohydrate-binding proteins, are capable of sticking cells (agglutination), are found in plants, humans, and pathogenic organisms and have a natural protective effect against various diseases and pathogens. The carbohydrate recognition abilities of lectins are targeted in the research and development of new drugs. Galectins have a broad specificity, regulating cell death intracellularly and extracellularly; they play a role in many diseases: cancer, autoimmune diseases, chronic inflammations. Gal-3- which is a chimera type galectin- expression is associated with various fibrosis, cancer cell growth, apoptosis, immunosuppression and metastasis. Galectin-3 is being used as a diagnostic marker for different cancers. Gal-3 has an affinity for β-galactosides, many studies reports various structured of Gal-3 inhibitors. The most widespread lung pathogen, the Gram-negative bacterium P. aeruginosa, produces LecA lectin. Several glycomimetics have been developed based on D-galactose for LecA, analyzed in vitro assays and showed excellent properties to block LecAmediated host cell binding and decrease bacterial invasion into human cells. During our research, we synthesized new, sulfur and selenium containing carbohydrate derivatives, as potential Gal-3 and LecA lectin inhibitors. Examination of the binding of selenium-containing derivatives is possible with 77Se NMR techniques. High-yielding synthetic route of TDG and SeDG we worked it out; a procedure for the synthesis of the novel 3,3′-di-O-(quinoline2-yl)methyl)-TDG and three other known, symmetric 3,3′-di-OTDG derivatives ((naphthalene-2yl)methyl, benzyl, (7-methoxy2H-1-benzopyran-2-on-4-yl)methyl) was optimized. Based on the biological effect of 3,3’-di-O-aralkyl-TDG derivatives, we prepared new quinoline-2-ylmethyl 32 and naphthalene-2-ylmethyl 26 SeDG derivatives started from monosaccharide derivatives. We have developed a new method for the removal of PMP groups in the starting compounds, using the Selectfluor® reagent, which method is suitable for the selective removal of the PMP group from 2 NAP and quinolin-2-ylmethyl groups. Divalent selenogalactoside derivatives containing a 1,2,3-triazole ring were synthesized by a Cu(I)-catalyzed 1,3-dipolar cycloaddition (CuAAC) reaction, as potencial divalent LecA inhibitors. The benzene 42, naphthalene 43, 1,1’-biphenyl 44 and pyridine 45 di(azidomethyl) derivatives were formed in good yield from the corresponding aromatic dibromides in DMF with sodium azide in reactions. Prop-2-yn-1-yl 2,3,4,6-tetra-O-acetyl-β-d-selenogalactopyranoside 33 was prepared from isoselenouronium salt 5. Reaction of di(azidomethyl) derivatives 38-41 with prop2-yn-1-yl 2,3,4,6-tetra-O-acetyl-β-d-selenogalactopyranoside afforded -seleno-β-d-galactopyransides 42-45. Homo- and heteroaromatic dimethyl diazides 42-45 ctowere synthesized from the corresponding bromides in dry DMF at room temperature in good yields. The removal of the acetyl protecting groups by the Zemplén method provided the bifunctional aralkyl 1,2,3-triazolo-seleno-β-d-galactopyranoside derivatives in good yields. New aralkyl 1-seleno-β-d-galacto- and glucopyranosides 55, 56, 55a, 56a were synthesized to expand the repertoire of monovalent derivatives, started from 2,3,4,6-tri-O-acetyl-β-d-glycopyranosyl isoselenouronium salts 5, 51 by reactions with 2-(bromomethyl) quinolin and 4-bromomethyl-7-methoxycoumarin under mild reaction conditions. Gluco-derivatives will be used as competitive ligands in binding studies. Gal-3 is known to be highly upregulated during infection with the African sleeping sickness parasite T. brucei. In parallel with the lectin binding studies, within the framework of foreign cooperation, the new selenoglycosides 52-53 and 52a-53a were tested in T. brucei (African sleeping sickness) parasitological studies by Professor Dr. Marcelo Comini of the Pasteur Institute in Montevideo. During the biological tests, it was established that the presence of the acetyl group is beneficial in terms of the bioactivity of the compounds. In order to further increase bioactivity, we also synthesised new fluorine-containing selenogalactoside derivatives. From 2-deoxy-2-fluoro-3,4,6-tri-O-acetylβ-d-galactopyranosyl-isoselenouronium bromide we prepared naphtalene-2-ylmethyl, quinolin-2-ylmethyl and 7-methoxycoumarin-4-ylmethyl derivatives. According to the results of parasitological tests with T. brucei, derivatives 52a (EC50 1.2 ± 0.1 µM) and 56 (EC50 4.1 ± 1.0 µM) were found to be active. Collaborative partners of Dr. Marcelo Comini in South Korea investigated SARS-CoV-2 antiviral activity, according to which derivatives 63 (EC50 21.3 µM) and 64 (EC50 29.5 µM) were active.

