Maximum Load Capacity Research Articles

Design Methods of Aluminium Pin-Ended Columns with Topology-Optimised Cross-Sections

This paper presents a numerical study of topology-optimised pin-end aluminium alloy columns using finite element analysis (FEA). The FEA models integrate geometric imperfections and material nonlinearity, and are validated against experimental findings from the existing literature. ABAQUS v.6.15 (release 2020) is used in preparing the FEA models and obtaining the analysis results. Furthermore, modern design methodologies including Eurocode 9, the direct strength method (DSM), and the continuous strength method (CSM) are employed to assess the maximum load capacity of such columns. Parametric investigations encompass diverse parameters such as varied cross-sections, column lengths, and global and local imperfections. By analysing a total of 288 FE models, incorporating 16 column cross-sections across two lengths with nine distinct imperfections, this study compares results with those derived from modern design methodologies. Thus, this research elucidates the behaviour of novel cross-sections and the application of contemporary design techniques in their analysis.

Research on rotational rollback suppression of diamond-shaped active locking flexure mechanism (ALFM) driven by piezoelectric wafers

Abstract Piezoelectric actuators have a wide range of applications in many areas due to their advantages of fast response speed, high resolution, compact and simple structure, diverse configurations, and resistance to electromagnetic interference. However, existing piezoelectric actuators generally have large fallback, and a few researchers have applied the ALFM to the fallback suppression of actuators. In this paper, an ALFM using a piezoelectric wafer as the driving source is innovatively designed, and the structure and dimensions are simulated and optimized using Finite Element Method, according to which the piezoelectric wafer-type ALFM is used to design a new inertial piezoelectric actuator that can suppress backward movement. The motion principle of the piezoelectric actuator is theoretically analyzed, followed by the establishment of the machine dynamics model of the piezoelectric actuator and simulation with MATLAB/simulink to verify the reasonableness of the dynamics model. Finally, a series of experiments are carried out on the processed drive model, and the results show that the maximum accuracy of the actuator is 8.5 μrad, and the maximum load capacity is 160 g. The comparison experiments at 30 Hz and 40 Hz with and without the ALFM prove that the locking mechanism does supress the actuator from backing off to a certain extent, which verifies the reasonableness of the scheme proposed in this paper.

Small scale laboratory monotonic and cyclic pull out testing on grout and resin encapsulated cable bolts

Axial studies on cable bolts can be conducted using various scale testing apparatuses. Large scale testing, while providing a powerful platform for testing, is expensive and time consuming. This study presents details of a small scale pull out testing campaign on cable bolts and investigates the results achieved. Six popular types of cable bolts were studied using an anti rotation apparatus while encapsulated in cementitious grout and resin. The resin samples were tested under both monotonic and cyclic loading patterns. The results showed that grouted bulbed cables require higher displacement to reach their maximum load capacity which is lost at failure, while plain cables tend to hold lower loads for a longer time. Resin samples provided strain softening behaviour with low capacities, particularly in absence of cable indentation or bulbs. Cyclic loading tended to adversely affect the post peak behaviour of the resin samples, especially in the bulbed cables. Failed samples inspected after the testing suggested a non-uniform damage profile along the cable with extensive damage at the exit point transitioning into almost no damage at the entry point.

Machine learning-based axial compressive capacity estimation of cold-formed steel build-up sections

To consider the highly nonlinear and complex buckling behaviour of various sections of cold-formed steel (CFS) built-up columns, experimental and finite element (FE) methods are commonly used for calculating their axial compressive capacity, although these methods are time-consuming and costly. This paper proposes machine learning (ML) methods to overcome the issues of traditional methods for predicting the maximum axial load capacity (MALC) of CFS built-up columns. A total of 3839 samples from more than 33 different types of sections were collected from 43 published papers, including 817 experimental data and 3,022 FE simulation data. A total of 15 characteristic parameters, such as the second moment of area, the radius of gyration, and the polar second moment of area, are considered when nine different ML models are trained. The robustness of these models was compared via the Monte Carlo simulation method, and the predicted results were compared with the calculated results from the current codes. The results show that the extreme gradient boosting (XGB) model has higher accuracy and smaller prediction errors in estimating the MALC. The proportion of data with a relative percentage error less than 10% in the prediction results of the AISI-DSM codes is 45.31%, whereas the XGB model achieves a proportion of 87.57%, and the results calculated from current codes tend to be more conservative, with a large deviation, which needs to be further considered.

Biomaterial-mediated delivery of traditional Chinese medicine ingredients for spinal cord injury: a systematic review.

