Optogenetic Modulation and Reprogramming of Bacteriorhodopsin-Transfected Human Fibroblasts on Self-Assembled Fullerene C60 Nanosheets

Advances in Optogenetics and Thermogenetics for Control of Non-Neuronal Cells and Tissues in Biomedical Research

Optogenetics and chemogenetics are relatively new biomedical technologies that emerged 20 years ago and have been evolving rapidly since then. This has been made possible by the combined use of genetic engineering, optics, and electrophysiology. With the development of optogenetics and thermogenetics, the molecular tools for cellular control are continuously being optimized, studied, and modified, expanding both their applications and their biomedical uses. The most notable changes have occurred in the basic life sciences, especially in neurobiology and the activation of neurons to control behavior. Currently, these methods of activation have gone far beyond neurobiology and are being used in cardiovascular research, for potential cancer therapy, to control metabolism, etc. In this review, we provide brief information on the types of molecular tools for optogenetic and thermogenetic methods─microbial rhodopsins and proteins of the TRP superfamily─and also consider their applications in the field of activation of non-neuronal tissues and mammalian cells. We also consider the potential of these technologies and the prospects for the use of optogenetics and thermogenetics in biomedical research.

Bacterial Pigments as a Promising Alternative to Synthetic Colorants: From Fundamentals to Applications

Pigments find widespread application in the fields of food, medicine, textiles, and cosmetics. At present, synthetic colorants dominate the global pigment market. However, the environmental and health hazards associated with synthetic colorants have spurred extensive research on eco-friendly and safe alternatives. Natural pigments are particularly intriguing for meeting consumer demands and sustainable development, as they not only exhibit various vibrant color shades without discernible toxic side effects but also offer additional healthful features such as antibacterial, antioxidant, anticancer, and antiviral properties compared with their synthetic counterparts. Among natural sources, bacterial strains share distinct advantages for large-scale pigment production because of their intrinsic robustness of cellular metabolic systems. This review comprehensively outlines the bacterial sources, extraction and purification methods, structural characteristics, biological activities, and potential applications of typical pigments, including but not limited to violacein, indigoidine, melanin, carotenoids, prodigiosin, and rhodopsin. Additionally, it underscores the primary obstacles to the development and production of bacterial pigments for commercial applications, discussing feasible strategies for overcoming production bottlenecks. This work also provides valuable insights for the scientific and rational advancement of bacterial pigment development.

Bacteriorhodopsin of purple membrane reverses anisotropy outside the pH range of proton pumping based on logic gate realization

The bacteriorhodopsin of purple membrane is the first discovered light-sensing protein among ion transporting microbial rhodopsins, some of which (e.g. Archaerhodopsin 3) could be broadly used as tools in optogenetics having wide potential of medical applications. Since its discovery as early as in 1971, bacteriorhodopsin has attracted wide interests in nano-biotechnology, particularly in optoelectronics devices. Therefore, the present work has been motivated due to two topics; firstly, anisotropy demand became indispensible in bioelectronics; secondly, the stationary level of electric response in bacteriorhodopsin within the pH range of proton pumping (pH 3 - pH 10) implies, in turn, raising here a question about whether the electric anisotropy is implicated for reducing (or switching off) such level beyond such pH range. Noteworthy is that the purple membrane converts to blue form upon acidification, while to reddish purple form upon alkalization. In the present study, the acidic and alkaline forms of bacteriorhodopsin have exhibited most probable state of reversal for the dielectric anisotropy around pH 2.5 and pH 10.5, respectively. This is underscored by proposing a correlation seemingly found between disassembly of the crystalline structure of bacteriorhodopsin and the reversal of dielectric anisotropy, at such acidic and alkaline reversal pH's, in terms of the essence of the crystalline lattice. Most importantly, the results have substantiated dual frequency characteristics and logic gate-based dielectric anisotropy reversal to bacteriorhodopsin, which may implicate it for potential applications in bioelectronics.

Uniaxial Symmetry Breaking in Bacteriorhodopsin at the Thermal Phase Transition of Lipids of Purple Membranes

