Preparation of monodisperse microspheres by electrospray and their biomedical applications / 国际生物医学工程杂志

Electrospray technology is a method to prepare microspheres by electrostatic force. Electrospray technology has the advantages of simple operation and mild reaction conditions. The polymer microspheres prepared by electrospray technology have uniform morphology and good monodispersity, which is a new and promising method. In this paper, the devices and principles of electrospray technology, the factors affecting the morphology and particle size of the prepared polymer microspheres by the electrospray process, and the types of polymer solutions commonly used in electrospray technology were described, and the applications of electrospray technology for drug delivery, loaded nanoparticles, cell therapy, and bioactive substance delivery were reviewed. It can be concluded that electrospray technology has a broad application prospect and potential application value.

Progress of research on chitosan-based microspheres in oral tissue lesions / 口腔医学

@#Chitosan-based microspheres use chitosan as the main material to obtain particles with special structures through microsphere processing technology. They have the ability of slow and controlled release of drugs and the role of scaffolding, which have great application prospect in stomatology, but the application of chitosan-based microspheres is still in the research stage and has not yet been applied in clinical practice. This article reviews progress of domestic and foreign research on chitosan-based microspheres, in aspects of treatment of oral and jawbone tissue defects, periodontal diseases, dental pulp diseases and nerve tissue injury, in order to provide reference for follow-up research.

Leukotriene B4 Loaded in Microspheres Inhibits Osteoclast Differentiation and Activation

Abstract To investigate osteoclast formation in vivo and if leukotriene B4 (LTB4) loaded in microspheres (MS) could be used as a therapeutical strategy to promote a sustained delivery of the mediator and prevent osteoclast differentiation. Methods: In vivo, apical periodontitis was induced in mice to investigate osteoclast differentiation and signaling in absence of 5-lipoxygenase (5-LO). In vitro, LTB4-MS were prepared using an oil-in-water emulsion solvent extraction-evaporation process. Characterization and efficiency of LTB4 encapsulation were investigated. J774A.1 macrophages were cultured in the presence of monocyte colony-stimulating factor (M-CSF) and ligand for receptor activator of nuclear factor kappa B (RANKL) and then stimulated with LTB4-MS. Cytotoxicity, in vitro MS-LTB4 uptake, osteoclast formation and gene expression were measured. Results: We found that 5-LO negatively regulates osteoclastic formation in vivo during apical periodontitis development. In vitro, LTB4-MS were up-taken by macrophages and were not cytotoxic to the cells. LTB4-MS inhibited osteoclast formation and the synthesis of osteoclastogenic genes Acp5, Mmp9, Calcr and Ctsk. LTB4-MS inhibited differentiation of macrophages into an osteoclastic phenotype and cell activation under M-CSF and RANKL stimulus.

Resumo O objetivo deste trabalho foi Investigar a formação de osteoclastos in vivo e se o leucotrieno B4 (LTB4) incorporado em microesferas (MS) poderia ser usado como estratégia terapêutica para promover uma entrega sustentada do mediador e prevenir a diferenciação dos osteoclastos. Métodos: In vivo, a periodontite apical foi induzida em camundongos para investigar a diferenciação e sinalização de osteoclastos na ausência de 5-lipoxigenase (5-LO). In vitro, LTB4-MS foi preparado usando um processo de evaporação e extração de solvente de emulsão de óleo em água. A caracterização e a eficiência do encapsulamento do LTB4 foram investigadas. Macrófagos J774A.1 foram cultivados na presença de fator estimulador de colônia de monócitos (M-CSF) e ligante para o receptor ativador do fator nuclear kappa B (RANKL) e, então, estimulados com LTB4-MS. Citotoxicidade, captação in vitro de MS-LTB4, formação de osteoclastos e expressão gênica foram avaliadas. Resultados: A via 5-LO regula negativamente a formação de osteoclastos in vivo durante o desenvolvimento da periodontite apical. In vitro, LTB4-MS foram fagocitadas pelos macrófagos e não foram citotóxicos para as células. LTB4-MS inibiu a formação de osteoclastos e a síntese dos genes pró-osteoclastogênicos Acp5, Mmp9, Calcr e Ctsk. Conclusões: LTB4-MS inibiu a diferenciação de macrófagos em um fenótipo osteoclástico e a ativação celular sob estímulo de M-CSF e RANKL.

