Previous studies have shown that, generally, microliters of droplets were needed to dry at room temperature for a long time ranging from tens of minutes and up to several hours before Raman spectral measurement.20–21 Here, we demonstrate a simple and rapid method to speed up evaporation to achieve fast drying by increasing the sample temperature (see Sec. 2). Compared with the long time (50 min) needed for passive air-dry at room temperature, the drying process takes a much shorter time to prepare the ECM samples ( for 30°C, for 50°C, and for 70°C). As shown in Fig. 4(a), Raman spectra from the droplet edge of the same sample under different drying temperatures (room temperature, 30°C, 50°C, and 70°C), demonstrate almost the same Raman spectral profile (e.g., the related coefficients between spectra obtained at room temperature and 50°C is 0.996) and the shaded area indicates the region where only two minor differences at Raman peaks of 1003 and were found. It should be noted that the latter was presented as a shoulder band, which is not always reliably detected. One potential concern of increasing the drying temperature is causing thermal-induced to the proteins. Previous study has reported that intensity of the band is associated with the content of proteins in the -helical state, and upon heating, the -helical conformation will become degraded and the increase in the ratio suggests a vital change in protein conformation.22 Our calculated intensity ratios in these four groups (room temperature, 30°C, 50°C, and 70°C) were shown in Fig. 4(b). The intensity ratio (as mentioned) betweeen different drying temperatures was compared and the significance of the differences was analyzed using Student t test test in the SPSS 15.0 software package (SPSS Inc., Chicago). It can be seen that although intensity ratios were similar, after careful comparison, the intensity ratios of 1003 to between 70°C and other three groups indicated significant difference (), suggesting a drying temperature of 70°C does bring somewhat thermally induced denature to protein. However, there is no significant difference () among the other three groups. Low temperature implies a slow evaporation rate and eventually a long time needed to prepare samples, a drying temperature of 50°C would be optimal for rapid dried ECM sample preparation, and consequently to achieve the stable and satisfactory Raman data. Pending further validation, the value derived in this study should not be considered a universal value to be applied to all samples by all instruments.