Biomaterials loaded with ingredients derived from traditional Chinese medicine (TCM) are viewed as a promising strategy for treating spinal cord injury (SCI). However, a comprehensive analysis of the existing literature on this topic has not yet been conducted. Therefore, this paper systematically reviews researches related to this approach, aiming to identify gaps and shortcomings in the field. PubMed, EMBASE, Web of Science, Chinese Biomedical Literature, Wanfang, and China National Knowledge Infrastructure (CNKI) were searched for retrieving studies on biomaterials loaded with TCM ingredients published from their inception to October 2024. Two reviewers performed screening of search results, information extraction, and literature quality assessment independently. For this systematic review, 41 publications were included. Six TCM ingredients-paclitaxel, curcumin, tetramethylpyrazine, resveratrol, berberine, and tanshinone IIA were combined with biomaterials for treatment of SCI. Biomaterials were categorized into hydrogels, biodegradable scaffolds, nanoparticles, and microspheres according to the type of scaffold. These drug delivery systems exhibit commendable biocompatibility, drug-loading capacity, and drug-release capabilities, and in combination with TCM ingredients, synergistically contribute to anti-oxidative stress, anti-inflammatory, neuroprotective, and anti-apoptotic effects. These studies demonstrated the efficacy of biomaterials loaded with TCM ingredients in facilitating motor function recovery and neuroprotection in SCI rats, providing evidence for future research. However, in the complex microenvironment of SCI, achieving the maximum drug loading capacity of TCM ingredients within biomaterials, along with sustained and controlled release to fully exert their pharmacological effects, remains a major challenge for future research. https://www.crd.york.ac.uk/PROSPERO/ identifier CRD42024505000.

Experimental study on seismic performance of bridge pier with new HRB650E high-strength steel bar

To facilitate the application of high-strength steel in reinforced concrete bridge structures, this study explores the seismic performance of full-scale HRB650E high-strength reinforced concrete bridge piers. Initially, monotonic tensile tests were conducted on HRB400 and HRB650E steel rebars with the same slenderness ratio to analyze the differences in their mechanical properties. Subsequently, quasi-static cyclic tests were carried out on four square full-scale RC bridge piers to examine the influence of new high-strength rebars, stirrup ratios, and axial load ratios on the seismic performance. Based on the experimental results, a hysteresis model suitable for HRB650E reinforced concrete columns was developed. The findings indicate that the HRB650E steel bar exhibited lower uniform elongation and fracture elongation compared to HRB400 steel bar. The displacement at which HRB650E piers reached crack damage was 36 % higher than that of HRB400 piers, and they also showed lower residual displacements at all load levels. The maximum lateral load capacity and the ductility coefficient of HRB650E piers increased significantly compared to HRB400 piers. While the initial secant stiffness of both types was comparable, HRB650E piers exhibited a slower rate of stiffness degradation, resulting in higher secant stiffness at the ultimate state. They also demonstrated 35 % higher cumulative energy dissipation at the ultimate state. When the stirrup ratio of HRB650E piers was increased from 1.1 % to 1.7 %, there was a slight reduction in residual displacement, a small increase of the yield strength, and a minor improvement in the maximum lateral load capacity. Furthermore, a higher stirrup ratio was observed to improve energy dissipation levels at all loading stages. Increasing the axial load ratio of HRB650E piers from 0.1 to 0.2 allowed the piers to withstand greater deformations at the same repairable ultimate state, with significant increases in yield strength, maximum lateral load capacity, initial secant stiffness, and secant stiffness at the ultimate state, but a small increase in the cumulative energy dissipation. The hysteresis model for HRB650E RC columns, based on experimental data, exhibited good computational accuracy.

A novel approach to enhance the structural integrity of a bottom-edge cracked I-beam with piezoelectric actuators

Structural health monitoring and repair have become increasingly crucial in confirming the safety and longevity of damaged structures. This study presents a novel approach to enhancing the structural integrity and extending the fatigue life of a bottom-edge cracked I-beam by applying piezoelectric actuators strategically placed along the crack location by actively suppressing crack propagation. An innovative actuation system induces controlled deformations in the I-beam, effectively reducing the Stress Intensity Factor (SIF) and preventing crack propagation. The efficacy of the proposed approach is validated through a series of numerical results on the ABAQUS platform, including static loading, fatigue loading, and crack growth monitoring. Various parameters, like maximum loading capacity under static loading, interpretation of crack growth rate, and service life, are monitored and analyzed throughout the cyclic loading process. The results demonstrate that the application of 500 V to the piezoelectric actuators significantly reduces the SIF by 16.62% under a 2 kN total load, a 2.86% enhanced maximum load-carrying capacity is obtained, delayed crack propagation is found after repair, and a 72.67% extended service life is achieved under a load range of 0.2 kN to 2 kN. Overall, the outcomes of this research lead to the development of innovative and efficient techniques for delaying the propagation of cracks, thereby preventing the premature onset of catastrophic failure of cracked I-beams.