HYDROTHERMAL SYNTHESIS OF SPHERE-LIKE ZINC COBALTITE FOR ENERGY STORAGE DEVICES

The electrochemical performance of zinc cobaltite–based nano/micromaterial depends on its shape and morphology. Here we report on the electrochemical performance of zinc cobaltite (ZnCo O ) material synthesized via a facile 2 4 hydrothermal method. The synthesized material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) analysis. It was found to be a single-phase zinc cobaltite material with a cubic spinel crystal structure. The electrochemical performance of the synthesized zinc cobaltite microstructure material was evaluated by cyclic voltammetry, cyclic chronopotentiometry and electrochemical impedance -1 -1 spectroscopy. The zinc cobaltite microspheres material displayed a high specific capacitance of 600.37 F g at a current density of 1 A g . Such electrochemical performance may qualify the zinc cobaltite microspheres material as a potential electroactive material in supercapacitors.

Accelerated stability test of sustained-release thienorphine loaded microspheres for injection / 药学学报

In order to meet the clinical needs of long-acting sustained-release thienorphine, injectable thienorphine loaded microspheres were developed, and the accelerated stability study was carried out to explore the suitable storage and transportation conditions of the microspheres. Using poly(lactic-co-glycolic acid) (PLGA) as carrier material, 3 batches of microspheres were prepared in pilot scale with emulsion solvent evaporation method. By investigating the in vitro release of thienorphine loaded microspheres at 37, 45, 52, and 60 ℃, and applying the Arrhenius equation, the linear relationship between the release rate constant (lgk) and the temperature (1/T) was established to obtain the equation: lgk = -8.073/T + 24.35 (R2 = 0.985 3), which showed that the release of microspheres at high temperature can be used to predict the release in vitro at 37 ℃, and 52.0 ± 0.5 ℃ was selected as the accelerated release condition in vitro. The quality research methods were established to investigate the changes of critical quality attributes such as microsphere morphology, drug loading, particle size and distribution, polymer molecular weight, and the related substances under accelerated conditions. The difference factor f1 and similarity factor f2 were used to assess the similarity of release behavior under accelerated conditions. The results showed that under the accelerated experimental conditions of 25 ± 2 ℃ and relative humidity (RH) 60% ± 5%, the critical quality attributes of injectable thienorphine loaded microspheres had no significant change in 6 months, suggesting that the long-term storage condition could be 5 ± 3 ℃.

Development of a method for determination of progesterone sustained-release formulation in Beagle dog plasma and its pharmacokinetic study / 药学学报

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to determine the plasma concentration of progesterone in Beagle dogs, and apply it to the study of the pharmacokinetics of progesterone sustained-release formulation in Beagle dogs. The plasma samples were processed by protein precipitation method and megestrol acetate was used as an internal standard (IS). The quantitation analysis was performed using multiple-reaction monitoring (MRM) mode at the specific ion transitions of m/z 315.2→97.0 for progesterone and m/z 385.2→267.1 for megestrol acetate (IS) under the positive ion condition. Male Beagle dogs were injected intramuscularly with progesterone sustained-release microspheres and the plasma samples were collected at different time points after administration. The relevant pharmacokinetic parameters were calculated by WinNonlin 8.1 software. A good linearity over the range of 0.1-500.0 ng·mL-1 was yielded by this method. The intra- and inter-day precision (RSD) were all less than 13.25% and the accuracy (RE) was within 8.92%. Stability test showed that progesterone in dog plasma was stable at room temperature for 12 h, up to 60 days at -20 ℃ and after three cycles of freeze-thaw. The recovery of it ranged from 71.43%-77.97%. After intramuscular injection of progesterone sustained-release microspheres in Beagle dogs, tmax was 19.00 ± 25.36 h, Cmax was 137.72 ± 11.59 ng·mL-1, t1/2 was 83.83 ± 26.43 h. The drug was released continuously in vivo and in a continuous absorption process for many times with good sustained-release effect. The method developed in this study is sensitive, rapid and stable. It is suitable for the determination of progesterone plasma concentration in Beagle dogs, and can be applied to the preclinical pharmacokinetic study of progesterone-related formulations. The animal experiment scheme of this study was approved by the Animal Ethics Committee of the Academy of Military Medical Sciences.

