Primary exploring the value of metagenomic next-generation sequencing in detecting pathogenic bacteria of cholangitis with biliary atresia after Kasai operation.

PURPOSE: To evaluate the value of metagenomic next-generation sequencing (mNGS) in detecting pathogenic bacteria of cholangitis for patients with biliary atresia after Kasai operation. METHODS: This study retrospectively analyzed patients of biliary atresia with cholangitis after Kasai operation who were admitted to Xi'an Children's Hospital from July 2019 to December 2021. Both blood culture and mNGS were carried out in all of these patients. We compared the detection rate of pathogenic bacteria, pathogenic bacteria spectrum, test time, inflammatory indicators and liver function. All the patients were followed up for 0.5-3 years to evaluate the onset of cholangitis and the survival status of autologous liver. RESULTS: This study included total of 30 cholangitis occurred in 25 patients. There were significant differences in the detection rate of pathogenic bacteria [23.3 vs.73.3%, P < 0.05] and the test time [120 (114.5-120) vs.16 (16-21) h, P < 0.001] between the blood culture and mNGS. These two methods showed significant statistical differences in comparing inflammatory indicators (CRP, PCT) and liver function (TB, DB, GGT) before and after anti-infection. Four kinds of bacteria were detected by blood cultures and ten kinds of bacteria were detected by mNGS. Cholangitis occurred 3 times in one case (4%) and twice in three cases (12%). Autologous liver survived in 17 cases (68%). CONCLUSION: Comparing with traditional blood culture, mNGS is more efficient, convenient and accurate in the detection of pathogens. It provides a new method for accurately detecting pathogenic bacteria of cholangitis after Kasai operation.

Molybdenum disulfide nanosheet/polyimide composites with improved tribological performances, surface properties, antibacterial effects and osteogenesis for facilitating osseointegration.

Polymeric biocomposites display some advantages over metal or ceramic biomaterials, and are regarded as a promising candidate for artificial joint application. Herein, molybdenum disulfide (MD) nanosheets were prepared and incorporated into polyimide (PI) to form MD/PI composites with a MD content of 20 wt% (PM20) and 40 wt% (PM40). The results revealed that incorporation of MD nanosheets obviously improved the tribological performances, surface properties (e.g., roughness, wettability and surface energy) and protein absorption of the composites, which enhanced with the increase of MD content. In addition, the composites containing MD nanosheets exhibited antibacterial effects, and the antibacterial effects of PM40 were higher than those of PM20 and PI. PM40 significantly stimulated the cellular responses of rat bone mesenchymal stem cells in vitro, which was better than PM20 and PI. Furthermore, PM40 remarkably accelerated osteogenesis and osseointegration in vivo, which was better than PM20 and PI. In summary, the MD content in composites played pivotal roles in improving not only tribological performances, surface properties, antibacterial effects and cellular response in vitro but also osteogenesis and osseointegration in vivo. As a result, PM40 with high MD content exhibited excellent osteogenic bioactivity and antibacterial effects, which would have great potential for artificial joint applications.

Microporous surface containing flower-like molybdenum disulfide submicro-spheres of sulfonated polyimide with antibacterial effect and promoting bone regeneration and osteointegration.

Implanted materials with both osteogenic and antibacterial functions are promising for facilitating osteointegration and preventing infection for orthopedic applications. In this work, we synthesized flower-like molybdenum disulfide (fMD) submicro-spheres containing nanosheets, which were incorporated onto the microporous surface of polyimide (PI) via concentrated sulfuric acid, suspending fMD contents of 5 wt% (SPM1) and 10 wt% (SPM2). Compared with sulfonated polyimide (SPM0), both SPM1 and SPM2 with microporous surfaces containing fMD exhibited nano-submicro-microporous surfaces, which improved the surface roughness, wettability, and surface energy. Due to there being more fMD submicro-spheres on the microporous surface, SPM2 revealed a better antibacterial effect than SPM1. In addition, compared with SPM1 and SPM0, SPM2 with more fMD significantly promoted rat bone marrow-derived stromal cell response in vitro. Moreover, SPM2 remarkably enhanced new bone formation and osteointegration in vivo. In summary, the combination of fMD with the microporous surface of SPM2 resulted in a nano-submicro-microporous surface with optimized surface performance, which possessed not only osteogenic bioactivity but also an antibacterial effect. As a bone implant, SPM2 with osteogenic and antibacterial functions may have enormous potential as a bone tissue substitute.