The article correlates between symmetry breaking and phase transition. An analogy, extending from physics to biology, is known to exist between these two topics. Bacteriorhodopsin (bR) as a paradigm of membrane proteins has been used as a case study in the present work. The bR, as the sole protein embedded in what is called a purple membrane (PM), has attracted widespread interest in bionanotechnological applications. The lipids of PM have a crucial role in maintaining the crystal lattice of bR inside PM. For this reason, the present work has been concerned with elucidating the thermal phase transition properties of the PM lipids in orthogonal directions. The results indicated that the axial symmetry of bR exhibits considerable changes occurring at the thermal phase transition of lipids. These changes are brought by an anomaly observed in the time course of orthogonal electric responses during the application of thermal fields on PM. The observed anomaly may bear on symmetry breaking in bR occurring at the phase transition of lipids based on such analogy found between symmetry breaking and phase transition. Lipid-protein interactions may underlie the broken axial symmetry of bR at such lipid thermal transition of PM. Accordingly, thermally perturbed axial symmetry of bR may be of biological relevance relying on the essence of the crystal lattice of bR. Most importantly, a question has to be raised in the present study: Can bR, as a helical protein with broken axial symmetry, affect the symmetry breaking of helical light? This may be of potential technical applications based on a recent discovery that bR breaks the symmetry of helical light.

Nanoarchitectonics horizons: materials for life sciences

Nanoarchitectonics relies on the fabrication of materials at the atomic/molecular level to achieve the desired shape and function. Significant advances have been made in understanding the characteristics and spatial assemblies that contribute to material performance. Biomaterials undergo several changes when presented with various environmental cues. The ability to overcome such challenges, maintaining the integrity and effective functioning of native properties, can be regarded as a characteristic of a successful biomaterial. Control over the shape and efficacy of target materials can be tailored via various processes, like self-assembly, supramolecular chemistry, atomic/molecular manipulation, etc. Interplay between the physicochemical properties of materials and biomolecule recognition sites defines the structural rigidity in hierarchical structures. Materials including polymers, metal nanoparticles, nucleic acid systems, metal-organic frameworks, and carbon-based nanostructures can be viewed as promising prospects for developing biocompatible systems. This review discusses recent advances relating to such biomaterials for life science applications, where nanoarchitectonics plays a decisive role either directly or indirectly.

Long-term maintenance of synaptic plasticity by Fullerenol Ameliorates lead-induced-impaired learning and memory in vivo

Fullerenol, a functional and water-soluble fullerene derivative, plays an important role in antioxidant, antitumor and antivirus, implying its enormous potential in biomedical applications. However, the in vivo performance of fullerenol remains largely unclear. We aimed to investigate the effect of fullerenol (i.p., 5 mg/kg) on the impaired hippocampus in a rat model of lead exposure. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) is a kind of newly developed soft-ionization mass spectrometry technology. In the present study, an innovative strategy for biological distribution analysis using MALDI-TOF-MS confirmed that fullerenol could across the blood-brain barrier and accumulate in the brain. Results from behavioral tests showed that a low dose of fullerenol could improve the impaired learning and memory induced by lead. Furthermore, electrophysiology examinations indicated that this potential repair effect of fullerenol was mainly due to the long-term changes in hippocampal synaptic plasticity, with enhancement lasting for more than 2-3 h. In addition, morphological observations and biochemistry analyses manifested that the long-term change in synaptic efficacy was accompanied by some structural alteration in synaptic connection. Our study demonstrates the therapeutic feature of fullerenol will be beneficial to the discovery and development as a new drug and lays a solid foundation for further biomedical applications of nanomedicines.

The Roles of Optogenetics and Technology in Neurobiology: A Review

Optogenetic is a technique that combines optics and genetics to control specific neurons. This technique usually uses adenoviruses that encode photosensitive protein. The adenovirus may concentrate in a specific neural region. By shining light on the target nerve region, the photosensitive protein encoded by the adenovirus is controlled. Photosensitive proteins controlled by light can selectively allow ions inside and outside the cell membrane to pass through, resulting in inhibition or activation effects. Due to the high precision and minimally invasive, optogenetics has achieved good results in many fields, especially in the field of neuron functions and neural circuits. Significant advances have also been made in the study of many clinical diseases. This review focuses on the research of optogenetics in the field of neurobiology. These include how to use optogenetics to control nerve cells, study neural circuits, and treat diseases by changing the state of neurons. We hoped that this review will give a comprehensive understanding of the progress of optogenetics in the field of neurobiology.

Bio-interactive nanoarchitectonics with two-dimensional materials and environments

Like the proposal of nanotechnology by Richard Feynman, the nanoarchitectonics concept was initially proposed by Masakazu Aono. The nanoarchitectonics strategy conceptually fuses nanotechnology with other research fields including organic chemistry, supramolecular chemistry, micro/nanofabrication, materials science, and bio-related sciences, and aims to produce functional materials from nanoscale components. In this review article, bio-interactive nanoarchitectonics and two-dimensional materials and environments are discussed as a selected topic. The account gives general examples of nanoarchitectonics of two-dimensional materials for energy storage, catalysis, and biomedical applications, followed by explanations of bio-related applications with two-dimensional materials such as two-dimensional biomimetic nanosheets, fullerene nanosheets, and two-dimensional assemblies of one-dimensional fullerene nanowhiskers (FNWs). The discussion on bio-interactive nanoarchitectonics in two-dimensional environments further extends to liquid-liquid interfaces such as fluorocarbon-medium interfaces and viscous liquid interfaces as new frontiers of two-dimensional environments for bio-related applications. Controlling differentiation of stem cells at fluidic liquid interfaces is also discussed. Finally, a conclusive section briefly summarizes features of bio-interactive nanoarchitectonics with two-dimensional materials and environments and discusses possible future perspectives.