Preparation of magnetic lidocaine microsphere and effects on sciatic nerve block in rabbits / 中华麻醉学杂志

Objective:To develop a novel sustained-release local anesthetic microspheres and evaluate the effects on sciatic nerve block in rabbits.Methods:The magnetic lidocaine microspheres were prepared by W 1/O/W 2 compound emulsion method, investigating their external morphology, measuring the magnetic response characteristics by the VSM and draw the hysteresis loop.The encapsulation efficiency and drug-loading rate were calculated, and the cumulative release curves in vitro were drawn.Fifteen healthy rabbits (half male and half female), aged 5-6 months, weighing 3.0-3.5 kg, were selected for sciatic nerve block and divided into 3 groups ( n=5 each) using a random number table method: magnetic response lidocaine microspheres group (PL group), normal saline control group (C group) and lidocaine group (L group). Magnetic response lidocaine microsphere buffer 2 ml, normal saline 2 ml and 2% lidocaine 2 ml were injected around the rabbit sciatic nerve through a catheter in PL, C and L groups, respectively.The applied magnetic field was withdrawn at 60 h after injection.Before injection (T 0) and at 30 min and 2 , 8, 16, 24, 48, 60, 62 and 64 h after injection (T 1-9), the compound action potentials and conduction velocities of bilateral sciatic nerve trunks were measured, and block was assessed using toe reflex score and modified Tarlov score. Results:The magnetic lidocaine microspheres were brown in color and observed as monodisperse, regular spheres with a diameter of (9±3) μm, an encapsulation rate of 46.18%, a drug loading of 6.02%, and a superparamagnetic release rate of 97% in vitro at 60 h. The hysteresis loop passed through the origin and no hysteresis occurred with the absence of an external magnetic field.Compared with C group, the action potentials and conduction velocities of the sciatic nerve, toe reflex score and modified Tarlov score were significantly decreased at T 1-T 8 in PL group ( P<0.05). Compared with L group, the action potentials and conduction velocities of the sciatic nerve were significantly increased at T 1, the action potential was decreased at T 2-T 8, the conduction velocity was decreased at T 3-T 8, the toe reflex score was increased at T 1 and decreased at T 3-T 8, and the modified Tarlov score was increased at T 1 and T 2 and decreased at T 3-T 8 in PL group ( P<0.05). Conclusions:Magnetic response lidocaine microsphere is successfully developed with good magnetic responsiveness and release and can prolong the sciatic nerve block time in rabbits.

Application and research progress of in situ gel for local treatment of periodontitis / 中国药科大学学报

@#Recently, in situ gel has been widely used as a local delivery system for periodontitis treatment because of its lesion injectability, local drug depot function, and drug sustained-release effect.Different therapeutic purposes can be achieved by loading different types of drugs such as antibiotics, bioactive factors, etc.In this review, different types of in situ gel with temperature-sensitive, ion-sensitive, pH-sensitive and solvent-exchanged characteristics were introduced for their applications and limitations in the delivery of drug for periodontitis;and the elimination of periodontal inflammation, periodontal tissue repair and the long-term role after loading microsphere achieved by the in situ gel system were also reviewed.

Application of percutaneous transluminal septal branch microsphere embolization in the treatment of hypertrophic obstructive cardiomyopathy / 中华急诊医学杂志

