The fabrication of hydroxyapatite mineralized hydrogels for bone tissue engineering

Bone is a complex but orderly mineralized tissue with hydroxyapatite(HA)as the inorganic phase and collagen as the organic phase.Inspired by natural bone tissues,HA-mineralized hydrogels have been widely designed and used in bone tissue engineering.HA is majorly utilized for the treatment of bone defects because of its excellent osteoconduction and bone inductivity.Hydrogel is a three-dimensional hydrophilic network structure with similar properties to the extracellular matrix(ECM).The combination of HA and hydrogels produces a new hybrid material that could effectively promote osteointegration and accelerate the healing of bone defects.In this review,the structure and growth of bone and the common strategies used to prepare HA were briefly introduced.Importantly,we discussed the fabrication of HA mineralized hydrogels from simple blending to in situ mineralization.We hope this review can provide a reference for the development of bone repair hydrogels.

Numerical Study of the Biomechanical Behavior of a 3D Printed Polymer Esophageal Stent in the Esophagus by BP Neural Network Algorithm

Esophageal disease is a common disorder of the digestive system that can severely affect the quality of life andprognosis of patients. Esophageal stenting is an effective treatment that has been widely used in clinical practice.However, esophageal stents of different types and parameters have varying adaptability and effectiveness forpatients, and they need to be individually selected according to the patient’s specific situation. The purposeof this study was to provide a reference for clinical doctors to choose suitable esophageal stents. We used 3Dprinting technology to fabricate esophageal stents with different ratios of thermoplastic polyurethane (TPU)/(Poly-ε-caprolactone) PCL polymer, and established an artificial neural network model that could predict the radial forceof esophageal stents based on the content of TPU, PCL and print parameter. We selected three optimal ratios formechanical performance tests and evaluated the biomechanical effects of different ratios of stents on esophagealimplantation, swallowing, and stent migration processes through finite element numerical simulation and in vitrosimulation tests. The results showed that different ratios of polymer stents had different mechanical properties,affecting the effectiveness of stent expansion treatment and the possibility of postoperative complications of stentimplantation.

Three-dimensional kagome structures in a PCL/HA-based hydrogel scaffold to lead slow BMP-2 release for effective bone regeneration

Osteoconductive function is remarkably low in bone disease in the absence of bone tissue surrounding the grafting site,or if the bone tissue is in poor condition.Thus,an effective bone graft in terms of both osteoconductivity and osteoinductivity is required for clinical therapy.Recently,the three-dimensional(3D)kagome structure has been shown to be advantageous for bone tissue regeneration due to its mechanical properties.In this study,a polycaprolactone(PCL)kagome-structure scaffold containing a hyaluronic acid(HA)-based hydrogel was fabricated using a 3D printing technique.The retention capacity of the hydrogel in the scaffold was assessed in vivo with a rat calvaria subcutaneous model for 3 weeks,and the results were compared with those obtained with conventional 3D-printed PCL grid-structure scaffolds containing HA-based hydrogel and bulk-type HA-based hydrogel.The retained hydrogel in the kagome-structure scaffold was further evaluated by in vivo imaging system analysis.To further reinforce the osteoinductivity of the kagome-structure scaffold,a PCL kagome-structure scaffold with bone morphogenetic protein-2(BMP-2)containing HA hydrogel was fabricated and implanted in a calvarial defect model of rabbits for 16 weeks.The bone regeneration characteristics were evaluated with hematoxylin and eosin(H&E),Masson’s trichrome staining,and micro-CT image analysis.

The rat eustachian tube:Anatomical, histological, and radiological features

Purpose: This study investigated the anatomical and histological characteristics of the rat Eustachian tube(E-tube)and the feasibility of Eustachian tubography in a rat model.Materials and methods: Fifteen male Wistar rats were used in this study, and the bilateral E-tubes of each rat were examined. Ten E-tubes were used for anatomical studies, another ten for histological analysis, and the other ten for Eustachian tubography. Five rats were euthanized and decapitated, and ten E-tubes were dissected to describe the anatomy of the E-tube. Ten E-tube specimens obtained from five other rats were sectioned to investigate Etube histology. Eustachian tubography was performed on the bilateral E-tubes of the other five rats using the trans-tympanic approach.Results: The rat E-tubes consisted of bony and membranous parts. Cartilage and bone tissue covered only the bony part. The E-tubes’ mean diameter and overall length were 2.97 mm and 4.96 mm, respectively. The tympanic orifices’ mean diameter was 1.21 mm. The epithelium of E-tubes was mainly composed of pseudostratified ciliated and goblet cells. Eustachian tubography was successfully performed on both sides of the E-tube for each rat.The technical success rate was 100%, the average running time was 4.9 min, and no procedure-related complications occurred. On tubography images, the E-tube, tympanic cavity, and nasopharynx could be identified because of the visualization of bony landmarks.Conclusion: In this study, we described the anatomical and histological features of rat E-tubes. With the aid of these findings, E-tube angiography was successfully performed using a transtympanic approach. These results will facilitate further investigation of E-tube dysfunction.