Engineered Bacteriorhodopsin May Induce Lung Cancer Cell Cycle Arrest and Suppress Their Proliferation and Migration

Highly expressible bacteriorhodopsin (HEBR) is a light-triggered protein (optogenetic protein) that has seven transmembrane regions with retinal bound as their chromophore to sense light. HEBR has controllable photochemical properties and regulates activity on proton pumping. In this study, we generated HEBR protein and incubated with lung cancer cell lines (A549 and H1299) to evaluate if there was a growth-inhibitory effect with or without light illumination. The data revealed that the HEBR protein suppressed cell proliferation and induced the G0/G1 cell cycle arrest without light illumination. Moreover, the migration abilities of A549 and H1299 cells were reduced by ~17% and ~31% after incubation with HEBR (40 μg/mL) for 4 h. The Snail-1 gene expression level of the A549 cells was significantly downregulated by ~50% after the treatment of HEBR. In addition, HEBR significantly inhibited the gene expression of Sox-2 and Oct-4 in H1299 cells. These results suggested that the HEBR protein may inhibit cell proliferation and cell cycle progression of lung cancer cells, reduce their migration activity, and suppress some stemness-related genes. These findings also suggested the potential of HEBR protein to regulate the growth and migration of tumor cells, which may offer the possibility for an anticancer drug.

Advanced Optogenetic-Based Biosensing and Related Biomaterials

The ability to stimulate mammalian cells with light, brought along by optogenetic control, has significantly broadened our understanding of electrically excitable tissues. Backed by advanced (bio)materials, it has recently paved the way towards novel biosensing concepts supporting bio-analytics applications transversal to the main biomedical stream. The advancements concerning enabling biomaterials and related novel biosensing concepts involving optogenetics are reviewed with particular focus on the use of engineered cells for cell-based sensing platforms and the available toolbox (from mere actuators and reporters to novel multifunctional opto-chemogenetic tools) for optogenetic-enabled real-time cellular diagnostics and biosensor development. The key advantages of these modified cell-based biosensors concern both significantly faster (minutes instead of hours) and higher sensitivity detection of low concentrations of bioactive/toxic analytes (below the threshold concentrations in classical cellular sensors) as well as improved standardization as warranted by unified analytic platforms. These novel multimodal functional electro-optical label-free assays are reviewed among the key elements for optogenetic-based biosensing standardization. This focused review is a potential guide for materials researchers interested in biosensing based on light-responsive biomaterials and related analytic tools.

Natural Pigments of Bacterial Origin and Their Possible Biomedical Applications

Microorganisms are considered one of the most promising niches for prospecting, production, and application of bioactive compounds of biotechnological interest. Among them, bacteria offer certain distinctive advantages due to their short life cycle, their low sensitivity to seasonal and climatic changes, their easy scaling as well as their ability to produce pigments of various colors and shades. Natural pigments have attracted the attention of industry due to an increasing interest in the generation of new products harmless to humans and nature. This is because pigments of artificial origin used in industry can have various deleterious effects. On this basis, bacterial pigments promise to be an attractive niche of new biotechnological applications, from functional food production to the generation of new drugs and biomedical therapies. This review endeavors to establish the beneficial properties of several relevant pigments of bacterial origin and their relation to applications in the biomedical area.

Identification of potential descriptors of water-soluble fullerene derivatives responsible for antitumor effects on lung cancer cells via QSAR analysis

Water-soluble fullerene derivatives are actively investigated as potential drugs for cancer treatment due to their favorable membranotropic properties. Herein, cytotoxic effects of twenty fullerene derivatives with different solubilizing addends were evaluated in three different types of non-small-cell lung carcinoma (NSCLC). The potential structural descriptors of the solubilizing addends related to the inhibitory activities on each type of lung cancer cell were investigated by the quantitative structure-activity relationship (QSAR) approach. The determination coefficient r2 for the recommended QSAR model were 0.9325, 0.8404, and 0.9011 for A549, H460, and H1299 cell lines, respectively. The results revealed that the chemical features of the fullerene-based compounds including aromatic bonds, sulfur-containing aromatic rings, and oxygen atoms are favored properties and promote the inhibitory effects on H460 and H1299 cells. Particularly, thiophene moiety is the key functional group, which was positively correlated with strong inhibitory effects on the three types of lung cancer cells. The useful information obtained from our regression models may lead to the design of more efficient inhibitors of the three types of NSCLC.

