Novel Functional Foods, Nanoencapsulation of Nutraceuticals/Drugs, Biosensors, Single Molecule Force Spectroscopy/Chemical Force Microscopy, Biopolymer Nanocomposites, Bionanotechnology
The overall theme of my research at Rutgers is the rational design of food nano- or micro-structure for improved quality and performance. Most of my research projects are multi-disciplinary in nature, and immerse students in research fields including bionanotechnology, biopolymers, biochemistry, food chemistry, and materials science. Following is a summary of my specific research areas:
(1) Nanoencapsulation of Nutraceuticals/Drugs. The development of high quality, stable dietary supplements with good oral bioavailability will have a major impact on the food industry. One of the major challenges of dietary flavonoids and carotenoids is their poor oral bioavailabily. A wide variety of encapsulation platforms, including nanostructured emulsions, W/O/W or O/W/W double emulsions, solid lipid or biopolymer–based nanoparticles, and direct conjugation of phytochemicals to biopolymer side chains have been developed in my lab to encapsulate plant polyphenolic compounds. Our results show that the body absorption and the blood circulation time of phytochemicals inside the body increase, therefore, the desired pharmaco-kinetics of these phytochemicals may be achieved.
(2) Self-Assembly of Biopolymers at Nanoscale. Because of the complexity of modern multi-component food systems, the physical properties of food materials, such as phase behaviors, mechanical properties, and intermolecular interactions between food components at different length scales (nano-, micro-, and macro-scales) must be understood. Polysaccharides and proteins are two key components in both natural and processed foods. The knowledge of their interactions is of importance not only in making cost-efficient use of functional ingredients, but also in designing novel food, controlling and improving food ingredient structures and textural properties of fabricated foods. We have developed new experimental techniques and computer simulation algorithms to provide new insights into the self-assembly of food polymers in a series of complex fluids:
- Hydrocolloid Gels: Hydrocolloids have been widely used as gelling or thickening agents in the food industry; however, many issues related to physical gelation in polymer solutions induced by self-assembly of polymer chains remain unclear. We have developed a novel method that can predict and construct phase diagram, as well as provide molecular level understanding of sol-gel transitions of polymers through a combination of small-angle neutron scattering and Monte Carlo simulation on the basis of a recently-developed eight-site bond fluctuation algorithm.
- Protein/Polysaccharide Hybrids: Hybrids formed by polysaccharides and proteins have already served as important materials in a variety of food/drug delivery applications because they create a barrier of protein between food ingredients and food matrices, and this barrier improves the ingredient performance and shelf-life stability in many food systems.
- Chemical Force Microscopy: The macroscopic properties of food biopolymers are determined to a great extent by the mechanical characteristics of individual components, including such aspects as entropic and enthalpic elasticities as well as their molecular conformations. Very recently, the conformation of BSA as well as its interactions with negatively-charged surface in saline solutions of different pH have been investigated by SANS and AFM-based chemical force microscopy (CFM) (J. Phys. Chem. B, 2008). A new approach to extract the contribution of elementary interactions from the statistically averaged force-extension curves through self-consistent fitting has been developed.
- Multilayer Biopolymer Films: In recent years considerable effort has been devoted to the development of methods for the preparation of composite food particles consisting of polymer cores covered with shells of different chemical composition. Our approach is to assemble edible films with controlled surface hydrophobicity and morphology through the formation of multi-layer biopolymer films using a layer-by-layer (LBL) approach. We have developed UV-Ozone treatment to modify the film hydrophobicity, and electrostatic LBL deposition of charged biopolymers to form nanostructured films with specific properties.
(3) Quantum Dots: To strengthen the power of these delivery systems with the addition of the traceable and targetable capabilities, we have developed a method to prepare water-soluble CdTe QDs with excellent chemical stability and quantum yields (J. Phys. Chem. B, 2006; J. Phys. Chem. C, 2008). Now these water-soluble QDs are ready to be incorporated into our nanoemulsion- or nanoparticle-based delivery systems.
(4) Drug/Protein Interactions: Many studies showed that the interactions between polyphenols in tea and proteins may lead to the loss of bioavailability of polyphenols and their antioxidant capacity. It is crucial to understand the mechanism of binding between tea polyphenols and proteins. Recently, we have used QCM-D to systematically monitor the binding between a series of tea polyphenols, including EGCG (J. Agr. Food Chem., 2007), theaflavin, thearubigin (J. Agr. Food Chem., 2007) and BSA surface. This approach can be easily expended to the screening of nutraceuticals, as well as the studies of binding between drugs and receptor proteins.
(5) Nanoscale Biosensors for Pathogen Detection and Disease Diagnosis: Two types of biosensors have been developed in my laboratory: (1) chip-based sensors, where high-capacity surfaces with increased number of probes (and subsequently the amount of bound target) have been fabricated to generate greater signal output, and (2) QCM-D based biosensors, where toxins or pathogenic cells can be detected through the incorporation of direct immunoassay