Modeling of external self-excitation and force generation on magnetic nanoparticles inside vitreous cavity.

The purpose of this manuscript was to design a better method for recovery from rhegmatogenous retinal detachment (RRD) surgery. We attempted to achieve this by designing a helmet that can manipulate intraocular magnetic nanoparticles (MNPs) and create a magnetic tamponade, eliminating the need for postoperative head positioning. A simulated analysis was developed to predict the pattern of magnetic force applied to the magnetic nanoparticles by external magnetic field. No participants were involved in this study. Instead, magnetic flux and force data for three different helmet designs were collected using virtual simulation tools. A prototype helmet was then constructed and magnetic flux and force data were recorded and compared to virtual data. For both virtual and physical scenarios, magnitude and direction of the resulting forces were compared to determine which design created the controlled direction and strongest forces into the back of the eye. Of the three virtual designs, both designs containing a visor had greater force magnitude than magnet alone. Between both designs with visors, the visor with bends resulted in forces more directed at the back of the eye. The physical prototype helmet shared similar measurements to virtual simulation with minimal percent error (Average = 5.47%, Standard deviation = 0.03). Of the three designs, the visor with bends generated stronger forces directed at the back of the eye, which is most appropriate for creating a tamponade on the retina. We believe that this design has shown promising capability for manipulating intraocular MNPs for the purpose of creating a tamponade for RRD.

Model for Gold Nanoparticle Synthesis: Effect of pH and Reaction Time.

The synthesis of gold nanoparticles is dependent on both the concentration of trisodium citrate dihydrate and the time that it interacts with tetrachloroauric acid. A wide range of gold nanoparticles with various sizes and dispersity can be produced based on control variables, such as time of reaction and acid concentration, using a similar approach to that of the Turkevich model. In this model, the pH of the solution decreases slightly throughout the reaction (0.005 unit/min) due to the chemical interactions between trisodium citrate dihydrate and tetrachloroauric acid. Dicarboxy acetone is formed during citrate oxidization, resulting in gold nuclei formation over time. In addition, gold nanoparticle nucleation causes pH fluctuation over time based on gold nanoparticle sizes. An inverse correlation (coefficient of smaller than -0.97) was calculated between the pH and reaction time at different ratios of trisodium citrate dihydrate to tetrachloroauric acid. Regression analysis was used to develop a model for the prediction of the size of gold nanoparticles ranging from 18 to 38 nm based on the concentration of trisodium citrate dihydrate and the reaction time.