Bioactive electrospun zein fibers integrated with ZnO nanoparticles: In vitro investigations

The objective of the current study was the fabrication and characterization of electrospun zein-ZnO fibers containing various concentrations of cumin essential oil (CEO) (0, 1, 2, and 3% (v/v)). The electrospinning solution's apparent viscosity, conductivity, and surface tension were measured. Also, the electrospun's morphological, color, encapsulation efficiency, antioxidant and antimicrobial properties, thermal stability, and release kinetic were investigated. The results represented that following the increase in CEO concentration, the conductivity and surface tension of the electrospinning solution changed from 182.92 μS/cm to 145.22 μS/cm and 19.52 mN/m to 22.35 mN/m, respectively. The scanning electron microscope (SEM) revealed the homogenous and free-bead structure of electrospun fibers. Besides, the diameter of fibers enhanced with a rise in CEO concentration from 217.13 nm to 321.67 nm. The finding estimated the maximum encapsulation efficiency and loading capacity at about 95.09% and 25.65%, respectively in electrospun containing the highest concentration of CEO (3%). CEO inclusion in electrospinning fibers augmented the value of contact angle, color difference, TPC, antioxidant, and antimicrobial properties. The favorable interaction between the CEO ingredients and electrospinning fibers was confirmed through FTIR and XRD analysis. Furthermore, the incorption of CEO enhanced the thermal stability of fibers. Release kinetic in different simulant (aqueous, acidic, alkaline, and fatty) revealed that Fick's diffusion was the main release mechanism. The highest diffusion coefficient was observed in electrospun fibers containing 3% CEO in the fatty media simulant. These findings could present a new horizon into electrospinning fiber's application in various fields of medicine, tissue engineering, food, and pharmaceutical industry.

Investigating the axial compressive behavior of cruciform CFST columns: An experimental study

Concrete-filled steel tube (CFST) columns enhance seismic resistance, enabling lighter-weight structures with improved fire performance. This study investigates the axial performance of cruciform CFST columns using three half-scale experiments. The cruciform sections were internally configured as unstiffened (UnS-CFST), stiffened (S-CFST), and multicell (M-CFST). Failure mode, stress, displacement, ductility, and strength were evaluated to determine the maximum load-bearing capacity. Compared to UnS-CFST columns, S-CFST and M-CFST exhibited improved ductility and axial compressive performance. The study also looks at how the proposed method for cruciform sections compares to existing design standards for square and circular CFST columns, such as AIJ, EC4, GB 50936–2014, CECS 159:2004, ACI 318R-05, and AS3600–2001. A novel method for determining the maximum load capacity of cruciform CFST columns is proposed, achieving an accuracy of approximately 95 % compared to experimental results. This novel method facilitates the design of cruciform CFST columns.

Design and performance evaluation of a stick–slip actuator with Z-shaped beam and two-stage amplification system

Abstract In the domain of piezoelectric driving, actuators that utilize the stick–slip effect at high speeds and low frequency have garnered significant interest. This study presents an innovative linear piezoelectric actuator that integrates a two-stage amplification system with a Z-shaped beam mechanism. The designed actuator has good driving speed at low frequency while overcoming the disadvantage of such actuators requiring two flexible mechanisms to achieve reverse motion and poor reverse performance. The structure and scale of the actuator are explained and designed through theory and simulation. The experimental results demonstrate the prototype’s capability for bidirectional motion. Subjected to a 400 Hz and 140 V excitation, the maximum speed of the actuator is 12.88 mm s−1. The maximum load capacity is tested to be of 0.35 N. This research introduces a new approach for the design of high-speed bidirectional motion stick–slip piezoelectric actuators.

Study on Static Biomechanical Model of Whole Body Based on Virtual Human.