Application of prompt-gamma activation analysis to determine the provenance of silicate archaeological finds and their raw materials

Zsolt Kasztovszky — Fri, 18 Jul 2025 00:00:00 +0000

The main tasks in heritage science, or more specifically in archaeometry, are to analyze our tangible heritage and preserving their condition using modern scientific methods – if possible, in a non-destructive way. The prompt-gamma activation analytical (PGAA) facility, which was built at the Budapest Research Reactor as early as in 1996, provides a tool for such investigations. The main advantage of PGAA is that the composition of an object of any size can be determined with a guided neutron beam, without sampling or damaging the object. The method is primarily suitable for measuring the main geological elements and also some trace elements (H, B, Cl, Nd, Sm, Gd) with high neutron absorption cross-section. Due to its favorable analytical properties, the idea of its applicability in archaeometry came first among the possible applications. The measured data are suitable for determining the origin of raw materials, so-called provenance, workshop identification, and also for filtering out counterfeits. In his paper, the author highlights a significant part of the research conducted at the Budapest Research Reactor over the past 25 years on the archaeometric applications of PGAA, dealing with archaeological finds made of silicate materials. The applicability of the method was examined by measuring international reference samples.

Investigating the activity and interactions of oncogenic KRas proteins

Nikolett Emődi — Fri, 18 Jul 2025 00:00:00 +0000

Mutations in the Ras protein family are responsible for one of the highest prevalence in cancer. Most commonly affecting the pancreas, colon and lung, these lesions remain challenging for medical science today. The KRas protein, encoded by the Ras gene, plays a central role in regulating signaling pathways. This enzyme can control signaling as a binary switch through its GTPase activity, thereby affecting cell proliferation and division. The function of the KRas protein is facilitated by GAP (GTPase activating protein) proteins, which can increase the rate of GTP hydrolysis by several magnitudes. However, this finely tuned system can easily be disrupted by mutations in the active site of the KRas protein. A single point mutation reduces the ability of GAP to activate KRas proteins, therefore the rate of hydrolysis is significantly reduced, resulting that the protein being unable to fulfil its role in the signaling network. This leds to inproper functioning of cellular processes and as a consequence uncontrolled cell division and tumor development. Several approaches have been developed to restore the signaling, the most common one is drug treatment with inhibitor molecules. However, the restoration of the activation of mutant KRas porteins by GAP proteins holds promise too. Despite being an important target, the mechanism of GAP-catalysed hydrolysis has not been precisely defined yet. To understand this, our collaborators have set up a QM/MM model to systematically design GAP mutants that can activate the KRas G12D mutant, which is the most abundant KRas mutant in the human cancers. In addition, researchers have recently discovered a GAP-like protein, RGS3, which can also cause a catalytic effect on mutant KRas proteins. Our aim is to test these alternative GAP proteins in practice. For this, we investigated the interaction between the mutant KRas and RGS3 by biolayer interferometry and measured the ability of GAP variants to activate KRas mutants by using MESG-PNP enzyme activity assay. These studies may help to understand the interaction of these proteins and thus improve the development of tumor therapeutics.

