Seniors: What is the best brand/type of mattress to buy these days?

I am about to buy new bedding and I am concerned about the synthetics used. I noticed when I purchased a mattress pad, it had antimicrobial properties. I wasn't looking for this and really don't feel too good about a chemical-laden pad but because of the price, I purchased it hoping if it wash it a couple of times this would reduce the chemical used. So has anyone purchased a natural/organic mattress or had problems with ones sold in the stores these days? Thanks