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BME 695L Lecture 10: Nanodelivery of Therapeutic Genes and Molecular Biosensor Feedback Control Systems
26 Oct 2011 | Online Presentations | Contributor(s): James Leary
See references below for related reading.
10.1 Introduction and overview
10.1.1 Some of the advantages of therapeutic genes
10.1.2 Some of the advantages of molecular biosensor feedback control systems
10.1.3 Why a nanodelivery approach is appropriate
10.2 The therapeutic gene approach
10.2.1 What constitutes a "therapeutic gene" ?
10.2.2 Transient versus stable expression modes
10.3 Molecular feedback control systems
10.3.1 Drug delivery has traditionally not used feedback controls
10.3.2 Why feedback control might be a very good idea!
10.3.3 Positive or negative feedback?
10.4 Molecular Biosensors as a component of a nanomedicine feedback control system
10.4.1 What is a molecular biosensor?
10.4.2 How a molecular biosensor functions as a therapeutic gene switch
10.5 Building integrated molecular biosensor/gene delivery systems –some examples
10.5.1 Example of a ribozyme/antivirus system
10.5.2 Example of an ARE biosensor/DNA repair system
10.5.3 Example of a feedback-controlled system for treatment of retinopathies
BME 695L Lecture 11: Assessing Nanotoxicity at the Single Cell Level
27 Oct 2011 | Online Presentations | Contributor(s): James Leary
11.1 Need for single cell measures of nanotoxicity
11.1.1 There is more than one way for a cell to die...
11.1.2 "Necrosis" vs. "Apoptosis"
11.1.3 There are other forms of "toxicity"
11.1.4 Some other challenges in measuring toxicity of nanomaterials
11.2 Necrosis vs. Apoptosis mechanisms
11.2.1 Necrosis is unplanned "cell injury"
11.2.2 Apoptosis is planned "programmed cell death"
11.2.3 Why it is important to distinguish between necrosis and apoptosis?
11.3 Single-cell assays for necrosis and apoptosis
11.3.1 Dye exclusion assays for necrosis
11.3.2 TUNEL assays for late apoptosis
11.3.3 Annexin V assays for early apoptosis
11.3.4 COMET assays for DNA damage and repair
11.3.5 Light scatter assays
11.3.6 Dihydroethidium assays for oxidative stress
11.4 Nanotoxicity in vivo – some additional challenges
11.4.1 Single-cell nanotoxicity, plus biodistribution measuring challenges….
11.4.2 Accumulations and agglomerations of nanoparticles can change toxicity locally to
tissues and organs
11.4.3 Filtration issues of nanoparticles – size matters – toxicity to kidney, liver and lung
11.4.4 Functional sensitivity of heart and brain to nanotoxicity largely unknown
BME 695L Lecture 12: Assessing Drug Efficacy and Nanotoxicity at the Single Cell Level
22 Nov 2011 | Online Presentations | Contributor(s): James Leary
12.1 Introduction to measures of efficacy for nanomedicine
12.1.1 for evaluation purposes, does structure/size reveal function?
12.1.2 nanomedical treatment at the single cell level requires evaluation at the single cell level
12.1.3 the difficulty of anything but simple functional assays (e.g. phosphorylated “functional” proteins)
12.1.4 the need for assays which at least show correlation to functional activity
12.2 Quantitative single cell measurements of one or more proteins per cell by flow and image/confocal cytometry
12.2.1 cell surface measures of protein expression on live, single cells
12.2.2 high-throughput flow cytometric screening of bioactive compounds
12.2.3 challenges of measuring protein expression inside fixed, single cells
12.2.4 when location is important 2D or 3D imaging is required to get spatial location of proteins inside cells (“locational proteomics” at the single-cell level)
12.3 Quantitative multiparameter phospho-specific flow/image cytometry as a single-cell,structural-functional measurement
12.3.1 attempts to measure "functional proteins" by detecting phosphorylation
12.3.2 example of phospho-specific, multiparameter flow cytometry
12.3.3 example of measuring single cell gene silencing by phospho-specific flow cytometry
12.4 Quantitative measures of gene expression – the promises and the realities
12.4.1 is gene expression at the single cell level really possible?
