"Now is not the time for tinkering around the edges," the Vermont senator said in an apparent swipe at Biden's plan to expand the Affordable Care Act.
Sanders' speech at George Washington University came as he is seeking to breathe new life into his campaign ahead of the second presidential debate later this month. He has slipped in some public polling and has been outraised by several of his rivals, including Biden.
Despite not mentioning Biden or any of his Democratic rivals by name, Sanders drew sharp contrasts in the speech between himself and the former vice president as the question of how to best provide health care for Americans has become an animating focus of the presidential race. Biden released his own health care plan on Monday, and the two campaigns have engaged in an increasingly bitter dispute over the issue.
Biden has warned that it would be dangerous to eliminate the Affordable Care Act, implemented when he was vice president in the Obama administration, and replace it with Medicare for All. While Sanders' plan would eliminate most private insurance, Biden's would create a public option that would allow people to sign up for a government-run health system like Medicare if they were unhappy with private insurance.
"Medicare goes away as you know it. All the Medicare you have is gone. It's a new Medicare system," Biden said this week at a presidential candidate forum held by the AARP. "It may be as good, you may like it as well, it may or may not, but the transition of dropping 300 million people on a totally new plan, I think is a little risky at this point."
On Wednesday, Sanders countered, "When our opponents talk about destabilization of the current system, they forget to tell you that the current system is already disrupting and destabilizing millions of people's lives."
And in challenging his 2020 rivals to avoid taking money from the health care industry, Sanders said any candidate who refused to take that pledge "should explain to the American people why those corporate interest and their donations are a good investment for the health care industry."
A central question in the debate over Medicare of All is how the cost of such a plan would be covered. Sanders has said taxes would increase on middle-income earners. California Sen. Kamala Harris, who supports Medicare for All, told CNN this week that she wasn't "prepared to engage" in such tax hikes.
The roaring health care debate also is likely to further draw in the full Democratic field. Beyond Harris, several other leading 2020 candidates, including Massachusetts Sen. Elizabeth Warren, support Medicare for All. However, some other Democratic hopefuls have warned that the party is moving too far left and have supported a more centrist approach.
Among them is Colorado Sen. Michael Bennet, who prefers a public option for health coverage that could be included in the current structure of the Affordable Care Act.
While campaigning in Iowa, Bennet said that Democrats would "never unify around Medicare for All," but that plans like his could bring the party together and notch wins in states like Colorado.
"If you're gonna stand up and commit the Democratic Party to taking away from 180 million people, you'd better be clear on what the nuances are because when you're running against Donald Trump, it's going to be too late," he said.
Associated Press writers Elana Schor and Hannah Fingerhut in Washington contributed to this report.
Follow Summers on Twitter at https://twitter.com/jmsummers .