We report the synthesis and characterization of a novel nanoparticle formulation designed
for skin penetration for the purpose of skin imaging. Solid lipid nanoparticles (SLNs), a
drug delivery vehicle, were used as the matrix for targeted delivery of peroxide-sensitive
chemiluminescent compounds to the epidermis. Luminol and oxalate were chosen as the
chemiluminescent test systems, and a formulation was determined based upon non-toxic
components, lotion-like properties, and longevity/visibility of a chemiluminescent
signal. The luminescence lifetime was extended in the lipid formulation in comparison to
the chemiluminescent system in solution. When applied to porcine skin, our formulation
remained detectable relative to negative and positive controls. Initial MTT toxicity
testing using HepG2 cells have indicated that this formulation is relatively non-toxic.
This formulation could be used to image native peroxides present in tissue that may be
indicative of skin disease.
Polyaromatic compounds, with terminal functional groups, can be non-covalently bonded to the sidewall of carbon
nanotubes. This architecture preserves the structural, mechanical, electrical, and electromechanical properties of the
CNTs and ensures that an unhindered functional group is available to bond with an extended polymer matrix.
Spectroscopic measurements and high resolution imaging are used to confirm the functionalization and incorporation of
functionalized MWNTs into a nylon 12 matrix.
Surface enhanced Raman spectroscopy (SERS) has promise as an optical sensor for the detection of chemical and biological agents, in particular when combined with front-end processing for sample preparation prior to analysis. In this paper, we report preliminary results from a SERS analysis of Bacillus cereus T strain (BcT), which was prepared for sensor analysis via a microfluidics-based sample processor. In the microfluidics hardware, low and high molecular weight analytes from a sonicated spore sample were separated via mass-dependent diffusion into two independent microchannels. SERS analysis of the sample outputs revealed a significant separation of the low molecular spore biomarker, dipicolinic acid, from the high molecular weight protein and nucleic acid background. In addition to the processing study, measurements were performed on gold core-shell nanospheres, which are considered a potential SERS substrate for the microfluidic system. Finally, field-induced aggregation of silver nanoparticles, an alternative to chemical aggregation, was shown to be an effective approach for the production of highly enhancing SERS substrates.
In this paper, we report the preliminary results from a microfabricated substrate system that is amenable to both electromagnetic field-enhanced spectroscopy such as surface enhanced Raman scattering (SERS) and analyte separation and detection. Substrates consisting of arrays of gold post-like and pit-like features of varying pitch on gold substrates were fabricated by electron beam lithography. These substrates were characterized and tested for reproducible SERS activity, as well as evaluated for incorporation into a microfluidic system for separation and identification of components of complex matrices. Identification of analytes relevant to biodetection and biological screening is reported.