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Microcarrier applications have made great advances in tissue engineering in recent years, which can load cells, drugs, and bioactive factors. These microcarriers can be minimally injected into the defect to help reconstruct a good microenvironment for tissue repair. In order to achieve more ideal performance and face more complex tissue damage, an increasing amount of effort has been focused on microcarriers that can actively respond to external stimuli. These microcarriers have the functions of directional movement, targeted enrichment, material release control, and providing signals conducive to tissue repair. Given the high controllability and designability of magnetic and electroactive microcarriers, the research progress of these microcarriers is highlighted in this review. Their structure, function and applications, potential tissue repair mechanisms, and challenges are discussed. In summary, through the design with clinical translation ability, meaningful and comprehensive experimental characterization, and in-depth study and application of tissue repair mechanisms, stimuli-responsive microcarriers have great potential in tissue repair.

Irregular articular cartilage injury is a common type of joint trauma, often resulting from intense impacts and other factors that lead to irregularly shaped wounds, the limited regenerative capacity of cartilage and the mismatched shape of the scaffods have contributed to unsatisfactory therapeutic outcomes. While injectable materials are a traditional solution to adapt to irregular cartilage defects, they have limitations, and injectable materials often lack the porous microstructures favorable for the rapid proliferation of cartilage cells. In this study, an injectable porous polyurethane scaffold named PU-BDO-Gelatin-Foam (PUBGF) was prepared. After injection into cartilage defects, PUBGF forms in situ at the site of the defect and exhibits a dynamic microstructure during the initial two weeks. This dynamic microstructure endows the scaffold with the ability to retain substances within its interior, thereby enhancing its capacity to promote chondrogenesis. Furthermore, the chondral repair efficacy of PUBGF was validated by directly injecting it into rat articular cartilage injury sites. The injectable PUBGF scaffold demonstrates a superior potential for promoting the repair of cartilage defects when compared to traditional porous polyurethane scaffolds. The substance retention ability of this injectable porous scaffold makes it a promising option for clinical applications.

Background: Osteochondral regeneration has long been recognized as a complex and challenging project in the field of tissue engineering. In particular, reconstructing the osteochondral interface is crucial for determining the effectiveness of the repair. Although several artificial layered or gradient scaffolds have been developed recently to simulate the natural interface, the functions of this unique structure have still not been fully replicated. In this paper, we utilized laser micro-patterning technology (LMPT) to modify the natural osteochondral “plugs” for use as grafts and aimed to directly apply the functional interface unit to repair osteochondral defects in a goat model. Methods: For in vitro evaluations, the optimal combination of LMPT parameters was confirmed through mechanical testing, finite element analysis, and comparing decellularization efficiency. The structural and biological properties of the laser micro-patterned osteochondral implants (LMP-OI) were verified by measuring the permeability of the interface and assessing the recellularization processes. In the goat model for osteochondral regeneration, a conical frustum-shaped defect was specifically created in the weight-bearing area of femoral condyles using a customized trephine with a variable diameter. This unreported defect shape enabled the implant to properly self-fix as expected. Results: The micro-patterning with the suitable pore density and morphology increased the permeability of the LMP-OIs, accelerated decellularization, maintained mechanical stability, and provided two relative independent microenvironments for subsequent recellularization. The LMP-OIs with goat's autologous bone marrow stromal cells in the cartilage layer have securely integrated into the osteochondral defects. At 6 and 12 months after implantation, both imaging and histological assessments showed a significant improvement in the healing of the cartilage and subchondral bone. Conclusion: With the natural interface unit and zonal recellularization, the LMP-OI is an ideal scaffold to repair osteochondral defects especially in large animals. The translational potential of this article: These findings suggest that such a modified xenogeneic osteochondral implant could potentially be explored in clinical translation for treatment of osteochondral injuries. Furthermore, trimming a conical frustum shape to the defect region, especially for large-sized defects, may be an effective way to achieve self-fixing for the implant.