Laparoscopic vs open Ladd's procedure for malrotation in neonates and infants: a propensity score matching analysis.

BACKGROUND: Laparoscopic Ladd's procedure for malrotation in children is still a controversial approach. Although some retrospective studies have compared the outcomes of the two types of procedure with inconsistency outcomes. Currently, there are few large-scale studies on laparoscopic treatment in malrotation with neonates and infants. We did a study based on propensity score matching to compare the effects of the two kinds of approach in neonates and infants. To investigate the therapeutic effect of laparoscopy and open Ladd's procedure by the propensity score-matching (PSM) to enhance the validity of the comparison. METHODS: A total series of 143 cases of intestinal malrotation without intestinal necrosis was included in the study during the 8 years from January 2012 to January 2020, including 68 cases of open Ladd's procedure and 75 cases of laparoscopic Ladd's procedure including five cases of transfer laparotomy. By a propensity score 1:1 matching, 62 patients were stratified for each group. RESULTS AND CONCLUSION: There was no significant difference in volvulus degree, weight and gender between the two groups (p > 0.05). Laparoscopic surgery took more time than open surgery (105.9 min vs 70.6 min, p < 0.05), but it had less hospital stay (12.4 days vs 14.6 days, p < 0.05) or less incision infection (0 vs 6, p < 0.05). There was no significant difference between the two groups at the time of first defecation, blood loss, time of full feeding and reoperation (p > 0.05). The cosmetic effect of laparoscopic surgery is better than that of open surgery. Laparoscopic Ladd's procedure is a safe approach. It can reduce the length of hospital stay and incision infection, but the operation time was extended, the other complications are similar compared with open procedure for intestinal malrotation in neonates and infants.

Maternal regulation of biliary disease in neonates via gut microbial metabolites.

Maternal seeding of the microbiome in neonates promotes a long-lasting biological footprint, but how it impacts disease susceptibility in early life remains unknown. We hypothesized that feeding butyrate to pregnant mice influences the newborn's susceptibility to biliary atresia, a severe cholangiopathy of neonates. Here, we show that butyrate administration to mothers renders newborn mice resistant to inflammation and injury of bile ducts and improves survival. The prevention of hepatic immune cell activation and survival trait is linked to fecal signatures of Bacteroidetes and Clostridia and increases glutamate/glutamine and hypoxanthine in stool metabolites of newborn mice. In human neonates with biliary atresia, the fecal microbiome signature of these bacteria is under-represented, with suppression of glutamate/glutamine and increased hypoxanthine pathways. The direct administration of butyrate or glutamine to newborn mice attenuates the disease phenotype, but only glutamine renders bile duct epithelial cells resistant to cytotoxicity by natural killer cells. Thus, maternal intake of butyrate influences the fecal microbial population and metabolites in newborn mice and the phenotypic expression of experimental biliary atresia, with glutamine promoting survival of bile duct epithelial cells.

Knockdown of RREB1 inhibits cell proliferation via enhanced p16 expression in gastric cancer.

