The fabrication of enzyme-based biosensors has received much attention for their selectivity and sensitivity. In particular, laccase-based biosensors have attracted a lot of interest for their capacity to detect highly toxic molecules in the environment, becoming essential tools in the fields of white biotechnology and green chemistry. The manufacturing of a new, metal-free, laccase-based biosensor with unprecedented reuse and storage capabilities has been achieved in this work through the application of the electrospray deposition (ESD) methodology as the enzyme immobilization technique. Electrospray ionization (ESI) has been used for ambient soft-landing of laccase enzymes on a carbon substrate, employing sustainable chemistry. This study shows how the ESD technique can be successfully exploited for the fabrication of a new promising environment-friendly electrochemical amperometric laccase-based biosensor, with storage capability up to two months without any particular care and reuse performance up to 63 measurements on the same electrode just prepared and 20 measurements on the one-year-old electrode subjected to redeposition. The laccase-based biosensor has been tested for catechol detection in the linear range 2–100 μM, with a limit of detection of 1.7 μM, without interference from chrome, cadmium, arsenic, and zinc and without any memory effects.
24 April 2020 in The Journal of Physical Chemistry A
The fragmentation of the isolated 5-bromouracil (5BrU) molecule and pure and nano-hydrated 5BrU clusters induced by low energy 12 C 4+ ions has been studied.
12 June 2017 in Physical Chemistry Chemical Physics
Understanding how energetic charged particles damage DNA is crucial for improving radiotherapy techniques such as hadron therapy and for the development of new radiosensitizer drugs. In the present study, the damage caused by energetic particles was simulated by measuring the action of extreme ultraviolet (XUV) attosecond pulses on the DNA building blocks thymine and thymidine. This allowed the ultrafast processes triggered by direct ionization to be probed with an optical pulse with a time resolution of a few femtoseconds. By measuring the yields of fragment ions as a function of the delay between the XUV pulse and the probe pulse, a number of transient processes typically lasting 100 femtoseconds or less were observed. These were particularly strong in thymidine which consists of the thymine base attached to a deoxyribose sugar. This dynamics was interpreted as excited states of the cation, formed by the XUV pulse, rapidly decaying via non-adiabatic coupling between electronic states. This provides the first experimental insight into the mechanisms which immediately proceed from the action of ionizing radiation on DNA and provides a basis on which further theoretical and experimental studies can be conducted.