Preparation of Chitosan-coated Nylon Membranes and their Application as Affinity Membranes

Chitosan-coated nylon membranes which possess a large number of reactive groups of-CH2OH and -NH2 were prepared by coupling chitosan onto the nylon membrane. Then polylysine as ligand was also immobilized onto the composite membranes by 1, 1＇-carbonyl-diimidazole activation to prepare affinity membranes for bilirubin adsorption. The results showed that these membranes exhibited high binding affinity capacities for bilirubin and the adsorption isotherm fitted the Freundlich model well.

Eriocalyxin B Inhibits Adipogenesis in 3T3-L1 Adipocytes by Cell Cycle Arrest

Eriocalyxin B,an ent-Kaurene diterpenoid extracted from a traditional Chinese herb Isodon eriocalyx,has been shown to possess multifunctional activities such as anti-cancer and anti-inflammatory.However,the function and mechanism of the compound in adipocyte differentiation is still unknown.Here we reported that eriocalyxin B blunted adipogenesis remarkably by inhibiting the accumulation of lipid droplets,triglycerides and the expressions of adipogenesis-related factors,including C/EBPβ,C/EBPα,PPARγ,and FABP4.Moreover,we showed that the inhibition might be the consequence of cell cycle being arrested at the G2/M phase during the mitotic clonal expansion of adipocyte differentiation,most likely by suppress-ing mRNAs and proteins of CDK1,CDK2,Cyclin A and Cyclin B1.Overall,we conclude that eriocalyxin B is capable of inhibiting adipocyte differentiation at the early stage through downregulating the proteins involved in cell cycle progression.

Overview of the improvement of the ring-stage survival assay - a novel phenotypic assay for the detection of artemisinin-resistant Plasmodium falciparum

Artemisinin resistance in Plasmodium falciparum threatens the remarkable efficacy of artemisininbased combination therapies worldwide. Thus, greater insight into the resistance mechanism using monitoring tools is essential. The ring-stage survival assay is used for phenotyping artemisinin-resistance or decreased artemisinin sensitivity. Here, we review the progress of this measurement assay and explore its limitations and potential applications.

Availability and safety assessment of infrared neural stimulation at high repetition rate through an implantable optrode

An implantable optrode with micro-thermal detectors was designed to investigate the availability and safety of INS using high repetition rates.Optical auditory brainstem responses(oABRs)were recorded in normal-hearing guinea pigs,and the energy thresholds,pulse durations,and ampli-tudes evoked by the varied stimulus repetitions were analyzed.Stable oABRs could be evoked through INS even as the repetition rate of stimulation reached 19 kHz.The energy threshold of oABRs was elevated,the amplitudes decreased as pulse durations increased and repetition rates were higher,and the latencies were delayed as the pulse durations increased.The temperature variation curves on the site of stimulation significantly increased as the pulse duration increased to 400μs.INS elevated the temperature around the stimulus site area via thermal accumulation during radiation,especially when higher repetition stimuli were used.Our results demonstrate that high repetition infrared stimulations can safely evoke stable and available oABRs in normal-hearing guinea pigs.

Outcomes of different minimally invasive surgical treatments for vertebral compression fractures:An observational study