Objective:To compare the clinical efficacy and safety of percutaneous transluminal septal branch anhydrous alcohol ablation (PTSAAA) and percutaneous transluminal septal branch microsphere embolization (PTSBME) in the treatment of patients with symptomatic hypertrophic obstructive cardiomyopathy.Methods:The clinical data of 55 patients with symptomatic hypertrophic obstructive cardiomyopathy treated by PTSAAA and PTSBME were retrospectively analyzed, among whom 27 were treated with PTSAAA and 28 with PTSBME. The changes of postoperative indicators of the two groups of patients were compared, including the improvement degree of symptoms [shortness of breath after activity (cardiac function NYHA classification), chest tightness, chest pain (angina CCS classification) and amaurosis, the decrease of left ventricular outflow tract pressure gradient (LVOTPG)], the ventricular septum thickness shown by color Doppler echocardiography, the incidences of complications at postoperative month 6 and 12, and the incidences of cardiovascular events at follow-up month 12. LSD- t, χ 2 or Fisher exact probability methods were used to compare the differences of indicators between the two groups. Results:Compared to the relative indicators before operation, there were significant differences in shortness of breath after activity, chest pain and amaurosis, LVOTPG, ventricular septum thickness, the incidences of complications at postoperative month 6 and 12 and the incidences of cardiovascular events at follow-up month 12 in both the PTSAAA group and PTSBME group ( P<0.05). The PTSBME group was not inferior to the PTSAAA group in the improvement degree of amaurosis, cardiac function NYHA classification and angina CCS classification and left ventricular ejection fraction (LVEF) at postoperative month 6 and 12 ( P>0.05) as well as in the LVOTPG decrease and the ventricular septum thickness at postoperative month 6 [(16.8±7.5) mmHg vs (15.8±7.3) mmHg, (19.8±4.9) mm vs (17.4±4.1) mm, P>0.05], but was superior to the PTSAAA group in the LVOTPG decrease and the ventricular septum thickness at postoperative month 12 [(15.2±6.7) mmHg vs (9.8±5.4) mmHg, (18.4±5.1) mm vs (12.2±3.2) mm, P<0.05]. There were statistical significances in the incidences of cardiovascular events and third degree atrio-ventricular block and nosocomial mortality between the two groups (6 vs 1; 5 vs 0, P<0.05), and the PTSBME group was superior to the PTSAAA group in safety. Conclusion:PTSBME may be a safe and effective method for the management of patients with symptomatic hypertrophic obstructive cardiomyopathy.

Immobilization of lactase on magnetic chitosan microspheres and its effect on enzymatic properties / 中国组织工程研究

BACKGROUND: The free enzyme has the problems of poor stability and inability to be reused during application. Using magnetic polymer microspheres as the carrier of the binding enzyme to prepare immobilized enzyme can maintain the natural activity of the enzyme, and can be reused, but also provide convenient conditions for automatic production management. OBJECTIVE: Magnetic chitosan microspheres as carrier of binding enzyme were used to prepare the immobilized lactase, which is easy to recycle, can be reused, and has high enzyme activity and stability. METHODS: By inputting a certain amount of magnetic chitosan microspheres into the phosphoric acid buffer for swelling for 2 hours, the swelling magnetic chitosan microspheres were collected with a magnet and added to a certain concentration of lactase phosphate buffer. They were shocked in a constant temperature shaker for 1 hour and preserved in refrigerator at 4 °C. The microspheres were precipitated with a magnet to pour out the supernatant. After full washing with buffer solution, the immobilized lactase was obtained. The properties of the magnetic microspheres (the amount of glutaraldehyde used in the preparation of microspheres was 2, 4, 6, 8, 10, 12, 14 mL), the amount of enzymes (0.5, 1, 1.5, 2 g/L) added, the pH (6.4, 6.8, 7.0, 7.2) of the buffer, and the immobilization time (1, 2, 5, 10, 15, 20 hours) were tested to determine the optimal immobilization conditions. RESULTS AND CONCLUSION: (1) The optimum conditions for immobilized lactose with magnetic chitosan microspheres were as follows: magnetic chitosan microspheres prepared with 10 mL of glutaraldehyde were selected as the immobilized carrier of lactase. The amount of enzyme added was 0.3 g/L, pH 7.0 and the immobilization time was 5 hours. (2) Compared with the free enzyme, immobilized lactase showed a wider range of reaction temperature and pH value. (3) The ability of immobilized enzyme binding substrate was enhanced. (4) After repeated use of the immobilized enzyme five times, the enzyme activity remained 65%. (5) The storage stability of lactase was also improved after immobilization.

Establishment and functional in vitro characteristics of three-dimensional collagen HepaRG microsphere / 中国组织工程研究

