Abstract: Provided herein are aptamer arrays useful to detect target molecules that are largely similar to each other in structure (such as monoamine neurotransmitters), and methods of detecting such molecules, employing aptamers with differing sensitivities to each target molecule.

Abstract: Provided herein is a coated biosensor and a method of preserving a coated biosensor to protect it during implantation into the brain or other tissues by coating the biosensor with a protective coating.

Abstract: The specification and drawings show an embodiment of the present invention in the form of a device comprising one or more biosensors either placed or imbedded in a catheter, needle or combination of the two. The catheter or needle comprises exclusionary slits upstream of the biosensor(s), angled so that fluid flows in through the slits and down past the biosensors. The wires connecting the biosensors to external monitoring and/or analytical apparatus are wired through the catheter or needle material. Also provided herein are methods for detection of small molecules using the device described herein.