BACKGROUND Osteoporosis with vertebral compression fractures is increasingly common in the elderly population.Cement augmentation is one of the effective surgical treatments for these patients.Currently,there are several different types of cement augmentation treatments.No studies have compared the safety and efficacy of different cement augmentation types for the treatment of such fractures;thus,we retrospectively compared vertebroplasty,balloon kyphoplasty,and kyphoplasty with SpineJack or an intravertebral expandable pillar.AIM To compare the postoperative safety and efficacy of each surgical intervention in treating vertebral compression fractures.METHODS We retrospectively analyzed 354 patients with acute vertebral compression fractures,defined as signal changes in the T1 weighted magnetic resonance imaging,and randomly divided the patients into five groups.Their visual analog scale scores for pain,kyphotic angle,average body height,rate of cement leakage,and occurrence of adjacent vertebral compression fractures were followed for 1 year.One-way analysis of variance,the post hoc Bonferroni test,and Fisher exact probability test were used for statistical analyses.RESULTS All pain scores significantly improved 12 mo postoperatively;however,there was no significant difference between the groups(P=0.325).Kyphoplasty with SpineJack significantly reduced the kyphotic angle(P=0.028)and restored the height of the vertebral body(P=0.02).The rate of adjacent compression fractures was the highest in the vertebroplasty group,with a statistically significant difference according to the Fisher exact probability test(P=0.02).The treatment with the lowest cement leakage rate cannot be identified because of the small sample size;however,kyphoplasty with SpineJack,an IVEP,and vesselplasty resulted in lower rates of cement leakage than balloon kyphoplasty and vertebroplasty.CONCLUSION Kyphoplasty with SpineJack has good outcomes in kyphotic angle reduction and body height restoration.Vertebroplasty has the highest cement leakage rate and adjacent compression fracture occurrence.

Radial nerve recovery following closed nailing of humeral shaft fractures without radial nerve exploration: A retrospective study

BACKGROUND Radial nerve palsy due to humeral shaft fracture is the most common peripheral nerve injury associated with long bone fractures.An antegrade nailing surgical technique is becoming popular for the fixation of these fractures with minimal invasiveness.We analyzed nerve recovery in patients with humeral shaft fracture and radial nerve palsy treated with humeral nail fixation without nerve exploration.AIM To assess the radial nerve recovery rate and time from humeral shaft fracture with surgical treatment using close nailing.METHODS We retrospectively collected data of patients who underwent undergone surgical nail fixation for humeral shaft fractures between October 1,2016,and March 31,2020.Subsequently,we analyzed the primary or secondary radial nerve palsy recovery rate and radial nerve motor function recovery time.RESULTS The study included 70 patients who underwent surgical treatment for closed-or Gustilo type I open humeral shaft fractures using a nail fixation technique without radial nerve exploration.The patients suffered from primary(n=5)and secondary(n=5)radial nerve palsy.A 100%radial nerve recovery rate was achieved.The mean recovery time was 4.3 mo.CONCLUSION The study results indicate full recovery of radial nerve palsies from humeral shaft fracture using close nailing treatment.Surgeons need not be concerned about the occurrence of permanent nerve palsies.

Glucose detection in a highly scattering medium with diffuse photon-pair density wave

We propose a novel optical method for glucose measurement based on difuse photon-pair density wave(DPPDW)in a multiple scattering medium(MSM)where the light scattering of photon-pair is induced by refractive index mismatch between scatters and phantom solution.Experi-mentally,the DPPDW propagates in MSM via a two frequency laser(TFL)beam wherein highly correlated pairs of linear polarized photons are generated.The reduced scattering coefficientμ2s and absorption coefficientμ2a of DPPDW are measured simultaneously in terms of the amplitude and phase measurements of the detected heterodyne signal under arrangement at different dis-tances between the source and detection fibers in MSM.The results show that the sensitivity of glucose detection via glucose-induced change of reduced scattering coefficient(δμ′2)is 0.049%mM^(-1)in a 1%intralipid solution.In addition,the linear range ofδμ′2s vs glucose concentration implies that this DPPDW method can be used to monitor glucose concentration continuously and noninvasively subcutaneously.

Correction to: Eriocalyxin B Inhibits Adipogenesis in 3T3-L1 Adipocytes by Cell Cycle Arrest

In the original publication of this article,we found an error under the section“Introduction”.The first sentence of the fourth paragraph appears incorrectly.The corrected sentence is given below.Eriocalyxin B,isolated and identified in 1982[1],is the major component in Chinese plant Isodon eriocalyx(Dunn.)Hara(family Lamiaceae)showing many pharmacological activities,such as inhibiting inflammatory response,regulat-ing immune cell differentiation,inhibiting tumor cells prolif-eration,causing cell cycle arrest affecting angiogenesis and promoting cancer cells apoptosis.

Evaluating Pressure Ulcer Development in Wheelchair-Bound Population Using Sitting Posture Identification

Pressure ulcers are a common complication among wheelchair-bound population. They are resulted from prolonged exposure to high pressure, which restricts blood flow and leads to tissue necrosis. In this work, a continuous pressure monitoring system is developed for pressure ulcer prevention. The system consists of 64 pressure sensors on a 40×50 cm2 sheet. Real time pressure data and corresponding maps are displayed on a computer simultaneously. Furthermore, a posture detection procedure is proposed for sitting posture identification. Having information about the patient’s postural history, caregivers are capable of a better decision about repositioning and treating the patient.

