A bioaffinity-driven cascade assay was developed to determine the time elapsed from the point a blood sample was left at a crime scene to the point of discovery.

A new biocatalytic assay analyzing the simultaneous presence of creatine kinase (CK) and alanine transaminase (ALT) was developed aiming at the recognition of biofluids of different gender for forensic applications. Knowing the difference in the concentrations of CK and ALT enzymes in the blood of healthy adults of male and female groups we mimicked the samples of different gender with various CK–ALT concentrations. The analysis was performed using a multi-enzyme/multi-step biocatalytic cascade where the differences in both included enzymes resulted in an amplified difference in the final analytical response. The analysis performed in human serum solutions allowed discrimination of samples corresponding to male/female groups. The robustness of the developed analysis allowed determination of the gender for serum solutions after their drying and ageing at least for 1 hour. Importantly for forensic applications, reaction with a chromogenic reactant nitroblue tetrazolium allowed qualitative discrimination of the “male” and “female” samples by the naked eye.

Recently, biosensors have been used in an increasing number of different fields and disciplines due to their wide applicability, reproducibility, and selectivity. Three large disciplines in which this has become relevant has been the forensic, biometric, and cybersecurity fields. The call for novel noninvasive biosensors for these three applications has been a focus of research in these fields. Recent advances in these three areas has relied on the use of biosensors based on primarily colorimetric assays based on bioaffinity interactions utilizing enzymatic assays. In forensics, the use of different bodily fluids for metabolite analysis provides an alternative to the use of DNA to avoid the backlog that is currently the main issue with DNA analysis by providing worthwhile information about the originator. In biometrics, the use of sweat-based systems for user authentication has been developed as a proof-of-concept design utilizing the levels of different metabolites found in sweat. Lastly, biosensor assays have been developed as a proof-of-concept for combination with cybersecurity, primarily cryptography, for the encryption and protection of data and messages.