MATERIALS AND METHODS: In this study, aptamer-antibody complementation was implemented on a multiwalled carbon nanotube-gold conjugated sensing surface with a dielectrode to detect pandemic pdmH1N1. Preliminary biomolecular and dielectrode surface analyses were performed by molecular and microscopic methods. A stable anti-pdmH1N1 aptamer sequence interacted with hemagglutinin (HA) and was compared with the antibody interaction. Both aptamer and antibody attachments on the surface as the basic molecule attained the saturation at nanomolar levels.
RESULTS: Aptamers were found to have higher affinity and electric response than antibodies against HA of pdmH1N1. Linear regression with aptamer-HA interaction displays sensitivity in the range of 10 fM, whereas antibody-HA interaction shows a 100-fold lower level (1 pM). When sandwich-based detection of aptamer-HA-antibody and antibody-HA-aptamer was performed, a higher response of current was observed in both cases. Moreover, the detection strategy with aptamer clearly discriminated the closely related HA of influenza B/Tokyo/53/99 and influenza A/Panama/2007/1999 (H3N2).
CONCLUSION: The high performance of the abovementioned detection methods was supported by the apparent specificity and reproducibility by the demonstrated sensing system.
Methods: The behaviour of GEM in MCT/surfactants/NaCl systems was studied in the ternary system at different ratios of Tween 80 and Span 80. The system with surfactant ratio 3:7 of Tween 80 and Span 80 was chosen for further study on the preparation of nanoemulsion formulation due to the highest isotropic region. Based on the selected ternary phase diagram, a composition of F1 was chosen and used for optimization by using the D-optimal mixture design. The interaction variables between medium chain triglyceride (MCT), surfactant mixture Tween 80: Span 80 (ratio 3:7), 0.9 % sodium chloride solution and gemcitabine were evaluated towards particle size as a response.
Results: The results showed that NaCl solution and GEM gave more effects on particle size, polydispersity index and zeta potential of 141.57±0.05 nm, 0.168 and -37.10 mV, respectively. The optimized nanoemulsion showed good stability (no phase separation) against centrifugation test and storage at three different temperatures. The in vitro release of gemcitabine at different pH buffer solution was evaluated. The results showed the release of GEM in buffer pH 6.5 (45.19%) was higher than GEM in buffer pH 7.4 (13.62%). The cytotoxicity study showed that the optimized nanoemulsion containing GEM induced cytotoxicity towards A549 cell and at the same time reduced cytotoxicity towards MRC5 when compared to the control (GEM solution).