Material handling tasks often lead to skeletal injury of workers. The whole-body static biomechanical modeling method based on virtual humans is the theoretical basis for analyzing the human factor index in the lifting process. This paper focuses on the study of humans' body static biomechanical model for virtual human ergonomics analysis: First, the whole-body static biomechanical model is constructed, which calculates the biomechanical data such as force and moment, average strength, and maximum hand load at human joints. Secondly, the prototype model test system is developed, and the real experiment environment is set up with the inertial motion capture system. Finally, the model reliability verification experiment and application simulation experiment are designed. The comparison results with the industrial ergonomic software show that the model is consistent with the output of the industrial ergonomic software, which proves the reliability of the model. The simulation results show that under the same load, the maximum joint load and the maximum hand load are strongly related to the working posture, and the working posture should be adjusted to adapt to the load. Upright or bent legs have less influence on the maximum load capacity of the hand. Lower hand load capacity is due to forearm extension, and the upper arm extension greatly reduces the load capacity of the hand. Compared with a one-handed load, the two-handed load has a greater load capacity.

Enhancing hydrogen storage efficiency: Computational insights into scandium-decorated 2D polyaramid

This study explores hydrogen storage in 2D polyaramid (2DPA) and its enhancement via scandium decoration for onboard storage in fuel cell vehicles. Sc decoration in 2DPA is accompanied by a net 1.6 e charge transfer from Sc to 2DPA. Hydrogen binding in 2DPA + Sc proceeds with a net charge transfer of 0.32 e from Sc towards H2. 2DPA + Sc demonstrates a maximum hydrogen loading capacity of 8.589 wt% with an average adsorption energy of −0.376 eV/H2. These findings meet the stipulated criteria by the US Department of Energy for solid-state hydrogen storage in light-duty vehicles. Feasibility studies were conducted considering practical limitations in transition metal-modified carbon nanomaterials, including Sc-Sc clustering tendencies, stability, and hydrogen desorption behavior via ab initio molecular dynamics simulations, phonon dispersion, and diffusion studies. The highest barrier height for hydrogen desorption from 2DPA + Sc is 0.48 eV, and desorption is predicted to occur at 412 K (5 bar) indicating possibility of room temperature and reversible hydrogen storage. Our findings indicate that 2DPA + Sc is a promising hydrogen storage substrate material and should be explored in experimental trials.

Numerical simulation and experimental study of the influence of disk groove structure optimization on the air film flow field signature of an air-cushion sandwich belt conveyor

A new type of disk groove mechanism was developed and manufactured. The effects of the structural and operating factors of the disk groove on the air film loading performance were examined using single factor and orthogonal experimental methods. The results of numerical simulation and experimental studies showed that the air film loading performance correlated positively with the orifice diameter and inlet pressure, with the orifice spacing and diameter having the most significant effects, and that the belt speed boosted the air film uniformity. Meanwhile, a comparative analysis of the corresponding level values showed that an air film thickness of 0.8 mm, orifice diameter of 5 mm, orifice spacing of 30 mm, inlet pressure of 8000 Pa, and conveyor speed of 5 m/s were the optimal parameter combinations for the maximum loading capacity. To verify the accuracy of the model, a field experiment was conducted at Jiangmen Southern Conveying Machinery Engineering Co., Ltd. The air film pressure at the experimental position matched the numerical simulation results. In addition, when the number of rows was one and the air volume was 10 m3/h, the smallest value of traction resistance was obtained under minimum power consumption.

Achieving smooth motion in displacement amplification piezoelectric stick-slip actuator.

Traditional piezoelectric stick-slip actuators often suffer from significant backward motion phenomena, which greatly impact their output performance. To overcome this issue, a novel displacement amplification piezoelectric stick-slip actuator was meticulously designed. It integrates an L-shaped displacement amplification mechanism with a parallelogram-compliant mechanism. By dynamically adjusting the compressive force between the stator and the mover, this actuator effectively increases the single-step displacement, resulting in smooth and stable motion output. The design process involved thorough structural feasibility validation and core dimension optimization, utilizing Castigliano's second theorem and finite element simulation analysis. These efforts successfully yielded a substantial increase in the single-step output displacement. Experimental results demonstrate the actuator's capability to achieve smooth and stable motion output, even under challenging conditions, such as symmetric excitation signals and horizontal loading. Under specific operating parameters-preloading force of 3 N, input voltage of 100VP-P, and driving frequency of 625Hz sinusoidal excitation signal, the actuator achieves an impressive maximum driving speed of 25.22 mm/s, with a substantial maximum load capacity of 2.1 N. Compared to previous studies, the designed actuator exhibits superior adaptability to various excitation signals, offering significant potential for enhancing the performance and expanding the applications of piezoelectric stick-slip actuators.