A Bis(Acridino)-Crown Ether for Recognizing Oligoamines in Spermine Biosynthesis

Péter Kisfaludi — Fri, 18 Jul 2025 00:00:00 +0000

Biogenic aliphatic oligoamines such as putrescine, cadaverine,
spermidine, and spermine are naturally occurring compounds
synthesized by enzymatic decarboxylation of amino acids. These
molecules play vital roles in biological systems, including cell
proliferation, gene expression, and nucleic acid stabilization.
Abnormal levels of these oligoamines are associated with various
diseases; for example, elevated spermine levels can be linked to
the presence of cancer cells, while decreased levels are observed
in aging-related illnesses like Parkinson’s disease.
A new bis(acridino)-crown ether was designed to selectively detect protonated oligoamines based on their chain length. The receptor contains two 18-crown-6-type macrocycles and two acridine units that provide strong fluorescence signaling upon guest
binding. The design enables it to distinguish between short- and
long-chain oligoamines through fluorescence intensity shifts.Two
synthetic strategies were developed to produce the host molecule,
both starting from commercially available compounds and resulting in low but usable yields. Structural and functional characterization was performed using DFT-based molecular modelling and
fluorescence titrations. These studies confirmed selective binding
of oligoamines, with spermine and spermidine forming the most
stable complexes.
Both the modelling and the titration experiments revealed sequential 1:1 and 1:2 host–guest complex formation. Binding constants
and cooperativity effects were calculated using global non-linear
regression of the titration data. Spermine showed strong binding
and negative cooperativity which made it the preferred analogue
for coordination, while spermidine exhibited the highest overall
stability in binding but no cooperativity effect. The receptor’s molecular recognition behaviour suggests potential for use in bioimaging, diagnostics, or targeted drug delivery applications—particularly in cancer research.

Design and synthesis of a photoresponsive subunit for molecular electronics

Marcell Márk Bogner — Fri, 18 Jul 2025 00:00:00 +0000

Molecular electronics is a prominent research area aiming to develop systems that mimic circuit elements at the molecular level. Among these, molecular switches such as diarylethenes have received considerable attention due to their controllable bistable behaviour. Dithienylethenes (DTEs) undergo reversible photocyclization, exhibiting different electronic properties in their two (open and closed) states. In this work, a photoswitchable molecular rectifier unit is introduced that integrates a DTE switch with a dibenzo[a,e]pentalene (DBP) core. DBP represents a stabilized antiaromatic system with low HOMO-LUMO gap and favourable π-stacking, making it attractive for nanoscale conductors. The system was designed to enable conjugation modulation upon photoisomerization, potentially altering both unimolecular conductivity and local aromaticity of the DBP core. The target molecule was synthesized in 11 steps via a convergent strategy considering both synthetic and functional requirements. UV/vis and NMR studies confirmed reversible switching, while computational analyses indicated minimal aromaticity changes in the DBP unit during isomerization. However, the photoisomerization significantly alters the chromophore structure, laying the groundwork for future single-molecule conductance measurements.

Synthesis and photochemical characterization of photoactivatable nerve growth factor mimetic compounds

Bence Szabó — Fri, 18 Jul 2025 00:00:00 +0000

Neurodegenerative diseases and injuries of the nervous system affect tens of millions of people worldwide. In our body, a number of different compounds play a crucial role in the development and survival of neurons, one of the most important being the nerve growth factor (NGF) protein. While this protein possesses neuroprotective properties and is able to direct the growth of axons, its use for therapeutic purposes faces several problems. To overcome this, a number of small molecule compounds–able to bind to the same receptors as NGF–have been identified in the last few decades. In this work, we synthesised two of the compounds that have previously been shown to have biological effects similar to those of NGF. Following their successful syntheses, we were able to create five novel caged compounds through the covalent attachment of commonly used photolabile protecting groups (Fig. 2). Four of the five novel compounds were then studied in detailed spectrophotometric and photolytic studies. First, we examined their spectroscopic properties, such as absorption maxima, fluorescence and molar absorption coefficients (Table 1). Next, to determine the quantum yield of their photolysis, a new methodology was adapted using the light-controlled cis–trans isomerisation process of 4,4’-dimethylazobenzene as a reference. This method can be used in systems in which the photon flux can not be directly quantified. Using the novel compounds, we plan to carry out several biological experiments in the future, in which the spatial and temporal release of the bioactive compounds will be achieved using focused light. This strategy offers the possibility of guided axon growth in three dimensions, and with that, the chance to create in vitro neural networks with custom topologies and, long term, to repair nerve injuries in vivo.