Immobilization of RGD Peptidcs onto Decellularized Valve Scaffolds to Promote Cell Adhesion

Porcine aortic valves were decellularized with trypsinase/EDTA and Triton-100.With the help of a coupling reagent Sulfo-LC-SPDP,the biological valve scaffolds were immobilized with one of RGD (arginine-glycine-aspartic acid)containing peptides,called GRGDSPC peptide.Myofibroblasts harvested from rats were seeded onto them.Based on the spectra of X-ray photoelectron spectroscopy,we could find conjugation of GRGDSPC peptide and the scaffolds.Cell count by both microscopy and MTT assay showed that myofibroblasts were easier to adhere to the modified scaffolds.It is proved that it is feasible to immobilize RGD peptides onto decellularized valve scaffolds,and effective to promote cell adhesion,which is beneficial for constructing tissue engineering heart valves in vitro.     

Fabrication of Porous Scaffolds Using NaHCO3 Particulates as the Porogen Material

A new method of fabricating porous polymer scaffolds was developed, using sodium hydrogen carbonate particulates as the porogen to foam. The pore structure of polymer scaffolds can easily be manipulated by controlling the size and weight fraction of sodium hydrogen carbonate particulates. The scaffolds are highly porous with a porosity greater than 90% and with a larger pore size ranging from 100-400μm, and are well distributed with the interconnected and open pore wall structure which is necessary for tissue engineering. We investigated the effect of the porosity of scaffolds, the pore size of scaffolds and material of polymer on the mechanical properties of scaffolds. The scaffolds fabricated by the method have more big pores than those by the convenient method of salt leaching.     

Biocompatibility of Tri-block Bone-matrix Material in vitro

To evaluate the biocompatibility of poly（lactic acid/glycolic acid/ asparagic acid-copolyethylene glycol）（PLGA-[ASP-PEG]） tri-block copolymer in vitro, L929 fibroblast was co-cultured with the copolymer for cytotoxicity, hemolysis and pyrogen tests. And, compared with PLGA, the adhesiveness rate of the copolymer was calculated. The experimental results show that the toxicity gradation of the material was 0-1; L929 fibroblasts had a good cell morphology and proliferated rapidly on the surface of the material; hemolysis ratio was 3.08%; there was no pyrogen reaction. The adhesiveness of PLGA-[ASP-PEG] was better than that of the PLGA＇s（P〈0.05）. The results confirm that the PLGA-[ASP-PEG] has a good biocompatibility.     

Biocompatibility Evaluation of Vessel Extraeellular Matrix as a Matrix for Urethral Reconstruction

The objective of this study was to evaluate the biocompatibility of vessel extracellular matrix （VECM） from rabbit and to discuss the feasibility of vessel extracellular matrix as a matrix for urethral reconstruction. Primary cultured bladder smooth muscle cells isolated from New Zealand rabbits were implanted on VECM .The effects of VECM on rabbit bladder smooth muscle cells （RBSMCs） metabolic activity, attachment, proliferation were monitored in vitro with the aid of an inverted light microscope and a scanning electron microscope. The cell viability was monitored by MTT（methythiazolye tetrazolium bromide） after 1, 3, 5 days seeding. The in vivo tissue response to VECM was investigated by implanting them into the subcutaneous of rabbits. VECM exhibited a nontoxic and bioactive effect on RBSMCs. RBSMCs could be attached to and proliferated on VECM and maintained their morphologies. MTT assay showed RBSMCs cultured with the extracts of VECM were not significantly different from those of negative controls. In vivo, VECM demonstrated a favorable tissue compatibility without tissue necrosis, fibrosis and other abnormal response. VECM exhibited nontoxic and bioactive effects on RBSMC. It is a suitable material for urethral reconstruction.     

基于Monte Carlo在体生物光学成像的光子传输模型

随着分子标记技术和光学成像技术的发展,在体生物光学成像倍受关注,并广泛应用于对生物组织的生理或病理过程的无损实时动态成像.研究生物组织中的光子传输模型和光子传输规律,是开展在体生物光学成像研究的两个关键环节.提出了一种基于Monte Carlo方法的在体生物光学成像中的光子传输模型.已知荧光光源参数、生物组织参数和探测器参数,建立荧光光源发射光子、光子在生物组织中传输的数学模型,并利用Monte Carlo方法实现这些模型.最后做了对比实验,实验结果表明了该算法的正确性和有效性.     

