The main objective of this study is to evaluate the antibacterial effect of antibacterial photodynamic therapy (aPDT) on Streptococcus mutans (S. mutans) biofilm model in vitro. The selection of photosensitizers is the key step for the efficacy of photodynamic therapy (PDT). However, no studies have been conducted in the oral field to compare the functional characteristics and application effects of PDT mediated by various photosensitizers. In this research, the antibacterial effect of Methylene blue (MB)/650 nm laser and Hematoporphyrin monomethyl ether (HMME)/532 nm laser on S. mutans biofilm was compared under different energy densities to provide experimental reference for the clinical application of the two PDT. The yield of lactic acid was analyzed by Colony forming unit (CFU) and spectrophotometry, and the complete biofilm activity was measured by Confocal Laser Scanning Microscopy (CLSM) to evaluate the bactericidal effect on each group. Based on the results of CFU, the bacterial colonies formed by 30.4 J/cm² 532 nm MB-aPDT group and 30.4 J/cm² 532 nm HMME-aPDT group were significantly less than those in other groups, and the bacterial colonies in HMME-aPDT group were less than those in HMME-aPDT group. Lactic acid production in all treatment groups except the photosensitizer group was statistically lower than that in the normal saline control group. The activity of bacterial plaque biofilm was significantly decreased in the two groups treated with 30.4 J/cm² aPDT. Therefore, aPDT suitable for energy measurement can kill S. mutans plaque biofilm, and MB-aPDT is better than HMME-aPDT.

研究了泡椒凤爪生产流程中微生物污染来源、60Co-γ射线辐照杀菌效果、及不同剂量处理的产品在不同温度下微生物繁殖情况。结果表明: 泡椒凤爪微生物污染主要途径是泡制和包装环节, 这是产品卫生质量控制的关键控制点; 60Co-γ射线对产品中微生物有很好的杀灭作用, 能显著延长产品的保质期, 辐照剂量为6 kGy时, 产品在30 ℃、20 ℃、10 ℃温度条件下保藏, 保质期比对照分别延长了53 d、120 d和180 d。

通过对人免疫缺陷病毒复制过程的抑制作用研究,探索光动力疗法(PDT)在艾滋病防治中的潜在价值。使用不同稀释浓度的光敏剂血卟啉单甲醚(HMME)和亚甲蓝(MB)分别与人免疫缺陷病毒HIV-1ⅢB或宿主细胞MT4,C8166或H9/HIV-1ⅢB孵育2 h,以波长630 nm能量密度0.3 J/cm2的半导体激光进行照射。继续孵育若干小时后,用噻唑蓝(MTT)比色法检测细胞存活率或合胞体计数,同时收集培养上清液用ELISA法检测HIV-1 p24抗原。结果表明,光动力疗法能显著抑制人免疫缺陷病毒诱导的细胞细胞融合(HMME-PDT抑制率64.68%,MB-PDT抑制率61.56%)和病毒细胞融合(HMME-PDT抑制率85%,MB-PDT抑制率73.64%),并对游离病毒有很强的杀伤作用,最高可达到100%。光动力疗法不能抑制慢性感染期和急性感染2 h后病毒的复制过程。可见光动力疗法对游离病毒和病毒感染诱导的膜融合有显著抑制作用,有可能为艾滋病的防治提供一种新的方法。

为探讨光动力疗法(PDT)对人工龋菌斑生物膜的的作用,选用变形链球菌在体外构建符合人体生理环境的人工龋模型,选择血卟啉单甲醚(HMME)为光敏剂,激光照射选用半导体激光器,波长为635 nm,输出功率为10 mW,能量密度为12.47 J/cm2。用50个釉质块形成人工龋模型,随机分成5组,每组10块,分别为:1) HMME组;2) 激光照射组;3) PDT防龋组;4) 0.05%(质量分数)洗必泰处理组为阳性对照;5) 0.9%(质量分数)生理盐水处理组为阴性对照。依照平板细菌计数法观察不同处理方法对人工龋菌斑生物膜变形链球菌活力的影响。结果表明,与阴性对照组相比,HMME组人工龋口腔生物膜中变形链球菌数量(CFU/mL)无显著性差异(P>0.05),杀菌率仅为0.05%;激光照射和0.05%洗必泰均能使人工龋口腔生物膜中变形链球菌数量显著减少(P<0.05),杀菌率分别为59.94%和58.52%;而PDT防龋处理可使人工龋口腔生物膜中变形链球菌数量更为显著减少(P<0.05),杀菌率高达99.36%。HMME-PDT可有效杀灭人工龋口腔生物膜中的变形链球菌,为预防龋病提供了一种有效的新途径。

