Yes, you may use loaned money to invest in the EB-5 visa program. However, the loan must be secured by the investor's personal assets. The loan cannot be secured by the new commercial enterprise.
A bank loan is acceptable, however, if it is invested in a Regional Center investment, you must be an accredited investor with a net worth of at least $1,000,000, not including your residence, or net income at least $200,000 in each of the last 2 years. Also, you need to show how you will pay off the loan.
In short, yes. That said, you must realize that--It's Just Not That Simple.
One can mortgage their home or other property to secure a loan but cannot pledge any property or assets of the EB-5 Commercial Enterprise to secure the funds used for an EB-5 investor's capital contribution.
I cannot imagine any lender handing over a $500,000 or $1,000,000 for an investment based solely on your signature. Can you?