Elon Musk's biotechnology startup Neuralink raised $280 million in a fundraising round, the company announced Monday via X, the Musk-owned social media platform formerly known as Twitter.

The Series D round was led by Founders Fund, a San Francisco-based VC firm established by Peter Thiel, the controversial billionaire who was also a cofounder at PayPal.

"We're extremely excited about this next chapter at Neuralink," the company wrote.

The brain chip startup wants to use implants to connect your brain to a computer, a goal Musk has been working on for five years. The company so far has only tested on animals and faced scrutiny after a monkey died in project testing in 2022 as part of efforts to get the animal to play Pong, a computer game.

Macaque monkeys have been used in testing by Neuralink as the company has been developing Bluetooth-enabled implantable chips — inserted into the monkey's brains — that ​the company says can communicate with computers via a small receiver.

The funding news comes months after Musk announced the company was moving towards human trials. The billionaire said at a December recruiting event that Neuralink has submitted "most" of its paperwork to the US Food and Drug Administration and could begin testing on humans within six months.

But employees have said the company is rushing to market, resulting in careless animal deaths and a federal investigation, according to a December report by Reuters.

Before Neuralink's brain implants are mass-produced and hit the broader market, they'll need regulatory approval. The FDA put out a paper in 2021 mapping out the agency's initial thoughts on brain-computer interface devices, noting the field is "progressing rapidly."

A tweet by Neuralink Monday announced they were hiring and invited those interested to "join in on engineering challenges to restore vision and mobility."