Alginate microspheres have recently become increasingly popular in the realm of drug delivery for their biocompatibility, nontoxicity, inexpensiveness, among other factors. Recent strict regulations on microsphere size have drastically increased manufacturing cost and waste, even though the effect of size variance on drug delivery and subsequent performance is unclear. If sphere size variance does not significantly affect drug release profiles, it is possible that future ordinances may loosen tolerances in manufacturing to limit waste produced and expenditures. We use a mathematical model developed by Nickel et al. [12], to theoretically predict drug delivery profiles based on sphere size, and correlate the expected release with experimental data. This model considers diffusion as the key component for drug delivery, which is defined by Fick’s Laws of Diffusion. Alginate, chosen for its simple fabrication method and biocompatibility, was formed into microspheres with a modified extrusion technique and characterized by size. Size variance was introduced in batches and delivery patterns were compared to control groups of identical size. Release patterns for brilliant blue dye, the mock drug chosen, were examined for both groups via UV spectrometry. The absorbance values were then converted to concentration value using a calibration curve done prior to experimentation. The concentration values were then converted to mass values. These values then produced curves representing the mass of the drug released over time. Although the control and experimental values were statistically significantly different, the curves were rather similar to each other. However, when compared to the predicted release pattern, the curves were not the same. Unexpected degradation caused this dissimilarity between the curves. The predictive model was then adjusted to account for degradation by changing the diffusion coefficient in the code to a reciprocal first order exponent. The similarity between the control and experimental curves can insinuate the notion that size tolerances for microsphere production can be somewhat lenient, as a batch containing fifteen beads of the same size and one with three different sizes yields similar release patterns.

Falls are known to be a common occurrence and a costly one as well, as they are the second leading cause of unintentional deaths and millions of other injuries worldwide. Falls often occur due to an increase in trunk flexion angle, so this experiment aims to reduce the trunk flexion received while stepping over an obstacle. To achieve this a soft actuator was attached to the trunk and pressure was sent as subjects walked and stepped over an obstacle presented on a treadmill. The pressure is meant to stiffen the back which should in theory reduce the trunk flexion angle and lower the chances of falling. In this experiment, two groups were tested: three participants from a control group (healthy young adults) and three participants from an experimental group (healthy elderly adults). Since elderly adults have the highest fall risk due to overall lack of stability, they are the experimental group and the focus for this experiment. The results from the study showed that elderly adults had a beneficial effect with the soft actuator as there was a noticeable difference in trunk flexion when the device was attached. The experiment also supported prior research that stated that trunk flexion was greater in elderly adults than younger adults. Despite the positive results, further studies should be done to prove that the soft devices influence lowering trunk flexion angle as well as to see if the device has any noticeable effect on younger adults.