BioMEMS Implantable BioMEMS Implantable Drug Delivery Systems Drug Delivery Systems Professor Horacio Espinosa – ME381 – Professor Horacio Espinosa – ME381 – Final project Final project Aaron Alexander Aaron Alexander Luke Rogers Luke Rogers Dan Sheehan Dan Sheehan Brent Willson Brent Willson
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BioMEMS Implantable Drug Delivery Systems Professor Horacio Espinosa – ME381 – Final project Aaron Alexander Luke Rogers Dan Sheehan Brent Willson.
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BioMEMS Implantable Drug BioMEMS Implantable Drug Delivery SystemsDelivery Systems
Professor Horacio Espinosa – ME381 – Final projectProfessor Horacio Espinosa – ME381 – Final project
Aaron AlexanderAaron Alexander
Luke RogersLuke Rogers
Dan SheehanDan Sheehan
Brent WillsonBrent Willson
Current TechnologyCurrent Technology
Include hypodermic needles, pills, and Include hypodermic needles, pills, and passive transdermal methodspassive transdermal methods
Disadvantages:Disadvantages: Highly InvasiveHighly Invasive Poor ControlPoor Control Can be IneffectiveCan be Ineffective
Drug Delivery by MEMSDrug Delivery by MEMS
AdvantagesAdvantages Improved ControlImproved Control More EffectiveMore Effective Less IntrusiveLess Intrusive
Activation of Redox ReactionActivation of Redox Reaction
The The in vivoin vivo environment can be environment can be considered as an considered as an aqueous NaCl aqueous NaCl solution with a PH solution with a PH between 6 and 7 between 6 and 7 When a minimum When a minimum of .8V is applied of .8V is applied [AuCl4][AuCl4]-- is the is the favorable state for favorable state for gold in this solution. gold in this solution.
Simpler than Simpler than previous devicesprevious devices
Standard/Mass Standard/Mass productionproduction
Dimensions Dimensions optimized for optimized for strengthstrength
Top of Base SubstrateTop of Base Substrate
• Drug enters entry flow chamber from entry port of top substrate
• Enters input fingers, passes through nano-channels
• Exits through output fingers and exit flow chamber
Glucose ReleaseGlucose Release
Solution to constant Solution to constant drug delivery needdrug delivery need
Drawback: drugs pass Drawback: drugs pass through nano-channels through nano-channels at different rates – at different rates – electrical integration electrical integration and control of flow and control of flow through nano-channelsthrough nano-channels
(PHSNP)(PHSNP) Used in many different Used in many different applicationsapplicationsPast drug carriers Past drug carriers primarily oil-in-water primarily oil-in-water units, liposomes, and units, liposomes, and nanoparticles and nanoparticles and microparticles made of microparticles made of synthetic polymers and or synthetic polymers and or natural macromoleculesnatural macromoleculesPHSNP diameter = 60-PHSNP diameter = 60-70nm, wall thickness = 70nm, wall thickness = 10nm10nmSynthesis of PHSNP Synthesis of PHSNP involves CaCO3 templateinvolves CaCO3 template
Fig. 3. TEM (Transmission Electron Microscope) image of PHSNP
Used for infection in Used for infection in airways, kidneys, post-airways, kidneys, post-surgery, othersurgery, other
Fig. 1. Molecular structure of cefradine.
Distribution of Cefradine in PHSNPDistribution of Cefradine in PHSNP
Fig. 4. Distribution of pore diameters in the wall of PHSNP (a) before entrapping cefradine; (b) after entrapping cefradine.
Fig. 2. Preparation process of drug carrier from PHSNP. (a) PHSNP; (b) suspension of cefradine and PHSNP; (c) PHSNP entrapped with cefradine.
•PHSNP and Cefradine mixed vigorously
Release of CefradineRelease of Cefradine
Stage oneStage one: 76% release in : 76% release in 20 min. – surface of PHSNP20 min. – surface of PHSNPStage twoStage two: 76%-82% : 76%-82% release in 10 hours– pores release in 10 hours– pores of PHSNPof PHSNPStage threeStage three: insignificant : insignificant release from PHSNP hollow release from PHSNP hollow centercenter
Gradual release over time Gradual release over time can be exploited in drug can be exploited in drug delievery applicationsdelievery applications
Fig. 5. In vitro release profile of cefradine from PHSNP
Quantum DotsQuantum Dots
Crystals containing a group of electrons – usually made Crystals containing a group of electrons – usually made of II-VI semiconductor cadmium selenideof II-VI semiconductor cadmium selenideNanometers wide, demonstrate quantum properties of Nanometers wide, demonstrate quantum properties of single atoms, absorb and emit specific wavelengths of single atoms, absorb and emit specific wavelengths of lightlightBind Taxol, a cancer-fighting drug, and a molecule with Bind Taxol, a cancer-fighting drug, and a molecule with affinity to folic acid receptors to quantum dots, also affinity to folic acid receptors to quantum dots, also effective when bound with antibodieseffective when bound with antibodiesCancer cells have high concentration of folic acid Cancer cells have high concentration of folic acid receptors and can be targetedreceptors and can be targetedOnce excited with IR light, the bond is broken with the Once excited with IR light, the bond is broken with the drug, Taxol, which is able to attack the cancerous celldrug, Taxol, which is able to attack the cancerous cell
IR Illuminated RatIR Illuminated Rat
Implanted with tumorImplanted with tumor
Injected with quantum dots, Injected with quantum dots, bound with Taxolbound with Taxol
High concentration around High concentration around tumortumor
Technique not as effective in Technique not as effective in humans due to deep internal humans due to deep internal organsorgans
May be effective for skin and May be effective for skin and breast cancerbreast cancer