BACKGROUND: Some recent studies have shown that the three-dimensional (3D) model of HepaRG cells can better mimic the in vivo microenvironment and show better liver differentiation and function compared with two-dimensional culture. OBJECTIVE: HepaRG was selected to prepare 3D collagen microspheres, and the adaptive culture and functional expression of cells in the collagen microspheres were evaluated. METHODS: Collagen hydrogel was used as the scaffold for 3D HepaRG and HepG2 microspheres. Stable cell spheres were formed. HepaRG microspheres, HepG2 microspheres, HepaRG two-dimensional culture and HepG2 two-dimensional culture were used as controls. At 1, 6, and 12 days of culture, cell survival was detected by the Live/Dead assay staining. After 1, 6, 12, and 16 days of culture, the urea synthesis and CYP3A4 secretion of the supernatant were detected in each group. After 12 days of culture, relative expression of CYP3A4, CYP1A2, UGT1A1, and CPS1 mRNA was detected by qPCR. The expression levels of hepatocyte marker albumin and CYP3A4 protein were determined using western blot assay. RESULTS AND CONCLUSION: (1) In 12 days of culture, Live/Dead assay staining showed that the cell viability in the 3D collagen microsphere was well-maintained and the amount of central necrotic cells was small, with high cell viability. In the 3D collagen microsphere, especially HepaRG cells, multiple cellular clusters formed and adjacent clusters were connected closely, which created a cross-linked structure. (2) After 1, 6, and 12 days of culture, the urea content of HepaRG 3D collagen microspheres was higher than that of HepaRG two-dimensional culture (P < 0.05). After 1, 6, 12, and 16 days of culture, the urea content of HepG2 3D collagen microspheres was higher than that of HepG2 two-dimensional culture (P < 0.05). After 1, 6, and 12 days of culture, the secretion of CYP3A4 in HepaRG 3D collagen microspheres was higher than that in HepaRG two-dimensional culture (P < 0.05). After 6 and 12 days of culture, the secretion of CYP3A4 in HepG2 3D collagen microspheres was higher than that in HepG2 two-dimensional culture (P < 0.05). (3) The relative expression of CYP3A4, CYP1A2, UGT1A1, and CPS1 mRNA in HepaRG 3D collagen microspheres was higher than that in HepaRG two-dimensional cells (P < 0.05), and the relative expression of CYP1A2 in HepG2 3D collagen microspheres was higher than that in HepG2 two-dimensional culture (P < 0.05). (4) The expression levels of albumin and CYP3A4 protein in HepaRG 3D collagen microspheres were higher than those of HepG2 3D collagen microspheres, ordinary microspheres, and two-dimensional culture (P < 0.05). (5) These results indicated the high-level expression of hepatocyte functions in 3D collagen HepaRG microsphere, which could be taken as a reference in drug metabolism evaluation in vitro and tissue engineering application.

Chinese expert consensus on selective internal radiation therapy with yttrium-90 for primary and metastatic hepatocellular carcinoma / 中华肝脏病杂志

Liver malignant tumors are one of the most common causes of cancer-related deaths in China. Selective internal yttrium-90 radioembolization therapy ((90)Y-SIRT) is a kind of promising local minimally invasive method, and its effectiveness and safety has been confirmed in clinical application over the past two decades. Moreover, it has been approved by the U.S. National Comprehensive Cancer Network and other international guidelines for the topical treatment of patients with liver malignancies. Taking into account the complexity of the (90)Y-SIRT and the need for multidisciplinary collaboration to improve the safety and success rate of treatment, the Nuclear Medicine Expert Committee of the Chinese society of Clinical Oncology, along with Beijing Nuclear Medicine Quality Control and Improvement Center invited experts from surgical oncology, interventional medicine, nuclear medicine, and other related fields to discuss and form a consensus on the clinical diagnosis, treatment and management, which mainly included definition, indications and contraindications, treatment procedures, postoperative follow-up, adverse reactions and complications, radiation safety management, etc. Herein, we provide the reference guidance to establish (90)Y-SIRT standardized management and treatment system various units for relevant practitioners.

Research progress of in vitro-in vivo correlation of injectable polylactide-polyglycolide microspheres / 药学学报

As a depot drug delivery system, injectable polylactide-polyglycolide (PLGA) sustained-release microspheres have been successfully used to treat many diseases since the first microsphere product Lupron depot was approved for marketing in the United States in 1989. It has the ability of long-term release in the body for several days to several months, which can not only reduce the times of administration, but also reduce the drug blood concentration fluctuations, significantly improve the safety and patient compliance. In vitro-in vivo correlation (IVIVC) makes the development of microspheres more possible. It can describe the dynamic information of drug release in vivo through the in vitro release behavior of microspheres, and can reduce the workload of each stage and shorten the time span while characterizing the performance of microspheres. IVIVC can provide guidance or support for drug development, production changes, supervision and management. This article summarizes the release mechanism of injectable PLGA sustained-release microspheres, common measurement methods and theories of in vitro and in vivo release. And we also focus on the establishment and application of IVIVC, especially A level IVIVC in the field of microsphere preparations, to provide a reference for further study on in vitro-in vivo correlation of microspheres.

