One of the hot topics in medical research involves using new materials for repairing human tissues. Graphene and its derivatives (which would be abbreviated as graphene in the following text for simplicity) happens to be one such novel material and has excellent properties due to ability to help regenerate tissues. This could be potentially useful for tissue engineering, and skin/muscle/nerve/bone/cartilage repair. Wound healing in eczema, bed sores or burning accidents have a high risk of bacterial infection, and some graphene materials have shown to provide good therapeutic efficacy in the improvement of wound healing with new dressing materials. The mechanism of wound healing might be due to its anti-bacterial properties, immunomodulatory effect, anti-inflammatory effect as well as angiogenic properties. The reason behind this unique properties could be its lack of cytotoxicity, its compatibility with biological material in terms of adhesiveness, and its lack of inhibition of healthy cell migration. Graphene could also have some antibacterial properties which might be due to its dehydrating properties or the ability of some functional groups to generate free radicals that kill pathogenic bacteria. The biocompatibility could be demonstrated by examination of the adhesion of fibroblasts cell lines and the morphology of their filopodia (or the feet). While many model systems concentrate on skin repair and wound healing, the use of graphene is not limited to skin cells: A human stem cell model has also been used to mimic cell regeneration from acute myocardial infarction (MI) using graphene in the form of hydrogels. This model has established the enhanced cell survival rate, increased expression of pro-inflammatory factors, factors that aid in the formation of new blood vessels, and early cardiogenic biomarkers, using graphene quantum dots as a soft injectable hydrogel for heart regenerative function after MI. The study of graphene and graphene-based materials on inflammatory biomarkers and acute phase proteins will be the subject of investigation in this review.

Talipot palm (Corypha umbraculifera L .) is a non-conventional source of stem starch with a starch yield of 76%. Talipot starch was cross-linked with epichlorohydrin (EPS) and phosphoric acid (PS), significantly altered the functional, pasting, rheological, and structural properties. Amylose content of talipot starch was significantly decreased by cross-linking, and it increased the relative crystallinity. The swelling power of talipot starch was increased in EPS; however, it was decreased in PS. A similar trend was observed in the pasting profile, and EPS has higher peak and final viscosities. The cross-linking with epichlorohydrin and phosphoric acid significantly decreased the pasting temperature of talipot starch. The native starch gel has a hardness of 45.54 N, which was increased to 149.69 N in EPS, whereas it decreased to 13.62 N in PS. The paste clarity of all the samples was found to be decreased during cold storage. As compared to the native, both EPS and PS exhibited high paste clarity. The percentage syneresis was considerably decreased in cross-linked starches. The magnitude of both G’ and G” was significantly changed by cross-linking. EPS exhibited increased G’ and G” values, whereas it decreased in PS.

Chronic wounds (CW) are a worldwide concern, causing serious strives on the health and quality of patients’ life. In CW, human neutrophil elastase (HNE) enzyme gets highly expressed during inflammation, reaching abnormally elevated concentrations. Additionally, prevalence of Staphylococcus aureus-induced infections remains very high and difficult to treat. Considering these phenomena, a drug delivery system made of co-axial wet-spun fibers, loaded with the tetrapeptide Ala-Ala-Pro-Val (AAPV, a known inhibitor of HNE activity) and N-carboxymethyl chitosan (NCMC, responsive to neutral-basic pH’s, characteristic of CW and endowed with antibacterial features), was proposed.

AAPV was synthesized by solid-phase peptide synthesis, whereas NCMC was synthesized from low molecular weight chitosan in a chloroacetic acid mixture. HNE inhibition tests were conducted to establish the AAPV IC₅₀ in 1.50 µg/mL and the NCMC minimum bactericidal concentration (MBC) against S. aureus in 6.40 mg/mL. These determinations were used to establish fiber loading amounts. Core-shell structures were produced with 10% w/v polycaprolactone (PCL) at the core and 2% w/v sodium alginate (SA) solutions at the shell. NCMC was mixed with SA at 2xMBC so neutral-basic pH-triggered solubility (characteristic of CW) would allow pores to be opened in the outer layer for accessing the core, where AAPV was combined with PCL.

