The OP is confusing since it refers to Biopace and elliptical as if they are the same. They're not. There have been elliptical rings from various makers (such as Durham) while Biopace was a very different shape only made by Shimano.
But, as already mentioned by others, the difference between 52 and 53t rings is very small and usually not worth worrying about. If you want a higher gear then go up to something significantly bigger. E.g. my folder has a 60t large chainring and this gives me gearing equivalent to a 45t ring on a bike with 700c wheels - so the resistance I feel is also the same as if using a 45t ring on such a bike. In combination with a small cog of 11t this gives me a high enough gear for my rides.
Fine if the OP wants a non-round chainring for some reason, but the fact that he's using a bike with smaller wheels is irrelevant from the standpoint of round vs. non-round rings.