12.4.2 is it even useful to measure a single gene's changes?
12.4.3 gene arrays of purified cell subpopulations
12.4.4 RNA amplification techniques to attempt to perform single cell gene arrays
BME 695L Lecture 13: Designing Nanomedical Systems (NMS) for In-vivo Use
13.1 Bringing in-vivo considerations into NMS design
13.1.1 the in-vitro to ex-vivo to in-vivo paradigm
126.96.36.199 In-vitro - importance of choosing suitable cell lines
188.8.131.52 adding the complexity of in-vivo background while keeping the simplicity of in-vitro
184.108.40.206 all the complexity of ex-vivo plus the “active” components of a real animal
13.1.2 In-vivo systems are open, “active” systems with multiple layers of complexity
220.127.116.11 In-vitro and ex-vivo are mostly “closed” systems, but not absolutely
18.104.22.168 What is an “open” system?
22.214.171.124 Attempts to isolate open systems
13.1.3 Layers of complexity of in-vivo systems
126.96.36.199 Human cells in nude mice – a mixture of in-vitro and in-vivo
188.8.131.52 “Model” small animal systems
184.108.40.206 better model larger animal systems
13.2 Circulation time and biodistribution
13.2.1 factors affecting circulation time
220.127.116.11 "stealth layer" coating
18.104.22.168 zeta potential in-vivo in varying environments
22.214.171.124 filtration and excretion
13.2.2 where do the NMS go in-vivo?
126.96.36.199 checking the obvious organs (liver, spleen, kidney, blood…)
188.8.131.52 finding NMS in tissues and organs
184.108.40.206.2 within dissected tissue sections
220.127.116.11.3 in blood (ex-vivo versus in-vivo flow cytometry)
18.104.22.168.4 what is excreted?
13.2.3 Circulation time and dose optimization
22.214.171.124 measure drug concentration over time
126.96.36.199 is there an optimal drug dose?
13.4 In-vivo targeting and mistargeting
13.4.1 mode of administration (intravenous, oral, intra-tumor…)
13.4.2 how can we assess targeting in-vivo? (MRI, fluorescence, …)
13.4.3 a rare-cell targeting problem
13.4.4 consequences of mistargeting
13.4.5 balancing dosing, therapeutic efficacy, and consequences of mistargeting
13.5 Evaluating therapeutic efficacy in-vivo
13.5.1 advantages of non-invasive measurements
13.5.2 measures of tumor load/shrinkage (tumor size, weight,..)
13.5.3 other measures of disease effects
188.8.131.52 direct measurement of restoration of lost or compromised functions
184.108.40.206 indirect measures of disease effects (e.g. behavior, weight gain/loss, .)
13.5.4 Some examples of in-vivo work with NMS
13.6.1 Choosing an appropriate animal model and getting it approved takes time!
13.6.2 Animal experiments are expensive and time-consuming
13.6.3 Performing in-vivo measurements of drug delivery and therapeutic efficacy are more challenging and expensive than in-vitro or ex-vivo work!
13.6.4 But ultimately you must show that the NMS works in-vivo
BME 695L Lecture 14: Designing and Testing Integrated Nanomedical Systems
14.1 Introduction to integrated designs
14.1.1 “Total design” but there is some order in the design process
14.1.2 A brief outline of the total design process
14.2 Choose autonomous or non-autonomous design
14.2.1 If autonomous, will there be error-checking to correct mistargeting?
14.2.2 If autonomous, does the NMS perform all of the multi-step process sufficiently to accomplish the objective?
14.2.3 If non-autonomous, what form of external modulation of the in-vivo nanomedical system will be used?
14.2.4 If non-autonomous, are the external interactions able to adequately control the actions of the NMS?
14.2.5 Evaluate reaction of NMS to external intervention
14.2.6 Compare actions of NMS with and without external intervention.
14.2.7 How do the actions of the NMS scale (linear? nonlinear? resonance? ) with the size or extent of the external intervention?