China is the most productive country in the world in terms of shellfish farming, with seawater shellfish occupying a dominant position in China´s shellfish farming industry. In the past two decades, China´s marine shellfish culture has been enriched in terms of species and culture methods. Moreover, its scale has expanded, with annual production remaining above 10 million tons and the total economic output exceeding 220 billion yuan. However, the economic losses caused by epidemic diseases in the shellfish aquaculture industry are also increasing annually, exceeding 10 billion yuan in 2021. These diseases have become some of the primary limiting factors for the healthy development of the shellfish aquaculture industry. Epidemiological surveys in recent years have shown that vibriosis is the most prevalent bacterial disease and the leading cause of mass mortality in shellfish farming. Vibrio alginolyticus is one of the most common Vibrio pathogens in shellfish diseases, posing a grave threat to the healthy development of the shellfish farming industry. However, effective methods for preventing and controlling V. alginolyticus are still lacking. The pathogenicity of V. alginolyticus is frequently closely related to its virulence factors and biological characteristics, and it is unclear how the virulence factors and biological characteristics of V. alginolyticus vary according to different sources and regions. Therefore, in this study, we aimed to gain a deeper understanding of the pathogenicity and scientific control of V. alginolyticus by analyzing the genetic variation and distribution patterns of V. alginolyticus in different aquaculture environments and shellfish tissues. The study was conducted to observe the external morphological characteristics and conduct 16S identification of twelve V. alginolyticus isolates collected from four regions: Qingdao, Weifang, Weihai, and Yantai. These were isolated and purified in TCBS selective medium; MLST typing of the strains by four housekeeping genes; the distribution of thirteen Vibrio virulence genes in V. alginolyticus; and the resistance of V. alginolyticus to 10 common antibiotics. The findings showed that all V. alginolyticus colonies were yellow or yellowish in color, round and transparent in shape with a raised center and smooth edges, moist, and difficult to harvest. 16S rRNA sequencing showed a homology of greater than 99% with V. alginolyticus, which was initially verified as V. alginolyticus and was consistent with the initial identification results. The ST typing of the twelve V. algolyticus strains differed from each other. Seven strains (A2, A3, B2, B3, C3, D2, and D3) contained ST types already included in the PubMLST database, with ST types 45, 87, 156, 56, 125, 96, and 57; five strains (A1, B1, C1, C2, and D1) formed new ST types owing to allelic locus changes in housekeeping genes, and four of the new ST types were isolated from shellfish tissue. The Qingdao isolate (A1) has similar ST types 38, 131, 134, 46, and 56 in the database; the Weihai isolate (C1, C2) has similar ST types 111, 322, and 61 in the database; and the Yantai isolate (D1) has similar ST types 268, 275, 341, 344, 351, and 358 in the database. These results suggested that V. alginolyticus in the shellfish culture environment had a high genetic diversity and that V. alginolyticus of shellfish origin might be more easily typed than V. alginolyticus from water sources. The MLST typing phylogenetic tree showed that there were four distinct branches: Group 1, Group 2, Group 3, and Group 4. All V. alginolyticus from shellfish tissues were predominantly observed in Group 1; isolates from Group 2 and Group 3 were mainly from marine environments and had closer evolutionary relationships with V. alginolyticus from the same region of the aquatic environment. The evolutionary relationships between V. alginolyticus from different areas of the aquatic environment and V. alginolyticus from shellfish tissues showed different characteristics. All V. alginolyticus strains carried three virulence genes: tlh, fur, and collagenase; VscB, Ompw, FlaA, and toxS virulence genes were present in most strains; UreB and AspA virulence genes were only present in a few strains; and tdh, trh, toxR, and tcpA virulence genes were not detected in any of the strains. The variety and number of virulence factors carried by V. alginolyticus were influenced by factors such as regional distribution. V. alginolyticus of different origins were characterized by multiple drug resistance interactions, but there were differences in the types of antibiotics to which resistance was developed. All V. alginolyticus species showed high susceptibility to cotrimoxazole and chloramphenicol, while they were resistant to penicillin and ampicillin. The majority of V. alginolyticus developed intermediate or high susceptibility to antibiotics such as butyraminecarbana, gentamicin, erythromycin, norfloxacin, and ciprofloxacin. Among all V. alginolyticus, one strain was resistant to ceftolozoline, five strains were intermediated, and six strains were highly sensitive. In addition, five strains were intermediated, and six were highly sensitive to butyraminecarbana, gentamicin, and erythromycin. Two strains were intermediated, and ten were highly sensitive to norfloxacin. Four strains were intermediated, and eight were highly sensitive to ciprofloxacin. Combining the MLST typing results, drug resistance results, and virulence genes in this study, no significant correlation between the three was found at this time. This study showed that V. alginolyticus in a shellfish culture environment was characterized by complex populations and high genetic diversity. There were large differences in virulence gene carriage and drug resistance among strains from different sources. The study provides a theoretical reference framework for understanding the pathogenicity of V. alginolyticus and assisting in the effective control of V. alginolyticus of shellfish origin by investigating the genetic variation and drug resistance of V. alginolyticus from different sources in various regions.

When a center pivot irrigation system is adopted in a square field, its four corners cannot be irrigated. Therefore, an end gun is often installed at the end of the system to expand the irrigated area; as such, proper selection of the end gun and optimization of water distribution are essential. In this study, we assessed the water distribution characteristics, application accuracies and uniformities under a three-span center pivot with an overhang and end gun without a boost pump. Two typical low-pressure sprinklers of Nelson R3000 and D3000 at two common operating pressures (0.15 and 0.20 MPa) and three representative nozzle diameters (8.73, 10.32, and 11.91 mm) of the end gun (Nelson P85A impact sprinkler) were considered. Additionally, the effects of various factors on the water distribution uniformity and accuracy were evaluated, and the optimal operating parameters of the center pivot with the end gun were proposed. Regardless of whether the end gun was on, the water application uniformity and accuracy of center pivot with R3000 sprinklers were highly significantly (P0.05) inversely proportional to the operating pressure. Taken together, the end gun nozzle diameter of 11.91 mm at an operating pressure of 0.15 MPa under the center pivot with R3000 sprinklers was recommended. This study provides a scientific basis for the optimal design of a center pivot with an end gun for a square field.

High oxidative stress and inflammatory cell infiltration are major causes of the persistent bone erosion and difficult tissue regeneration in rheumatoid arthritis (RA). Triptolide (TPL) has become a highly anticipated anti-rheumatic drug due to its excellent immunomodulatory and anti-inflammatory effects. However, the sudden drug accumulation caused by the binding of “stimulus-response” and “drug release” in a general smart delivery system is difficult to meet the shortcoming of extreme toxicity and the demand for long-term administration of TPL. Herein, we developed a dual dynamically cross-linked hydrogel (SPT@TPL), which demonstrated sensitive RA microenvironment regulation and microenvironment modulation-independent TPL release for 30 days. The abundant borate ester/tea polyphenol units in SPT@TPL possessed the capability to respond and regulate high reactive oxygen species (ROS) levels on-demand. Meanwhile, based on its dense dual crosslinked structure as well as the spontaneous healing behavior of numerous intermolecular hydrogen bonds formed after the breakage of borate ester, TPL could remain stable and slowly release under high ROS environments of RA, which dramatically reduced the risk of TPL exerting toxicity while maximized its long-term efficacy. Through the dual effects of ROS regulation and TPL sustained-release, SPT@TPL alleviated oxidative stress and reprogrammed macrophages into M2 phenotype, showing marked inhibition of inflammation and optimal regeneration of articular cartilage in RA rat model. In conclusion, this hydrogel platform with both microenvironment initiative regulation and TPL long-term sustained release provides a potential scheme for rheumatoid arthritis.

