FTIR-ATR detection of proteins and small molecules through DNA conjugation

With the help of chemical modification of silicon surfaces, FTIR-ATR was developed into a biosensing method to monitor biochemical processes on surfaces. In this proof-of principle work, FTIR-ATR crystals were covalently modified by oligonucleotides and two model systems were investigated, including recognition of anti-thrombin aptamer with thrombin and organic molecule binding to double helix DNA with sequence-specific photocleavage. The affinity of aptamer recognition and the affinity of photocleavage reagent towards double helix of DNA were quantitatively measured. Thus, it was shown that the proposed FTIR-ATR-based biosensing method allows for high-sensitive label-free detection of various biological systems.