Bio-inspired Method Research Articles

Bioinspired 3D Culture in Nanoliter Hyaluronic Acid-Rich Core-Shell Hydrogel Microcapsules Isolates Highly Pluripotent Human iPSCs.

Human induced pluripotent stem cells (iPSCs) are ideal for developing personalized medicine. However, the spontaneous differentiation of human iPSCs under conventional 2D and 3D cultures results in significant heterogeneity and compromised quality. Therefore, a method for effectively isolating and expanding high-quality human iPSCs is critically needed. Here, a biomimetic microencapsulation approach for isolating and culturing high-quality human iPSCs is reported. This is inspired by the natural proliferation and development of blastomeres into early blastocyst where the early embryonic stem cells-containing core is enclosed in a semipermeable hydrogel shell known as the zona pellucida (Zona). Blastomere cluster-like human iPSC clusters are encapsulated in a miniaturized (≈10 nanoliter) hyaluronic acid (HA)-rich core of microcapsules with a semipermeable Zona-like hydrogel shell and subsequently cultured to form pluripotent human iPSC spheroids with significantly improved quality. This is indicated by their high expression of pluripotency markers and highly efficient 3D cardiac differentiation. In particular, HA is found to be crucial for isolating the high-quality human iPSCs with the biomimetic core-shell microencapsulation culture. Interestingly, the isolated human iPSCs can maintain high pluripotency even after being cultured again in 2D. These discoveries and the bioinspired culture method may be valuable to facilitate the human iPSC-based personalized medicine.

Hybrid intelligent telemedical monitoring and predictive systems

Healthcare systems need to overcome the high mortality rate associated with cardiovascular disease and improve patients’ health by using decision support models that are both quantitative and qualitative. However, existing models emphasize mathematical procedures, which are only good for analyzing quantitative decision variables and have failed to consider several relevant qualitative decision variables which cannot be simply quantified. In solving this problem, some models such as interval type-2 fuzzy logic (IT2FL) and flower pollination algorithm (FPA) have been used in isolation. IT2FL is a simplified version of T2FL, with a reduced computation complexity and additional design degrees of freedom, but it cannot naturally achieve the rules it uses in making decisions. FPA is a bio-inspired method based on the process of pollination, executed by the flowering plants, with the ability to learn, generalize and process numerous measurable data, but it is not able to describe how it reaches its decisions. The hybrid intelligent IT2FL-FPA system can conquer the constraints of individual approaches and strengthens their robustness to cope with healthcare data. This work develops a hybrid intelligent telemedical monitoring and predictive system using IT2FL and FPA. The main objective of this paper is to find the best membership functions (MFs) parameters of the IT2FL for an optimal solution. The FPA technique is employed to find the optimal parameters of the MFs used for IT2FLSs. The authors tested two data sets for the monitoring and prediction problems, namely: cardiovascular disease patients’ clinical and real-time datasets for shock-level monitoring and prediction.

Bioinspired Building Structural Conceptual Design by Graphic Static and Layout Optimization: a case study of human femur structure

This paper introduces a bioinspired structure design method in the conceptual stage and takes the human femur section as an example, to extract the structural principle from the natural form, and summarizes as the morphological operation rules. The morphological manipulation rules provide a geometric feedback-based design process of both the building structural performance and its space with the manipulation rule of Graphic static. While extracting building structural principle, the Layout Optimization method is applied to obtain the force flow inside the nature biological form boundary under a certain load, and the force flow is presented with strut and tie model, summarizing the structural characteristic of human femur. The combinatorial and transformation methods of graphic statics are employed in the morphological operation stage to transform the form diagram while maintaining equilibrium, which facilitates designers to explore the structural form from both performance and space perspectives. Finally, the design process of a stadium inspired by the human femur is taken as an example to demonstrate how the introduced workflow can be used in the conceptual design stage and optimization of buildings.