Fourier-transform infrared spectroscopy and brightfield microscopy were used to confirm the presence of the four components on the fibers and the co-axial architecture, respectively. Fibers presented maximum elongations of over 100%. Release kinetics studies conducted via UV-visible absorption spectroscopy mapped NCMC liberation overtime but were uncapable of detecting AAPV, since polymer degradation masked AAPV absorption peaks. Time-kill kinetics studies against S. aureus demonstrated the effectiveness of NCMC in eliminating this bacterium, particularly after 6 h of incubation. On its turn, AAPV guaranteed HNE inhibition. Data demonstrated the potential of SA-NCMC-PCL-AAPV co-axial systems to work as stepwise, pH-triggered delivery platforms.

Flightless-I is a unique member of the gelsolin superfamily alloying six gelsolin homology (GH) domains and leucine-rich repeats. Flightless-I is an established regulator of the actin cytoskeleton. However, its biochemical activities in actin dynamics regulation are still largely elusive. To better understand its biological functioning, we studied Flightless-I by in vitro fluorescence spectroscopy and single filament TIRF microscopy approaches. We found that Flightless-I inhibits actin assembly by high-affinity (∼ nM) filament barbed end capping, moderately facilitates nucleation by low-affinity (∼ µM) monomer binding and does not sever actin filaments in vitro. Flightless-I was found to interact with actin and affect actin dynamics in a calcium-independent fashion. Notably, our functional analyses indicate that GSN and Flightless-I respond to calcium differently implying different conformational characteristics of the GH domains in the two proteins. Bioinformatics analyses predict that the sequence elements responsible for calcium activation of GSN are not conserved in the GH domains of Flightless-I. Consistently, the use of the hydrophobic fluorescent dye (8-anilinonaphthalene-1-sulfonic acid; ANS) revealed that unlike that of GSN the conformational behavior of the GH domains Flightless-I was not significantly affected by calcium-binding. Altogether, our work reveals different calcium-response and predicts distinct modes of activation of GSN and Flightless-I.

New National Excellence Program of the Ministry for Innovation and Technology ÚNKP-21-3-II-PTE-997 (PG), University of Pécs, Medical School, KA-2021-30 (AV). We thank József Mihály (Institute of Genetics, Biological Research Centre) for the Flightless-I plasmids and Robert C. Robinson (Okoyama University) for the GSN plasmid.

Since December 2019, the problem caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has grown to a global threat. The search for new treatment strategies is strongly associated with both fundamental research on mechanisms of virus life cycle and development of new screening platforms for anti-viral drug candidates. In this project we labelled SARS-CoV-2 membrane proteins M, E, S and studied their localization in mammalian cell compartments using fluorescent microscopy. We tested N- and C-oriented sensor designs and different fluorescent proteins. Also, we successfully visualized the early stages of M protein transport in real time. We found that M protein localizes in cell lysosomes, which supports the recent hypothesis that β-coronaviruses use lysosomal organelles for egress instead of traditional Golgi-mediated secretory pathway. Further we plan to study interactions between M, E and S using the FRET method. In addition, we developed several types of FRET-based and translocational sensors to track SARS-CoV-2 PLpro protease and measure its activity in living cells. Preliminary experiments showed the expected increase in donor fluorescence after proteolysis of PLpro site between the FRET-pair. Results of the current project will provide unique information on spatial-temporal dynamics and interaction between SARS-CoV-2 membrane proteins during the viral lifecycle. The developed system for real-time visualization of PLpro activity can potentially serve as a basis for safe cell antiviral drug screening platforms. The proposed strategy for studying viral proteins combines two important properties. Firstly, research is conducted on human living cells, which is closely approximated to native conditions in contrast to in vitro experiments. Secondly, the experimental system lacks interaction with a functional virus which makes it completely safe for the researcher.