Gastric cancer (GC) is the most common gastrointestinal malignancy worldwide. However, the molecular mechanisms of the progression of GC are not fully understood. Ras-responsive element binding protein 1 (RREB1) is an oncogene in many types of cancer that is involved in various biological processes, such as DNA damage repair, cell growth and proliferation, cell differentiation, fat development, and fasting glucose balance. In this study, we demonstrate the role of RREB1 in gastric cancer. First, by immunohistochemistry staining (IHC) and bioinformatics analysis, we demonstrated the expression of RREB1 in gastric cancer and paired normal gastric tissues. Then, we established RREB1 overexpression and knockdown cell lines via lentiviral transfection and detected cell proliferation by using MTT, colony-forming, cell cycle and apoptosis assays in vitro. We demonstrated the effect of RREB1 on cell proliferation in vivo by using a subcutaneous xenograft tumor model in nude mice. Finally, by using Western blotting and IHC, we demonstrated the possible mechanism by which RREB1 affects cell proliferation. The IHC and bioinformatics analyses demonstrated that RREB1 was highly expressed in gastric cancer and showed that RREB1-expressing patients had a larger tumor size and more lymphovascular invasion than RREB1-negative patients. Knockdown of RREB1 inhibited cell proliferation in vivo and in vitro. Knockdown of RREB1 enhanced p16 expression in vivo and in vitro, and p16 expression was negatively related to RREB1 in gastric cancer tissue. RREB1 was highly expressed in gastric cancer, and knockdown of RREB1 inhibited cell proliferation via enhanced p16 expression.

A novel two-port single-site laparoscopic pyloromyotomy for infantile hypertrophic pyloric stenosis.

OBJECTIVE: The objective of the study is to explore a less invasive laparoscopic pyloromyotomy for treating infantile hypertrophic pyloric stenosis. PATIENTS AND METHODS: A series of 154 cases from January 2014 to January 2020 were retrospectively analysed. Seventy patients were treated with the method of transumbilical single-site laparoscopic pyloromyotomy (SSLP), and 84 patients were treated with two-site laparoscopic pyloromyotomy. There was no difference in the body weight, sex ratio or age between the two groups. The operation time, blood loss, post-operative feeding time and complications between the two groups were compared. RESULTS: The novel single-site method had better cosmetic effect than the two-site approach. There was no difference in the operation time, blood loss, post-operative feeding time or complications between the two groups. CONCLUSION: The novel SSLP method requires only two incisions through the umbilicus to complete the procedure, with barely visible scars and similar surgical complications to that of the two-site approach; thus, the novel method is worth promoting.

SIRT1 relieves Necrotizing Enterocolitis through inactivation of Hypoxia-inducible factor (HIF)-1a.

Necrotizing enterocolitis (NEC) is a major cause of mortality and morbidity in newborns, characterized by inflammatory intestinal necrosis. Sirtuin-1 (SIRT1), a NAD-dependent deacetylase, is involved in multiple biological functions. It has been reported that SIRT1 was downregulated in NEC tissues. However, the precise role of SIRT1 in NEC progress remains unknown. In this study, we found that SIRT1 was decreased in serum samples of NEC patients, associated with an inflammation response. an in vitro model was established by using LPS-induced NEC-like cell in this study. The results indicate that overexpression of SIRT1 inhibited the cell apoptosis induced by LPS. Besides, overexpression of SIRT1 suppressed the high expression of proinflammatory factors (IL-6, IL-8, and TNF-α), the decrease of transepithelial electrical resistance (TEER), and the decline expression of tight junction proteins (ZO-1, ZO-2, and Claudin-4) induced by LPS in Caco-2 cells. What is more, serum HIF-1α was increased in NEC patients. SIRT1 overexpression suppressed the expression and activity of HIF-1a, while knockdown of SIRT1 made the opposite effect. In summary, this study indicates that overexpression of SIRT1 alleviates the inflammation response and intestinal epithelial barrier dysfunction through regulating the expression and inactivation of HIF-1a.

Novel technique to manage refractory chylous ascites with carbon nanoparticle suspension in infants.

