Biophysica, Volume 4, Issue 1 (March 2024) – 8 articles

A coarse-grained model of linear polyfunctional weak charged biopolymers was implemented, formed of different proportions of acid-base groups resembling the composition of humic substances. These substances are mainly present in dissolved organic matter in natural water. The influence of electrostatic interactions computing methods, factors concerning the structure of the chain, different functional groups, and the ionic strength on polyelectrolytes were studied. Langevin dynamics with constant pH simulations were performed using the ESPResSO package and the Python-based Molecule Builder for ESPResSo (pyMBE) library. The coverage was fitted to a polyfunctional Frumkin isotherm, with a mean-field interaction between charged beads. The composition of the chain affects the charge while ionic strength affects both the charge and the radius of gyration. Additionally, the parameters intrinsic to the polyelectrolyte model were well reproduced by fitting the polyfunctional Frumkin isotherm. In contrast, the non-intrinsic parameters depended on the ionic strength. The method developed and applied to a polyfunctional polypeptide model, that resembles a humic acid, will be very useful for characterizing biopolymers with several acid-base functional groups, where their structure, the composition of the different functional groups, and the determination of the main intrinsic proton binding constants and their proportion are not exactly known. Full article

As the water molecules found at the interface of lipid bilayers exhibit distinct structural and reorientation dynamics compared to water molecules found in bulk, the fluctuations in their hydrogen bond (HB) network are expected to be different from those generated by the bulk water molecules. The research presented here aims to gain an insight into temperature-dependent fluctuations of a HB network of water molecules found in an interfacial layer of multilamellar liposomes (MLVs) composed of anionic 1,2-dimyristoyl-sn-glycero-3-phospho-L-serine (DMPS) lipids. Besides suspending DMPS lipids in phosphate buffer saline (PBS) of different pH values (6.0, 7.4, and 8.0), the changes in HB network fluctuations were altered by the incorporation of a non-polar flavonoid molecule myricetin (MCE) within the hydrocarbon chain region. By performing a multivariate analysis on the water combination band observed in temperature-dependent FTIR spectra, the results of which were further mathematically analyzed, the temperature-dependent fluctuations of interfacial water molecules were captured; the latter were the greatest for DMPS in PBS with a pH value of 7.4 and in general were greater for DMPS multibilayers in the absence of MCE. The presence of MCE made DMPS lipids more separated, allowing deeper penetration of water molecules towards the non-polar region and their restricted motion that resulted in decreased fluctuations. The experimentally observed results were supported by MD simulations of DMPS (+MCE) lipid bilayers. Full article

Nanomaterials play a crucial role in various aspects of modern life. Zirconia nanoparticles, extensively employed in medicine for fortifying and stabilizing implants in reconstructive medicine, exhibit unique electrical, thermal, catalytic, sensory, optical, and mechanical properties. While these nanoparticles have shown antibacterial activity, they also exhibit cytotoxic effects on human cells. Our research focuses on understanding how the cells of the human immune system (both the innate response, namely HL-60 and U-937, and the acquired response, namely HUT-78 and COLO-720L) respond to the presence of zirconium (IV) oxide nanoparticles (ZrO₂-NPs). Viability tests indicate that ZrO₂-NPs exert the highest cytotoxicity on HL-60 > U-937 > HUT-78 > COLO 720L cell lines. Notably, concentrations exceeding 100 μg mL⁻¹ of ZrO₂-NPs result in significant cytotoxicity. These nanoparticles readily penetrate the cell membrane, causing mitochondrial damage, and their cytotoxicity is associated with heightened oxidative stress in cells. The use of ZrO₂-NP-based materials may pose a risk to immune system cells, the first responders to foreign entities in the body. Biofunctionalizing the surface of ZrO₂-NPs could serve as an effective strategy to mitigate cytotoxicity and introduce new properties for biomedical applications. Full article

Cells are continually exposed to a range of electromagnetic fields (EMFs), including those from the Schumann resonance to radio waves. The effects of EMFs on cells are diverse and vary based on the specific EMF type. Recent research suggests potential therapeutic applications of EMFs for various diseases. In this study, we explored the impact of a physiologically patterned EMF, inspired by the H3 receptor associated with wakefulness, on PC-12 cells in vitro. Our hypothesis posited that the application of this EMF to differentiated PC-12 cells could enhance firing patterns at specific frequencies. Cell electrophysiology was assessed using a novel device, allowing the computation of spectral power density (SPD) scores for frequencies between 1 Hz and 128 Hz. T-tests comparing SPD at certain frequencies (e.g., 29 Hz, 30 Hz, and 79 Hz) between the H3-EMF and control groups showed a significantly higher SPD in the H3 group (p < 0.050). Moreover, at 7.8 Hz and 71 Hz, a significant correlation was observed between predicted and percentages of cells with neurites (R = 0.542). Key findings indicate the efficacy of the new electrophysiology measure for assessing PC-12 cell activity, a significant increase in cellular activity with the H3-receptor-inspired EMF at specific frequencies, and the influence of 7.8 Hz and 71 Hz frequencies on neurite growth. The overall findings support the idea that the electrical frequency profiles of developing cell systems can serve as an indicator of their progression and eventual cellular outcomes. Full article