Canopy height serves as an important dynamic indicator of crop growth in the decision-making process of field management. Compared with other commonly used canopy height measurement techniques, ultrasonic sensors are inexpensive and can be exposed in fields for long periods of time to obtain easy-to-process data. However, the acoustic wave characteristics and crop canopy structure affect the measurement accuracy. To improve the ultrasonic sensor measurement accuracy, a four-year (2018−2021) field experiment was conducted on maize and wheat, and a measurement platform was developed. A series of single-factor experiments were conducted to investigate the significant factors affecting measurements, including the observation angle (0−60°), observation height (0.5−2.5 m), observation period (8:00−18:00), platform moving speed with respect to the crop (0−2.0 m min−1), planting density (0.2−1 time of standard planting density), and growth stage (maize from three−leaf to harvest period and wheat from regreening to maturity period). The results indicated that both the observation angle and planting density significantly affected the results of ultrasonic measurements (p-value< 0.05), whereas the effects of other factors on measurement accuracy were negligible (p-value > 0.05). Moreover, a double-input factor calibration model was constructed to assess canopy height under different years by utilizing the normalized difference vegetation index and ultrasonic measurements. The model was developed by employing the least-squares method, and ultrasonic measurement accuracy was significantly improved when integrating the measured value of canopy heights and the normalized difference vegetation index (NDVI). The maize measurement accuracy had a root mean squared error (RMSE) ranging from 81.4 mm to 93.6 mm, while the wheat measurement accuracy had an RMSE from 37.1 mm to 47.2 mm. The research results effectively combine stable and low-cost commercial sensors with ground-based agricultural machinery platforms, enabling efficient and non-destructive acquisition of crop height information.

Ostreid herpesvirus 1 (OsHV-1) has caused a serious economic loss to the global bivalve aquaculture industry. Given its wide host range and the frequent emergence of mutated strains, OsHV-1 infection threatens mollusk production. Unlike the common vertebrate herpesviruses that generally exhibit high host specificity, more than ten bivalve species have been identified as potentially susceptible to OsHV-1 infection, including members of Ostreoida, Pterioida, Arcoida, and Veneroida. A variety of OsHV-1 detection methods have been developed, such as PCR, in situ hybridization, in situ PCR, histopathology, transmission electron microscopy, ring-mediated isothermal nucleic acid amplification (LAMP), and recombinase polymerase amplification (RPA). The sensitivity and specificity of transmission electron microscopy detection are low, and specific complementary detection methods such as PCR are needed to confirm the occurrence of OsHV-1. In situ hybridization, although highly specific, has the disadvantages of low sensitivity, complicated procedures, and high investment of effort. PCR methods are still the most widely used for epidemiological investigation of OsHV-1. However, PCR cannot alone confirm infection, which has led to the emergence of unconfirmed cases of OsHV-1 infection in many species and regions. According to the World Organization for Animal Health´s (OIE) Aquatic Animal Manual, positive nucleic acid-specific detection combined with histopathology and transmission electron microscopy is required for the confirmed diagnosis of OsHV-1 infection. Other detection methods, such as LAMP and RPA, which use nucleic acid amplification alone to detect OsHV-1, can not confirm infection as the presence of nucleic acids is not equivalent to viral infection. As a result, the susceptibility of several bivalve species to OsHV-1 infection has not been evaluated. Instead, several obstacles remain with regards to the development of epidemiological surveillance programs and the implementation of quarantine, prevention, and control measures for OsHV-1 infection. Compared with traditional in situ hybridization and in situ PCR assays, in situ LAMP has the advantages of low nucleic acid amplification reaction temperature, less damage to tissue, constant temperature amplification that does not require special experimental equipment, and more convenient and efficient experimental design. In this study, we selected a set of LAMP primers designed for specific detection of OsHV-1, and a pair of loop primers were designed to improve the specificity and stability of the LAMP reaction on slides. An optimized in situ LAMP method for OsHV-1 detection was developed, which provides a rapid diagnostic method with high specificity and sensitivity to identify hosts that are potentially susceptible to OsHV-1 infection, and to characterize the distribution pattern and tissue affinity of the virus in new hosts. The optimized protocol and quantitative PCR (qPCR) were then used to detect OsHV-1 infection in bivalve samples (Crassostrea gigas, C. angulata, Chlamys farreri, Mizuhopecten yessoensis, Ruditapes philippinarum, and Scapharca subcrenata) collected from 2019 to 2021. OsHV-1 hybridization signals were observed in S. subcrenata samples alone, although positive qPCR results were obtained in more species. Further investigation of pathological characteristics and associated viral hybridization signals indicated that OsHV-1 infection always occurred in fibroblasts and hemocytes in the connective tissues of the mantle and hepatopancreas, nucleus of muscle cells in the foot, and adductor muscle. Signals were also occasionally observed in infiltrated hemocytes between and within the gill filaments. OsHV-1 hybridization signals were observed within the hemocytes infiltrating several organs of the furcula visceral cluster. The hemocytes of S. subcrenata seem to be particularly susceptible to OsHV-1 infection. Histopathological lesions and viral hybridization signals in the hepatopancreas organ were consistently observed in individuals with clinical signs, and we recommend the hepatopancreas as the preferred target organ for histopathological and in situ LAMP assays for OsHV-1 infection in S. subcrenata. In situ LAMP-based detection indicated that S. subcrenata was a susceptible host for OsHV-1, and the connective tissue, muscle tissue, and hemolymph cells had a strong affinity for the virus. At present, the susceptibility of many cultured and wild shellfish to OsHV-1 infection is still unknown. Since the emergence of mollusk mortalities associated with OsHV-1 infection occurred in China in the 1990s, its host range has expanded and changed along with the environment, which has complicated its prevention and control. In recent years, the scale of artificial breeding and cultivation of triploid C. gigas has expanded in China, and larval mortalities are frequently associated with OsHV-1 infection. The in situ LAMP detection method for OsHV-1 infection developed in this study proved to be convenient and fast and could be a valuable tool for the rapid detection and confirmation of OsHV-1 infection.