Formulation and optimization of Enalapril Maleate-loaded floating microsphere using Box–Behnken design: in vitro study

The objective was to prepare an Enalapril Maleate (EnM)-loaded floating microsphere with minimum particle size,maximum drug loading, and drug entrapment efficiency. Formulations were prepared by varying drug-to-polymerratio (A), solvent ratio (B), and stirring time (C). The solvent evaporation method was used to prepare the microsphere.“Box–Behnken’s design” (3 factors × 3 levels) was utilized for optimization. The independent variables were polymerto-drug ratio (A), solvent ratio (B), and stirring time (C), while particle size (R1), drug loading (R2), and entrapmentefficiency (R3) were considered as dependent variables. EnM-loaded alcohol microsphere (Formulation-A) wasprepared and optimized. Both Formulation-A and EnM-loaded acetonitrile microspheres (Formulation-B) weresubjected to morphological, micrometric, characterization, and in vitro release studies. The particle size, drug loading,and entrapment efficiency of Formulation-A and Formulation-B were 143 ± 27.75 µm, 37.31% ± 5.73%, and 76.89%± 4.97%, and 158.13 ± 25.1 µm, 40.13% ± 6.12%, and 99.19% ± 1.14%, respectively. The cumulative drug releasesof Formulation-A and Formulation-B were 90.52% ± 4.11% and 86.23% ± 3.81%, respectively. Both formulationsfollowed the Higuchi model of drug release. EnM-floating microsphere was effectively prepared and both formulationsshowed excellent continuous release properties for more than 12 hours.

Formulation And Evaluation Of Racecadotril Mucoadhesive Microspheres

Objective: To develop and evaluate the mucoadhesive microsphere using combinations of natural polymers chitosan and xanthan gum for sustained release. Methods: In the present work mucoadhesive microspheres were prepared by using natural polymers like chitosan and xanthan gum by using the emulsion chemical cross-linking method. Chemical cross-linking was done by using glutaraldehyde. The 22 factorial design was employed to show the effect of cross-linking agent and processing factor-like stirring and speed. Prepared microspheres were evaluated for their particle size, surface morphology, drug entrapment efficiency, in vitro drug release, swelling index, and mucoadhesive strength. Results: The size of microspheres of factorial batches were in the range of 26-46 µm. The swelling index was showed in the range of 1.51-1.66 percentage. The equation of multiple regression revealed that there was significant interaction among factors. The glutaraldehyde concentration had a positive effect on % entrapment efficiency, % cumulative drug release and % mucoadhesion. Stirring speed showed a negative impact on % entrapment efficiency, % cumulative drug release and % mucoadhesion. The interactive effect of glutaraldehyde concentration and the stirring speed was found to be positive for % entrapment efficiency and % cumulative drug release. In vitro drug release study of optimized formulation F2 show 96 % of drug release with 6 h indicating sustained release behavior with diffusion mechanism. The SEM image of the optimized batch was spherical with a porous surface. Conclusion: The results obtained in this research work indicated that a promising potential of chitosan and xanthan gum combination for the preparation of the mucoadhesive microsphere of Racecadotril.

Preparation and in vitro release profiling of PLGA microspheres containing BSA as a model protein

Conventional drug formulations are incapable of adequate delivery of proteins and peptides for therapeutic purposes. As these molecules have very short biological half-life, multiple dosing is required to achieve the desirable therapeutic effects. Microspheres are able to encapsulate proteins and peptide in the polymeric matrix while protecting them from enzymatic degradation. In this study Bovine Serum Albumin (BSA) matrix type microspheres were fabricated using Polylactide-co-glycolide (PLGA) by double emulsion solvent evaporation method. The effects of variables such as homogenizer speed, molecular weight of polymer and the effect of pH of the water phases, were investigated against factors such as drug loading, encapsulation efficiency, morphology, size, drug distribution and release profile of the microspheres. Results, suggested that an increase in homogenization speed leads to a decrease in microsphere size. The increase in homogenization speed also caused a significant effect on the release profile only when higher molecular weight of polymer had been used.. The pH change of the internal aqueous phase led to modification of surface morphology of spheres to a porous structure that significantly increased the total amount of released protein. Integrity of protein structure was intact as shown by SDS-PAGE. According to the results, it can be concluded that we achieved a reproducible method regarding controlled protein delivery for different sizes of particles.