Globally, thousands of people are affected by severe nerve injuries or neurodegenerative disorders. These conditions cannot always be cured because nerve tissue either does not regenerate or does so at a slow rate. Therefore, tissue engineering has emerged as a potential treatment approach. This review discusses 3D bioprinting for scaffold manufacturing, highlights the advantages and disadvantages of common bioprinting techniques, describes important considerations for bioinks, biomaterial inks, and scaffolds, and discusses some drug delivery systems. The primary goal of this review is to bring attention to recent advances in nerve tissue engineering and its possible clinical applications in peripheral nerve, spinal cord, and cerebral nerve regeneration. Only studies that use 3D bioprinting or 3D printing to manufacture hydrogel scaffolds and incorporate the sustained release of a drug or growth factor for nerve regeneration are included. This review indicates that 3D printing is a fast and precise scaffold manufacturing technique but requires printing materials with specific properties to be effective in nervous tissue applications. The results indicate that the sustained release of certain drugs and growth factors from scaffolds can significantly improve post-printing cell viability, cell proliferation, adhesion, and differentiation, as well as functional recovery compared with scaffolds alone. However, more in vivo research needs to be conducted before this approach can be used in clinical applications. Full article

The long-range supercritical changes of dielectric constant, resembling ones observed in the isotropic liquid phase of liquid crystalline compounds, are evidenced for linseed oil—although in the given case, the phenomenon is associated with the liquid–solid melting/freezing discontinuous phase transitions. This ‘supercriticality’ can be an additional factor supporting the unique pro-health properties of linseed oil. Broadband dielectric spectroscopy studies also revealed the ‘glassy’ changes of relaxation times, well portrayed by the ‘activated and critical’ equation recently introduced. In the solid phase, the premelting effect characteristic for the canonic melting/freezing discontinuous transition, i.e., without any pretransitional effect in the liquid phase, has been detected. It is interpreted within the grain model, and its parameterization is possible using the Lipovsky model and the ‘reversed’ Mossotti catastrophe concept. For the premelting effect in the solid state, the singular ‘critical’ temperature correlates with the bulk discontinuous melting and freezing temperatures. Consequently, the report shows that linseed oil, despite its ‘natural and complex’ origins, can be considered a unique model system for two fundamental problems: (i) pretransitional (supercritical) effects in the liquid state associated with a weakly discontinuous phase transition, and (ii) the premelting behavior in the solid side of the discontinuous melting/freezing discontinuous transition. Full article

As a vital biomolecule, DNA is known as a target of antineoplastic drugs for cancer therapy. These drugs can show different modes of interaction with DNA, with intercalation and groove binding being the most common types. The intercalation of anticancer drugs with DNA can lead to the disruption of its normal function, influencing cell proliferation. Methylene blue (MB) and acridine orange (AO) are examples of DNA-intercalating agents that have been studied for their application against some types of cancer, mainly for photodynamic therapy. In this work, the impact of light irradiation on these compounds in the absence and presence of DNA was analyzed by means of UV-vis spectroscopy. Bathochromic and hypochromic shifts were observed in the absorbance spectra, revealing the intercalation of the dyes with the DNA base pairs. Dyes with and without DNA present different profiles of photodegradation, whereby the dyes alone were more susceptible to degradation. This can be justified by the intercalation of the dyes on the DNA base pairs allowing the DNA molecule to partially hinder the molecules’ exposition and, therefore, reducing their degradation. Full article

Life on Earth evolved to accommodate the biochemical and biophysical boundary conditions of the planet millions of years ago. The former includes nutrients, water, and the ability to synthesize other needed chemicals. The latter includes the 1 g gravity of the planet, radiation, and the geomagnetic field (GMF) of the planet. How complex life forms have accommodated the GMF is not known in detail, considering that Homo sapiens evolved a neurological system, a neuromuscular system, and a cardiovascular system that developed electromagnetic fields as part of their functioning. Therefore, all of these could be impacted by magnetic fields. In addition, many proteins and physiologic processes utilize iron ions, which exhibit magnetic properties. Thus, complex organisms, such as humans, generate magnetic fields, contain significant quantities of iron ions, and respond to exogenous static and electromagnetic fields. Given the current body of literature, it remains somewhat unclear if Homo sapiens use exogenous magnetic fields to regulate function and what can happen if the boundary condition of the GMF no longer exerts an effect. Proposed deep space flights to destinations such as Mars will provide some insights, as space flight could not have been anticipated by evolution. The results of such space flight “experiments” will provide new insights into the role of magnetic fields on human functioning. This review will discuss the literature regarding the involvement of magnetic fields in various normal and disturbed processes in humans while on Earth and then further discuss potential outcomes when the GMF is no longer present to impact host systems, as well as the limitations in the current knowledge. The GMF has been present throughout evolution, but many details of its role in human functioning remain to be elucidated, and how humans have adapted to such fields in order to develop and retain function remains to be elucidated. Why this understudied area has not received the attention required to elucidate the critical information remains a conundrum for both health professionals and those embarking on space flight. However, proposed deep space flights to destinations such as Mars may provide the environments to test and assess the potential roles of magnetic fields in human functioning. Full article