Background fluorescence of plastic chips

Chemists in the US are working towards using plastic chips rather than the more traditional glass for analysis of potential drug candidates. Disposable plastic chips would be cheaper than reusable glass devices and would eliminate time-consuming cleaning steps. 

Carl Seliskar and colleagues from the University of Cincinnati have examined the background fluorescence (autofluorescence) of several different plastic materials under a range of laser excitation wavelengths. These have been compared to BoroFloat, a commonly used glass material.

Seliskar’s team found that the plastics all had higher and more variable autofluorescence than the glass and that when made into chips, the effect was further increased. Their results also show that the autofluorescence can be temporarily bleached by strong laser light, increasing the usability of the chip.

Optical detection using laser-induced fluorescent spectroscopy is a common way of monitoring chip-based processes occurring at the microscale. When excited by laser irradiation, plastic materials are known to emit a significant amount of autofluorescence. This effect can severely interfere with chip detection measurements and limits the extent of their use in devices.

Seliskar says, ’additional work needs to be done on the chemical formulations of the plastics themselves with an eye toward reducing the autofluorescence of chips made from them’.

Sophia Anderton