Objective:To design a novel electromagnetic ejection device for endoscopic suturing to achieve continuous deployment of suture nails.Methods:An electromagnetic ejection device and its accompanying suture nail structure were designed and a prototype was fabricated based on electromagnetic ejection principles. A finite element model of the electromagnetic ejection device was constructed to study the effects of armature-coil center distance and different driving voltages on suture nail ejection speed. An experimental platform for testing electromagnetic ejection velocity was constructed, and a high-speed camera was used to detect the ejection velocity. A platform for the suture embedding experiment was built to measure the effects of different voltages on the inserting speed of suture into the gastric wall tissue. A platform for a suture extraction force experiment was built to evaluate the extraction force of sutures embedded in tissues under different driving voltages.Results:A suture nail structure and electromagnetic ejection device were designed, and a prototype was fabricated. The ejection velocity increased and then decreased with the increase of the armature-coil center distance, and the maximum ejection velocity was 15.81 m/s at the center distance of 18 mm. At this distance, the voltage was linearly related to the ejection velocity, and the experimental values of the staple basically coincided with the simulated values. When the driving voltage was in the range of 150 to 180 V, the suture nails could successfully insert in the tissues, and the 180 V voltage group had a greater insertion depth. The extraction force of the suture nails at 120, 150, 180, and 210 V voltages were (0.49 ± 0.19), (1.14 ± 0.19), (1.23 ± 0.15), and (1.85 ± 0.31) N, respectively.Conclusions:A novel electromagnetic ejection device for endoscopic suturing is proposed that is capable of continuous firing of suture nails. This device provides a new long-distance driving method for intelligent, minimally invasive surgical instruments.

Objective:To develop a skeleton structure for the flexible manipulator of a robotic system used in natural orifice transluminal endoscopic surgery (NOTES), meeting the performance requirements of surgical actuators.Methods:A flexible manipulator structure and a control strategy for the corresponding structure were designed based on metal braiding technology. Geometric relationship formulas were derived according to the mechanical structure characteristics of the flexible manipulator. A theoretical model was established using the chained beam-constraint-model (CBCM) and mechanical spring theory. The finite element model of the mechanical structure was established, and simulation analysis was performed to verify the accuracy of the theoretical model. The bending stiffness of the metal-braided structure was tested to verify the load capacity of the flexible manipulator.Results:A flexible manipulator structure and a control strategy for the corresponding structure were designed based on metal braiding technology. With proper constraints, the maximum strain of the metal ring as a single stressed unit was about 1.49% when subjected to an axial force of 0.5 N. At this time, the material was in the linear elastic phase and the maximum deformation was about 0.308 9 mm, which was 3.26% higher than the theoretical value. The maximum strain of the manipulator skeleton was about 0.21% in the linear elastic phase. The maximum total deformation was about 7.135 5 mm, which was 6.30% higher than the theoretical value. The flexural stiffness of the manipulator skeleton was calculated to be 3.19 N·mm 2, which was comparable to a flexible manipulator made of shape memory polymers (SMPs) of the same magnitude and size. Conclusions:A skeleton structure for application to NOTES robotic flexible manipulators is developed that meets the support stiffness requirements for performing NOTES surgical tasks.

