CHARLESTON, S.C. -- Bernie Sanders has drawn contrasts with Hillary Clinton on health care, paid family leave and Wall Street reform.

He even released a new ad last week with an oblique reference to the former secretary of state that said there were two visions for the Democratic Party: "One says it's OK to take millions from big banks and then tell them what to do. My plan: Break up the big banks, close the tax loopholes and make them pay their fair share. Then we can expand health care to all and provide universal college education.”

During tonight’s Democratic debate in South Carolina, Sanders went one step further, launching arguably his most personal attacks of the former secretary of state yet.

NBC’s Lester Holt asked the progressive what the biggest differences are between him and Clinton on the issue. “Well, the first difference is I don't take money from big banks. I don't get personal speaking fees from Goldman Sachs,” Sanders responded.

He went on to talk about his promise to break up the nation’s biggest banks, and doubled-down on his argument that a candidate who takes money from Wall Street will have a harder time regulating banks.

“But here is the issue, secretary touched on it, can you really reform Wall Street? When they are spending millions and millions of dollars on campaign contributions. And when they are providing speaker fees to individuals,” he continued. “I am very proud, I do not have a super PAC. I do not want Wall Street's money.”

His campaign’s driving home the point with this tweet.

Clinton did not respond to the attacks about the speaking fees, but defended her position on Wall Street. “There's no daylight on the basic premise that there should be no bank too big to fail, and no individual too powerful to jail. We agree on that.”

Clinton has come under fire for the millions of dollars she and her husband, Bill Clinton, have earned in paid speaking gigs since leaving public offices.

After leaving the State Department, Hillary Clinton’s individual speaking fees — many of which came from big, corporate banks — reportedly averaged $200,000 per appearance.