Personalized Biological Engineering Heart Toddler Long Sleeve T-Shirt. Biological engineering text in a heart with pimples is a humorous design for bioengineers. Fun gift ideas for birthdays, holidays, graduation and Valentine's Day. A classic for Fall, Winter and Spring, these long sleeve toddler t-shirts are sure to be a staple in your child's wardrobe. Whether layered or alone, this t-shirt is soft yet durable enough to stand up to your toddler's playtime demands.