中文摘要：

目的探讨并明确量子点核酸传感器检测微生物核酸样本时探针长度对杂交效率和检测结果的影响。方法首先合成金黄色葡萄球菌16S rDNA探针，然后在其5′端添加不同长度的重复碱基序列，分别合成5条长度不同的以胸腺嘧啶结尾的探针；采用巯基法固定金黄色葡萄球菌16S rDNA探针于石英晶体微阵列上，并用石英晶体微天平（QCM）检测样品频率漂移量以判断不同核酸长度时的杂交效率，并用荧光显微镜观察形成不同双链复合物的荧光强度和荧光效率，以此判断不同碱基序列长度探针对荧光效率和杂交效率的影响，并运用SPSS软件对数据进行统计分析。结果对于普通的短链核酸杂交反应，随着探针长度增加，杂交效率呈现依次递增的趋势，当离子强度为40mmol／L时，杂交效率和荧光强度增加最快，其后再增加探针长度，杂交效率增加速度变缓。结论探针长度是影响杂交效率的主要原因之一，通过增加探针长度可以提高杂交效率和荧光强度，但同时也会增加二聚体产生概率，故应根据实际需要设计长度适合的探针。

英文摘要：

OBJECTIVE To discuss and identify the influence of probe length on the hybridization effect and fluorescence intensity during the detection of microorganism biosensor. METHODS Hydrosulfide group was adopted to immobilize the 16S rDNA probes of Staphylococcus aureus on the quartz crystal biosensor array. Firstly we synthesized series of probes with different length. Then we detected the frequency shifts induced by nucleic acid hybridization. Then we detected the total fluorescence intensity with fluorescence microscopy. All of the data were analyzed by the SPSS software. RESULTS The hybridization efficiency increased gradually with the increase in probe length. The hybridization efficiency firstly climbed quickly then slow down when the probe length reached 40 bp. Similarly, the peak fluorescence intensities produced were the same when the probe length was 40 bp and 60 bp. CONCLUSIONS Probe length is the important factor influencing the results of quantum dot microorganism biosensor. And the long probe can increase hybridization effect and fluorescence intensity. However, multiple parameters should be considered when determining the optimal length in practice.