Lerchner J, Wolf A, Buchholz F, Mertens F, Neu T R, Harms H, Maskow T
TU Bergakademie Freiberg, Institute of Physical Chemistry, Freiberg, Germany.
J Microbiol Methods. 2008 Aug;74(2-3):74-81. doi: 10.1016/j.mimet.2008.04.004. Epub 2008 May 27.
The partial dissipation of Gibbs energy as heat reflects the metabolic dynamic of biofilms in real time and may also allow quantitative conclusions about the chemical composition of the biofilm via Hess' law. Presently, the potential information content of heat is hardly exploited due to the low flexibility, the low throughput and the high price of conventional calorimeters. In order to overcome the limitations of conventional calorimetry a miniaturized calorimeter for biofilm investigations has been evaluated. Using four thermopiles a heat production with spatial and temporal resolutions of 2.5 cm(-1) and 2 s(-1) could be determined. The limit of detection of the heat flow measurement was 20 nW, which corresponds to the cell density of an early stage biofilm (approx. 3x10(5) cells cm(-2)). By separating biofilm cultivation from the actual heat measurement, a high flexibility and a much higher throughput was achieved if compared with conventional calorimeters. The approach suggested allows cultivation of biofilms in places of interest such as technological settings as well as in nature followed by highly efficient measurements in the laboratory. Functionality of the miniaturized calorimeter was supported by parallel measurements with confocal laser scanning microscopy and a fiber optic based oxygen sensor using the oxycaloric equivalent (-460 kJ mol-O2(-1)).
吉布斯自由能以热的形式部分耗散实时反映了生物膜的代谢动态，并且还可能通过赫斯定律得出关于生物膜化学成分的定量结论。目前，由于传统量热仪灵活性低、通量低且价格高，热量的潜在信息含量几乎未得到利用。为了克服传统量热法的局限性，已对一种用于生物膜研究的小型化量热仪进行了评估。使用四个热电堆，可以确定空间和时间分辨率分别为2.5 cm⁻¹和2 s⁻¹的产热情况。热流测量的检测限为20 nW，这对应于早期生物膜的细胞密度（约3×10⁵个细胞/cm²）。通过将生物膜培养与实际热测量分开，与传统量热仪相比，实现了更高的灵活性和更高的通量。所建议的方法允许在感兴趣的地方（如技术环境以及自然界）培养生物膜，然后在实验室进行高效测量。通过使用氧热当量（-460 kJ mol⁻¹ O₂）的共聚焦激光扫描显微镜和基于光纤的氧传感器进行平行测量，支持了小型化量热仪的功能。