Cellulose/chitosan composite, as a mature commercial antibacterial dressing, is an important type of wound repair material. However, how to achieve the perfect compound of two components and improve antibacterial activity is a major, lingering issue. In this study, a bifunctional group modified bacterial cellulose (DCBC) was prepared by carboxymethylation and selective oxidation. Further, the chitosan (CS) was compounded in the network of DCBC by self-crosslinking to form dialdehyde carboxymethyl bacterial cellulose/chitosan composites (S-DCBC/CS). The aldehyde group can react with amino of CS by Schiff base reaction. The carboxyl group of DCBC and the amorphous distribution of CS molecular chains increase the antimicrobial properties of composites. The bacteriostatic rate of composites could be higher than 95%. Bacteria can be attracted onto the surface of composites, what we call it “directional adhesion antibacterial effects”. In particular, a kind of large animal wound model, deep Ⅱ degree infected scald of Bama miniature pig, was used to research the antimicrobial and healing properties of materials. The S-DCBC/CS can effectively inhibit bacterial proliferation of wound and kill the bacteria. The wound healing rate of S-DCBC/CS was up to 80% after three weeks. The composites show better antibacterial and promoting concrescence effects than traditional chitosan dressings.

Effective strategy of hemostasis and promoting angiogenesis are becoming increasingly urgent in modern medicine due to millions of deaths caused by tissue damage and inflammation. The tissue adhesive has been favored as an optimistic and efficient path to stop bleeding, while, current adhesive presents limitations on wound care or potential degradation safety in clinical practice. Therefore, it is of great clinical significance to construct multifunctional wound adhesive to address the issues. Based on pro-angiogenic property of l-Arginine (L-Arg), in this study, the novel tissue adhesive (G-DLPUs) constructed by L-Arg-based degradable polyurethane (DLPU) and GelMA were prepared for wound care. After systematic characterization, we found that the G-DLPUs were endowed with excellent capability in shape-adaptive adhesion. Moreover, the L-Arg released and the generation of NO during degradation were verified which would enhance wound healing. Following the in vivo biocompatibility was verified, the hemostatic effect of the damaged organ was tested using a rat liver hemorrhage model, from which reveals that the G-DLPUs can reduce liver bleeding by nearly 75% and no obvious inflammatory cells observed around the tissue. Moreover, the wound care effect was confirmed in a mouse full-thickness skin defect model, showing that the hydrogel adhesive significantly improves the thickness of newly formed dermis and enhance vascularization (CD31 staining). In summary, the G-DLPUs are promising candidate to act as multifunctional wound care adhesive for both damaged organ and trauma.

At present, peptidoglycan (PGN) is commonly used as an immunostimulant in shrimp. However, little has been known about its mechanism. In this study, comparative transcriptome analysis was employed to investigate the impact of dietary PGN on the immune response in Litopenaeus vannamei. A total of 720 healthy juvenile L. vannamei (initial weight 0.31 ± 0.05 g) were randomly evenly allocated to 18 fibreglass buckets as 6 groups, fed with six isonitrogen (41.05%) and isolipid diets (8.16%) containing PGN at the doses of 0 (control), 0.2, 1, 5, 25, and 125 mg/kg, respectively. After 8 weeks feeding trail, the growth performance, immunity, and transcriptome response of L. vannamei were analyzed. The results showed that the growth performance of L. vannamei was not significantly influenced by dietary PGN (P > 0.05). According to the analysis of weight gain rate (WGR), the optimum dietary PGN level was 71.46 mg/kg. Compared with the control group, the survival rate (SR) after Vibrio parahaemolyticus infection of L. vannamei were significantly increased by dietary PGN at 5 mg/kg and the SR after white spot syndrome virus (WSSV) infection was improved by dietary PGN at 25 mg/kg (P

Abstract Background Urethral stricture and reconstruction are one of the thorny difficult problems in the field of urology. The continuous development of tissue engineering and biomaterials has given new therapeutic thinking to this problem. Bacterial cellulose (BC) is an excellent biomaterial due to its accessibility and strong plasticity. Moreover, adipose-derived stem cells (ADSCs) could enhance their wound healing ability through directional modification. Methods First, we used physical drilling and sulfonation in this study to make BC more conducive to cell attachment and degradation. We tested the relevant mechanical properties of these materials. After that, we attached Fibroblast Growth Factor Receptor 2 (FGFR2)-modified ADSCs to the material to construct a urethra for tissue engineering. Afterward, we verified this finding in the male New Zealand rabbit model and carried out immunohistochemical and imaging examinations 1 and 3 months after the operation. At the same time, we detected the potential biological function of FGFR2 by bioinformatics and a cytokine chip. Results The results show that the composite has excellent repairability and that this ability is correlated with angiogenesis. The new composite in this study provides new insight and therapeutic methods for urethral reconstruction. The preliminary mechanism showed that FGFR2 could promote angiogenesis and tissue repair by promoting the secretion of Vascular Endothelial Growth Factor A (VEGFA) from ADSCs. Conclusions Double-modified sulfonated bacterial cellulose scaffolds combined with FGFR2-modified ADSCs provide new sight and treatments for patients with urethral strictures.

