You are allowed to get a percentage of your investment fund from a bank loan. But then again, unless you have credit history based on your social security number you don’t have yet, banks would be reluctant to provide you with a loan. You could potentially raise debt against cash deposited as debt collateral. Once you had your visa and established a credit history, you could request the bank to free some of that deposit. Doing so would also help to build your credit history faster.
You are also allowed to get a loan from a friend or relative if you do not have the entire investment fund from your own financial resources. The loan must be transferred directly into your account and you must have control over the funds.