14.3 Choose core material, size and shape
14.3.1 How will the core be used for diagnosis? Therapeutics?
14.3.2 Does this dictate the core material? Size?
14.3.3 Does shape alter circulation time or target cell penetration?
14.3.4 Evaluate size and shape of nanosized core by transmission (TEM) or scanning electron microscopy (SEM), or by atomic force microscopy (AFM)
14.3.5 Evaluate size of complete NMS (other parts may not be electron dense) by dynamic light scattering (DLS)
14.3.6 Evaluate materials present at each layer of construction by x-ray photoelectron spectroscopy (XPS)
14.4 Design NMS targeting and evaluate its effectiveness
14.4.1 Choose cell surface biomarker on diseased cell. Is it unique or just elevated in expression (e.g. folate receptors)
14.4.2 Choose targeting molecule type (antibody, peptide, aptamer…)
14.4.3 Use flow or image cytometry to evaluate correctness of targeting to diseased cell using that biomarker system
14.4.4 How much mis-targeting is anticipated? What are the consequences of mistargeting?
14.4.5 Determine degree of mistargeting and consider the costs of misclassification (e.g. how many normal cells are mis-targeted for each diseased cell successfully targeted)
14.4.6 Based on the costs of misclassification, reconsider additional or alternative diseased cell biomarkers?
14.4.7 Evaluate intracellular targeting by TEM if NMS is not fluorescent)
14.4.8 Evaluate intracellular targeting by 3D confocal fluorescence microscopy (if NMS is fluorescent)
14.4.9 Evaluate intracellular targeting by 2D fluorescence microscopy if confocal microcopy is unavailable
14.5 Choose zeta potential
14.5.1 Determine required zeta potential for outer/inner layers
14.5.2 Determine pH of encountered microenvironments
14.5.3 Determine ionic strength of encountered microenvironments
14.5.4 Evaluate suitability of zeta potential
14.5.5 If signs of agglomeration, modify zeta potential of NMS.
14.5.6 Are the NMS sticking to any surfaces or cell types?
14.5.7 Are the NMS being rapidly filtered by the kidneys in-vivo?
14.6 Choose stealth molecule
14.6.1 Determine required time of circulation
14.6.2 Circulation time will determine dose needed
14.6.3 Evaluate effectiveness of stealth molecule
220.127.116.11 Do the NMS show signs of protein deposition in-vitro or in-vivo?
18.104.22.168 Are the circulation times of the NMS adequate to sufficiently target the diseased cells in-vivo?
14.7 Choose type and intracellular target of therapy
14.7.1 Eliminate or fix the diseased cells?
14.7.2 If choice is elimination, choose appropriate therapeutic molecule that will accomplish this action
14.7.3 If choice is to fix the diseased cells, what therapeutic molecule can accomplish this action and how will it be controlled?
14.7.4 Choose molecular measure of effectiveness of therapy (induced apoptosis, restoration of normal phenotype, …)
14.7.5 Use single cell analysis by flow cytometry to measure that molecular measure, if cells are in suspension.
14.7.6 Use scanning image cytometry to measure that molecular measure, if cells are attached
14.8 A few final words on design of integrated nanomedical systems
14.8.1 We are still in the early days of designing nanomedical systems. Some of the necessary feedback we need for better designs awaits early clinical trials on human patients and volunteers
14.8.2 We do not understand some of the processes well enough to fully control their design. Still it is important to know what is important even if can not yet control it!
