THINK 2010 Laboratory Project Category Winners



Finalist: BRANDON LI

Jericho, New York
Jericho Senior High School

Project Title

Pore Size Reduction of Electrospun Polyacrylonitrile (PAN) Scaffolds for High Performance Microfiltration

Abstract

Phase immersion membranes suffer from low porosity, low flux, and difficulty of production. Electrospinning, a process that creates continuous and uniform nanofibers and microfibers, can overcome these limitations, though large pore sizes have limited its application in microfiltration. This study sought to reduce the pore size of electrospun polyacrylonitrile (PAN) through controlling fiber diameter, tip-to-collector distance, and membrane thickness. Electrospun PAN was compressed under deionized water for 0-4 minutes to further reduce the pore size. Pure water flux and rejection percentage of .2 μm carboxylate microspheres of electrospun PAN was compared to that of commercial Millipore™ Millex-GS microfilters both before and after water compression. Though not optimized, the PAN membranes (after 4 minutes of compression) exhibited significantly higher flux (p = 5.65 x 10-7), rejection (p =1.12 x 10-7), and porosity (p = 2.49 x 10-15) than Millex-GS. A new class of high performance electrospun microfilters was developed.




Semi-finalist: GHAZAL ERFANI

Plainview, New York
Plainview Old Bethpage JFK High School

Project Title

Surface Modified pH-Sensitive Liposomes for Targeted Cancer Therapy

Abstract

Ovarian cancer is the deadliest gynecologic cancer with an estimated 14,000 deaths projected by the end of 2009. Due to the limited effectiveness of conventional drug delivery methods, an optimized targeted drug delivery system is essential in the advancement of chemotherapeutic means. Since liposomes are nontoxic amphiphilic molecules of natural origin, they are often used in the creation of nanocarriers. Polyethylene glycol (PEGylated) pH-sensitive liposomes were prepared and loaded with the chemotherapeutic drug, Doxorubicin. Herceptin, a monoclonal antibody which binds to receptor--HER2--commonly overexpressed on the surface of certain cancer cells, was attached to these liposomes to target SKOV3 ovarian cancer cells. Fluorometer measurements were used to show an increased efficacy of liposome targeting, binding, and internalization and a faster, more efficient drug release rate. Furthermore, (MTT) assays were used to quantitatively assess that greater concentrations and uptake of drug initiated significantly higher cell death rates. In the future, liposomes will be exposed to breast cancer cell lines SKBR3 and BT474, which both also overexpress HER2, to further confirm the efficacy of this novel liposomal chemotherapeutic strategy.




Semi-finalist: DANIEL CHUN

Plain, New York
Plainview Old Bethpage JFK High School

Project Title

Modification of PET via a Biocatalyst

Abstract

Poly(ethylene terephthalate) (PET) is widely used in textile and medical industries because of its superior physical, mechanical, and chemical properties. However, its hydrophobic surface significantly diminishes its versatility. Previous studies utilized harsh chemical methods and conditions to increase its hydrophilicity, raising numerous environmental concerns. Thus, a need exists for a “green chemistry” inspired biocatalyst that can catalyze the modification of PET. In this study, PET was modified through transesterification and transamidation reactions using an amine media, Humicola insolens Cutinase (HiC), and a new HiC-AOT complex synthesized through ion-pairing. Fourier Transform Infrared (FT-IR) spectroscopy showed that only the HiC-AOT functionalized the PET with both hydroxyl and amine groups, proving that transesterification and transamidation occurred. Contact angle measurements confirmed that PET modified using HiC-AOT was more hydrophilic than the other modified polymers without sacrificing mechanical stability. Through the enhanced biocatalytic activity of the HiC-AOT complex, the commercial applications of the modified PET are drastically improved. Now, the direct application of dyes onto polyester fibers is feasible, greatly reducing chemical wastes in textile production.