Sunday, February 19, 2012
Exhibit Hall A-B1 (VCC West Building)
Silicone inter-ocular lenses (IOL’s) and laparoscopic lenses made from boro-silicate, can become opaque or “fog” during surgery, due to optical refraction by coalescing droplets from bodily fluids. Fluids evaporate inside warm body cavities during surgery and then condense on inorganic surfaces. “Fogging” interferes with surgeons’ vision and increase (1) duration of surgery by up to 40%, (2) trauma to patients via infection from repeated wiping, and (3) costs from time lost for other procedures. In this work, condensation is modelled at the nano-scale to control it via adsorbed molecular films. First, water affinity, or hydroaffinity, of silicone and acrylic IOL’s, implant devices, and laparoscopic silica lenses, is analyzed. Simple molecular models for hydroaffinity, water condensation, hydration and adsorption of long chain polymeric gels in emulsions and on Si-based surfaces are combined. Next, a hydrophilic gel is optimized using bio-compatible visco-elastic colloids into a uniquely stable adsorbate emulsion, VitreOx™ , synthesized using FDA approved components. Surgery simulations at T=38°C use artificial eyes, medical grade IOL’s, USP boro-silicate and other Si-based surfaces for comparison, as well as USP balanced saline solutions. After reaching ex vivo success rates of 100% in preventing vision loss through 500+ comparative tests, ten initial trials during vitro-retineal surgery emergencies yield a success rate of 80% with two failures initially inferred from the presence of either blood or blood proteins. Consequently, in a second round of modeling and experiments, one of nature's most electronegative molecules, the blood protein heparin, a common anti-coagulant in surgery, is investigated. Low and physiological dilutions (3 mg/ml) in both saline and VitreOx™ are applied to implant and lenses surfaces. Heparin behaves identically to water on hydrophobic surfaces. It does not prevent fogging nor interfere with VitreOx™. Next, fibrinogen, a large, labile blood protein agonist to heparin, is used in dilution varying between 3 mg/ml and 18 mg/ml. It does prevent fogging, and presents a unique affinity to surfaces, unlike any other blood protein examined. Unexpectedly, the blood proteins studied as well as whole blood do not modify the hydro-affinity of the surfaces treated nor their condensation behavior. However, from these data, an optimized combination of bio-identical visco-elastic colloidal emulsions and blood proteins is developed to control cell and tissue accumulation on implant surfaces, ProteinKnoxTM.