OBJECTIVE: Chylous ascites (CA) is a rare form of ascites that results from the leakage of lipid-rich lymph into the peritoneal cavity. In infants, CA is mostly caused by lymphatic malformation or unknown reasons. The creation of a shunt for the lymphorrhea is the last option for patients unresponsive to all other conservative treatments. Localization of the leakage is a critical problem during surgery. We applied a carbon nanoparticle suspension (CNS) in CA patients to locate the external lymphatic leakage and evaluated its utility during surgery. PATIENTS AND METHODS: Twelve infants with CA were treated in our center recently. Ten patients received laparotomy, one refused therapy, and one was cured after undergoing conservative treatment. Recently, two infants with CA received CNS in the visceral peritoneum during laparotomy. The results of the traditional procedure were compared to our innovative technique for CA to evaluate the use of CNS in treating CA. RESULTS: The features of the baseline data did not differ substantially. Location of the leakage with CNS was employed in 2 of the 10 patients whose lymphatic leakages were identified with the resolution of the refractory CA. Overall, in 5 patients, ascites was resolved successfully. The refractory CA was resolved more effectively in patients in whom the leakage site was identified with CNS than in patients in whom the leakage site could not be identified under conventional surgery. CONCLUSIONS: Injecting CNS improved the accuracy of lymphorrhagia leakage site identification and the outcomes of infants who underwent surgical treatment for refractory CA. LEVEL OF EVIDENCE: II-III.

A hierarchical nanostructural coating of amorphous silicon nitride on polyetheretherketone with antibacterial activity and promoting responses of rBMSCs for orthopedic applications.

Silicon nitride (SN) with good osteoconductivity has been introduced as an implantable biomaterial for joint replacement and interbody fusion devices. In this study, SN was coated on a polyetheretherketone (PEEK) surface by inductively coupled plasma-enhanced chemical vapor deposition (ICPECVD). The results showed that a dense coating (thickness of about 500 nm) of amorphous SN was closely combined with a PEEK substrate (PKSN) with a binding strength of 6.88 N. In addition, the coating surface showed hierarchical nanostructures containing many spherical bulges (sizes about 150 nm), which were composed of many small humps (sizes about 10 nm). Moreover, the roughness, hydrophilicity, surface energy, surface charge and adsorption of bovine serum albumin (BSA) of PKSN were obviously higher than those of PEEK. After immersion into simulated body fluid (SBF), the Si ions were gradually released from PKSN into SBF and a weak alkaline environment was created. Antibacterial experiments showed that PKSN exhibited a greater antibacterial activity than that of PEEK. Moreover, compared with PEEK, PKSN significantly promoted adhesion, proliferation, differentiation and expression of osteogenic related genes of the rat bone marrow stromal cells (rBMSCs). In conclusion, the SN coating of PKSN with hierarchical nanostructures exhibited excellent antibacterial activity and cytocompatibility, which would make it a great candidate for orthopedic applications.

Downregulation of Protein Tyrosine Phosphatase Receptor Type R Accounts for the Progression of Hirschsprung Disease.

Hirschsprung disease (HSCR) is a common developmental disorder of the enteric nervous system (ENS). However, the disease mechanisms have not been fully elucidated. To better understand the etiology of HSCR, the role and mechanism of HSCR associated PTPRR (protein tyrosine phosphatase receptor-type R) in the multipotency of ENS progenitors and ENS development were explored. In the present study, the downregulated PTPRR expression in HSCR was reflected by microarray and validated by real-time PCR analyses. Moreover, PTPRR protein was mainly expressed in the cytoplasmic area of primary cultured ENS progenitors (Enteric neural crest cells, ENCCs) and significantly decreased after differentiation induction, which implies the anti-differentiation role in ENCCs. Further study employed an adenovirus transfection system. After genetic modulation, the ENCCs maintained undifferentiated patterns even in GDNF (Glial cell-line derived neurotrophic factor)-mediated directional differentiation, as well as significantly increased EdU positive immunofluorescence in the PTPRR overexpressing group while the development of the ENS was stunted in the PTPRR knockdown fetal gut. Moreover, the expression of ERK1/2 activated by GDNF was significantly decreased as reflected by western-blot or immunofluorescence analyses after genetic modulation in the PTPRR overexpressing group, which suggests the potential mechanism in regulating the MAPK/ERK1/2 pathway. Taken together, These data support the idea that PTPRR may ensure a certain number of neural precursor cells by inhibiting ENCC overt differentiation and maintaining ENCC proliferation, which is considered to be the multipotency of ENCCs, and eventually participate in the development of the ENS, and establish PTPRR protein as negative regulator of MAPK/ERK1/2 signaling cascades in neuronal differentiation and demonstrate their involvement in the pathophysiology of HSCR.