Cooperative Multivalent Weak and Strong Interfacial Interactions Enhance the Adhesion of Mussel-Inspired Adhesives

Inspired by the strong adhesion of mussel byssal threads to surfaces, the incorporation of 3,4-dihydroxyphenylalanine (DOPA) in polymer architecture has become a popular strategy to improve the adhesion of the polymers. There are numerous literature reports of this bioinspired method to improve the adhesion performance of polymers. However, the mechanism behind the success of DOPA-based adhesion continues to be a puzzle as decoupling the contribution of interfacial adhesion to the alteration in chemistry is experimentally challenging. Herein, we designed mussel-inspired elastomers with four different functionalities to test the importance of aromatic and hydroxyl groups in determining the adhesion performance. With a combination of adhesion measurements, surface-sensitive spectroscopy, and molecular dynamics simulations, we show that the aromatic groups form weak multivalent acid–base interactions with the surface hydroxyl groups on sapphire. Also, the interaction of both phenyl (weak acid–base interaction) and −OH groups (strong acid–base interaction) of DOPA with sapphire −OH groups increases the adhesion of DOPA-based polymers compared to polymer analogs functionalized with either phenylalanine (only aromatic), serine (only hydroxyl), or tyrosine (aromatic and one hydroxyl) groups. Thus, this study illustrates the importance of both strong and weak acid–base interactions in enhancing adhesion.

Long-term stabilized amorphous calcium carbonate-an ink for bio-inspired 3D printing.

Biominerals formed by organisms in the course of biomineralization often demonstrate complex morphologies despite their single-crystalline nature. This is achieved owing to the crystallization via a predeposited amorphous calcium carbonate (ACC) phase, a precursor that is particularly widespread in biominerals. Inspired by this natural strategy, we used robocasting, an additive manufacturing three-dimensional (3D) printing technique, for printing 3D objects from novel long-term, Mg-stabilized ACC pastes with high solids loading. We demonstrated, for the first time, that the ACC remains stable for at least a couple of months, even after printing. Crystallization, if desired, occurs only after the 3D object is already formed and at temperatures significantly lower than those of common postprinting sintering. We also examined the effects different organic binders have on the crystallization, the morphology, and the final amount of incorporated Mg. This novel bio-inspired method may pave the way for a new bio-inspired route to low-temperature 3D printing of ceramic materials for a multitude of applications.

Flow separation control using the cetacean species nose design

Most of the flow separation control devices used in the aircraft wing are effective at high angles of attack, and adversely affect the performance of the wing at low angles of attack. In flight mission, the cruise phase takes major portion than the take-off and landing. Therefore, the flow separation control devices installed on wing may reduce the performance of the aircraft in total flight mission. A bio-inspired passive flow control method is used by introducing leading edge modification. The leading edge modification inspired by the cetacean species (Porpoise) has been analyzed on NACA2412 and NACA66215 airfoils at different subsonic speed using 2D analysis. The effect of the spanwise location and extent of these leading edge modifications is analyzed using a three-dimensional numerical investigation. The porpoise nose design (shorter length and medium depth i.e. depth — 2.25 % of chord, nose length — 0.75 % chord, and nose diameter — 2 % chord) delay the flow separation and improves the aerodynamic efficiency up to the critical Mach number. After critical Mach number, the shock wave formation affects the porpoise nose performance and shows similar flow behavior as base airfoil. A finite wing with a porpoise nose design of full spanwise length showed the better aerodynamic efficiency than base wing model. This rigid design improves aerodynamic performance of a wing without major structural modification.

A bio-inspired method to fabricate the substrate-independent Janus membranes with outstanding floatability for precise oil/water separation

A bio-inspired method to fabricate the substrate-independent Janus membranes with outstanding floatability for precise oil/water separation

Effects of bio-inspired integration of laser-induced microstructure and coated cemented carbide on tool performance in green intermittent turning

