Discipline: Biological Sciences
Room: Exhibit Hall A
Daijah Lofton - Virginia State University
Co-Author(s): Dipti Biswal, Virginia State University
Hydrogels are network of crosslink hydrophilic polymer chains that are very absorbent in water. The swelling properties of hydrogel can be influenced by the changes of the environment such as pH and temperature. There are various applications of hydrogels in the biomedical and pharmaceutical area such as tissue engineering, wound dressing material, contact lenses, drug delivery and molecular imprinting.1,2 Hydrogel nanocomposites are formed by various types of nanoparticles such as carbon-based, metal/metal-oxide or inorganic/ceramic that integrates to the polymeric network of hydrogel. Iron oxide incorporated hydrogel nanocomposites have potential for various biomedical applications, including magnetic resonance imaging (MRI) contrast enhancement, targeted drug delivery, hyperthermia, biological separation, protein immobilization, and biosensors.3 The incorporation of iron oxide nanoparticles (NPs) in hydrogel matrices exhibit unique properties with capability of actuation by magnetic field at a distance. However, the formation of monodisperse hydrogel nanocomposite is still a challenge. Due to the high surface-to-volume ratio these nanoparticles aggregates during or before the gelation process. We have synthesized monodisperse nanocomposites by in-situ formation of magnetic iron oxide nanoparticles in stimuli responsive hydrogels. Two responsive hydrogels, N-isopropylacrylamide (NIPAAm) and polyethylene glycol (PEG) were used as scaffolds for in-situ synthesis of NPs. The hydrogel matrics were synthesized by free radical polymerization method using N-isopropylacrylamide (NIPAAm) and polyethylene glycol (PEG) as monomers, polyethylene glycol diacrylate (PEGDA) as crosslinker. The redox reactions were carried out by using ammonium persulfate (APS) as initiator and tetramethylethylenediamine (TEMED) as accelerator. The nanocomposites were fabricated by a two-step method. Firstly, the NP precursor solution was loaded into the crosslinked hydrogel. Then, an in situ reduction process of the metal ions occurred, resulting in the formation of NPs throughout the hydrogel matrix. We used a 2:1 molar ratio of Iron (III) chloride hexahydrate (FeCl3.6H2O) and Iron (II) chloride tetrahydrate (FeCl2. 4H2O) solution and ammonium hydroxide (NH4OH) as reducing agent. We continued this cycle several times in order to incorporate maximum amount of nanoparticles in the hydrogel matrix. The hydrogel nanocomposites were characterized by using various techniques such as, Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscope (SEM). Our future research includes the quantitative measurement of NPs and the stimuli response properties of the nanocomposites.
Funder Acknowledgement(s): Department of Defense, Award # W911NF-17-1-0451.
Faculty Advisor: Diptirani Samantaray, email@example.com
Role: I did the synthesis of the hydrogel and monodisperse hydrogel nanocomposites by insitu precipitation method. Also I did the characterization of the nanocomposites.