Influences of tantalum pentoxide and surface coarsening on surface roughness, hydrophilicity, surface energy, protein adsorption and cell responses to PEEK based biocomposite.

Polyetheretherketone (PEEK) biomaterial has become increasingly popular in orthopedic applications due to its favorable biocompatibility, biostability, mechanical strength and elastic modulus similar to natural bones. In this research, in order to improve the biological performances of PEEK, tantalum pentoxide (Ta2O5) was incorporated into PEEK to fabricate PEEK/Ta2O5 composites (PTC) using a method of cold press-sintering, and surface coarsening of PTC was prepared by sand blasting. The results showed that the Ta2O5 particles were uniformly disperse into PEEK, and thermal and mechanical properties of PTC were enhanced with the increase of Ta2O5 content. In addition, incorporating Ta2O5 into PEEK and surface coarsening could improve surface roughness, hydrophilicity, surface energy and protein absorption of PTC. Furthermore, the adhesion and proliferation as well as osteogenic differentiation of BMSCs on PTC were significantly promoted and regulated by Ta2O5 content and surface coarsening. The results indicated that surface coarsening of PTC (PTCS) with high surface roughness, hydrophilicity and surface energy could induce positive cellular responses, showing good cytocompatibility. PTCS might have a great potential as implants for bone repair.

Microporous Coatings of PEKK/SN Composites Integration with PEKK Exhibiting Antibacterial and Osteogenic Activity, and Promotion of Osseointegration for Bone Substitutes.

To improve the antibacterial and osteogenic activities of poly(etherketoneketone) (PEKK), concentrated sulfuric acid (H2SO4) suspension with silicon nitride (SN) microparticle was utilized to modify PEKK surface. Through sulfonation reaction, microporous coatings of PEKK/SN composites were created on PEKK surface, which were integrated with PEKK substrate. The results showed that the content of SN in the microporous coatings increased with the increase of SN content in H2SO4 suspension (PKS without SN, PKSC5 and PKSC10 with 5 and 10 wt % SN content in H2SO4) and that the surface roughness and hydrophilicity of microporous coatings on PEKK were significantly improved with the SN content increasing. In addition, the microporous coating of PKSC10 with high SN content exhibited excellent antibacterial activity due to the synergistic action of the presence of amino (-NH2) and sulfonic acid (-SO3H) groups as well as the improvement of protein absorption. Moreover, the microporous coating of PKSC10 obviously stimulated adhesion, proliferation, and osteogenic differentiation of rat bone mesenchymal stem cells. Furthermore, histological and push-out load evaluation indicated that the microporous coating of PKSC10 significantly promoted osteogenesis and osseointegration in vivo. The results suggested that the microporous coating of PKSC10 with high SN content display good biocompatibility, antibacterial and osteogenic activities, and osseointegration ability, which would have great potential for bone substitutes.

Stimulation of cell responses and bone ingrowth into macro-microporous implants of nano-bioglass/polyetheretherketone composite and enhanced antibacterial activity by release of hinokitiol.

Poor osteogenesis and bacterial infection lead to the failure of implants, thus enhancements of osteogenic activity and antibacterial activity of the implants have significances in orthopedic applications. In this study, macro-microporous bone implants of nano-bioglass (nBG) and polyetheretherketone (PK) composite (mBPC) were fabricated. The results indicated that the mBPC with the porosity of around 70% exhibited interconnected macropores (sizes of about 400 µm) and micropores (sizes of about 10 µm). The apatite mineralization ability of mBPC in simulated body fluid (SBF) was significantly improved compared with macroporous nBG/PK composite (BPC) without micropores and macroporous PK (mPK). Drug of hinokitiol (HK) was loaded into mBPC (dmBPC), which displayed excellent in vitro antibacterial activity against Staphylococcus aureus. The MC3T3-E1 cells proliferation and ALP activity were significantly promoted by mBPC and dmBPC as compared with BPC and mPK. The micro-CT and histological evaluation showed that both mBPC and dmBPC containing nBG and micropores induced higher new bone formation into porous implants than mPK and BPC. The immunohistochemistry analysis indicated that the expression of BMP-2 in mBPC and dmBPC exhibited obviously higher level than mPK and BPC. The results suggested that the incorporation of nBG and micropores in mBPC obviously improved the osteogenic activity, and mBPC load with HK also promoted osteogenesis, indicating good biocompatibility. The dmBPC with HK significantly enhanced osteogenesis and antibacterial activity, which had great potential as bone implant for hard tissue repair.

