1. RESEARCH POSTER PRESENTATION DESIGN © 2011
www.PosterPresentations.com
The study of organisms such as bacteria and viruses
has increasingly developed over the years.
Researchers are on a quest to perfectly understand
the existence of microbes, mode of survival,
usefulness, how to eradicate harmful ones and their
effects on life as we know it.
The basis of my research work is synthesizing
polyhedral oligomeric silsesquioxanes commonly
called POSS compounds. These cube like structures
serve as a backbone for all the ligands I have made
to fight microbes; targeting bacteria cell walls.
Starting from synthesized POSS polymer and various
imidazoles, new water soluble compounds were
synthesized. In addition, a silver (I) complex was also
formed using this ligand system. I hope to present a
summary of my work in a poster at the ACES
symposium. This research work is important to
groundbreaking development of anti-microbial
studies with hopeful synthesis of a novel worthy
compound that effectively attacks harmful bacteria.
ABSTRACT
The study of microorganisms such as bacteria and
viruses has advanced over the years. It is important
to understand how and where these organisms can
survive, their benefits, disadvantages and how to
destroy harmful ones.
Bacteria are usually a common pick as they are
easier to analyze and manipulate.
INTRODUCTION
Octakis(3-chloropropyl)octasilsesquioxane is synthesized after a six weeks long experiment. The eight branches
on this POSS cube are used as point of attachment for nucleophile attack and ligand formation.
•Water soluble POSS-methylimidazolium chloride ligand, with methyl imidazoles attached to each branch of the
cube is formed and toxicology tests are conducted on different bacterial cells. Yield: 82%. This sticky white
compound is moisture sensitive.
•In addition, a silver (I) complex was also formed using the same ligand system by reaction with Ag2O. Yield:
45%. Solid obtained is light sensitive due to presence of silver (Ag ) metal.
RESULTS
According to popular research, bacterial cell walls are permeated by poisons, heavy metals like silver and
mercury, and alcohols. In addition, the highly negatively charged bacterial walls are more prone to attack of
positively charged antimicrobial agents by electrostatic and hydrophobic interactions. This cellular association
causes a break down of the cell wall or prevents the bacterium from forming more cell wall- hence it cannot grow.
These interactions are mimicked by the synthesis of bulky metal coordinated compounds (ligands) to disrupt the
formation of bacterial cell walls.
DISCUSSION
CONCLUSION
Ligands successfully synthesized and crystallized are
tested in microbiology labs to confirm antimicrobial
activity. POSS-methylimidazoilum chloride ligand
shows positive activity in affecting bacterial cells.
However, it proves too reactive because it disrupts
both good and bad bacterial cell walls.
Toxicology tests are currently being carried out with
the other ligands on different strands and types of
bacteria.
REFERENCES
•Cordes, D.B., Lickiss, P.D., Rataboul, F. “Recent
Developments in the Chemistry of Polyhedral
Oligosilsesquioxanes.” Chem. Rev. 2010, 110, 2081–
2173.
•Filho, N.L.D., Costa, R.M., Schultz, M.S. “Structure
of copper(II) complexes adsorbed on functionalized
polyhedral oligomeric silsesquioxane.” Inorg. Chim.
Acta. 2008, 361, 2314-2320.
ACKNOWLEDGEMENTS
I give my sincere thanks and gratitude to Dr. Rasika
Dias for giving me the opportunity to be a member of
his research lab. I am thankful to everyone in the
research group most especially Chandrakanta Dash
for his assistance and supervision.
Synthesis of antimicrobial agents from POSS compounds
Department of Chemistry and Biochemistry, The University of Texas at Arlington
Omobonike Osunloye, Rasika Dias
Figure 1: Diagram of bacterium cell
According to developments by a Danish physician, Dr. Hans Christian Gram, bacteria in all forms are classified as
gram negative or gram positive bacteria, which differ basically in structure. Bacteria can be further classified into
good, neutral and bad or pathogenic bacteria.
Figure 2: Diagram of gram- positive and gram-negative bacterium
Polyhedral oligomeric silsesquioxanes popularly called POSS compounds are utilized for many scientific purposes
especially in biomedical applications, as dental nanocomposites and in different aspects of chemistry.
Experimental research work done is based on the synthesis of antimicrobial agents using POSS compounds. The
eight arm cube like structure synthesized (Octakis(3-chloropropyl)octasilsesquioxane) serves as a backbone for all
the ligands aimed at fighting microbes; targeting bacteria cell walls. The goal is to destroy only harmful bacteria
without hurting good bacteria or cells.
Scheme 1: Reaction scheme for synthesis of POSS compound , POSS-methylimidazolium chloride ligand and
silver complex.
FUTURE RESEARCH
Further research on synthesizing anti-microbial agents
using long chain imidazoles coordinated with selenium
and other metals.