Immobilization of Amino Acids Leucine and Glycine on Polypyrrole for Biosensor Applications: A Density Functional Theory Study

Hermawan K. Dipojono (1Laboratory of Computational Material Design and Quantum Engineering, Engineering Physics Research Group, Faculty of Industrial Technology, Institut Teknologi Bandung, Indonesia)
Irna Safitri (dipo1Laboratory of Computational Material Design and Quantum Engineering, Engineering Physics Research Group, Faculty of Industrial Technology, Institut Teknologi Bandung, Indonesia)
Nugraha Nugraha (1Laboratory of Computational Material Design and Quantum Engineering, Engineering Physics Research Group, Faculty of Industrial Technology, Institut Teknologi Bandung, Indonesia)
Eko Mursito Budi (1Laboratory of Computational Material Design and Quantum Engineering, Engineering Physics Research Group, Faculty of Industrial Technology, Institut Teknologi Bandung, Indonesia)
Nuryanti Nuryanti (1Laboratory of Computational Material Design and Quantum Engineering, Engineering Physics Research Group, Faculty of Industrial Technology, Institut Teknologi Bandung, Indonesia)
Adhitya G. Saputro (1Laboratory of Computational Material Design and Quantum Engineering, Engineering Physics Research Group, Faculty of Industrial Technology, Institut Teknologi Bandung, Indonesia)
Melanie Y. David (2Division of Precision Science & Technology, and Applied Physics, Osaka University, Japan 3Physics Department, College of Science, De La Salle University, Malate, Manila, Philippines)
Hideaki Kasai (2Division of Precision Science & Technology, and Applied Physics, Osaka University, Japan)

Journal of Mathematical and Fundamental Sciences
Vol. 43 No. 2 (2011)

Adsorption based on the immobilization of amino acids, i.e. leucine and glycine, on the surface of undoped polypyrrole (Ppy) is investigated. Calculations are done based on density functional theory using Gaussian03 software and applying GGA with 6-31G(d) basis set and exchange-correlation model of PBE (Perdew, Burke, Ernzerhof) level of theory. The energy of the Ppy doped with amino acids are minimized with respect to the orientation and distance of the amino acids to the Ppy. Neutral leucine carboxyl shows greater binding energy as compared to that other leucine configurations. It has adsorption energy of 0.25 eV at optimum distance of 2.2 Ã… from the surface of Ppy. As for the glycine, the zwitterionic carboxyl exhibits the strongest binding energy among other glycine configurations. It has adsorption energy of 0.76 eV at optimum distance of 1.7 Ã… from the surface of Ppy. The adsorption processes for both amino acids should proceed easily because the activation barriers are either absent or very small.