This article [J. Biomed. Opt.. 18, , 036011 (2013)] was originally published online on 20 March 2013 with two errors in the Conclusion on p. 4. The quantities 3 mg/cm 2 and 77 mg/cm 2 should refer to micrograms, not milligrams. They were corrected to read 3 μg/cm 2 and 77 μg/cm 2 , respectively.
First measurements of biomedical imaging using quantum cascade lasers (QCL) are presented. We report spectroscopic imaging of serum proteins using QCLs as an example for monitoring surface biocontamination. We found that dry smears of human serum can be spectroscopically imaged, identified, and quantified with high sensitivity and specificity. The core parts of the imaging platform consist of optically multiplexing three QCLs and an uncooled microbolometer camera. We show imaging of human serum proteins at 6.1, 9.25, and 9.5 μm QCLs with high sensitivity and specificity. The sensitivity limit of 3 μg/cm 2 of the human serum spot was measured at an S/N=3 .The specificity of human serum detection was measured at 99% probability at a threshold of 77 μg/cm 2 . We anticipate our imaging technique to be a starting point for more sophisticated biomolecular diagnostic applications.