It is possible, but you may run into a few problems. For starters, are you going to use signiture based detections as the method of detecting malicious files? How will you update these? Modern AV applications have literally 1000s of these signitures used for detections that are updated daily.
Also, I'd imagine the actual process of scanning each file and checking it against each file on the system would take a long time. Most AV applications nowadays use whitelisting or hueristic based scanning to reduce scan times. Your application may also be limited to 'On Demand Scanning' (user manually kicks off a scan) with no support for 'On Access Scanning' (scanning a file immediately once it is invoked).
Finally, things like boot sector scanning and detection of rootkits may not be possible.