Electret materials have attracted extensive attention because of their permanent polarization and electrostatic effect. However, it is one of problem that needs to be solved in biological application to manipulate the change of surface charge of electret by external stimulation. In this work, a drug-loaded electret with flexibility and no cytotoxicity was prepared under relatively mild conditions. The electret can release the charge through stress change and ultrasonic stimulation, and the drug release can be accurately controlled with the help of ultrasonic and electric double stimulation response. Here, the dipoles like particles of carnauba wax nanoparticles (nCW) are fixed in the matrix based on the interpenetrating polymer network structure, and “frozen” oriented dipolar particles that are treated by thermal polarization and cooled at high field strength. Subsequently, the charge density of the prepared composite electret can reach 101.1 ​nC/m2 at the initial stage of polarization and 21.1 ​nC/m2 after 3 weeks. In addition, the stimulated change of electret surface charge flow under cyclic tensile stress and cyclic compressive stress can generate a current of 0.187 ​nA and 0.105 ​nA at most. The ultrasonic stimulation results show that when the ultrasonic emission power was 90% (Pmax ​= ​1200 ​W), the current of 0.472 ​nA can be generated. Finally, the drug release characteristics and biocompatibility of the nCW composite electret containing curcumin were tested. The results showed that it not only had the ability to accurately control the release by ultrasound, but also triggered the electrical effect of the material. The prepared drug loaded composite bioelectret provides a new way for the construction, design and testing of the bioelectret. Its ultrasonic and electrical double stimulation response can be accurately controlled and released as required, and it has broad application prospects.

Cell transplantation is an effective strategy to improve the repair effect of nerve guide conduits (NGCs). However, problems such as low loading efficiency and cell anoikis undermine the outcomes. Microcarriers are efficient 3D cell culture scaffolds, which can also prevent cell anoikis by providing substrate for adhesion during transplantation. Here, we demonstrate for the first time microcarrier-based cell transplantation in peripheral nerve repair. We first prepared macroporous chitosan microcarriers (CSMCs) by the emulsion-phase separation method, and then decorated the CSMCs with polylysine (pl-CSMCs) to improve cell affinity. We then loaded the pl-CSMCs with adipose-derived stem cells (ADSCs) and injected them into electrospun polycaprolactone/chitosan NGCs to repair rat sciatic nerve defects. The ADSCs-laden pl-CSMCs effectively improved nerve regeneration as demonstrated by evaluation of histology, motor function recovery, electrophysiology, and gastrocnemius recovery. With efficient cell transplantation, convenient operation, and the multiple merits of ADSCs, the ADSCs-laden pl-CSMCs hold good potential in peripheral nerve repair.

This study investigated the effect of dietary protein levels on Litopenaeus vannamei. Five isolipid diets with protein levels of 32%, 36%, 40%, 44% and 48% were prepared using C. sorokiniana as the main protein source. L. vannamei (initial body weight 0.83 ± 0.02 g) were fed these five diets for 8 weeks and referred to as the CHL32, CHL36, CHL40, CHL44 and CHL48 groups, respectively. When the feeding trial was finished, the growth performance, body composition, intestinal digestion and microbiota of L. vannamei were studied. The results showed that the maximum weight gain rate (WGR) of L. vannamei was in the CHL40 group while the lowest feed conversion ratio (FCR) was in the CHL48 group. According to the regression analysis using WGR as the evaluation index, the best growth performance of L. vannamei was obtained when the dietary protein level was 40.81%. The crude protein content of whole shrimp showed an increasing and then decreasing trend with increasing dietary protein levels. Furthermore, the L. vannamei muscle amino acid composition was relatively stable and, to some extent, independent of dietary protein levels. Trypsin, lipase and amylase (AMS) activity increased and then decreased with increasing dietary protein levels and, significantly, peaked in the CHL44 group. Analysis of the alpha diversity of the intestinal microbiota showed that the Chao1 index peaked in the CHL40 group and was significantly lower in the CHL48 group. Additionally, the relative abundance of pathogenic bacteria decreased significantly while the relative abundance of beneficial bacteria increased significantly in the intestine of L. vannamei as the dietary protein levels increased. The functional prediction of the intestinal microbiota revealed that dietary protein levels may influence the growth of L. vannamei by regulating various metabolic activities, and the highest WGR in the CHL40 group may have been related to the significant enrichment of nicotinate and nicotinamide metabolism and biotin metabolism functions. In summary, the optimal protein requirement for L. vannamei was around 40% when C. sorokiniana was used as the primary protein source. Too high or too low dietary protein levels could adversely affect shrimp body composition, intestinal digestion and microbiota.

The type of protein source in diets has many effects on shrimp. In this study, Litopenaeus vannamei with an initial body weight of 3.68 ± 0.002 g were fed for 8 weeks on three experimental diets (isoproteic: 41.00%; isolipidic: 7.61%) that were formulated using fish meal (FM), Chlorella sorokiniana (CHL), and Clostridium autoethanogenum protein (CAP) as the primary protein sources, respectively. This study examined the growth, non-specific immunity, intestinal digestion, and microbiota of L. vannamei after the feeding experiment concluded. Compared to the FM group, the findings indicate that the weight gain rate (WGR), specific growth rate (SGR), and protein efficiency ratio (PER) of L. vannamei were notably enhanced via dietary CAP. The CHL group exhibited the highest levels of catalase (CAT), phenoloxidase (PO), and superoxide dismutase (SOD) activities in the gills of L. vannamei, whereas the FM group had the lowest levels. Conversely, the malondialdehyde (MDA) content showed the opposite trend. Both dietary CHL and CAP promoted the digestive enzyme activities of L. vannamei, with dietary CAP having a more pronounced promotional effect. An analysis of alpha diversity indicated that the consumption of dietary CHL substantially enhanced the abundance and diversity of microbiota in the intestinal tract of L. vannamei. Furthermore, the dietary CHL significantly increased the colonization of immune-associated beneficial bacteria and inhibited the colonization of pathogenic bacteria in the intestinal tract of L. vannamei, whereas dietary CAP mainly increased the colonization of growth-associated beneficial bacteria. Functional predictions showed that different dietary protein sources affect various metabolic activities and signaling pathways of L. vannamei, and some functions, including signal transduction, cell motility, and the immune system, were significantly enhanced in the CHL group. In summary, both dietary CHL and dietary CAP promoted growth and immunity in L. vannamei compared to dietary FM. The results of this study could be helpful for the sustainable development of shrimp farming.

