In 1994, his paper Molecular Computation of Solutions To Combinatorial Problems described the experimental use of DNA as a computational system. In it, he solved a seven-node instance of the Hamiltonian Graph problem, an NP-Complete problem similar to the traveling salesman problem. While the solution to a seven-node instance is trivial, this paper is the first known instance of the successful use of DNA to compute an algorithm. DNA computing has been shown to have potential as a means to solve several other large-scale combinatorial search problems.
For his contribution to the invention of the RSA cryptosystem, Adleman was a recipient along with Ron Rivest and Adi Shamir of the 2002 ACM Turing Award, often called the Nobel Prize of Computer Science.
On an unusual note Prof. Adleman was the mathematical consultant on the movie Sneakers directed by Larry Lasker. Follow the link below to read his first person account.