A scientist recently convicted of making illegal campaign contributions will no longer be allowed to travel to China before he is sentenced.

John Dong, who is free on bail, had been granted permission by a federal judge to travel overseas so he could try to save his embattled Mount Pleasant biotechnology company by meeting with investors to request more funding.

Last week, U.S. District Judge Weston Houck issued an order saying he wanted to reconsider his decision, and voided the permission until Dong’s attorneys and prosecutors could present oral arguments.

During a hearing Tuesday in downtown Charleston, Houck pulled the plug on Dong’s trip and also said he is considering having Dong wear GPS satellite monitoring while he awaits his sentencing hearing. Dong also is awaiting trial on charges of defrauding the federal government out of millions of dollars in grant funding.

During the hearing, Dong’s attorneys said he would lose his biotechnology company, GenPhar, without the China trip scheduled for August. Dong was going to meet with investors face-to-face to request a loan to “keep the lights on” at GenPhar, they said.

“I sympathized with what he wanted to do,” Houck said.

Houck said he based his original ruling approving the trip on his own miscalculation of the prison time Dong could receive. He has been convicted of lying to federal agents and illegally making campaign contributions to U.S. Sen. Lindsey Graham, who had been unaware of the violation.

“I thought he was looking at a probationary sentence,” Houck said. “That had a tremendous impact on what I thought, letting him travel.”

A probation agent recently informed Houck that Dong faces a possible sentence of 51 to 63 months in prison. “That changes several things,” Houck said during the hearing.

With a possible three- to four-year prison sentence hanging over Dong’s head, there’s a risk that he might not return to the U.S. if allowed to travel, Houck said.

Dong has previously violated his bail conditions, and the possible prison time “ups the ante substantially,” said Mark Moore, the assistant U.S. Attorney prosecuting the cases.

Dong’s attorneys told Houck that Dong is the only person left at GenPhar and needs the funding to keep the company afloat. Dong needs about $50,000 a month to keep the power on at the Long Point Road facility, where the company is housing vaccines it developed against the Ebola and Marburg viruses, Dong’s attorney said.

“If the power is turned off, they would all die,” Dong said during his testimony at his trial in March.

Dong recently had to forgo receiving a salary and the company has run out of money, his attorneys said.

During the hearing, Houck also said he wants to modify Dong’s bail conditions and require a GPS monitoring bracelet be worn while he remains free in South Carolina.

Chris Adams, one of Dong’s attorney, told Houck that it wasn’t necessary because Dong always appears for his court hearings and that his entire life and his daughter are here.

Adams said he also likely will file an objection to the probation officer’s report, challenging the calculation that suggests a 51- to 63-month prison sentence.

Houck will make his decision about the GPS monitoring during a hearing Monday.

Dong’s second trial is scheduled for November, when he will face other allegations involving GenPhar, in which he is charged with using false claims and bogus paperwork to steal $3.6 million worth of federal grant money that was intended for vaccine research. Authorities said Dong used the money to pay for lobbying and to entertain a mistress in China, among other things.

Reach Natalie Caula at 937-5594 or Twitter.com/ncaula.