Both laser-induced microstructure and coated cemented carbide material have shown the ability to improve the performance of cutting tools. Biomimetics offers the possibility to integrate them according to the structures and the functions of creatures. The present work explored the effects of the bio-inspired integration of them on tool performance in green intermittent turning. Design of the bio-inspired integration was achieved by analyzing Odontodactylus scyllarus. Ellipsoid-shaped microstructure was fabricated on Al2O3/TiCN coated WC–Co cemented carbide material by nanosecond laser according to the design. Ablation of the material during microstructure formation was quantitatively revealed based on the analysis of heat flux distribution and material temperature. A theoretical indicator of tool performance was established incorporating material damage and cutting load on the basis of damage mechanics and fracture mechanics. This work identified the evolutions of the theoretical tool performance indicator and the experimental tool wear index with WC grain size sg and laser angle ϕ. Both the theoretical indicator and the experimental index can be used to distinguish the optimum combination of sg and ϕ. The optimum combination was sg = 0.5 μm and ϕ = 120° for the dry cutting process. It varied to be sg = 0.5 μm and ϕ = 60° in soybean-oil-based nanofluid minimum quantity lubrication cutting. The proposed bio-inspired integration method efficiently enhanced tool performance in green intermittent turning.

Ti3C2Tx MXene Sheets: Sequentially Bridged Ti3C2Tx MXene Sheets for High Performance Applications (Adv. Mater. Interfaces 7/2021)

Translating the excellent properties of two-dimensional Ti3C2Tx MXene sheets into bulk architectures, both pure and composite, remains challenging due to several factors, including poor inter-sheet connectivity, uncontrolled spacing and sheet-misalignment In article number 2002043, Ken Aldren S. Usman, Jizhen Zhang, Joselito M. Razal, and co-workers report a two-step, bio-inspired bridging method that permits surface modi?cation of Ti3C2Tx MXene sheets while still yielding stable dispersions, thereby enabling production of films comprised of aligned, evenly-spaced, and strongly interconnected sheets, resulting in excellent electrical conductivity, mechanical strength, and uncompromised electrochemical properties.

A New Bio-Inspired Method for Spam Image-Based Emails Filtering

Electronic mail has become one of the most popular and frequently used channels for personal and professional online communication. Despite its benefits, e-mail faces a major security problem, which is the daily reception of a large number of unsolicited electronic messages, known as “spam emails.” Today, most electronic mail systems have simple spam filtering mechanisms based on text spam filtering technologies. To circumvent these filters, spammers are introducing new techniques of embedding spam messages in the image attached to the mail. In this article, the authors propose a new method for spam image filtering. The proposed system can distinguish between legitimate images from spam images based on the texture characteristics of the image attached to an email. From each image, around 20 characteristics can be extracted from the gray level co-occurrence matrix (GLCM). Then, to classify the images as spam or ham, the authors use a new metaheuristic nature-inspired model for building classifiers based on the social worker bees and enhanced nearest-centroid classification method.

Crystallization, Luminescence and Cytocompatibility of Hexagonal Calcium Doped Terbium Phosphate Hydrate Nanoparticles.

Luminescent lanthanide-containing biocompatible nanosystems represent promising candidates as nanoplatforms for bioimaging applications. Herein, citrate-functionalized calcium-doped terbium phosphate hydrate nanophosphors of the rhabdophane type were prepared at different synthesis times and different Ca2+/Tb3+ ratios by a bioinspired crystallization method consisting of thermal decomplexing of Ca2+/Tb3+/citrate/phosphate/carbonate solutions. Nanoparticles were characterized by XRD, TEM, SEM, HR-TEM, FTIR, Raman, Thermogravimetry, inductively coupled plasma spectroscopy, thermoanalysis, dynamic light scattering, electrophoretic mobility, and fluorescence spectroscopy. They displayed ill-defined isometric morphologies with sizes ≤50 nm, hydration number n ~ 0.9, tailored Ca2+ content (0.42–8.11 wt%), and long luminescent lifetimes (800–2600 µs). Their relative luminescence intensities in solid state are neither affected by Ca2+, citrate content, nor by maturation time for Ca2+ doping concentration in solution below 0.07 M Ca2+. Only at this doping concentration does the maturation time strongly affect this property, decreasing it. In aqueous suspensions, neither pH nor ionic strength nor temperature affect their luminescence properties. All the nanoparticles displayed high cytocompatibility on two human carcinoma cell lines and cell viability correlated positively with the amount of doping Ca2+. Thus, these nanocrystals represent promising new luminescent nanoprobes for potential biomedical applications and, if coupled with targeting and therapeutic moieties, they could be effective tools for theranostics.