BME 695L Lecture 15: GMP and Issues of Quality Control Manufacture of Nanodelivery Systems
02 Dec 2011 | Online Presentations | Contributor(s): James Leary
15.1.1 What does cGMP mean?
15.1.2 Why GMP? Controlling processes means more predictable outcomes…
15.1.4 What can be learned from the semi-conductor industry clean-room and manufacturing?
15.1.5 What doesn’t fit this paradigm?
15.2 cGMP-level manufacturing
15.2.1 Predictable methods lead to predictable products
15.2.2 The CFR (Code of Federal Regulations) sections on GMPs
15.2.3 What is covered under cGMP?
15.3.1 So what is special about biomanufacturing?
15.3.2 Nano-clean water necessary for nano-pharmaceuticals
15.3.3 Contaminants at the nano-level
15.3.4 Can you scale up the process?
15.4 Some quality control issues – how to test
15.4.1 Correctness of size – size matters!
15.4.2 Composition – atomic level analyses
15.4.3 Monodispersity versus agglomeration
15.4.4 Order and correctness of layers2
15.4.5 Correctness of zeta potentials
15.4.6 Does the nanomedical system contain the correct payload?
15.4.7 Targeting (and mis-targeting) specificity and sensitivity
BME 695L Lecture 16: FDA and EPA Regulatory Issues
16.1 Introduction and overview
16.1.1 How does the FDA think about nanomedical systems?
16.1.2 The 2006 Nanotechnology Task Force
16.2 Some details of the Nanotechnology Task Force Report
16.2.1 General findings of the report
16.2.2 Some initial recommendations of the Task Force
16.2.3 Where the FDA may need to meet EPA on nanoscale materials
16.2.4 Will FDA re-visit GRAS products containing nanomaterials?
16.3 How will the FDA consider nanomedical systems?
16.3.1 Nanomedical systems are integrated nanoscale drug and drug delivery devices
16.3.2 Either a drug or a device? How about a "Combination Product"?
16.3.3 Drug-Biologic combination products
16.4 Types of human clinical trials
16.4.2 “Phase 0”