Study on Chitosan-Lactate Sponges with Oriented Pores as Potential Wound Dressing

The motive of this work was to provide an inexpensive potential wound dressing using chitosan lactate (LCH) which was synthesized by the grafting lactic acid onto the amino groups in chitosan (CH) without a catalyst. The XRD and 13CNMR results demonstrated that the grafting by lactic acid took place at C2 site in CH, leading to the destruction of the regularity of the packing in the original CH chains and formation of the amorphous CH salts. The unique device was developed in our experiments which could yield an approximately vertical thermal gradient, forming the uniformly vertical pores in LCH sponges. TEM images revealed that both TBA and LCH concentration affected the micro-structure of the sponges, although they worked via different mechanisms. In the water suction experiments, the capillary coefficient Ks was introduced to evaluate the structure-function relationship. The positive or negative influence of LCH, TBA and porosity on Ks clearly stood out when their relationships were plotted graphically. The in vitro biocompatibility of LCH sponges was evaluated. The results obtained indicated that LCH sponges exhibited bio-safety at lower concentration (25%) during short time (1 day). However, highly concentrated extraction showed a serious toxic effect on both HSF and HaCaT cells. The release kinetics for hydrophilic and hydrophobic drugs with different formulation sponges was determined in in vitro release experiments. The contribution of the drug diffusion, matrix erosion and microstructure of porous materials must be taken into account on the release mechanism. The method and the structure described in present paper provided a starting point for the design and fabrication of a family of chitosan derivatives based porous materials with potentially broad

Preparation and functional study of pH-sensitive amorphous calcium phosphate nanocarriers

Recently,multifunctional nanoparticles have shown great prospects in cancer treatment,which have the ability to simultaneously deliver the drug,image and target tumor cells.In this paper,we designed a luminescent nanoparticles platform based on hydrothermal hyaluronic acid/amorphous calcium phosphate(HA-FCNs/ACP)with multifunctional properties for drug delivery,bio-imaging,and targeting treatment.HA-FCNs/ACP shows an ability to load curcumin(Cur)with pH-sensitive responsive drug release behavior and excellent biocompatibility.HA-FCNs/ACP dispersed in the cytoplasm through the overexpressed CD44 receptor that is actively targeted into human lung cancer cells(A549 cells).Meanwhile,the viability of A549 cells was significantly inhibited in vitro.The prepared HA-FCNs and HA-FCNs/ACP both exhibit excellent targeted bioimaging performance on cancer cells.Hence,the as-prepared nanoparticles have promising applications in treating tumor disease.

A comprehensive review on surface modifications of black phosphorus using biological macromolecules

Black phosphorus(BP),a novel two dimensional material,exhibits remarkable photoelectric characteristics,ultrahigh photothermal conversion efficiency,substantial specific surface area,high carrier mobility,and tunable band gap properties.These attributes have positioned it as a promising candidate in domains such as energy,medicine,and the environment.Nonetheless,its vulnerability to light,oxygen,and water can lead to rapid degradation and loss of crystallinity,thereby limiting its synthesis,preservation,and application.Moreover,BP has demonstrated cytotoxic tendencies,substantially constraining its viability in the realm of biomedicine.Consequently,the imperative for surface modification arises to bolster its stability and biocompatibility,while concurrently expanding its utility spectrum.Biological macromolecules,integral components of living organisms,proffer innate advantages over chemical agents and polymers for the purpose of the BP modifications.This review comprehensively surveys the advancements in utilizing biological macromolecules for the modifications of BP.In doing so,it aims to pave the way for enhanced stability,biocompatibility,and diversified applications of this material.

Tunning the bandgap of MnO_(2)homojunction by building active high-index facet to achieve rapid electron transfer for enhanced photocatalytic sterilization

Photocatalysis has been a research hotspot in recent years,and the design and modification of photocat-alysts have been the key points.Common methods for designing photocatalysts,including constructing heterojunctions and homojunctions,have been developed on the basis of heterojunctions.In this study,two homojunctions of manganese dioxide(MnO_(2)),including a high-index crystal plane homojunction and a general homojunction,are prepared using a stepwise hydrothermal method.Using a capping agent,the high-index crystal surface of the MnO_(2)is exposed.It is found that the electron transport efficiency be-tween the two components of the homojunction with high-index planes is higher and the adsorption capacity of the oxygen is stronger,which leads to higher photocatalytic efficiency.In addition,the newly designed high-index homojunction is used for the treatment of bacterial infections,and it kills Staphy-lococcus aureus(S.aureus)and Escherichia coli(E.coli)at rates of 99.95%±0.04%and 99.31%±0.25%,respectively.It also has excellent therapeutic effects on mouse wounds,which implies superb practical application value.This work provides a new strategy for the improved design of homojunctions and the application of photocatalytic materials.