Uncontrollable hemorrhage leads to high mortality and thus effective bleeding control becomes increasingly important in the military field and civilian trauma arena. However, current hemostats not only present limitation when treating major bleeding, but also have various side effects. Here we report a self-expanding porous composites (CMCP) based on novel carboxymethyl cellulose (CMC) fibers and acetalized polyvinyl alcohol (PVA) for lethal hemorrhage control. The CMC fibers with uniform fibrous structure, high liquid absorption and procoagulant ability, are evenly interspersed inside the composite matrix. The obtained composites possess unique fiber-porous network, excellent absorption capacity, fast liquid-triggered self-expanding ability and robust fatigue resistance, and their physicochemical performance can be fine-tuned through varying the CMC content. In vitro tests show that the porous composite exhibits strong blood clotting ability, high adhesion to blood cells and protein, and the ability to activate platelet and the coagulation system. In vivo hemostatic evaluation further confirms that the CMCP presents high hemostatic efficacy and multiple hemostatic effects in swine femoral artery major hemorrhage model. Additionally, the CMCP will not fall off from the injury site, and is also easy to surgically remove from the wound cavity after the hemostasis. Importantly, results of CT tomography and 3D reconstruction indicate that CMCP can achieve shape adaptation to the surrounding tissues and the wound cavities with different depths and shapes, to accelerate hemostasis while protecting wound tissue and preventing infection.

Regulatory science for medical devices aims to develop new tools, standards and approaches to assess the safety, effectiveness, quality and performance of medical devices. In the field of biomaterials, hernia mesh is a class of implants that have been successfully translated to clinical applications. With a focus on hernia mesh and its regulatory science system, this paper collected and reviewed information on hernia mesh products and biomaterials in both Chinese and American markets. The current development of regulatory science for hernia mesh, including its regulations, standards, guidance documents and classification, and the scientific evaluation of its safety and effectiveness was first reported. Then the research prospect of regulatory science for hernia mesh was discussed. New methods for the preclinical animal study and new tools for the evaluation of the safety and effectiveness of hernia mesh, such as computational modeling, big data platform and evidence-based research, were assessed. By taking the regulatory science of hernia mesh as a case study, this review provided a research basis for developing a regulatory science system of implantable medical devices, furthering the systematic evaluation of the safety and effectiveness of medical devices for better regulatory decision-making. This was the first article reviewing the regulatory science of hernia mesh and biomaterial-based implants. It also proposed and explained the concepts of evidence-based regulatory science and technical review for the first time.

The effects of dietary zymosan A on the growth performance and histological structure, digestive capacity, and microbiota were investigated in Litopenaeus vannamei, an important shrimp species used in aquaculture. L. vannamei (initial body weight = 0.41 ± 0.05 g) were fed diets supplemented with zymosan-A at doses of 0 mg/kg (Z0, control), 1 mg/kg (Z1), 5 mg/kg (Z5), 25 mg/kg (Z25), 125 mg/kg (Z125), or 625 mg/kg (Z625) for 8 weeks. The results showed that doses of 25 and 125 mg/kg significantly increased the final body weight, weight gain rate (WGR), and specific growth rate (SGR) and significantly decreased the feed conversion rate compared with the controls (p < 0.05). Analyses of the WGR and SGR revealed that the optimum dietary zymosan-A levels were 308.56 and 300.00 mg/kg, respectively. Compared with the controls, the intestinal villus height was significantly increased by the addition of zymosan-A at doses ≥25 mg/kg (p < 0.05). An obvious upregulation of the activities of trypsin and amylase was observed in all groups that received zymosan-A supplementation, while the activity of lipase was significantly increased in groups Z125 and Z625 (p < 0.05). Consistently, the gene expressions of trypsin and lipase were significantly higher in group Z125, while the gene expression of amylase was significantly increased in all zymosan-A-supplemented groups (p < 0.05). Analysis of the intestinal microbiota showed significant differences in the alpha diversity between group Z125 and controls. The supplemented groups showed altered intestinal bacterial community structures and compositions at the phylum, family, and genus levels, with statistical differences observed in the relative abundances of some dominant species. Tax4Fun predictions of the microbiota indicated that multiple intestinal functions were significantly altered in all zymosan-A-supplemented groups, except Z1. Among these groups, the functions related to transport and catabolism, substance dependence, cardiovascular disease, and signaling molecules and interactions were obviously increased by the addition of zymosan-A at different levels. In conclusion, dietary supplementation of the optimum amount of zymosan-A can improve growth and intestinal function in L. vannamei, which will be valuable in aquaculture.