We investigated the effect of photodynamic therapy (PDT) with hematoporphyrin monomethyl ether (HMME) on the viability of Streptococcus mutans (S. mutans) cells on biofilms in vitro. Streptococcus mutans is the primary etiological agent of human dental caries. Since dental caries are localized infections, such plaque-related diseases would be well suited to PDT. The diode laser used in this study had the wavelength of 635 nm, whose output power was 10 mW and the energy density was 12.74 J/cm2. HMME was used as photosensitizer. Samples were prepared and divided into five groups: (1) HMME; (2) Laser; (3) HMME+Laser; (4) Control group (+) with chlorhexidine; and (5) Control group (-) with sterile physiological saline. Inoculum of S. mutans incubated with HMME also examined with fluorescence microscopy. PDT exhibited a significantly (P&lt;0.05) increased antimicrobial potential compared with 20 \mum/mL HMME only, laser only, 0.05% chlorhexidine, and 0.9% sterile physiological saline, which reduced the S. mutans of the biofilm most effectively. Laser and 0.05% chlorhexidine were caused reduction in the viable counts of S. mutans significantly different (P&lt;0.05) also, but these two test treatments did not statistically differ from each other. HMME group did not statistically differ with negative control group. Fluorescence microscopy indicated that HMME localized primarily in the S. mutans of the biofilm. It was demonstrated that HMME-mediated PDT was efficient at killing S. mutans of biofilms and a useful approach in the treatment of dental plaque-related diseases.

To investigate the effect of photodynamic therapy (PDT) with hematoporphrin monomethyl ether (HMME) on bovine immunodeficiency virus (BIV) can provide the basis theory for photoinactivation of human immunodeficiency virus (HIV). To assess the protection of HMME-PDT on the cell line Cf2Th infected with BIVR29 by 3-(4,5)-dimethylthiahiazol-2-y1-3,5-di-phenytetrazolium bromide (MTT) with power density of 5 and 25 mW/cm2 and energy density from 0.6 to 3 J/cm2. To observe the inhibition of membrane fusion using a new reporter cell line BIVE by fluorescence microscope. HMME-PDT has significant protectant effects on Cf2Th-BIVR29 with both power densities, especially in the group of high power density. Fluorescent microscope shows that there is no significant difference between the group of PDT and control, which means PDT could not inhibit the BIV-mediated membrane fusion.

研究了光动力疗法(PDT)制备的抗小鼠H22肝癌肿瘤疫苗的抗瘤效应。将昆明鼠60只,随机分为2组,每组30只。实验组取6～12周龄的昆明鼠背部皮下接种光动力疗法产生的疫苗,每3天注射一次,每次注射50 μL(相当于3×105个细胞),连续两周。隔一周于第22天注射H22肿瘤细胞悬液0.1 mL(1×106个细胞); 对照组:每周每次注射50 μL生理盐水,连续两周。隔一周于第22天注射H22肿瘤细胞悬液0.1 mL(1×106个细胞)。比较两组的抑瘤率、生存率以及两组之间免疫学的相关指标。结果表明,实验组小鼠具有显著的抑瘤效果,抑瘤率、生存率较对照组有显著提高。实验组肿瘤抑瘤率最高可达60%且长期有效,100天生存率达56%。说明光动力疗法产生的抗小鼠H22肝癌疫苗可以有效地抑制肿瘤生长,提高荷瘤小鼠的生存率,具有明显的抗瘤效应。该方法可能成为一种辅助性治疗肿瘤的手段而应用于临床。