Professor Chuan-Jian Zhong of SUNY at Binghamton is supported by the Analytical and Surface Chemistry Program in the Division of Chemistry to study the interparticle structures and properties of magnetic core-shell nanoparticles and assemblies. Methods for the synthesis of magnetic nanoparticle cores of controlled sizes, and for the subsequent coating of the particles with Au and Ag shells of controlled thickness will be developed. The particles will be used as SERS nanoprobes for application in bio-recognition. Functional ligands will be employed to assemble the particles into organized structures to investigate the effects of particle core size, shell composition, core-shell structure, surface ligands, and interparticle interactions on SERS activity. This research addresses the need for core-shell magnetic particles with nanoscale size and surface biocompatibility for applications in biomolecular separations, drug targeting, medical diagnostics, and biosensing. This research will be integrated with educational activities including training of graduate and undergraduate students, and outreach efforts directed at high school students.
This project investigates the structures and functional properties of composite nanoparticles and assemblies as nanoprobes for molecular and biomolecular recognition. The composite nanoparticles consist of cores with magnetic properties and shells with surface-binding properties. New techniques have been developed for the synthesis of such nanostructured materials. The materials can function as spectroscopic probes for enhancing the detection of targeting of biomolecules, such as amino acids, proteins, DNAs, and miRNAs which are associated with certain medical problems such as cancers. The spectroscopic detection mainly focused on surface enhanced Raman scattering, the signal of which can be dramatically enhanced by the interparticle interactions of the core-shell nanomaterials with gold or silver as the shell materials. There are increasing needs of the nanoscale size and surface biocompatibility in applications such as biomolecular separation, drug targeting, medical diagnostics, and bio-sensing, which is addressed by nanoscale of coupling magnetic cores with gold or silver shells. One important element of the nanoprobes is the ability to produce surface enhanced Raman scattering sites (the so-called "hot spots") through the interparticle interactions to provide fingerprinting capabilities for the targeted biomolecular recognition applications. Major findings can be summarized in four areas, including successful synthesis of core-shell structured magnetic-spectroscopic functional nanoprobes; assembly of nanoparticles with defined interparticle structural properties; exploration of the nanoparticles as functional antibacterial agents; and exploration of the nanoprobes conjugated with biomolecules for biomolecular probing. For example, the core-shell nanoparticles with silver nanoparticles as an antibacterial agent while being separable form the target fluids through the magnetic core were demonstrated as functional antimicrobial agent. This approach enables the capability of effective separation, delivery and targeting of the antibacterial agents, which could be useful for bacterial inactivation of blood platelets. Another example involved the conjugation of gold nanoparticles with microRNAs (small and non-coding RNA molecules which function in transcriptional and post-transcriptional regulation of gene expression) for controlled delivery of miRNAs into specific cells. The conjugation of gold nanoparticles with miRNAs (miRNA-AuNPs) was shown to be viable for cell transfection, which constituted a first step in understanding the mechanistic details of cell transfection involving miRNA-conjugated nanoparticles without toxicity left behind and in developing cancer treatment or manipulation of genetic expression. Work is further expanding to developing the nanoprobes for monitoring biomolecular recognition such as DNA hybridization and enzymatic reactivity in solutions as effective bioassay strategies. The core-shell nanoprobes are being explored to produce interparticle "hot-spots" for real-time monitoring of DNA mediated assembly and enzyme induced cleavage in a solution phase in which the magnetic component provides an effective means for intervention. The unique combination of the nanoscale bifunctional or multifunctional properties serves a new paradigm for the design of functional nanoprobes in biomolecular recognition and intervention In this project, postdoctoral researchers, graduate students, undergraduate students, and high school summer internship students were trained with the skills in the synthesis, processing and characterization of metal and magnetic nanoparticles, and in the construction of nanoparticle-structured interfaces for probing molecular or biomolecular interactions involving protein, DNA, miRNA, and bacteria. Some of the graduated PhDs are currently working in academic institutions, industries, national labs. They presented their findings in major national/international meetings, including American Chemical Society and Materials Research Society Meetings. To further broaden the impact of the project and the research topic area, the PI organized an ACS northeast regional meeting symposium on "Nanotechnology - Emerging analytical/bioanalytical & medical applications" (NERM 2010, Potsdam June, 2010), and co-organized an ACS national meeting symposium on "Functional Nanoparticles for Bioanalysis and Bioelectronic Devices" (ACS National Meeting, Denver, Aug., 2011). Based on these symposia, an ACS Symposium Book "Functional Nanoparticles for Bioanalysis, Nanomedicine and Bioelectronic Devices" (Volumes I and II, Ed. M. Hepel and C.J. Zhong) has been published.