Objective: Variation of the solute diffusion within articular cartilage is an important feature of osteoarthritis (OA) progression. For in vitro study of monitoring of the diffusion process, it is essential to simulate physiological conditions as much as possible. Our objective was to investigate the effects of loading patterns on diffusion processes of neutral solutes within osteoarthritic cartilage. Methods: Osteochondral plugs were harvested from human tibial plateaus and separated into three OA stages according to modified Mankin scoring system. The samples were subjected to static or cyclic compression using a carefully designed loading device. Contrast-enhanced micro-computed tomography (CEμCT) was applied to acquire image sequences while the cartilage was being compressed. The apparent diffusion maps and diffusion coefficients were analysed, as well as histological and stereological assessments of the plugs. Results: The diffusion of neutral solutes was significantly affected by the loading patterns. For OA cartilage with early and middle stages, cyclic loading accelerated contrast agent infiltration compared with static loading. However, for late-stage OA samples, no acceleration of diffusion was observed in the first 2 ​h because of the insufficient resilience of compressed cartilage. The accumulation of neutral solutes in an upward invasive fissure also suggested that solutes could penetrate into the fissure under cyclic loading. Conclusions: To our knowledge, this is the first study to combine the cyclic compression and CEμCT scanning in the diffusion testing of human OA cartilage. This loading pattern could simulate the physiological conditions and reduce the time to reach solute equilibrium within cartilage. The diffusion data may contribute to joint drug-injection therapies for early OA. The translational potential of this article: The combination of cyclic loading and CEμCT scanning enabled diffusion analysis of osteoarthritic cartilage under different compressions. A comprehensive evaluation of OA cartilage and subchondral bone may benefit from this technique. The diffusion data provide theoretical support and reference for intra-articular injection of drugs.

Alginate hydrogels have the most extensively explored injection system among natural molecular. The injectable alginate hydrogel has special physical and biological properties without toxicity, therefore, it has been served as minimally invasive treatments to treat various irregular defects. However, the inconvenient truth is low formability and poor mechanical properties of injectable alginate hydrogels; besides, there are little relevant studies about controlling, measurement and analysis of the sol-gel transition and degradation process. We synthesized an injectable nanocomposite alginate hydrogel, used specific methods and equipment to regulate and evaluate the sol-gel transition of the hydrogel, moreover, we researched the degradation behaviour using scanning electron microscope, nano-indenter and titration analysis. The results showed that gelation time and mechanical properties could be regulated and effectively described. Compression properties of the hydrogels increased to 150%–300% compared with common alginate hydrogels, in addition, the degradation behaviour with ions release could be regulated by the formula. The results will be propitious to solve problems in quality control of hydrogel manufacturing engineering and the nanocomposite hydrogels with good biocompatibility will have great potential for multifunctional biological scaffolds and tissue engineering.

Our previous studies on Wnt/β-catenin signalling have shown that it plays a positive role in the immunity of Litopenaeus vannamei. In this study, the effects of changes in Wnt/β-catenin signalling activity on growth performance, immunity and transcriptomes were investigated in L. vannamei. Wnt/β-catenin signalling was inhibited by injection with IWR-1 and activated by injection with TWS119. IWR-1 and TWS119 injection significantly reduced and increased, respectively, the survival rates of L. vannamei in response to white spot syndrome virus (WSSV) infection. Compared with the control group, the growth performance of L. vannamei significantly decreased after feeding with IWR-1 but was not notably changed after feeding with TWS119. The L. vannamei fed IWR-1 had a significantly reduced survival rate after WSSV infection but there were no notable effects after Vibrio parahemolyticus infection. The L.vannamei fed TWS119 had a significantly increased survival rate after WSSV and Vibrio parahemolyticus infection. The catalase (CAT) of the IWR-1-fed L. vannamei showed decreased activity, while the alkaline phosphatase (AKP) activity of the TWS119-fed L. vannamei was significantly increased, in comparison to the control group. Transcriptome analysis identified 272 differentially expressed genes (DEGs) (19 up-regulated and 253 down-regulated) in the IWR-1-fed L. vannamei and 430 DEGs (31 up-regulated and 399 down-regulated) in TWS119-fed L. vannamei, when compared with the control group. The functional annotation and enriched pathway results showed that the DEGs were mainly involved in lipid metabolism, transport and catabolism and carbohydrate metabolism. All of the results indicated that growth performance and immunity of L. vannamei could be regulated through changing the Wnt/β-catenin signalling activity, which was probably due to alterations at the metabolic level. The findings in this study provide some insights for exploiting immunostimulants in aquaculture.

Dura substitutes are applied in duraplasty to repair lost or damaged dura. Collagen-based dura substitutes are mainstream products in both the US and Chinese markets. In this study, dura substitute devices with potential dura regeneration ability are evaluated. The dura substitutes are composed of fibrous type I collagen that were purified from bovine tendon. Physical and chemical characterization demonstrated that the tested dura substitute has desirable porous scaffolding structures and is composed of highly purified type I collagen. The collagen dura substitutes were further investigated in vivo with a rabbit model for 6 months to evaluate their safety and performance to repair and regenerate dura. No inflammation or infection was observed during the course of in vivo study. The integration of the collagen dura substitutes with surrounding tissue was normal as compared to native tissue. The macroscopic and microscopic histological assessments of the sampled animal tissue showed that the damaged dura were regenerated. The collagen dura substitutes were resorbed between 3 and 6 months along with newly regenerated dura. Both tissue adhesion and dura repair was the worst in blank control group as compared to those in the collagen dura substitutes. Taken together, regenerative collagen dura substitutes demonstrated with suitable physicochemical properties. The in vivo evaluation in a rabbit model further demonstrated the safety and performance of such substitutes for dura repair and regeneration.