Semi-Interpenetrating Polymer Network of Hyaluronan and Chitosan Self-Healing Hydrogels for Central Nervous System Repair

The repair of the central nervous system (CNS) is a major challenge because of the difficulty for neurons or axons to regenerate after damages. Injectable hydrogels have been developed to deliver drugs or cells for neural repair, but these hydrogels usually require conditional stimuli or additional catalysts to control the gelling process. Self-healing hydrogels, which can be injected locally to fill tissue defects after stable gelation, are attractive candidates for CNS treatment. In the current study, the self-healing hydrogel with a semi-interpenetrating polymer network (SIPN) was prepared by incorporation of hyaluronan (HA) into the chitosan-based self-healing hydrogel. The addition of HA allowed the hydrogel to pass through a narrow needle much more easily. As the HA content increased, the hydrogel showed a more packed nanostructure and a more porous microstructure verified by coherent small-angle X-ray scattering and scanning electron microscopy. The unique structure of SIPN hydrogel enhanced the spreading, migration, proliferation, and differentiation of encapsulated neural stem cells in vitro. Compared to the pristine chitosan-based self-healing hydrogel, the SIPN hydrogel showed better biocompatibility, CNS injury repair, and functional recovery evaluated by the traumatic brain injury zebrafish model and intracerebral hemorrhage rat model. We proposed that the SIPN of HA and chitosan self-healing hydrogel allowed an adaptable environment for cell spreading and migration and had the potential as an injectable defect support for CNS repair.

Two-Dimensional Mesoporous Carbon Materials Derived from Fullerene Microsheets for Energy Applications

Porous carbon materials rich in defects are promising candidates in energy storage and conversion applications. Herein, a facile template-free approach is reported for the synthesis of a two-dimensional (2 D) mesoporous carbon material derived from fullerene (C₆₀ ) microsheets (FMSs) through simple heat treatment. The sample obtained at 1000 °C (FMS1000) shows a large surface area of 1507.6 m²  g^-1 owing to the presence of mesopores and rich defects, which promote electron and mass transfer in the electrocatalytic process of the oxygen reduction reaction (ORR), showing an excellent performance with an onset potential of 0.95 V, a half-wave potential of 0.85 V, and long-term durability of 2000 cycles, comparable to the performance of commercial Pt/C. Moreover, FMS1000 displays a remarkable supercapacitive property with a specific capacitance of 330.7 F g^-1 at 0.2 A g^-1 and good long-term stability with a capacitance retention of 97 % over 50 000 cycles. Thus, a practical strategy for the production of mesoporous carbon materials with different morphological structures and porous defects as high-performance energy materials is advanced.

Materials nanoarchitectonics at two-dimensional liquid interfaces

Much attention has been paid to the synthesis of low-dimensional materials from small units such as functional molecules. Bottom-up approaches to create new low-dimensional materials with various functional units can be realized with the emerging concept of nanoarchitectonics. In this review article, we overview recent research progresses on materials nanoarchitectonics at two-dimensional liquid interfaces, which are dimensionally restricted media with some freedoms of molecular motion. Specific characteristics of molecular interactions and functions at liquid interfaces are briefly explained in the first parts. The following sections overview several topics on materials nanoarchitectonics at liquid interfaces, such as the preparation of two-dimensional metal-organic frameworks and covalent organic frameworks, and the fabrication of low-dimensional and specifically structured nanocarbons and their assemblies at liquid-liquid interfaces. Finally, interfacial nanoarchitectonics of biomaterials including the regulation of orientation and differentiation of living cells are explained. In the recent examples described in this review, various materials such as molecular machines, molecular receptors, block-copolymer, DNA origami, nanocarbon, phages, and stem cells were assembled at liquid interfaces by using various useful techniques. This review overviews techniques such as conventional Langmuir-Blodgett method, vortex Langmuir-Blodgett method, liquid-liquid interfacial precipitation, instructed assembly, and layer-by-layer assembly to give low-dimensional materials including nanowires, nanowhiskers, nanosheets, cubic objects, molecular patterns, supramolecular polymers, metal-organic frameworks and covalent organic frameworks. The nanoarchitecture materials can be used for various applications such as molecular recognition, sensors, photodetectors, supercapacitors, supramolecular differentiation, enzyme reactors, cell differentiation control, and hemodialysis.