A Miniature Probe for Ultrasonic Penetration of a Single Cell

Although ultrasound cavitation must be avoided for safe diagnostic applications, the ability of ultrasound to disrupt cell membranes has taken on increasing significance as a method to facilitate drug and gene delivery. A new ultrasonic resonance driving method is introduced to penetrate rigid wall plant cells or oocytes with springy cell membranes. When a reasonable design is created, ultrasound can gather energy and increase the amplitude factor. Ultrasonic penetration enables exogenous materials to enter cells without damaging them by utilizing instant acceleration. This paper seeks to develop a miniature ultrasonic probe experiment system for cell penetration. A miniature ultrasonic probe is designed and optimized using the Precise Four Terminal Network Method and Finite Element Method (FEM) and an ultrasonic generator to drive the probe is designed. The system was able to successfully puncture a single fish cell

Preparation and Purification of Enlarged Multinucleated U937 Human Leukemia Cells and their Susceptibility to Physical Damage by Ultrasound

Multinucleation occurs in neoplastic cells that have been treated with cytochalasin B, a fungal toxin that disrupts actin microfilament structures. When the actin cytoskeleton is disrupted, contractile ring formation and cytokinesis are inhibited. In normal cells cytochalasin B prevents the cells from entering the cell cycle. However in neoplastic cells, since cytokinesis no longer occurs, the dividing cell becomes enlarged and heavily multinucleated. We propose that enlarged leukemia cells may be more sensitive to ultrasound treatment because of their increased size and weakened cytoskeletal structure. To determine the differential chemical and physical response of enlarged, multinucleated cells in comparison with non-enlarged mononucleated leukemia cells, physical separation of the large and small cells is needed. Using 19 μ steel mesh, a filter system was devised to separate enlarged cells greater than 19 μ in diameter from normal leukemia cells with diameters of 15 μ by settling through a 3.5 cm diameter 19 μ stainless steel mesh sieve with no hydrostatic head and no fluid flow through the filter. The distribution of cells sizes was determined with a Coulter Counter, and the viability was determined by hemocytometer counts, re-growth assays, and cloning assays in agarose. We used the purified cells from this experiment to test the cells’ susceptibility to damage by ultrasound. Acoustic cavitation produced by ultrasound is the process by which high intensity acoustic fields in liquids lead to the creation and oscillation of cavities or gas bubbles. Previous research has shown that ultrasound can transiently disrupt cell membranes and, thereby, facilitate the loading of drugs and genes into viable cells without killing the cells. In our experiments, rather, we sought to determine whether there was a sonic sensitivity in cells treated with cytochalasin B that can lead to cell disruption and cell death, which might be exploitable as a potential modality in leukemia therapy. By exposing both CBtreated and control U937 leukemia cells to ultrasound, we have found that at greater lengths of sonic exposure, the CB-treated cells are more damaged than the control cells. Furthermore, we found that there was a statistically significant retardation in growth rate of sonicated CB-treated cells two and six days post-sonication. This same response to the ultrasound was not seen in the control cells. This physical treatment may be applicable to enhancing the cytotoxic effects of microfilament agents in treatment of leukemia in pre-clinical animal models, and may introduce ultrasound as a physical modality in leukemia treatmen

Novelty processing and smart delivery of Ganoderma Lucidum spores

In recent decades the traditional Chinese medicinal mushroom Ganoderma lucidum (GL), a fungal specie widely consumed homoeopathically in the Eastern Hemisphere, has been studied particularly with respect to antitumour and immunoenhancing effects. Research into the various claims however remains limited owing to the lack of quality and consistency across investigations. As such, efficacy and feasibility of scaleup has not been evaluated in a way that allows widespread consumption or approved treatment. This project tackles three aspects of drug development from Ganoderma lucidum: Biocompound extraction, healthcare evaluation via in-vitro testing, and encapsulation for smart delivery. These avenues are brought together for the first time to evaluate the prospects of developing GL for effective and safe healthcare. This research investigates the parameters that would influence the extractability of a biocompound from the spores of Ganoderma lucidum (GLS), via two conventional methods: Hot Water Extraction (HWE) and Ultrasound-Assisted Extraction (UAE). They are evaluated with respect to their crude water-soluble polysaccharide yield (GLPS). Solvent polarity and process duration were statistically significant factors affecting extract yield, with both extraction methods showing considerable gains over similar setups in literature, recovering over 6% crude GLPS using shorter durations and lower temperatures than other published investigations. This investigation highlighted the importance of solvent viscosity on specific DGlucan extraction in the GLPS yield. Bioactive effects of the extract were evaluated via cytotoxicity toward Human Osteosarcoma (HOS) cells in-vitro, achieving over 40% cell growth inhibition. Cytotoxicity however was only achieved when water-insoluble fractions were administered – suggesting cytotoxicity was a result of the unextracted crude triterpenoids (GLTP) containing Ganoderic Acids. Therefore, HOS-inhibitory capabilities are then compared to a GLPS extract containing Ganoderic Acids (in this work termed “PSGA”), extracted using HWE subject to supervised machine learning optimisation. As well as determining that this yield was maximised at the longest HWE duration and smallest solvent volume, it was observed to inhibit HOS growth by nearly 58% after 24 hours. Low doses and shorter incubation were most effective - suggesting concepts such as resistance (clonal selectivity) and delayed apoptosis, but further work will verify the reported effects of PSGA dosage and exposure time on cancer proliferation. Lastly, research effort is devoted to creating an alginate matrix for the controllable delivery of GLS using Electrohydrodynamic Atomisation (EHDA). Significant effects of the system’s process parameters on particle morphology are observed, in particular EHDA voltage. The carrier’s size, shape and surface features are correlated with its release profile. Importantly, GLS content (something traditionally compromised to maintain particle integrity) was maximised at 50 wt% whilst maintaining a controlled and spherical shape and size – making this study novel and extremely important. It is established that GLS-Alginate particles could offer controlled release over a 2-week administration in pH-neutral conditions; an environment not yet established as “stable” for alginate, yet reflective of physiological passage. Thus, for the first time sodium alginate is proven to be a real contender in controlling the delivery of GLS biomolecules. The reconciliation of these essential stages of drug development highlights some crucial points of focus as GL continues to undergo rigorous development in the realm of drug discovery

Aerospace Medicine and Biology: 1983 cumulative index

This publication is a cumulative index to the abstracts contained in the Supplements 242 through 253 of Aerospace Medicine and Biology: A Continuing Bibliography. It includes six indexes--subject, personal author, corporate source, contract number, report number, and accession number

2012 Annual Research Symposium Abstract Book

2012 annual volume of abstracts for science research projects conducted by students at Trinity College