Table 1.

Troubleshooting.

Step	Problems	Causes	Suggestions
2	Poor transfection efficiency	DNA quantity is too low	Modify the transfection reagent/DNA ratio by adding more DNA to the mixture
2	Low cell viability	• DNA quantity is too high • Incubation time is too high	• Decrease the amount of transfection solution and DNA added to the cells • Decrease the incubation time NOTE: Longer incubation times may result in higher efficiency but higher toxicity also
3	Low BCA result	Low protein linked to the bead	Check that the amount of protein added is at saturation for the linker reaction to successfully take place
4	No lipid vesicles detected in the solution	• No lipid vesicles present • Wrong molarity of the solutions	• Be careful in all the washing procedures • Check the correct molarity of the glucose and sucrose solutions
5	No fluorescence intensity is detected in the FRET channel	FRET signal is very low	Increase the exposure time or the light intensity; this may bring to excessive photobleaching or phototoxicity, adjust these parameters to optimize the image acquisition
5	Lipid vesicles and beads cannot be trapped	• IR laser is out of focus • IR laser power is too low	• Check the IR laser focus and align the beam • Increase the laser power
5	Lipid vesicles cannot be broken	UV and IR laser are not overlapping	Check the UV and IR laser relative position and focus and align the beam
6	Biosensors 2.1 package doesn't run	MATLAB version does not support it	This package works on MATLAB 2012b or below