Objective:To design a specialized ultrasound therapeutic device for rabbit urethral scars and to verify its applicability and effectiveness.Methods:New Zealand male rabbits were used as the experimental objects, and the ultrasound therapeutic instrument was customized according to the structure and size of the rabbit penises. The ultrasound therapeutic instrument included the ultrasound pulse emission and control system, the final-stage amplifier, and the ultrasound probe. Firstly, the ultrasound probe was designed according to the size and structure of rabbit penises, and the parameters of the ultrasound probe were determined by COMSOL finite element simulation and actual testing of the sound field distribution. Secondly, the driving circuit of the ultrasound probe was designed according to the parameters of the elements. Then the ultrasound pulse emission and control system based on the field-programmable gate array (FPGA) and the serial screen were designed. Subsequently, the ultrasound therapeutic instrument was subjected to a performance test and a safety test. The ultrasound therapeutic instrument was constructed to include the ultrasound amplifier and the ultrasound probe. Finally, a rabbit urethra reconstruction model was constructed, and eight white rabbits were randomly divided into a model group and an experimental group. The rabbits in the experimental group received the ultrasound therapeutic instrument for treatment of the urethra immediately, with an ultrasound frequency of 2 MHz, a pulse interval of 10 ms, and an output sound intensity of 0.73 W/cm 2. The treatment was performed twice a week (on Tuesday and Thursday), with 10 min of irradiation each time, lasting for four weeks. The rabbits in the model group did not receive any treatment. The area percentage of transforming growth factor-β1 (TGF-β1), matrix metalloproteinase-2 (MMP-2), and tumor necrosis factor-α (TNF-α) staining-positive areas in rabbit urethral tissues were quantitatively analyzed, and the urethral circumference was calculated using Image J software. Results:Due to the addition of sound-absorbing materials, the sound pressure distribution in the treatment chamber was more uniform, and the average value of the standing wave ratio was 1.11, indicating that the structural design met the design requirements. In the overall performance test, the natural focal position of the three ultrasonic transducers was 10 mm, and the consistency of the sound field distribution meet the experimental requirements. The relationship between the peak sound pressure of each transducer and the power supply voltage was close to linear. The output sound intensity ranged from 0.35 to 0.74 W/cm 2, which met the experimental requirements. With the ultrasound output, the temperature of the test point increased slowly, and this experiment could increase the temperature of the tissue by up to 3.3 ℃, which would not lead to thermal damage to the tissue. Animal experiment results showed that the immunopositive area fraction of TGF-β1 in the urethral tissues of rabbits in the experimental group [(4.21 ± 1.32)%] was smaller than that of the model group [(8.53 ± 3.43)%] ( t = ?4.24, P < 0.001). The immunopositive area fraction of TNF-α in the urethral tissues of rabbits in the experimental group [(5.14 ± 2.72)%] was smaller than that of the model group [(7.23 ± 1.57)%] ( t = ?3.37, P < 0.05). The MMP-2 level in the urethral tissue of rabbits in the experimental group [(10.65 ± 2.24)%] was higher than that of the model group[(6.98 ± 2.74)%] ( t = 2.19, P < 0.05). The urethral circumference [(12 209 ± 2 743) μm] was higher than that of the model group [(10 127 ± 2 237) μm] ( t = 15.46, P < 0.05). Conclusions:An ultrasound therapeutic instrument dedicated to rabbit urethral scars has been successfully designed and can be used for the study of ultrasound treatment of rabbit urethral scars.

Red blood cells and platelets are widely present in the blood. They are easily isolated from the blood and relatively stable in nature, making them an ideal drug delivery vehicle. In recent years, a large number of studies have been conducted to use red blood cells and platelets to deliver antitumor drugs and achieve efficient drug delivery. Red blood cells and platelets have shown excellent results in optimizing the in vivo behavior of drugs, increasing efficacy, and reducing the dose administered. In addition, its cell membrane can be used as a coating material to improve the properties of nanodrug delivery systems and achieve biomimetic functions while reducing the toxic side effects of nanoparticles. The characteristics and preparation methods of red blood cells and platelets and their membrane materials were introduced, and their diagnostic and therapeutic applications in antitumor drug delivery was looked forward.

Extracellular vesicles are recognized as a kind of membranous vesicle derived from endosomes and cell membranes that play important roles in intercellular communication. Strict biogenesis pathways dictate that extracellular vesicles have a wide range of origins and specific parental characteristics, while complex contents and surface proteins facilitate their recognition by receptor cells. Extracellular vesicles are considered a promising drug delivery system due to their natural biocompatibility and vesicle structure, where more functional biomolecules can be accommodated. The classification, biological functions, and characteristics of extracellular vesicles in different types of drug delivery were introduced. The application of extracellular vesicles in disease therapy and the clinical transformation and challenges of the extracellular vesicle delivery system were discussed.

The human body contains a large microbial community composed of eukaryotes, archaea, bacteria, and phages. Bacteria are the most prominent members of this community, numbering in the same order of magnitude as human cells. Many commensal or pathogenic bacteria interact with their hosts through biochemical signals. Based on these bacterial properties, commensal and attenuated pathogens have been designed to deliver therapeutic molecules to target specific diseases. The engineered bacteria or bacteria-derived particles and their encapsulation, secretion, and expression of surface therapeutic molecules developed in the past five years were introduced. Their applications in anti-inflammatory, anti-tumor, thrombosis treatment, and imaging were reviewed, and the clinical translational potential of microbial drug delivery systems was discussed.