Preparation and characterization of magnetic chitosan microspheres / 中国组织工程研究

BACKGROUND: As carriers of enzymes, cells and drugs, magnetic polymer microspheres have been widely used in the fields of bioengineering, cytology, and biomedicine. OBJECTIVE: To prepare the magnetic polymer microspheres characterized by small particle size, good dispersion, strong magnetic response, safety, and non-toxicity. METHODS: Magnetic chitosan microspheres were prepared by reverse phase suspension process using Fe3O4 as core, paraffin as dispersed medium, Span-80 as emulsifier, and glutaraldehyde as cross-linking agent. The effects of factors including crosslinking time (0, 20, 40, 60, 80, 100, 120, 150 and 180 minutes), reaction temperature (20→50 °C, 30→60 °C, 40→70 °C, 50→80 °C), the concentration of chitosan (0. 01, 0. 02, 0. 03, 0. 04, 0. 05 g/mL), Fe3O4/chitosan mass ratio (1:1, 1:2, 1:3, 1:4), the amount of glutaraldehyde (8-10 mL), the amount of liquid paraffin (40, 60, 80, 100 mL), and stirring speed (0-2 000 r/min) on the properties of magnetic chitosan microspheres. The morphology, particle size, dispersion, and magnetic responsiveness of magnetic chitosan microspheres were characterized. RESULTS AND CONCLUSION: The optimum conditions for preparing magnetic chitosan microspheres were as follows: Starting with glutaraldehyde as crosslinking agent, the reaction was performed at 40 °C for 1 hour and then at 70 °C for 120 minutes. The concentration of chitosan was 0. 02 g/mL, the mass ratio of Fe3O4/chitosan was 1∶2, the dosage of liquid paraffin was 80 mL, the stirring speed was 1 200 r/min, and the dosage of glutaraldehyde was 8-10 mL. Magnetic chitosan microspheres had strong magnetic properties under the applied magnetic field and had good suspension stability in the natural state. The Fe3O4/chitosan composites were spherical, and the nanoparticles were encapsulated in the microspheres, which were core-shell structure. The surface of the microspheres was smooth and monodisperse. The magnetic chitosan microspheres prepared had a diameter of 1-15 μm, which is beneficial to the dispersion and magnetic separation of the microspheres in the reaction system.

Changes in pain rating index, visual analogue score, and present pain intensity after far-infrared ceramic microsphere intervention for the treatment of muscle injury / 中国组织工程研究

BACKGROUND: The far-infrared ceramic microspheres developed by the State Key Laboratory of “new ceramics and fine technology” of School of Materials, Tsinghua University, are made with ceramic colloidal injection molding technology. It is a new type of physical therapy material in the field of sports rehabilitation and daily health care. With its unique small circular structure, it can completely cover the damaged parts such as feet, waist, thigh, etc. to achieve comprehensive stimulation intervention. OBJECTIVE: To investigate the effect of far-infrared ceramic microspheres on pain Intensity after muscle injury. METHODS: Thirty college students aged 18-21 years who met the diagnosis standard of posterior femoral muscle group injury were included in this study. All of them provided informed consent. They were randomly divided into three groups, with 10 students per group. Students in the massage group underwent massage therapy. Students in the far-infrared instrument group were treated with ordinary far-infrared therapeutic apparatus. Students in the far-infrared ceramic microsphere Intervention group underwent far-infrared ceramic microsphere intervention. All treatments lasted 2 successive weeks. Before and 3, 7, and 14 days after treatment, McGill pain scale score (including pain rating index, visual analogue score and present pain intensity) was measured and compared within and between groups. RESULTS AND CONCLUSION: (1) Before treatment, there were no significant differences in pain rating index (sensory, affective, and total pain rating index scores), visual analogue score and present pain intensity between three groups (P > 0.05). (2) At 3 days of treatment, pain rating index, visual analogue score and present pain intensity score in the far-infrared ceramic microsphere intervention group were significantly lower compared with the massage and far-infrared instrument groups (P < 0.05). After 7 and 14 days of treatment, each studied indicator in the far-infrared ceramic microsphere intervention group was highly significantly lower compared with the other two groups (P < 0.01). (3) At 3 days of treatment, score of each pain indicator in the far-infrared ceramic microsphere intervention group was significantly lower compared with before treatment (P < 0.05), and it was significantly decreased compared with that measured concurrently in the other two groups (P < 0.05). (4) At 7 days of treatment, score of each pain indicator in the far-infrared ceramic microsphere intervention group was significantly lower compared with before treatment (P < 0.01), and it was significantly decreased compared with that measured concurrently in the other two groups (P < 0.05). (5) After 14 days of treatment, score of each pain indicator in the massage and far-infrared instrument groups was significantly lower compared with before treatment (P < 0.05). After 14 days of treatment, score of each pain indicator in the far-infrared ceramic microsphere intervention group was highly significantly lower compared with before treatment (P < 0.01). After 14 days of treatment, score of each pain indicator in the far-infrared ceramic microsphere intervention group was significantly lower compared with the other two groups. These findings suggest that far-infrared ceramic microsphere intervention can effectively reduce the degree of posterior femoral muscle group Injury and effectively promote the recovery of muscle injury.