Nanoporosity improved water absorption, in vitro degradability, mineralization, osteoblast responses and drug release of poly(butylene succinate)-based composite scaffolds containing nanoporous magnesium silicate compared with magnesium silicate.

Bioactive composite macroporous scaffold containing nanoporosity was prepared by incorporation of nanoporous magnesium silicate (NMS) into poly(butylene succinate) (PBSu) using solvent casting-particulate leaching method. The results showed that the water absorption and in vitro degradability of NMS/PBSu composite (NMPC) scaffold significantly improved compared with magnesium silicate (MS)/PBSu composite (MPC) scaffold. In addition, the NMPC scaffold showed improved apatite mineralization ability, indicating better bioactivity, as the NMPC containing nanoporosity could induce more apatite and homogeneous apatite layer on the surfaces than MPC scaffold. The attachment and proliferation of MC3T3-E1 cells on NMPC scaffold increased significantly compared with MPC scaffold, and the alkaline phosphatase (ALP) activity of the cells on NMPC scaffold was expressed at considerably higher levels compared with MPC scaffold. Moreover, NMPC scaffold with nanoporosity not only had large drug loading (vancomycin) but also exhibited drug sustained release. The results suggested that the incorporation of NMS into PBSu could produce bioactive composite scaffold with nanoporosity, which could enhance water absorption, degradability, apatite mineralization and drug sustained release and promote cell responses.

Influences of mesoporous zinc-calcium silicate on water absorption, degradability, antibacterial efficacy, hemostatic performances and cell viability to microporous starch based hemostat.

Efficacious hemostatic agents have significant potential application in visceral organ or large vessel arterial injure. In this study, mesoporous zinc-calcium silicate (m-ZCS) was synthesized, and microporous starch (MS) based hemostatic agents of m-ZCS/MS composites for hemorrhage control was fabricated. The results showed that the incorporation of m-ZCS into MS significantly enhanced the water absorption and degradability of the composites, which were dependent on the m-ZCS content. Moreover, the composites with antibacterial property could inhibit the growth of Escherichia coli (E. coli) and the antibacterial ratios increased with the m-ZCS content. The in vitro coagulation evaluation by using activated partial thromboplastin time (APTT) and prothrombin time (PT) revealed that the composites significantly activated the intrinsic and extrinsic pathway of coagulation cascade. In addition, for the animal model of rabbits in ear vein, skin, arterial and liver injuries, the hemostatic time of the composites obviously reduced with the increase of m-ZSC content, in which the composite with 15wt% m-ZCS content (15mZSC) showed remarkable efficacy on bleeding control. The composites could promote the viability of L929 cells, indicating no cytotoxicity of the composites. The results suggested that the m-ZCS/MS composites with excellent hemostatic and antibacterial properties might be a candidate for controlling bleeding and infection.

Macro-mesoporous composites containing PEEK and mesoporous diopside as bone implants: characterization, in vitro mineralization, cytocompatibility, and vascularization potential and osteogenesis in vivo.