16.4.3 Phase 1
16.4.4 Phase 2
16.4.5 Phase 3
16.4.6 Phase 4
16.5 EPA and other regulatory agency issues
16.5.1 Assessing environmental impact of emerging nanotechnologies
16.5.2 Concept of life cycle assessment (LCA)
16.5.3 Toxicity of nanomaterials
16.5.4 Some recommendations of the 2006 International Conference on Nanotechnology and Life Cycle Assessment
16.6 Nanotechnologies and the workplace
16.6.1 NIOSH – Formulating workplace safety standards for nanotechnology
16.6.2 Protecting workers in the workplace
16.6.3 Assessing hazards in the workplace
16.6.4 Establishing a Nanotechnology Safety System
16.7 The future of nano-healthcare products
BME 695L Lecture 1: Need for New Perspectives on Medicine
31 Aug 2011 | Online Presentations | Contributor(s): James Leary
1.1 Nanotechnology – Why is something so small so big?
1.1.1 Definitions of nanotechnology based on size
1.1.2 A “bottoms up” rather than “tops down” approach
1.1.3 The nanoworld challenges our perspectives on size
1.2 The Progression of Medicine
1.2.1 Conventional "modern" medicine
1.2.2 "Personalized" or "molecular" medicine
1.2.3 Nanomedicine "single-cell" medicine
1.3 How Conventional Medicine Works for Diagnosis of Disease
1.3.1 Identification of the "diseased state"
1.3.2 Simple measurements of body structure and function
1.3.3 Follow-up clinical tests
1.3.4 Internal examinations by non-invasive in-vivo imaging
1.3.5 Molecular tests for specific gene properties
1.3.6 Comparison of individual results with "normal ranges"
1.4 How Conventional Medicine Works for Treatment of Disease
1.4.1 Stabilization of patient – "heal thyself"
1.4.2 Surgical repair of injuries
1.4.3 Treatment with drugs locally
1.4.4 Treatment with drugs systemically
1.4.5 Treatment with targeted therapies
1.5 Factors Limiting the Progress of Medicine
1.6 Some Specific Problems with Conventional Medicine
1.6.1 Consequences of waiting for patient symptoms
1.6.2 Trained people and modern drugs are expensive
1.6.3 Diagnostic technologies, if available, are still relatively primitive and/or expensive
1.6.4 Crude targeting of drugs
1.7 What is the Basis for Nanomedicine?
1.7.1 Creation of nano-sized tools
1.7.2 These nanotools permit single-cell medicine
1.7.3 These “nanomedical systems” can be “smart” devices
1.8 Some ways that nanotechnologies will impact on healthcare
1.8.1 Nanomedicine will be “pro-active” rather than “reactive” medicine
1.8.2 Possibility of "regenerative medicine"
1.8.3 Blurring of distinction between prevention and treatment
BME 695L Lecture 2: Designing Nanomedical Systems
2.1 Elements of good engineering design
2.1.1 Whenever possible, use a general design that has already been tested
2.1.2 Whenever possible, take advantage of “biomimicry” – Nature has tried many designs!
2.1.3 Avoid “general purpose” design. Use multiple specific molecules to do specific tasks.
2.1.4 Control the order of molecular assembly to control the order of events
2.1.5 Therefore, perform the nano assembly in reverse order to the desired order of events
2.2 Building a nanodevice
2.2.1 Choice of core materials
2.2.2 Add drug or therapeutic gene
2.2.3 Add molecular biosensors to control drug/gene delivery
2.2.4 Add intracellular targeting molecules
2.2.5 Result is multi-component, multi-functional nanomedical device
2.2.6 For use, design to de-layer, one layer at a time
2.2.7 The multi-step drug/gene delivery process in nanomedical systems
2.3 The challenge of drug/gene dosing to single cells
2.3.1 Precise targeting of drug delivery system while protecting non-targeted cells from exposure to the drug
2.3.2 How to minimize mis-targeting
2.3.3 How to deliver the right dose per cell
2.3.4 One possible solution – in situ manufacture of therapeutic genes
2.4 Bridging the gap between diagnostics and therapeutics
2.4.1 how conventional medicine is practiced in terms of diagnostics and therapeutics
2.4.2 the consequences of separating diagnostics and therapeutics
2.4.3 a new approach – "theragnostics" (or "theranostics")
2.5 Examples of current theragnostic systems
2.5.1 example 1: Rituxan ("Rituximab)(an example of not using diagnostics to guide the therapy)
2.5.2 example 2: Herceptin ("terastuzumab")
2.5.3 example 3: Iressa ("Gefitinib)
2.5.4 other examples
2.6 How theragnostics relates to Molecular Imaging
2.6.1 conventional imaging is not very specific
2.6.2 types of In-vivo Imaging
22.214.171.124 X-rays, CAT (Computed Axial Tomography) scans
126.96.36.199 MRI (magnetic Resonance Imaging)
188.8.131.52 PET (Positron Emission Tomography) scans
2.6.3 "molecular imaging" of nanoparticles in-vivo for diagnostics/monitoring of therapeutics
2.8 Engineering nanomedical systems for simultaneous molecular imaging
2.8.1 using nanomedical cores for MRI contrast agents
2.8.2 difficulties in using PET probes for nanomedical devices
2.8.3 using cell-specific probes for molecular imaging of nanomedical devices
2.8.4 breaking the "diffraction limit" – new nano-level imaging modalities
2.9 Theragnostic nanomedical devices
2.9.1 using nanomedical devices to guide separate therapeutic device
2.9.2 when might we want to combine diagnostics and therapeutics?
BME 695L Lecture 3: Theranostics and Molecular Imaging
07 Sep 2011 | Online Presentations | Contributor(s): James Leary
3.1 Nanomedical systems – levels of challenges
3.1.1 Diagnosis - difficult
3.1.2 Therapy – more difficult
3.1.3 Both ("Theragnosis") – most difficult!
3.2 How theragnostics relates to Molecular Imaging
3.2.1 conventional imaging is not very specific
3.2.2 types of In-vivo Imaging
184.108.40.206 X-rays, CAT (Computed Axial Tomography) scans
220.127.116.11 MRI (magnetic Resonance Imaging)
18.104.22.168 PET (Positron Emission Tomography) scans
3.2.3 "molecular imaging" of nanoparticles in-vivo for diagnostics/monitoring of therapeutics
3.3 Engineering nanomedical systems for simultaneous molecular imaging
3.3.1 using nanomedical cores for MRI contrast agents
3.3.2 difficulties in using PET probes for nanomedical devices
3.3.3 using cell-specific probes for molecular imaging of nanomedical devices
3.3.4 breaking the "diffraction limit" – new nano-level imaging modalities
3.4 Theragnostic nanomedical devices
3.4.1 using nanomedical devices to guide separate therapeutic device
3.4.2 when might we want to combine diagnostics and therapeutics?