Synthesis and Characterization of Chitosan/Silver Nanocomposite Using Rutin for Antibacterial, Antioxidant and Photocatalytic Applications

The present study reports an eco-friendly synthesis of chitosan/silver (CS/Ag) nanocomposite using rutin by a bio-inspired method. The formation of brown color and UV–visible absorbance peak at 415 nm confirmed the synthesis of CS/Ag nanocomposite. X-ray diffraction (XRD) analysis revealed the crystalline peaks of both chitosan and silver in synthesized CS/Ag nanocomposite. Field emission-scanning electron microscopy (FE-SEM) analysis showed that the synthesized CS/Ag nanocomposite having predominant spherical shaped nanostructure with an average size of 23–78 nm. Fourier transform infrared spectroscopy (FTIR) analysis indicated the presence of functional derivatives related to chitosan and rutin in CS/Ag nanocomposite. Synthesized CS/Ag nanocomposite exhibited superior disc diffusion antibacterial activity against Bacillus subtilis and Escherichia coli. The in vitro antioxidant of CS/Ag nanocomposite was evaluated spectrophotometrically by using DPPH method. The percentage of antioxidant activity was increased with increasing concentration of CS/Ag nanocomposite. Furthermore, photocatalytic activity of CS/Ag nanocomposite was evaluated by the removal of methylene blue (MB) dye from aqueous solution under sunlight irradiation. Results showed that the degradation efficiency of MB reached up to 88% after irradiation for 220 min. Thus, the obtained results indicated that the synthesized CS/Ag nanocomposite using rutin can be a promising nanomaterial for multifunctional applications.

A social immunity based approach to suppress rumors in online social networks

Online social networks (OSNs) connect people around the globe under one virtual society. It helps people gather, communate and share their common interests. But many times, OSNs are also exploited and eventually become a major platform for rumor or false information propagation. Controlling such rumors in OSNs has been the most challenging research interest in recent days. Since OSNs are a platform of collective behavior, we focus on a collective rumor containment approach to control or eradicate rumors. In this paper, an anti-rumor information spreading approach is proposed to contain rumors collectively by following a bio-inspired immunization method called social immunity. First, A competitive information propagation model called competitive cascade (CC) model that spreads rumor and true information simultaneously is defined. This model continuously updates the trustworthiness of individuals in the network on every communication among the participants of OSNs. Then, the initial spreaders of anti-rumors are identified with the help of the intensity of the rumor in the network as well as the individual’s trustworthiness. Finally, a collective rumor containment approach is applied by considering the cost of rumor containment and a rumor intensity threshold. The proposed approach is compared with recent and well-known rumor control approaches and the results show that the proposed approach is effective in eradicating rumors.

Optimal Smart Inverter Control for PV and BESS to Improve PV Hosting Capacity of Distribution Networks Using Slime Mould Algorithm

In this study, an optimal reactive power (Volt/VAr) control of smart inverters for photovoltaic (PV) and battery energy storage systems (BESSs) to improve the PV hosting capacity (PVHC) of distribution networks is proposed. The primary objective of the proposed method is to improve the PVHC of a distribution network by determining the optimal oversize, dispatch, and control setting of the Volt/VAr functions of the smart inverters for both PVs and BESSs. Concurrently, the optimal locations of the PVs and BESSs are determined. The problem is formulated as a multi-objective mixed-integer nonlinear optimization to maximize the PVHC and minimize the voltage deviation simultaneously. A bio-inspired metaheuristic optimization method, i.e., the slime mould algorithm (SMA), is employed to solve the optimization problem. To assess the efficacy of the proposed PVHC improvement method, extensive simulations are conducted on an IEEE 33-node system using MATLAB software. The simulation results verify that the proposed method improves the PVHC of the distribution network compared to different cases and the default Volt/VAr control settings of the smart inverters. Furthermore, the SMA optimization method provides superior performance in finding the optimal PVHC of a distribution network compared to the conventional metaheuristic optimization methods.

