The Putnam LabDelivery of Nucleic Acid-BasedTherapeuticsBiomaterial DesignandSynthesisProject DistributionsOuter MembraneVesicle Engineering

Approachpolymeric libraries with serial changes in compositionGoal: Quantitative, mechanistic understanding of transfection

The Putnam LabDelivery of Nucleic Acid-BasedTherapeuticsBiomaterial DesignandSynthesisProject DistributionsOuter MembraneVesicle Engineering

Motivationthe human body is a monomer factoryNew polymeric biomaterials from metabolic synthonsInvestigate metabolic pathwaysIdentify interesting monomersAkin to PLGA polyesters

http://www.science.gmu.edu/~gsudama/csi803s97/met2.gifRational/targeted selectionEngineered polymer propertiesSynthetically challenging

Dihydroxyacetone (DHA)Scheme 1: Glycolysis pathwayGlucolytic metabolite GlucosePyruvic acidDHA

Dihydroxyacetone (DHA)FDA approved for use in oral and topical administration (the active ingredient in sunless tanning lotions). Glucolytic metabolite http://www.premiersalonsystems.com/http://www.procyte.com/products/brand/asp/titanfoaming.shtmlScheme 1: Glycolysis pathwayGlucosePyruvic acidDHA

Zawaneh, P.; Doody, A.; Zelikin, A.; Putnam, D. Biomacromolecules (2006)PEG-pDHA Synthesis, characterization and applicationPostoperative adhesionsSeroma closureFistula blockadeChemo-emboli

DHA-based lipidsSynthesis

DHA-based lipidsRelease kinetics

Career path and research which have led youDelivery of Nucleic Acid-BasedTherapeuticsBiomaterial DesignandSynthesisProject DistributionsOuter MembraneVesicle Engineering

Outer membrane vesicles (OMVs)natural vesicles for transfer of proteins and DNAGOALEngineered vesicles to correctly foldand stabilize proteins

Optimize antigen presentation to APCs

APPLICATIONSExpression/stabilization/delivery ofconformational antigens

Novel adjuvants to enhance existingor poorly effective vaccines

OMPGPerCytLPSIMPeriplasmic proteins are entrapped within the OMV lumenKuehn and Kesty (2005) Genes Dev 19: 2645-55

Section 2Joint project with Neurological SurgeryChemoCoils and Brain Phantom Creation and Validation of a Novel Drug Delivery Technique

Michael Shuler, Susan Pannullo, David Putnam, Jian Tan

ChemoCoils and Brain Phantom Creation and Validation of a Novel Drug Delivery TechniqueCornell Cross-Campus Neurological Surgery/Biomedical Engineering Project

Michael Shuler, Susan Pannullo, David Putnam, Jian TanJuly 2007

Reviewing the ProblemMalignant GliomasHighly aggressive brain cancersRecur locally need good local control techniquesOnly 1 validated/FDA approved device: chemotherapy wafersMinimal survival benefitPoor conformality to resection cavityMinimal brain penetrationSubmaximal doseOnly one drug (BCNU) deliveredDrug delivery poorly understood

Chemotherapy Coils and Brain Phantom: The ProjectYear 1Development of an in vitro Brain Phantom based upon Magnetic Resonance Imaging of human brain and brain tumor

Development of polymer coils with appropriate mechanical, chemical, and drug release properties.

Test, using dyes and IMAGING, the distribution, depth of penetration, and duration of chemical dyes from different polymer formulations

Year 2Refinement of delivery system/drug mixturesAnimal trialsClinical trialsHypothesisMaintaining contact with cavity wall willimprove treatment outcomes

Controlled Release PolymerIncorporate both p(CPP:SA) (poly (carboxyphenoxypropane-sebacic acid) and polyester of -caprolactone Diameter and porosity are controlled by electrospinningWafer: 14mm in diameter and 1mm thickMesh: interwoven fibers (

Pressure ModelBrain experiences around 10mmHg of pressure in brain cavity.For our first experiments we will use a simple water tank to create the pressure.14cm

Alternate Pressure ModelAgarose BrainSilicone EncapsulationPressure ProbeSyringe to alter pressure

Mathematical ModelSimulate the transport of drugs from various polymer constructs to the brain

Assumption: transport of drug occurs by diffusion and convection (due to edema) with elimination (e.g. internationalization)

Goal: to predict drug concentration and deduce drug penetration in the artificial tissue, then compare with our brain phantom model

Section 3Bill OlbrichtMicrocatheters for drug delivery to the brain

Microcatheters for Convection-Enhanced DeliveryDiffusion only gets you so far.

Convection can get you further.

Remodeling ECM to enhance nanoparticle deliveryChannel 1: Deliver enzymes that degrade ECM components (hyaluronan and chondroitan sulfate proteoglycans) to increase permeability OR hyperosmolar solutions that swell interstitium to increase permeability

Channel 2: Deliver drug-laden nanoparticles to reduce drug elimination during transport in tissue and extend release time

Flexible microfluidic catheters

Section 4C. C. ChuMaterials for drug delivery

C. C. Chu Biodegradable hydrogels as cytokine (IL-12) carriers for immunotherapy of cancer.

Estone carrier from polysaccharides.

Biodegradable carriers of nitric oxide derivatives for nitric oxide biofunctionality.

Biodegradable hydrogels and microspheres as anticancer drug (e.g., Doxorubicin, Paclitaxel) carriers.

Biodegradable hydrogels as gene carriers

Burst release followed by sustained release over 3 mo. wo/ bioactivity loss. 4 factors control IL-12 release charge, hydrophilicity, gel crosslinking density, biomaterial biodegradation. waterDryCytokine carriers for immunotherapy:Interleukin 12 impregnated within Arginine-based biodegradable hydrogels.

3. Estrone carrier from polysaccharides:a. Starch-estrone conjugate.b. Dextran-estrone conjugate. Polysaccharide O C CH2 - EstroneOpH 7.4pH 84. Biodegradable hydrogels and microspheres as anticancer drug carriers :a. from poly(ester amide) gel and microspheresb. from intelligent polysaccharide-synthetic hydrogelsPoly(ester amide) gelIntelligent Dextran-synthetic hydrogels

Treatment of Brain Tumors with Drug Eluting Polymeric Meshes or Coils Current commercially available solutions to local therapy delivery for malignant gliomas are: chemotherapy wafers, radiation emitting implanted balloons and stereotactic radiosurgery. Infusion of therapeutic agents via implanted catheters has been tested in clinical trials. Of these approaches, randomized studies have thus far shown a demonstrable benefit only for chemotherapy wafers. In addition, only chemotherapy wafers can deliver therapy without the need for additional procedures.

MAY BE APPLICABLE TO OTHER BRAIN CANCERS TOOWe use microfabrication methods at the CNF to design microcatheters for Convection-Enhanced drug delivery. The microcathers allow higher flow rates than can be achieved using standard needles. They can also be equipped with sensors to measure tissue properties during infusions or with multiple channels to infuse compounds in parallel, as shown on the next slide.In one channel enzymes are delivered to dissolve ECM components to enhance the permeability of brain tissue. Then, a drug or drug-laden nanoparticles are delivered in the second channel.We can also fabricate flexible devices for drug delivery, which mitigates tissue reaction to an implanted microcatheter.