3.5 Requirements for specific cell targeting
3.5.1 must be cell surface biomarker that at least partially identifies that cell
3.5.2 OR a Boolean set of several biomarkers whose composite "signature" identifies a cell
3.5.3 OR a set of biomarkers that excludes all other cells
3.5.4 challenge – how to "multiplex" a Boolean set of targeting molecules
3.6 Consequences of mis-targeting
3.6.1 “side effects” to innocent bystander (normal) cells
3.6.2 these side effects may be lethal to bystander cells, or they may change the overall state of the patient so that the treatment problem is no longer the same
3.6.3 Side effects may be unpredictable and may lead to dangerous non-linear patient responses what are difficult to correct and potentially dangerous or even life threatening
3.7 Engineering around the consequences of mis-targeting
3.7.1 measure number of good (normal) cells destroyed to eliminate a diseased cell
3.7.2 put a weighting factor on the relative “goodness” or “badness” of normal cells and diseased cells
3.7.3 example: How many stem cells are you willing to lose to purge tumor cells during a bone marrow transplantation?
3.8 Some ways to lower mis-targeting to non-diseased cells
3.8.1 lower numbers of nanoparticles
3.8.2 improve specificity of targeting molecules according to what is learned about the identity of the mis-targeted cells
3.8.3 if possible, require an AND condition requiring simultaneous presence of two target molecules on the same cells being targeted
3.8.4 if necessary, design a non-specific targeting control switch on a secondary non-specific target molecule which inactivates subsequent nanomedical device action (off control switch upon detecting an error in targeting).