We propose a flexible, dry, and antibacterial electrode with a low and stable skin electrode contact impedance for bio-potential signal monitoring. We fabricated a bacterial cellulose/polyaniline/AgNO3 nanocomposite membrane (BC/PANI/AgNO3) and used it for bio-potential signal monitoring. The bacterial cellulose (BC) provides a 3-D nanoporous network structure, and it was used as a substrate material in the BC/PANI/AgNO3 nanocomposite membrane. Polyaniline (PANI) and AgNO3, acting as conductive and antibacterial components, respectively, were polymerized and deposited on the surfaces of BC nanofibers to produce uniform thin film membrane with flexible, antibacterial, and conductive properties. Various measurements were conducted, in terms of antibacterial activity, skin electrode contact impedance, and qualitative analysis of ECG signal recordings. The BC/PANI/AgNO3 membrane revealed 100% antibacterial activities against both the Staphylococcus aureus and Escherichia coli bacteria. The skin electrode contact impedance of the proposed BC/PANI/AgNO3 electrode is lower than that of the Ag/AgCl gel electrode, with the same active area. In addition, the electrocardiogram (ECG) signals acquired with the proposed electrodes have stable characteristic waveforms, and they are not contaminated by noise. The waveform fidelity of the BC/PANI/AgNO3 membrane electrodes over 800 ECG cardiac cycles is 99.49%, and after the electrodes were worn for 24 hours, a fidelity of 98.40% was recorded over the same number of cardiac cycles. With the low and stable skin electrode contact impedance, the proposed dry BC/PANI/AgNO3 membrane electrode provided high fidelity for ECG signal recordings, thus offering a potential approach for bio-potential signal monitoring. With the above benefits, the novel flexible and dry BC/PANI/AgNO3 electrode has a significant antibacterial. Most of all, it is the first research to develop antibacterial in the electrode design.

Demineralized bone matrix (DBM) is a decalcified allo/xenograft retaining collagen and noncollagenous proteins, which has been extensively used because of its osteoconductive and osteoinductive properties. Calcium sulfate (CaSO4, CS) is a synthetic bone substitute used in bone healing with biocompatible, nontoxic, bioabsorbable, osteoconductive, and good mechanical characteristics. This study aims to prepare a DBM/CS composite bone graft material in a moldable putty form without compromising the peculiar properties of DBM and CS. For this purpose, firstly, porcine femur was defatted using chloroform/methanol and extracted by acid for demineralization, then freeze-dried and milled/sieved to obtain DBM powder. Secondly, the α-form and β-form of calcium sulfate hemihydrate (CaSO4·0.5H2O, CSH) were produced by heating gypsum (CaSO4·2H2O). The morphology and particle sizes of α- and β-CSH were obtained by SEM, and their chemical properties were confirmed by EDS, FTIR and XRD. Furthermore, the DBM-based graft was mixed with α- or β-CSH at a ratio of 9:1, and glycerol/4% HPMC was added as a carrier to produce a putty. DBM/CSH putty possesses a low washout rate, good mechanical strength and biocompatibility. In conclusion, we believe that the moldable DBM/CSH composite putty developed in this study could be a promising substitute for the currently available bone grafts, and might have practical application in the orthopedics field as a potential bone void filler.

Objective: To investigate the effectiveness and accuracy of internal fixation of calcaneal fractures with a three-dimensional (3-D) printing navigation module via the sinus approach. Methods: Eleven lateral lower extremity specimens were used in the experiment and divided into the digital design (DD) group ( n = 11) and the real surgery (RS) group ( n = 11). For the DD group, thin-section computed tomography (CT) scans, virtual fracture modeling, virtual bone plate fixation, sinus occlusal module design, and navigation module design were performed for the cadaver specimens. A 3-D navigation module was printed using a 3-D printer. For the RS group, the sinus approach incision was made, and the navigation module was used to assist the placement of screw fixation and anatomically locked bone plate fixation. Thin-layer CT scans, 3-D reconstructions, and reconstruction of the nail paths were performed in the RS group and 3-D registered with the DD group. 3-D coordinate values for the screw entry and exit points in the RS and DD groups were recorded, and the corresponding offset values of the screw points were calculated. The number of qualified nails at different accuracy levels was counted. The χ 2 test was used to compare the data for the DD and RS groups to obtain the accuracy level for both groups when p > 0.05, which is the critical value for experimental accuracy. Results: A total of 11 bone plates were placed and 120 screws were locked. None of them protruded from the inferior articular surface. The screw entry and exit point offsets were 1.71 ± 0.11 mm and 3.10 ± 0.19 mm, respectively. When the accuracy requirement for the entry point was 3.8 mm, there was no statistically significant difference between the two groups ( p > 0.05). Similarly, the accuracy of the exit point of the screw could only reach 6.6 mm. Conclusion: Internal fixation of calcaneal fractures via the sinus tarsi approach with an anatomical locking plate based on the 3-D printing navigation module can achieve accurate screw placement and good overall internal fixation.

Bacterial infection and inferior osseointegration are major complications associated with titanium (Ti) based implants. Although surface-engineered zinc oxide (ZnO) nanorods exhibit remarkable antibacterial ability, their potential biomedical applications are hampered by their pronounced cytotoxicity. Herein, inspired by the in vivo degradation process of znic, ZnO nanorods are converted into thermodynamically more stable zinc phosphate (Zn3(PO4)2 )through a simple hydrothermal treatment in a hydrogen phosphate solution. By adjusting the conversion ratio, the surface morphology, release of zinc ions (Zn2+), and generation of reactive oxygen species can be finely tailored to overcome the cytotoxicity of ZnO nanorods while preserving their antibacterial capability. Furthermore, an optimized amount of Zn2+ released from the ZnO/Zn3(PO4)2 hybrid coating enhances osteogenic differentiation and extracellular matrix mineralization of human bone marrow mesenchymal stem cells by reprogramming their metabolic configuration. An implant-related infection model in rabbit femurs indicates that the hybrid ZnO/Zn3(PO4)2 coating can even promote osseointegration in the presence of pathogenic bacteria. This surface modification strategy which endows Ti-based implants with superior anti-bacterial and pro-osteogenic properties holds great clinical potential for orthopedic and dental applications. [ABSTRACT FROM AUTHOR]