Rapid Optical Detection Strategy for Human Pathogens
Quick, sensitive and specific detection of infectious agents can aid in better treatment of patients and forrecognition of contaminants. Traditional methods suffer from drawbacks of being time consuming and tedious toperform and modern medicine advances call for better detection methods. Strategies employing nanoparticle basedsystems are under investigation to allow for efficient and rapid detection of pathogenic microorganisms.Nanoparticles have been conjugated with nucleic acid probes and antibodies to serve as one step detection system,based on conserved genomic DNA sequences and specific surface proteins expressed by the microorganisms,respectively. Unique size based colorimetric properties are being exploited for developing optical sensors enablingresult visualization with the help of naked eye or simple spectroscopic techniques. The current communication dealswith basic ideology of conjugate synthesis, strategy adopted for deduction of positive and negative interaction withthe test sample and some lab tested examples employing these conjugate systems.
A simple bacterial infection can lead to life threatening situations,when invading bacteria enter bloodstream of the patient, a conditionknown as bacteremia. Rapid detection of the causative infectiousagents is the foremost necessity when it comes to effective and timelytreatment for such infections. Traditionally used methods for pathogendetection have been followed since decades involving isolation andcharacterization of pathogens from the patients. These processes arenot only time consuming but can also lead to arbitrary results since,human body has a rich flora of resident microorganisms. Hence,accurate diagnosis needs repeated culturing and specific correlationwith disease symptoms observed. Molecular diagnosis, based onorganism specific nucleic acid sequences and proteins, has led toimprovement in both sensitivity and specificity of diagnosticprocedures. These methods employ the use of labeled probes or PCRamplification for more reliable detection. A pleasant development inthe world of nucleic acid probes is the advent of Peptide Nucleic Acid(PNA) probes. These probes are a modification of already occurringDNA probes where the phosphodiester backbone is replaced by apeptide backbone but DNA bases remain the same and sustain theircomplementary binding properties. PNA probes offer the advantagesof being uncharged and hydrophobic which allow for easy transportinside the cell and more efficient target binding. PNA probes have beensuccessfully used for direct detection of microorganisms formmicrobiological smears [2,3]. However, these methods requireexpensive apparatus and trained personnel making these more or lessunavailable for underprivileged creating a necessity for alternativemeasures that are cheap and affordable.
Nanotechnology is an emerging field with nanostructures findingextensive applications in the field of biosensing, imaging and detectionof an array of biological entities that provide for point of care diagnosisof diseases and their pathogenesis examination and tracking . Thishas been made possible owing to some extraordinary physico-chemicalproperties exhibited by nanoparticles (NPs), which in turn result fromtheir ultra-fine size and high surface-to-volume ratio  and these sizedependant properties make NPs advantageous over their bulkcounterparts
Journal of Infectious Diseases and Diagnosis