Freeform trajectory generation for fiber reinforced polymer composites additive manufacturing with variable-deposition-width

Continuous carbon fiber-reinforced polymers (CCFRPs) printing is a unique additive manufacturing (AM) technique that enhances design flexibility and enables on-demand production of lightweight, high-strength composite parts. However, current trajectory generation methods for CCFRPs-AM have limited control over fiber placement and flexible matrix path infill, particularly in complex regions, often using constant deposition widths that restrict path coverage and mechanical properties. To address these limitations, this paper presents a variable-deposition-width (VDW) trajectory generation method for CCFRPs-AM. The approach integrates a streamline-based technique for fiber paths with a Voronoi diagram-based method for matrix path generation, optimizing path placement based on 2D stress fields while accommodating user-defined fiber paths. Mechanical tests by us on fabricated open-hole composite components demonstrate that the proposed approach enhances the interfacial bonding and increases the maximal loading capacity under tensile stress.

Preparation and Evaluation of Stability and Acute Oral Toxicity of a Drug Delivery System Combining MIL‐100(Fe) with Chloroquine Phosphate

AbstractMetal‐organic framework materials (MOFs) are highly porous and are the subject of growing interest among scientists globally for their utilization in drug delivery. In this work, iron‐based metal‐organic frameworks (MOFs) MIL‐100(Fe) were synthesized by ultrasonic method and studied for the loading of the chloroquine phosphate (CQP). The CQP‐release behavior of the material was investigated in water media with various pH solutions of 1.2, 2, 4.5, and phosphate‐buffered saline (PBS) at temperatures of 25 °C to 45 °C. MIL‐100(Fe) material had a high surface area of up to 1080 m2/g and could completely release the CQP at a pH of 1.2 after 25 hours. At other pH conditions, the drug exhibited an initial rapid release, followed by a gradual slowdown, ultimately achieving complete release after 96 hours. The maximal loading capacity for the CQP by the MIL‐100(Fe) was determined to be approximately 30 % at the pH solution of 2 (stomach environment). The findings from the activity assessment against the K1 malaria parasite strain (P. falciparum) indicated that the concentration at which the active ingredient, when carried by the material, exhibited inhibition was 193 nM/L. The evaluation outcomes for acute toxicity of the drug carrier material revealed an LD50 value exceeding 5000 mg/kg (equivalent to 1500 mg of CQP base). In contrast, when using the active substance alone, acute toxicity resulted in an LD50 value of 675 mg/kg.

The Structural Behavior of Lightweight Self-Compacting Concrete Slabs Using Different Types of Reinforcement

The purpose of this study is to examine how the type of reinforcement used in self-compacting concrete (SCC) and lightweight self-compacting concrete (LWSCC) affects their structural behavior. There were three forms of reinforcement used: wire mesh, glass fiber-reinforced rebars, and regular steel rebars. To evaluate the mechanical characteristics of reinforced concrete slabs with various types of reinforcement, extensive experiments were carried out. The tensile strength, stiffness, and crack resistance of the concrete were studied in each case. The finite element program Abaqus was utilized in addition to the experimental investigations to create the numerical simulation of the test. The experimental results revealed that the reinforcement type significantly affects the structural behavior of SCC and LWSCC slabs. Conventional steel rebars provided high tensile strength and excellent crack resistance, while glass fiber-reinforced rebars contributed to enhanced flexibility and reduced overall weight of the concrete. On the other hand, the wire mesh exhibited average mechanical and structural properties. These findings emphasize the importance of selecting the appropriate reinforcement type based on specific applications and desired performance requirements. This research provides valuable guidance for architects and civil engineers in choosing optimal reinforcement for SCC and LWSCC. Furthermore, it can contribute to the advancement of techniques and potential improvements in these materials to achieve better performance and enhance sustainability in infrastructure and building construction. From the practical results, it was found that in the case of using lightweight self-compacting concrete and self-compacting concrete, it is preferable to reinforce it with ordinary reinforcement steel, as it gives the best results in terms of maximum load capacity at failure. Although the use of steel reinforcement in self-compacting concrete also gives the best results, but from the laboratory results it is possible to improve the performance of self-compacting concrete by reinforcing it with GFRP or welded wire mesh.