Performance analysis of the bioinspired method for optimizing irregular codes with a low density of parity checks

This paper reports the principles of building irregular codes with a low density of parity checks. It has been determined that finding irregular finite-length codes with improved characteristics necessitates the optimization of the distributions of powers of the symbol and test vertices of the corresponding Tanner graph. The optimization problem has been stated and the application of a bioinspired approach to solving it has been substantiated. The paper considers the main stages of the bioinspired method to optimize the finite-length irregular codes with a low density of parity checks. It is shown that a given method is based on the combined application of the bioinspired procedure of bats, a special method for building Tanner graphs, and computer simulation. The reported study aimed to evaluate the effectiveness of the proposed method for optimizing irregular codes when using the selected bioinspired procedure and the predefined model of a communication channel. Based on the study results, it has been determined that the optimized relatively short irregular codes with a low density of parity checks possess better characteristics compared to existing codes. It is shown that the derived codes do not demonstrate the effect of an floor and ensure an energy win via encoding of about 0.5 dB compared to regular codes depending on the length of the code. It has been determined that the optimization of irregular codes with a low value of the maximum power in the distribution of powers of the symbol vertices of the Tanner graph leads to a decrease in the order of an error coefficient in the region with a high signal/noise ratio. The application of the optimized irregular codes with a low density of parity checks could improve the efficiency of next-generation wireless telecommunication systems

Virtual Point Control for Step-Down Perturbations and Downhill Slopes in Bipedal Running.

Bipedal running is a difficult task to realize in robots, since the trunk is underactuated and control is limited by intermittent ground contacts. Stabilizing the trunk becomes even more challenging if the terrain is uneven and causes perturbations. One bio-inspired method to achieve postural stability is the virtual point (VP) control, which is able to generate natural motion. However, so far it has only been studied for level running. In this work, we investigate whether the VP control method can accommodate single step-down perturbations and downhill terrains. We provide guidelines on the model and controller parameterizations for handling varying terrain conditions. Next, we show that the VP method is able to stabilize single step-down perturbations up to 40 cm, and downhill grades up to 20–40° corresponding to running speeds of 2–5 ms−1. Our results show that the VP approach leads to asymmetrically bounded ground reaction forces for downhill running, unlike the commonly-used symmetric friction cone constraints. Overall, VP control is a promising candidate for terrain-adaptive running control of bipedal robots.

Physicochemical and magnetic properties of functionalized lanthanide oxides with enhanced hydrophobicity

According to the developed bioinspired method in the one-step procedure, the material with the petal effect was switched to lotus one. Therefore, highly hydrophobic and super-hydrophobic materials with tunable adhesive properties and fractal-like structures were successfully produced with high efficiency (67–84%). The work's essence was to modify chemically selected powders of lanthanide oxides (CeO2, Pr6O11, Nd2O3, and Gd2O3). High effectiveness of the functionalization process with 1H,1H,2H,2H-perfluorooctyltriethoxysilane (FC6) and n-octyltriethoxysilane (C6) was proven by various techniques, e.g. XPS, HR-TEM, ATR, XRD, zeta potential. Materials with water contact angle between 143.6° (CeO2-C6) and 175.5° (Nd2O3-FC6) with thermally stable nanolayer (up to 380 °C) were generated. Surfaces functionalized with FC6 possessed a polar component of surface free energy (SFE) close to zero. Water behavior in contact with the modified materials was studied, taking into consideration the unique electron structure of lanthanides assessed by goniometric measurement, also adhesion and spreading pressure were determined. Very low adhesion and polar SFE partly resulted in immediate bouncing of water droplet upon contact with the modified surface. The presented method allows preparing stable materials with a high potential in materials chemistry and modulation of surface features and engineering (e.g. heat transfer fluids, specific coating).

