Research and asking professors

So I really want to be able to do research next summer at a lab (specifically molecular biology), and fortunately there are many colleges within commuting distance from where I live. I’m thinking about emailing a couple of professors from a college that I’m kinda familiar with. I was also looking at the research profiles of professors at Hopkins and they sound really interesting and cool, but what are the chances of one of those professors allowing me to work in his/her lab? Would it be a waste of time and effort to email them and make each email personal, etc? Also when should I email professors in general if I want to volunteer over summer? And any tips on emails or research experiences you’ve had are welcome!