Objective:To prepare the anti-programmed death-ligand 1 (PD-L1) nanoantibody P3C8-C3Fab by ligating with C3Fab and to investigate its role in plasma half-life.Methods:The C3Fab peptide derived from protein G was molecularly fused with the nanobody P3C8 by DNA recombination technology. The nanoantibody P3C8-C3Fab was inducibly expressed and purified in the E. coli BL21 strain, and the binding of it to PD-L1 protein, mouse IgG, and PD-L1-expressing tumor cells was detected by enzyme-linked immunosorbent assay (ELISA). The residual P3C8-C3Fab was detected in mouse serum at different times using double-antibody sandwich ELISA to assess the prolongation of the plasma half-life of PD-L1 nanobodies by C3Fab. Results:The nanoantibody P3C8-C3Fab was successfully constructed, and it could efficiently express itself in soluble form in BL21. The purified NbP3C8-C3Fab protein was obtained with a mass fraction of about 90% at a yield of 7.18 mg/L. The affinity of P3C8-C3Fab for PD-L1 protein and mouse IgG gradually increased with increasing mass concentration and showed a concentration correlation. The binding of P3C8-C3Fab to lung cancer A549 cells showed a concentration correlation. The concentration standard curve of P3C8-C3Fab in mouse serum showed a typical S-shape with a concentration correlation. The plasma half-life of P3C8 was only 0.44 h, while the plasma half-life of P3C8-C3Fab was 21.27-fold higher, up to 9.36 h.Conclusions:The linkage of C3Fab to the nanobodies of P3C8 can significantly prolong the plasma half-life of P3C8, which is valuable for the improvement of in vivo nanobody effects.

Objective:To investigate the changes in γ-aminobutyric acid (GABA) receptor currents of hippocampal dentate gyrus granule cells in prepubertal and early pubertal female mice.Methods:Female mice were selected as the study objects; 3 to 4 -week-old mice were selected as the pre-puberty group ( n=6); and 5 to 6 -week-old mice were selected as the puberty group ( n=6). The whole-cell patch clamp technique was used to record the spontaneous inhibitory post-synaptic current (sIPSC), mini-inhibitory post-synaptic current (mIPSC), and tonic current of hippocampal granulosa cells in the DG region of pre-pubertal and early pubertal female mice, and their changes were analyzed. Results:The frequency of sIPSC in the pre-puberty group and puberty group was (2.22 ± 0.12) Hz and (2.30 ± 0.21) Hz, respectively. The amplitude of sIPSC in the pre-puberty group and the puberty group was (19.97 ± 2.01) pA and (23.80 ± 2.86) pA, respectively. The experimental results showed no significant changes in frequency and amplitude of sIPSC of hippocampal granulosa cells in pre-pubertal and early pubertal mice (all P > 0.05), and no statistical significance in the cumulative frequency and amplitude of sIPSC between two groups (all P > 0.05). The frequency of mIPSC in the pre-puberty group and the puberty group was (0.87 ± 0.08) Hz and (2.15 ± 0.21) Hz, respectively. The amplitude of mIPSC in the pre-puberty group and puberty group was (12.51 ± 0.11) pA and (29.67 ± 0.19) pA, respectively. Compared with the pre-pubertal mice, the frequency and amplitude of mIPSC from hippocampal granulosa cells in early pubertal mice are significantly increased ( P < 0.001). There was also a significant difference in the cumulative frequency and amplitude of sIPSC between the two groups ( P < 0.001). The tonic current of the pre-puberty group and puberty group was (17.40 ± 1.64) pA and (24.70 ± 2.81) pA, respectively, and the tonic current in early pubertal mice was significantly higher than that in pre-pubertal mice ( P < 0.05). Conclusions:GABA receptor current is enhanced in early pubertal female mice compared with pre-pubertal females. The inhibitory activity of hippocampal granulosa cells in early adolescent female mice was increased.