Synthesis and evaluation of iron oxide nanoparticles from banana peel (Musa spp.) extract for the delivery of ciprofloxacin against resistant Escherichia coli

Background and objectiveResistance to antimicrobials is one of our most significant worldwide challenges. In Africa, around 31 % of the infections of urinary tract (UTIs) initiated by Escherichia coli (E. coli) have been observed to develop ciprofloxacin (CIP) resistance. As a result, significant efforts have been made to investigate novel and improved antibiotics. This study aimed at synthesizing iron oxide nanoparticles (IONPs) using banana peels (Musa Spp.) extract for delivery of CIP against resistant E. coli. MethodsA green synthesis method was used for the synthesis of IONPs using FeCl3.6H2O as a precursor and banana peel extract as a reducing and stabilizing agent. The physicochemical characteristics of the formed nanoparticles (NPs) were characterized using different methods. ResultsThe formation of hematite (α-Fe2O3) was confirmed with its FTIR characteristic peak at 461 cm−1, 542 cm−1, and 1131 cm−1. The size of synthesized IONPs was found to be 10.4 nm ± 1.98, 48 nm ± 0.9, and 67.3 nm ± 0.9 under XRD, SEM, and DLS measurements respectively. CIP-IONPs had almost the maximum drug loading capacity (33.3 % ± 0.67) with fast and slow drug release patterns at gastric and intestinal or blood pH respectively, and it had a promising resistant reversal with a zone of inhibition (ZOI) 22 mm ± 0.15 against resistance E. coli. ConclusionThe green synthesis of IONP using banana peel extract represents a novel and eco-friendly approach for the delivery of ciprofloxacin, with potential applications in addressing antimicrobial resistance.

Development of reinforced concrete column with replaceable plastic hinge based on metabolism concept

To update seismic performance and rapidly restore the transportation capacity of a bridge following an earthquake, this study introduces a new reinforced concrete (RC) column, termed “Metabolic RC column,” which incorporates the Design for Disassembly and Metabolism Movement concepts. The proposed column features a plastic hinge comprising a permanent hinge and replaceable plastic zones. A Mesnager hinge is employed as the permanent hinge to resist the axial loads within the column cross section. In addition, cast-in-place RC members are used in replaceable plastic zones to dissipate the seismic energy. By replacing the plastic zone with an equivalent or superior alternative while the permanent hinge continues to carry the axial forces, the updating (i.e., metabolization) of the column seismic performance can be achieved without interrupting the daily operations of the structure. The feasibility of replacing plastic hinges while maintaining the resistance to axial loads was demonstrated through plastic zone replacement tests. Cyclic loading tests indicated that the maximum lateral load of the proposed Metabolic RC Column remained unchanged before and after the plastic zone replacement. The energy dissipated also remained nearly consistent before and after the plastic zone replacement. The largest reduction in dissipated energy at each displacement amplitude was approximately 6.7 % before and after replacement. Additionally, the cyclic loading tests emphasized the importance of minimizing damage to the permanent hinge and preventing the axial stiffness reduction to ensure maximum load capacity of the column after plastic zone replacement. Further, a numerical model was developed to replicate the load-displacement relationship of the specimens. The proposed model accurately calculated the maximum load of the specimen with an average error of approximately 3 % for each displacement amplitude and the dissipated energy with an error of approximately 6 %. The numerical analysis effectively captured the changes in the secondary stiffness of the columns before and after plastic zone replacement, attributing the differences in secondary stiffness to the reduced tensile forces exerted by the permanent hinge rebar.

A Self-Assembling γPFD-SpyCatcher Hydrogel Scaffold for the Coimmobilization of SpyTag-Enzymes to Facilitate the Catalysis of Regulated Enzymes.

In this study, a γPFD-SpyCatcher hydrogel scaffold with the capacity for spontaneous assembly was established. With a maximum loading capacity of a 1:1 molar ratio with SpyTag-enzymes, the immobilized proteins can not only rapidly provide pure enzymes but also exhibit improved thermal and pH stability. The results of the transmission electron microscopic analysis and the traits they present indicated that SpyCatcher promotes the aggregation of γPFD and the formation of hydrogels. In the cell-free pyruvate synthesis system, the γPFD-SpyCatcher coimmobilized SpyTag-hexokinase (HK), SpyTag-phosphofructokinase (PFK) and SpyTag-pyruvate kinase (PK) were employed, and the production of pyruvate increased by 43, 78 and 47% respectively. In in vitro experiments, the oxidative deamination activity of glutamate dehydrogenase (GDH) coimmobilized with γPFD-SpyCatcher was 38% higher than that of purified enzymes. These findings indicate that the γPFD-SpyCatcher-based hydrogels play an important role in breaking the barrier of regulatory enzymes and will provide more strategies for the development of synthetic biology.