Establishment of fluorescence immunochromatography detection for cytoskeleton-associated protein 4 / 生物工程学报

A rapid and simple method to detect tumor markers in liver cancer was established by combining immunochromatography technique with fluorescent microsphere labeling. According to the principle of double antibody sandwich, the cytoskeleton-associated protein 4 (CKAP4) paired antibody was used as the labeled and coated antibody, and the goat anti-rabbit polyclonal antibody was used as the quality control line coated antibody in the preparation of the CKAP4 fluorescent immunochromatographic test strips. After the preparation, the test strips were evaluated on various performance indicators, such as linearity, precision and stability. The CKAP4 immunochromatographic strip prepared by time-resolved fluorescent microspheres had high sensitivity, and good specificity. Its precision was within 15%, recovery between 85% and 115%, and linear range between 25 and 1 000 pg/mL. The test strip could be kept stable at 37 °C for 20 days, and it correlated well with commercial ELISA kits. The CKAP4 fluorescence immunochromatography method can quantitatively detect the content of CKAP4 in serum. Furthermore, it is rapid, sensitive, simple, economical and single-person operation. This method has the potential of becoming a new method for the diagnosis and treatment of liver cancer.

Injectable hydrogel loaded with bone morphogenetic protein-2 microspheres for bacteriostasis and osteogenesis / 上海交通大学学报（医学版）

Objective: To construct a novel antibacterial and injectable hydrogel (BMP/Gel/SH-Ag) loaded with bone morphogenetic protein-2 (BMP-2) microspheres, and investigate its biocompatibility, antibacterial properties and bone-promoting properties. Methods: The photocrosslinked gelatin microspheres loaded with BMP-2 were prepared by microfluidics. The microspheres were mixed with 4-arm thiol-terminated poly (ethylene glycol) (4SH-PEG) and crosslinked with Ag+ to prepare injectable sulfhydrylated PEG hydrogels (BMP/Gel/SH-Ag). The micromorphology of microspheres and hydrogels was observed by light microscope and scanning electron microscope. The drug release profile was investigated at 37℃ in a shaker (100 r/min). The injectability of BMP/Gel/SH-Ag was evaluated by injecting hydrogel using a syringe with a tip diameter of 0.5 mm. The antibacterial activity of BMP/Gel/SH-Ag against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) was evaluated by agar diffusion test. The biocompatibility of BMP/Gel/SH-Ag was verified by CCK-8, and the bone-promoting activity was evaluated by alkaline phosphatase (ALP) assay and calcium nodule staining in bone marrow mesenchymal stem cells (BMSCs). Results: Gelatin microspheres had smooth appearance and uniform particle size distribution (~ 350 μm). BMP/Gel/SH-Ag had porous micro-structure and can be injected with a syringe needle with a diameter of up to 0.5 mm in diameter to produce hydrogel filament. The cumulative release of BMP-2 from BMP/Gel/SH-Ag was (81.8±3.6)% after being incubated for 8 d. BMP/Gel/SH-Ag had obvious inhibitory effect on S. aureus and E. coli. CCK-8 results showed that BMP/Gel/SH-Ag had good biocompatibility. BMP/Gel/SH-Ag can increase the expression of ALP and the content of calcium nodules in rat BMSCs. Conclusion: The BMP/Gel/SH-Ag has good performance in promoting osteogenesis and an-ti-infection.