A string of life sciences companies have attempted to develop sensors that can monitor blood sugar without drawing blood. Thus far, all of these efforts have failed.

Now, it's Silicon Valley's turn.

Apple is the latest to throw its hat in the ring, CNBC reported on Wednesday. The company has a team of about 30 people in an office in Palo Alto working on this problem using optical sensors, which suggests it intends to bring blood sugar tracking to its devices.

Biotechnology experts said such a breakthrough would make the Apple Watch a must-have device for millions of people with diabetes. "There is definitely a huge market opportunity here," said Steve Pacelli, executive vice president of strategy and corporate development at Dexcom, maker of glucose monitoring products.

Shares of Dexcom briefly dipped on Thursday, following the news of Apple's efforts in the space.

A device that could accurately monitor glucose non-invasively and continuously would be a boon for people with type 1 diabetes, who currently rely on finger-pricks and test strips for accurate measurements. It might also prove alluring for people with type 2 diabetes, which affects 29 million adults in the U.S. alone, and so-called "quantified selfers" who are buying glucose monitors to track their blood sugar proactively.

The market opportunity is huge, but many are skeptical about whether such technology is viable -- at least in the near-term.

"Abbott, Medtronic, Johnson & Johnson, Becton, Dickinson and Company and Roche, just to name five established big clinical companies, have taken decades to where we are today," said Doug Schenkel, a senior research analyst with Cowen and Company. "What Apple is trying to do is harder," he added. "This is really tough stuff."

Companies like Dexcom have developed continuous glucose monitors for users to get readings every five minutes with a tiny wire under the skin.

Alphabet's life sciences arm Verily is also making a bid in this space. Unlike Apple, it is taking a partnership-driven approach. One of its experimental efforts is a contact lens, which reads blood sugar levels in tears. Verily is also working with Dexcom on smaller, cheaper glucose sensors.

Despite the challenges with developing non-invasive alternatives, those in the space are not surprised that the opportunity has attracted interest from both Apple and Alphabet.

This is "the most expensive health care problem in society today," said Jeff Dachis, chief executive for diabetes app One Drop. The cost of care and related complications is already costing hundreds of billions of dollars, he said, and 1 in 3 people in the United States are at high risk of the disease. "It's a runaway freight train," he said.

--Additional reporting by Meg Tirrell and Anita Balakrishnan