Double-crosslinked PNIPAM-based hydrogel dressings with adjustable adhesion and contractility

Rapid post-wound closure is necessary to avoid wound infection and promote scar-free healing when skin trauma occurs.In this study,new types of hydrogel dressings with adjustable contractility were fabricated based on N-isopropyl acrylamide/sodium alginate/graphene oxide(P/SA/GO).Then,the chitosan(CS)solution was used as a bridging polymer to achieve tissue adhesion to the hydrogel.The results show that the hydrogel based on poly(N-isopropyl acrylamide)(PNIPAM)not only has the ability to self-shrink but also can adjust the rate of shrinkage through near-infrared thermal stimulation.At the same time,high adhesion strength(7.86±1.22 kPa)between the tissue and the dressing is achieved through the introduction of bridging polymers(CS),and the coating area of the bridging polymer can be adjusted to achieve regional adhesion.The mouse total skin defects experiments have shown that sutures-free wound closure in the early stages of wound healing could be obtained by adjusting the material temperature.Besides,the dressings can promote scar-free wound healing by reducing inflammatory cell infiltration and collagen deposition.These results indicate that double-crosslinked PNIPAM-based hydrogel dressings with adjustable adhesion and contractility proposed in this study provide a candidate material for achieving trackless wound healing.

Recent advances of medical polyhydroxyalkanoates in musculoskeletal system

Infection and rejection in musculoskeletal trauma often pose challenges for natural healing,prompting the exploration of biomimetic organ and tissue transplantation as a common alternative solution.Polyhydroxyalkanoates(PHAs)are a large family of biopolyesters synthesised in microorganism,demonstrating excellent biocompatibility and controllable biodegradability for tissue remodelling and drug delivery.With different monomer-combination and polymer-types,multi-mechanical properties of PHAs making them have great application prospects in medical devices with stretching,compression,twist in long time,especially in musculoskeletal tissue engineering.This review systematically summarises the applications of PHAs in multiple tissues repair and drug release,encompassing areas such as bone,cartilage,joint,skin,tendons,ligament,cardiovascular tissue,and nervous tissue.It also discusses challenges encountered in their application,including high production costs,potential cytotoxicity,and uncontrollable particle size distribution.In conclusion,PHAs offer a compelling avenue for musculoskeletal system applications,striking a balance between biocompatibility and mechanical performance.However,addressing challenges in their production and application requires further research to unleash their full potential in tackling the complexities of musculoskeletal regeneration.

Double crosslinked biomimetic composite hydrogels containing topographical cues and WAY-316606 induce neural tissue regeneration and functional recovery after spinal cord injury

Spinal cord injury(SCI)is an overwhelming and incurable disabling condition,for which increasing forms of multifunctional biomaterials are being tested,but with limited progression.The promising material should be able to fill SCI-induced cavities and direct the growth of new neurons,with effective drug loading to improve the local micro-organism environment and promote neural tissue regeneration.In this study,a double crosslinked biomimetic composite hydrogel comprised of acellularized spinal cord matrix(ASCM)and gelatin-acrylated-β-cyclodextrin-polyethene glycol diacrylate(designated G-CD-PEGDA)hydrogel,loaded with WAY-316606 to activate canonical Wnt/β-catenin signaling,and reinforced by a bundle of three-dimensionally printed aligned polycaprolactone(PCL)microfibers,was constructed.The G-CD-PEGDA component endowed the composite hydrogel with a dynamic structure with a self-healing capability which enabled cell migration,while the ASCM component promoted neural cell affinity and proliferation.The diffusion of WAY-316606 could recruit endogenous neural stem cells and improve neuronal differentiation.The aligned PCL microfibers guided neurite elongation in the longitudinal direction.Animal behavior studies further showed that the composite hydrogel could significantly recover the motor function of rats after SCI.This study provides a proficient approach to produce a multifunctional system with desirable physiological,chemical,and topographical cues for treating patients with SCI.