Gelatin Diffusion Experiment Nanotechnology in Medicine Neil S. Forbes.
Presentation on theme: "Gelatin Diffusion Experiment"— Presentation transcript:
1Gelatin Diffusion Experiment Nanotechnology in MedicineNeil S. Forbes
2BackgroundThe delivery of nanoscale medicines to cells in the human body requires diffusion through tissues, organs and cell membranesThis activity explores the affect of different diffusion ratesUnderstanding molecular diffusion through human tissues is important for designing effective drug delivery systems
3IntroductionMeasuring the diffusion of dyes in gelatin illustrates the transport of drugs in the extra-vascular spaceGelatin is a biological polymeric material with similar properties to the connective extracellular matrix in tumor tissueDyes are similar in molecular weight and transport properties to chemotherapeuticsTheir concentration can be easily determined simply by color intensityGreen food dye contains tartrazine (FD&C yellow #5) and brilliant blue FCF (FD&C blue #1), which have molecular formulae of C16H9N4Na3O9S2 and C37H34N2Na2O9S3, and absorb yellow light at 427nm and blue light at 630nm
4Experiment OverviewThe diffusion of the dyes is measured to demonstrate the effect of molecular weight on transport in tumorsGelatin will be formed into cylindrical shapes in Petri dishes and colored solutions will be added to the outer ringOver several days the distance that the dyes and particles penetrate into the gelatin cylinders will be measured
5Experimental SetupGelatin cylinders are formed in Petri dishes. This represents tumor tissue.Food dye is added to the space surrounding the gelatin. This represents the lumen of blood vessels.Each day, two images are of dye diffusion are acquired. This captures the penetration of nanoparticles or drugs in to the tumor.The rate of diffusion is calculated from the images.The diffusion rates of different dyes can be compared.
6Questions to consider What did you expect to happen? Which dyes do you expect to penetrate better?Does fast diffusion mean greater or poorer retention?Why does diffusion matter?Does retention matter?Could diffusion and retention be optimized?
7Start3 hoursDiffusion is first visible8 hoursGreen Food Color
16Questions to Consider Are the results expected? Which dyes penetrated better?Do your results make sense?Which would penetrate the best?Which would have the best retention?Which would be the best drug (based on transport alone)?Do you have enough information to answer these questions?What else would you need to know?How could nanotechnology be used to optimize drug diffusion and retention?
18Results Diffusion is very slow (millimeters per hour) The physical properties of a dye (or drug) affect the diffusion rate
19ImplicationsUnderstanding the relation between diffusion and convective delivery (through the vasculature) is essentialThe properties of delivery systems should be carefully tailored to enhance drug penetration and retention