Gel Diffusion Gel Diffusion ExperimentExperiment

STEM ED/CHMSTEM ED/CHM

Nanotechnology Saturday Nanotechnology Saturday SeminarSeminar

Presented by Jennifer Welborn Presented by Jennifer Welborn

Learning GoalsLearning Goals

In this activity, Saturday seminar In this activity, Saturday seminar participants will:participants will:

learn the concept of diffusion and its learn the concept of diffusion and its connection to frameworksconnection to frameworks

See how food dyes and gelatin are See how food dyes and gelatin are used to model the delivery of used to model the delivery of nanoscale medicines to cells in the nanoscale medicines to cells in the human bodyhuman body

Diffusion and Teaching StandardsThis lab has content which is applicable to various disciplines/standards

Physical Science/Chemistry: particle motion theory

Biology: passive transport; cellular structure, etc.

Ecology/Environmental Science: environmental effects on living systems

Math: rates; proportions, data collection, measurement, precision/accuracy

Diffusion

Diffusion– movement of a substance from a region of higher concentration to a region of lower concentration.

Diffusion continues until equilibrium--- the concentration of a substance is equal throughout a space

Diffusion and Cells

• Dissolved particles that are small or non-polar can diffuse through the cell membranes.

• The process of diffusion is one of the ways in which substances like oxygen, carbon dioxide and water move into and out of cells.

Carbon dioxide from the environment diffuses into plant cells

Background For Lab ActivityBackground For Lab Activity

The delivery of nanoscale medicines The delivery of nanoscale medicines to cells in the human body requires to cells in the human body requires diffusion through tissues, organs and diffusion through tissues, organs and cell membranescell membranes

This activity will explore the affect of This activity will explore the affect of particle size on diffusion ratesparticle size on diffusion rates

Understanding molecular diffusion Understanding molecular diffusion through human tissues is important through human tissues is important for designing effective drug delivery for designing effective drug delivery systems systems

Background ContinuedBackground Continued

Measuring the diffusion of dyes in Measuring the diffusion of dyes in gelatin is a model for the transport of gelatin is a model for the transport of drugs in the extra-vascular space drugs in the extra-vascular space

Gelatin: biological polymeric material Gelatin: biological polymeric material with similar properties to the with similar properties to the connective extracellular matrix in connective extracellular matrix in tumor tissuetumor tissue

Dyes are similar in molecular weight Dyes are similar in molecular weight and transport properties to and transport properties to chemotherapeuticschemotherapeutics

Experiment OverviewExperiment Overview

Gelatin was cut into cylindrical disks, Gelatin was cut into cylindrical disks, placed in Petri dishes and colored placed in Petri dishes and colored solutions were added to the outer ringsolutions were added to the outer ring

The distance that the dye particles The distance that the dye particles diffused into the gelatin disks is observeddiffused into the gelatin disks is observed

The diffusion of the dyes is a model of The diffusion of the dyes is a model of the effect of molecular weight on the effect of molecular weight on movement of molecules in tumors movement of molecules in tumors

Lab PrepLab Prep

Collect materialsCollect materials– Petri DishesPetri Dishes– Food DyeFood Dye– Syringes/10 ml Syringes/10 ml

graduated cylindersgraduated cylinders– Paper CupsPaper Cups– Plain GelatinPlain Gelatin– Crisco/Petroleum JellyCrisco/Petroleum Jelly– Baking PanBaking Pan– Biscuit cutterBiscuit cutter

Prepare Gel DisksPrepare Gel Disks– Determine amount of Determine amount of

water needed to fill up a water needed to fill up a pan to a depth of 1 cm. pan to a depth of 1 cm.

– Dissolve gel into cold Dissolve gel into cold water (2Pks/Cup/200 ml)water (2Pks/Cup/200 ml)

– Microwave for 90 Sec.Microwave for 90 Sec.– Pour into pan which has Pour into pan which has

been coated with been coated with petroleum jelly and let petroleum jelly and let set.set.

Lab ProcedureLab Procedure

Gel DisksGel Disks– Cut disks--bisquit Cut disks--bisquit

cuttercutter– Thin coating of Thin coating of

Petroleum jelly on Petroleum jelly on inside bottom of Petri inside bottom of Petri dishdish

– Put gel disk –top side Put gel disk –top side down and centered- down and centered- on bottom of dishon bottom of dish

– Gently press disk to Gently press disk to secure secure

Adding DyeAdding Dye– Mix dyes in cupsMix dyes in cups– Inject one Inject one

color/petri dishcolor/petri dish– No dye on top of gelNo dye on top of gel– No seepage under No seepage under

gelgel– Do not move dishes Do not move dishes

after dye insertedafter dye inserted

Important Details For ProcedureImportant Details For Procedure Make the dye solutions according to directions.Make the dye solutions according to directions. Inject dye towards the outside of the petri dish, Inject dye towards the outside of the petri dish,

not towards the gel.not towards the gel.