Bone implants of polyetheretherketone (PEEK) have become increasingly popular in the orthopedic field but its bioinertness and poor osteogenic properties significantly limit its applications for bone regeneration and osseointegration with host bone. In this study, by incorporation of mesoporous diopside (MD) into the PEEK matrix, macro-mesoporous PEEK/MD (PM) composites as bone implants with interconnected macropores of 300-400 µm were fabricated using the method of cold press-sintering and salt-leaching. The results showed that the compressive strength, porosity and water absorption of the porous PM composites significantly increased with an increase in the MD content. In addition, the incorporation of MD into PEEK obviously enhanced the mineralization ability of the PM composites, indicating good bioactivity. Moreover, the in vitro cell experiments indicated that the macro-mesoporous PM composites significantly promoted the adhesion and proliferation as well as osteogenic differentiation of MC3T3-E1 cells, which depended on the MD content. The results of synchrotron radiation-based micro-computed tomography (SRmCT) and histological analysis revealed that the porous PM composites possessed excellent osteogenic properties in vivo, which were obviously enhanced with an increase in the MD content. Moreover, the immunohistochemistry evaluation of type I collagen (COL I) and vascular endothelial growth factor (VEGF) confirmed that addition of MD into PEEK obviously enhanced the osteogenesis and vascularization potential of the macro-mesoporous PM composites in vivo. The results suggested that the PM composites containing macropores and mesopores as bone implants had great potential for bone repair/substitution.

Osseointegration of nanohydroxyapatite- or nano-calcium silicate-incorporated polyetheretherketone bioactive composites in vivo.

Polyetheretherketone (PEEK) exhibits appropriate biomechanical strength as well as good biocompatibility and stable chemical properties but lacks bioactivity and cannot achieve highly efficient osseointegration after implantation. Incorporating bioceramics into the PEEK matrix is a feasible approach for improving its bioactivity. In this study, nanohydroxyapatite (n-HA) and nano-calcium silicate (n-CS) were separately incorporated into PEEK to prepare n-HA/PEEK and n-CS/PEEK biocomposites, respectively, using a compounding and injection-molding technique, and the in vitro degradation characteristics were evaluated. Discs with a diameter of 8 mm were inserted in 8 mm full-thickness cranial defects in rabbits for 4 and 8 weeks, and implantation of pure PEEK was used as the control. Three-dimensional microcomputed tomography, histological analysis, fluorescence microscopy of new bone formation, and scanning electron microscopy were used to evaluate the osseointegration performance at the bone/implant interface. The results of the in vitro degradation study demonstrated that degradation of n-CS on the surface of n-CS/PEEK could release Ca and Si ions and form a porous structure. In vivo tests revealed that both n-CS/PEEK and n-HA/PEEK promoted osseointegration at the bone/implant interface compared to PEEK, and n-CS/PEEK exhibited higher bone contact ratio and more new bone formation compared with those of n-HA/PEEK, implying that n-CS/PEEK possessed a stronger ability to promote osseointegration. These two PEEK biocomposites are promising materials for the preparation of orthopedic or craniofacial implants.

Influences of mesoporous magnesium silicate on the hydrophilicity, degradability, mineralization and primary cell response to a wheat protein based biocomposite.

A novel bioactive composite based on wheat protein (WP) and mesoporous magnesium silicate (m-MS) with a high specific surface area is presented in this study for potential bone tissue regeneration. Wheat protein (WP) is a type of a biodegradable natural polymer material. The m-MS was prepared by the sol-gel technique, which was incorporated into WP to fabricate m-MS/WP composites. The increasing amount of m-MS improved the surface hydrophilicity of m-MS/WP composites. The results showed that the degradation ratio of the m-MS/WP composites increased with an increase in the m-MS content after it was soaked in a Tris-HCl solution for 12 weeks. Moreover, the m-MS/WP composites with 40 wt% m-MS content (WP40) were able to maintain a suitable pH value over a prolonged soaking time, which might be dependent on the content of the m-MS. The WP40 showed a good apatite formation ability after it was soaked in simulated body fluid (SBF) for 7 days, indicating good bioactivity. Moreover, the WP40 with cytocompatibility stimulated the attachment, proliferation and differentiation of MC3T3-E1 osteoblast cells. Briefly, the results indicated that WP40 had good bioactivity, degradability, cytocompatibility and osteogenesis and might be a new biomaterial for bone regeneration.