Objective:To investigate the effects of ginkgolide B on neurological function recovery and the Wnt/β-catenin pathway after ischemic stroke in mice.Methods:Fifty-five C57/BL6 mice were selected, of which 10 mice were kept as the sham group and the remaining 45 mice were constructed as the ischemic stroke model. There were 40 mice who finally completed the modeling, and then they were randomly divided into the blank control group (GB0w), short-course administration group (GB1w), long-term administration group (GB2w), and long-term administration+antagonist group (GB2w+PRI-724), with 10 mice in each group. There was no drug intervention after MCAO in GB0w. The mice in GB1w were given ginkgolide B (10 mg/kg) 0.1 ml within 1 week after MCAO; in GB2w were given ginkgolide B (10 mg/kg) 0.1 ml within 2 weeks after MCAO; and in GB2w+PRI-724 were nasally fed ginkgolide B (10 mg/kg) 0.1 ml within 2 weeks after MCAO; and selective antagonist PRI-724 was given 3 h before administration of ginkgolide B on days 8 to 14. Neurological function scores, walking on rotor bar test scores, expression of transforming growth factor-β1 (TGF-β1), fibroblast growth factor 4 (FGF4), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), Wnt, β-catenin, and glycogen synthase kinase-3β (GSK-3β) were compared among the groups.Results:Compared with the sham group, the expressions of MDA, TNF-α, IL-6, FGF4, and GSK-3β in GB0w, GB1w, GB2w, and GB2w+ PRI-724 were increased, and the expressions of GSH-Px, SOD, TGF-β1, β-catenin, and Wnt were decreased (all P < 0.001). Compared with GB0w, the expressions of SOD, GSH-Px, TGF-β1, Wnt, and β-catenin were increased in GB1w, GB2w, and GB2w+PRI-724, and the expressions of MDA, TNF-α, IL-6, FGF4, and GSK-3β were decreased (all P < 0.001). Compared with GB1w, the expressions of GSH-Px, SOD, TGF-β 1, Wnt, and β-catenin were increased in GB2w and GB2w+PRI-724, and the expressions of IL-6, TNF-α, MDA, FGF4, and GSK-3β were decreased (all P < 0.001). Compared with GB2w, the neural function score, walking on the stick test score, and expressions of IL-6, TNF-α, FGF4, MDA, and GSK-3β were increased in GB2w+PRI-724, while the expressions of GSH-Px, TGF-β1, SOD, Wnt, and β-catenin were decreased (all P < 0.001). Conclusions:Ginkgolide B can effectively improve the neurological function of ischemic stroke mice and may be related to the Wnt/β-catenin pathway.

Objective:To investigate the effect of modified citrus pectin (MCP) on the glucose metabolism of rabbit articular chondrocytes.Methods:The third generation (P3) rabbit knee chondrocytes were extracted and cultured with 0 μg/ml (MCP0, control group) and 500 μg/ml of MCP (MCP500) for 3 days. Chondrocytes (P2-P7)were cultured continuously, and each generation of chondrocytes was treated with MCP0 and MCP500 medium for 3 days. Chondrocytes were treated with interleukin-1β (IL-1β) for 1 day and then treated with MCP0 and MCP500 medium for 3 days, respectively. Chondrocytes were treated with 2-deoxy-glucose (2DG) for 1 day and then treated with MCP0 and MCP500 medium for 3 days, respectively. After three days of culture, the proliferation of chondrocytes was calculated by CCK-8. Glucose uptake activity and lactate production of chondrocytes were measured by glucose and lactate detection kits. The synthesis of type Ⅱ collagen (COL2A1) in sequential chondrocytes was investigated by immunofluorescence staining. The gene expression of COL2A1, proteoglycan ( ACAN), SOX9, hypoxia-inducible factor-1α ( HIF-1α), glucose transporter-1 ( Glut-1), pyruvate kinase M2 ( PKM2), lactate dehydrogenase-A ( LDHA) and glucose transporter-1 ( Glut-3) were further detected by RT-qPCR. Results:Compared with the control group, MCP treatment could increase the glucose uptake activity and lactate production of chondrocytes, and enhance the gene expression ability of HIF-1α, Glut-1, PKM2 and ACAN. Besides, MCP treatment could stimulate chondrocyte proliferation, maintain chondrocyte phenotype, increase lactate production, and upregulate the expression of COL2A1, ACAN, SOX9, HIF-1α, Glut-1, PKM2 and LDHA. After the treatment with IL-1β, MCP treatment could increase glucose uptake activity and upregulate the expression of COL2A1, ACAN, HIF-1α and Glut-1. After treatment with 2DG, MCP treatment could increase glucose uptake activity and upregulate the expression of SOX9, HIF-1α, PKM2 and Glut-3 genes. Conclusions:MCP can enhance the glucose uptake capacity of chondrocytes and increase the level of chondrocyte glycolytic metabolism.