Figure 1. Bacterial culture infected with phage
We are developing reagents call NProbes to detect nanomaterials (e.g. carbon nanotubes, quantum dots, metal and metal oxide nanoparticles) in tissues that may not observed using common analytical techniques. This may be due for example, to their low presence, a high tissue autofluorescence background, an inability to achieve adequate nanoscale resolution or an inability to distinguish them from endogenous features. NProbe reagents will function similar to antibodies. NProbes will fuse with an enzymatic reporter thereby allowing signal amplification and detection using standard immunohistochemistry. The NProbe reagents will thus serve as diagnostic tools to aid in the detection of both fluorescent and non-fluorescent nanomaterials in biological systems that may be present in low levels using commonly used microscopic techniques.
Phage display technology is used to identify NProbes. Their binding will be dictated by nanomaterial properties such as size, surface chemistry, agglomeration state and charge. After panning (mixing the phage with nanomaterials) and washing , the bound phage are recovered and amplified in bacteria (Fig. 1). To test for enrichment, colonies are randomly selected from the culture plate and an endonuclease digest is performed to look for duplicates (Fig. 2). Binders that are observed are converted to NProbe reagents that can be used to analyze histologic sections. Areas that stain dark blue indicate presence of nanomaterials which in some case can be confirmed using other analytical techniques.
Figure 2. 2 Clones are randomly selected
and digested to look for repeats
Figure 3. Histologic skin section treated
with nanoparticles and examined with NProbes