生物组织自体荧光光谱诊断的模拟实验研究

讨论了一种快速、无损伤定位疾病的生物组织自体荧光诊断技术，并对正常和病变的猪血溶液进行了模拟研究，得出了在530－550nm范围内，正常组织荧光强度明显低于病变组织的结果，在531．6、532．6nm三处光谱峰是正常血液组织荧光谱的特征峰，对临床有一定的指导意义。     

荧光淬灭氧含量检测法中两种荧光寿命定量方法的差异性实验

氧含量检测是生物医学界一个重要课题,故研制开发了以荧光氧淬灭为原理的氧检测实验系统.通过采用Marquardt-Levenberg非线性模拟,表明该实验系统能够真实可靠地反映媒质中氧含量状态.同时,对两种数据记录方法--直接记录法和数据模拟法进行了比较,发现虽然采用数据模拟法需要增加一定的硬件支持和软件数据处理,但就准确性和精确性而言,其应该成为氧检测数据记录的首选方法.     

三层组织织物的设计与生产

介绍了三层机织物组织的设计、接结方法和生产工艺,以及在生产过程中出现的疵点解决措施。     

Mechanism of Blood–Heart-Barrier Leakage: Implications for COVID-19 Induced Cardiovascular Injury

Although blood–heart-barrier (BHB) leakage is the hallmark of congestive (cardio-pulmonary) heart failure (CHF), the primary cause of death in elderly, and during viral myocarditis resulting from the novel coronavirus variants such as the severe acute respiratory syndrome novel corona virus 2 (SARS-CoV-2) known as COVID-19, the mechanism is unclear. The goal of this project is to determine the mechanism of the BHB in CHF. Endocardial endothelium (EE) is the BHB against leakage of blood from endocardium to the interstitium; however, this BHB is broken during CHF. Previous studies from our laboratory, and others have shown a robust activation of matrix metalloproteinase-9 (MMP-9) during CHF. MMP-9 degrades the connexins leading to EE dysfunction. We demonstrated juxtacrine coupling of EE with myocyte and mitochondria (Mito) but how it works still remains at large. To test whether activation of MMP-9 causes EE barrier dysfunction, we hypothesized that if that were the case then treatment with hydroxychloroquine (HCQ) could, in fact, inhibit MMP-9, and thus preserve the EE barrier/juxtacrine signaling, and synchronous endothelial-myocyte coupling. To determine this, CHF was created by aorta-vena cava fistula (AVF) employing the mouse as a model system. The sham, and AVF mice were treated with HCQ. Cardiac hypertrophy, tissue remodeling-induced mitochondrial-myocyte, and endothelial-myocyte contractions were measured. Microvascular leakage was measured using FITC-albumin conjugate. The cardiac function was measured by echocardiography (Echo). Results suggest that MMP-9 activation, endocardial endothelial leakage, endothelial-myocyte (E-M) uncoupling, dyssynchronous mitochondrial fusion-fission (Mfn2/Drp1 ratio), and mito-myocyte uncoupling in the AVF heart failure were found to be rampant; however, treatment with HCQ successfully mitigated some of the deleterious cardiac alterations during CHF. The findings have direct relevance to the gamut of cardiac manifestations, and the resultant phenotypes arising from the ongoing complications of COVID-19 in human subjects.     

Docosahexaenoic Acid Modulates Paracellular Absorption of Testosterone and Claudin-1 Expression in a Tissue-Engineered Skin Model

Healthy skin moLEdels produced by tissue-engineering often present a suboptimal skin barrier function as compared with normal human skin. Moreover, skin substitutes reconstructed according to the self-assembly method were found to be deficient in polyunsaturated fatty acids (PUFAs). Therefore, in this study, we investigated the effects of a supplementation of the culture media with docosahexaenoic acid (DHA) on the barrier function of skin substitutes. To this end, 10 μM DHA-supplemented skin substitutes were produced (n = 3), analyzed, and compared with controls (substitutes without supplementation). A Franz cell diffusion system, followed by ultra-performance liquid chromatography, was used to perform a skin permeability to testosterone assay. We then used gas chromatography to quantify the PUFAs found in the epidermal phospholipid fraction of the skin substitutes, which showed successful DHA incorporation. The permeability to testosterone was decreased following DHA supplementation and the lipid profile was improved. Differences in the expression of the tight junction (TJ) proteins claudin-1, claudin-4, occludin, and TJ protein-1 were observed, principally a significant increase in claudin-1 expression, which was furthermore confirmed by Western blot analyses. In conclusion, these results confirm that the DHA supplementation of cell culture media modulates different aspects of skin barrier function in vitro and reflects the importance of n-3 PUFAs regarding the lipid metabolism in keratinocytes.