Santillan needed a second transplant because doctors discovered during her first transplant that she received organs that were not compatible with her blood type.
Many of those who attended the memorial said they did not know Jesica, but knew of her and were touched by her story and struggle for life.
One mourner wrote a poem in her honor.
"When you think of Jesica, think of a beautiful flower, someone with great power -- power to smile in the midst of a storm, power to keep her loving heart warm."
"She was only 17 and it really upset me. Her whole life is completely gone, and I just feel sorry for her and her family," mourner Niela Davis said.
"Everytime you saw her, she was always smiling. She always had a good outlook. She was a real sweet girl," mourner Belinda Peoples said.
The service was conducted in English and Spanish. Those in attendance said the memorial fit the sweet, smiling young girl.
Jesica's cousin, Americas Santillan, spoke on behalf of the family. She talked about Jesica's childhood, her warm heart and her dreams.
"She always wanted to be famous because she loved people. And she wanted to know the world and for the world to know and love her. And through this tragic situation this wish of Jesica's has become true," Santillan said.
The Santillan family said they are not sure whether they will return Jesica's body to Mexico for burial.
Family attorney Kurt Dixon said he received about 500 pages of Jesica's medical records from Duke University Hospital Wednesday.
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