Bio-inspired algorithm for variable selection in i-PLSR to determine physical properties, thorium and rare earth elements in soils from Brazilian semiarid region

Studies regarding physical parameters and Rare Earth Elements (REEs) in soils are essential for agriculture and raw material extraction. The determination of such parameters is costly and time-consuming. On the other hand, Near-Infrared Spectroscopy (NIRS) is a low cost, non-destructive, and fast alternative to predict REEs and physical properties in soils. Moreover, the specific wavelengths or intervals correlated to target properties are not clearly identified in the spectra, drawing attention to using the variable selection algorithm to resolve this problem. In this sense, this study aimed to develop and test the bio-inspired variable selection method known as Firefly intervals Partial Least Square Regression (FF-iPLSR). This heuristic approach is based on the attractiveness between fireflies as swarm behavior when searching for food. The performance of the FF-i-PLSR was evaluated using six soil profiles from the Brazilian semiarid region using raw data and the preprocessing MSC, SNV, baseline adjusts, and Savitzky-Golay derivative. The following variables were quantified: sand, silt, clay, Th, and total REE. Comparatively, four chemometrics methods were used: full-spectrum PLS, PLS based on variable intervals (iPLS), and the Successive Projections Algorithm for iPLS (iSPA-PLS). The proposed algorithm for variable interval selection obtained a well-adjusted and more parsimonious chemometric model, mainly for silt, sand, and clay, with lower LV’s and variable intervals than the comparative models. These results indicated the robustness of the proposed algorithm. The models’ quality parameters showed that FF-iPLS achieved low average values for RMSEP, bias, and REP. Thus, the proposed algorithm of variables interval selection FF-iPLS is an interesting tool for analyzing environmental matrices such as soil. However, more studies are necessary to evaluate the algorithm’s efficiency using other samples and environmental conditions.

Covert underwater communication based on combined encoding of diverse time-frequency characteristics of sperm whale clicks

Bio-inspired camouflage covert underwater acoustic communication has been studied widely recently. In order to improve the camouflage ability and communication rate, a bio-inspired covert underwater acoustic communication method based on combined encoding of diverse time–frequency characteristics of sperm whale clicks is proposed. The characteristics of time–frequency contour shapes and frequency-band distributions are classified and counted, and the communication codes are constructed based on the two characteristics. According to the inter-click interval characteristic of sperm whale click pulse trains, the bionic communication sequences are constructed through differential time delay difference encoding between different communication codes. Based on the proposed combined encoding method of diverse time–frequency characteristics, the constructed communication sequence contains a large number of different modulated clicks. It conforms to the characteristic that there exists a large number of and a variety of clicks in the true click pulse train, which improves the camouflage ability. The true sperm whale click pulses are inserted into the communication sequences as camouflage pulses to further improve the camouflage ability. Furthermore, the communication rate is improved due to using multiple characteristics to represent different encoding information in the proposed method. Simulations are implemented to demonstrate the effectiveness, reliability and covertness of the proposed covert communication method.

The Bionics and its Application in Energy Management Strategy of Plug-in Hybrid Electric Vehicle Formation

A novel distributed cooperative formation control method inspired by the aggregate behaviors of fish groups is proposed for plug-in hybrid electric vehicle (PHEV) formation. Firstly, a hierarchical control architecture is established for formation keeping with fuel consumption (FC) optimization simultaneously. The top layer is to generate a leader with the optimal performance based on the nonlinear model predictive control (MPC) technique. A fish swarm optimization (FSO) algorithm is proposed to solve the nonlinear MPC problem by imitating the predation behaviors of the fish swarm. The middle layer is a decentralized intelligent cruise control (ICC) for follower vehicles to track their leader imitated the behaviors of fish swarm, and some design criteria are presented based on the Lyapunov stability theory. The under layer is to achieve a satisfying performance for the hybrid powertrain systems of followers. Finally, the bio-inspired method applied for PHEV formation is verified with a satisfying robustness, fuel economy, car-following and also real-time processing performances. According to the results, the PHEV formation using the proposed method represents a better car-following performance compared with the normal adaptive cruise control (ACC) method and a 21.26% improvement of FC compared with the rule-based energy management strategy (EMS). The computational burden is also reduced by the bio-inspired method.