Synthesis And Application Of Novel Smart Nanogels In Small Size

In recent decades, nanogels, i.e., hydrogel nanoparticles with diameters in the range of tens to hundreds of nanometers, have attracted interest because of their significant importance in fundamental studies and practical applications such as cancer diagnosis and therapy, DNA and protein separation, tissue engineering, and biosensors. Due to their small size, stimuli-responsive nanogels can show a much more rapid(almost instantaneous) response to micro environmental stimuli such as temperature, pH, light and magnetic, compared with bulk hydrogels. In this paper, we investigated the synthesis and application of smart nanogels in small size.1. Novel nanogels in small size were synthesized using N-tert-butylacrylamide(TBA), N-isopropylacrylamide(NIPA), acrylic acid(AA) as functional monomer, N,N’-methylenebisacrylamide(Bis) as crosslinker, lauryl sodium sulfate(SDS) as dispersant, ammonium persulfate(APS) as initiator and sodium metabisulfite(Na2S2O5) as catalyst. Then we systematically explored the effect of temperature, crosslinker concentration, dispersant concentration and monomer ratio on size and size distribution of nanogels, and we drew some conclusions as follows: size and polydispersity index(PDI) are bigger below 40 ℃ than above 40 ℃, the best temperature to synthesis TBA series nanogels is 60℃; Bis makes no difference to size but show a minimal value in PDI when the concentration of Bis is 0.2mol%, so the most favorite Bis concentration is 0.2mol%; size decreases when SDS concentration increases while PDI goes down on the contrary, the optimal SDS concentration is 0.04 wt.%; monomer ratio almost has no effect on size and size distribution.2. Temperature and glucose dual-responsive smart P(NIPA-co-VPBA) nanogels were synthesized by vinylbenzeneboronic(VPBA) and NIPA as functional monomer, Bis as cross linker, SDS as dispersant and APS as initiator. Then the effect of pH and VPBA ratio on nanogels size and temperature sensitivity were investigated, conclusions were summarized as follows: all nanogels prepared are smaller than 300 nm and have good polydispersity; pH makes no difference to nanogel size and temperature response; size increases at the beginning and decreases later as VPBA ratio augments, temperature sensitivity changes little with VPBA ration varying; P(NIPA-co-VPBA) nanogels show glucose sensitivity in pH=9.50 buffer solution and the one containing 10mol% VPBA performs the strongest responsitivity. P(NIPA-co-VPBA) nanogels are applied to detect glucose via observing color by naked eyes.