Make sure there is a uniform coating of petroleum Make sure there is a uniform coating of petroleum jelly on the bottom of the petri dish and the gel jelly on the bottom of the petri dish and the gel disk is firmly pressed down so no dye leaks under disk is firmly pressed down so no dye leaks under the gel.the gel.

Data CollectionData Collection

Method 1-- By eyeMethod 1-- By eye: measure (in mm) the : measure (in mm) the distance each dye has diffused for each distance each dye has diffused for each time interval. Record data in a data table time interval. Record data in a data table or use excel spreadsheet or use excel spreadsheet

Method 2--Using a digital cameraMethod 2--Using a digital camera: take : take photos of each petri dish at the same time photos of each petri dish at the same time each day, from the same height and each day, from the same height and perpendicular to the gel (to avoid perpendicular to the gel (to avoid parallax) parallax)

Nano-medicine connection: Nano-medicine connection: Targeted TherapiesTargeted Therapies

Nanoparticles diffuse into cancer cells and then heated in a magnetic Nanoparticles diffuse into cancer cells and then heated in a magnetic field to weaken them. Chemotherapy is more effective on the field to weaken them. Chemotherapy is more effective on the weakened cells. weakened cells.

The dye in blue jeans or ballpoint pens has also been paired with The dye in blue jeans or ballpoint pens has also been paired with gold nanoparticles to fight cancer. This dye, known as gold nanoparticles to fight cancer. This dye, known as phthalocyaninephthalocyanine, reacts with light. The nanoparticles take the dye , reacts with light. The nanoparticles take the dye directly to cancer cells while normal cells reject the dye. Once the directly to cancer cells while normal cells reject the dye. Once the particles are inside, scientists "activate" them with light to destroy particles are inside, scientists "activate" them with light to destroy the cancer. the cancer.

Similar therapies have existed to treat skin cancers with light-Similar therapies have existed to treat skin cancers with light-activated dye, but scientists are now working to use nanoparticles activated dye, but scientists are now working to use nanoparticles and dye to treat tumors deep in the body.and dye to treat tumors deep in the body.

http://science.howstuffworks.com/life/human-biology/gold http://science.howstuffworks.com/life/human-biology/gold

nanotech1.htmnanotech1.htm

The next 3 slides are from Professor The next 3 slides are from Professor Jonathan Rothstein’s presentation at Jonathan Rothstein’s presentation at the Nanotech summer institute. The the Nanotech summer institute. The full slide show along with the details full slide show along with the details of the gelatin experiment can be of the gelatin experiment can be found at:found at:

http://umassk12.net/nano/http://umassk12.net/nano/

Targeted Delivery to Tumors

• Goal is to inject treatment far from tumor and have large accumulation in tumor and minimal accumulation in normal cells/organs.

Cancer Treatments

• Tumor penetration is a key issue for successful chemotherapy

Nanoparticle use in Cancer Treatments

• Because of their small size, nanoparticles can pass through interstitial spaces

between necrotic and quiescent cells.

• Tumor cells typically have larger interstitial spaces than healthy cells

• Particles collect in center bringing therapeutics to kill the tumor from inside

out.

Nanomedicine connection-Nanomedicine connection-youtubeyoutube

Youtube video made by the Center for Youtube video made by the Center for Hierarchical Manufactoring at UMASS, Hierarchical Manufactoring at UMASS, Amherst:Amherst:

http://www.youtube.com/watch?http://www.youtube.com/watch?v=bUvi5eQhPTcv=bUvi5eQhPTc

5:40-7:40 shows specific uses of 5:40-7:40 shows specific uses of diffusion of nano-scale particles in diffusion of nano-scale particles in medicine. The rest of the video is medicine. The rest of the video is AWESOME!AWESOME!

Additional Applications of this Additional Applications of this LabLab

Fungal growth! Fungal growth! Kidding KiddingContent– Content–

– Particle motion theory – Particle motion theory – temperature and concentration temperature and concentration

– Molecular weight (chromatography)Molecular weight (chromatography)– Diffusion of materials into and out Diffusion of materials into and out

of cells – connection to cancer of cells – connection to cancer tissue/therapytissue/therapy

Applications, ContinuedApplications, Continued

Process SkillsProcess Skills

- Controlled experiments- Controlled experiments-precision/accuracyprecision/accuracy-Repeated trials Repeated trials -Measurement skills Measurement skills