It seems likely that IMC will
soon become a standard method in clinically related microbiology. The clinical need is actually for multicalorimeter instruments, which are simpler (e.g. having a narrower range of set temperatures) than current multicalorimeter research instruments. However, for more research-oriented applications, it is, as mentioned earlier, difficult to identify unknown specific phenomena based on IMC only (Lewis & Daniels, 2003). Therefore, to support and interpret nonspecific microcalorimetric results, other analytical measurements are often desirable (Wadsö, 2002). Such analytical capabilities can include added in-line sensors in the case of a flow-cell IMC instrument. However, as stated earlier, such systems Ku-0059436 ic50 are difficult to set up and sterilize. On the other hand, several attempts have been made to add sensors to the measurement ampoule. For example, Johansson & Wadsö (1999) constructed an isothermal microcalorimeter vessel that contained a miniaturized spectrophotometer, plus pH and oxygen electrodes. Johansson & Wadsö (1999) emphasize that many different types of analytical sensors or microsensors are available
and could be added. Similarly, Criddle et al. (1991) have demonstrated that a device consisting of two microcalorimetric ampoules connected by tubing could be used to measure metabolic heat and CO2 production simultaneously. PLX3397 molecular weight In this system, one ampoule served as the sample container, and the other contained NaOH and acted as a CO2 trap, with CO2 trapping resulting in measurable heat flow production as well. An additional pressure sensor was added to this system to deduce oxygen concentration from the pressure decrease. Masitinib (AB1010) Both the approaches presented above, coupling IMC and analytical sensors, seem to be highly promising. However, both of these early setups were ‘home-made,’ and commercial instruments including such features have not yet emerged. This has probably strongly discouraged other experimenters from supplementing isothermal
microcalorimeters in this manner in more recent years. Conversely, it perhaps also indicates how much can already be accomplished with sealed IMC ampoules, followed by postanalysis application of other analytical methods. Another promising area of IMC instrumentation has emerged with the development of ‘calorimeter chips’ (van Herwaarden, 2005). These commercially available chips are only a few millimeters in size and are usually encased in an aluminum block that acts as a heat sink. These chips have already been used to monitor bacterial growth from the heat produced (Higuera-Guisset et al., 2005; Maskow et al., 2006). Modified calorimeter chips have also been used as biosensors. Using chip-immobilized glucose oxidase, urease and penicillinase, the heat generated by the oxidation of glucose and the hydrolysis of urea and penicillin were easily detected (Bataillard, 1993; Bataillard et al.