BME 695L Lecture 4: Cell Targeting and its Evaluation
03 Oct 2011 | Online Presentations | Contributor(s): James Leary
4.1 Overview: targeting nanosystems to cells
4.1.1 antibody targeting
4.1.2 peptide targeting
4.1.3 aptamer targeting
4.1.4 ligand-receptor targeting
4.2 Antibodies – polyclonal and monoclonal
4.2.1 Where do antibodies come from – in nature?
4.2.2 How do we make them in the laboratory?
4.2.3 Monoclonal antibodies – some details you need to know!
4.2.4 Labeling strategies
4.2.5 Therapy problems with mouse monoclonal antibodies
4.2.6 “Humanizing” monoclonal antibodies to reduce adverse host immune reactions
4.2.7 Why antibodies may not be a good overall choices for targeting nanosystems to cells
4.3 Peptide targeting
4.3.1 How does a peptide target?
4.3.2 Examples of peptide targeting
4.3.3 Creating new peptides by random peptide phage display libraries
4.3.4 High-throughput screening of those peptide libraries
4.3.5 Advantages and disadvantages of peptide targeting
4.4 Aptamer targeting
4.4.1 What are aptamers and how do they target?
4.4.2 Some different types of aptamers
4.4.3 How do you make aptamers?
4.4.4 How do you screen for useful aptamers?
4.5 Ligand-receptor targeting
4.5.1 What are ligands?
4.5.2 What are their advantages/disadvantages?
4.5.3 Example – folate receptors
4.6 How do we quantitatively evaluate targeting?
4.6.1 Technologies for evaluating targeting
22.214.171.124 Flow cytometry
126.96.36.199 Scanning image cytometry
4.6.2 Evaluating targeting specificity
4.6.3 Evaluating targeting sensitivity
BME 695L Lecture 5: Nanomaterials for Core Design
5.1.1 core building blocks
5.1.2 functional cores
5.1.3 functionalizing the core surface
5.2 Ferric oxide cores
5.2.1 paramagnetic cores
5.2.2 superparamagnetic cores
5.2.3 ferric nanorods
5.2.4 advantages and disadvantages
5.3 C60 and carbon nanotubes
5.3.1 size and structure of C60
5.3.2 elongation of C60 into carbon nanotubes
5.3.3 advantages and disadvantages
5.4 Gold cores
5.4.1 gold nanoparticles
5.4.2 gold nanorods
5.4.3 other shapes (e.g. "stars")
5.4.4 gold nanoshells
5.4.5 advantages and disadvantages
5.5 Silica cores
5.5.1 silica nanoparticles
5.5.2 mesoporous silica NP for drug delivery and biosensing
5.5.3 advantages and disadvantages
5.6 Quantum dots
5.6.1 size determines color
5.6.2 good for multicolor fluorescence
5.6.3 importance of coatings
5.6.4 conjugating targeting molecules
5.6.5 examples from studies
5.6.6 finding sub-optical nanoparticles
5.6.7 cytotoxicity issues
5.7 Next generation quantum dots
5.7.1 Water-Soluble Doped ZnSe Nanocrystal Emitters
5.7.2 Organic quantum dots
5.8 Hybrid materials
5.8.1 gold-ferric oxide nanoparticles and nanorods
5.8.2 NIR fluorescent-chitosan polymer-iron oxide core hybrids
5.8.3 dual-modality MRI/NIRF imaging with hybrid nanoparticles
BME 695L Lecture 6: Normal & Facilitated Cell Entry Mechanisms
04 Oct 2011 | Online Presentations | Contributor(s): James Leary
6.1.1 the general problem of cell entry
6.1.2 choosing modes of cell entry
6.1.3 how does Nature do it? (biomimetics)
6.2 Non-specific uptake mechanisms
6.2.1 pinocytosis by all cells
6.2.2 phagocytosis by some cells
6.2.3 a recent study of Qdot NP uptake
6.3 Nanoparticle uptake
6.3.1 NP size matters
6.3.2 NP shape matters
6.3.3 NP agglomeration reduces uptake
6.3.4 A sample study
6.4 Receptor-mediated uptake
6.4.1 Receptor mediated transport of desired molecules
6.4.2 How to study uptake mechanisms by inhibiting pathways with specific drugs
6.4.3 Some sample studies
6.5 Effects of nanoparticle coatings
6.5.1 Acrylate-Facilitated Cellular Uptake
6.5.2 Polyethyleneimine Coating Enhancement of Cellular Uptake
6.6 Effects of microenvironment and external stimuli
BME 695L Lecture 7: Assessing Zeta Potentials
7.1 Introduction – the importance of the zeta potential
7.1.1 nanoparticle-nanoparticle interactions
7.1.2 nanoparticle-cell interactions
7.1.3 part of the initial nanomedical system-cell targeting process
7.1.4 low zeta potential leads to low serum protein binding and potentially longer circulation
7.2 Zeta potential basics
7.2.1 What is the zeta potential?
188.8.131.52 surface layer potential
184.108.40.206 Stern layer potential
220.127.116.11 slip layer
18.104.22.168 zeta potential layer
7.2.2 How is it measured?
22.214.171.124 conversion of electrophoretic mobility to zeta potential
7.2.3 Zeta potential is the potential barrier to cell-nanoparticle interactions
7.2.4 Optimal zeta potential is complicated but some general advice
7.3 Some factors affecting the zeta potential
7.3.2 ionic strength
7.4 Some zeta potential experiences
7.4.1 Size and zeta potential changes during LBL assembly of NPs
7.4.2 Effects of pH and dilution on NP zeta potential
7.5 "Zeta sizing" measuring size on a zeta potential instrument
7.5.1 DLS (Dynamic Light Scattering) sizing
7.5.2 Relating scattering intensity to diffusion coefficients and hydrodynamic size
7.5.3 Computing the hydrodynamic radius from the Stokes-Einstein equation
7.5.4 Actual versus measured DLS values
BME 695L Lecture 8: Surface Chemistry: attaching nanomedical structures to the core
12 Oct 2011 | Online Presentations | Contributor(s): James Leary
8.1.1 attachment strategies typically depend on core composition
8.1.2 but the attachment strategy should not drive the core choice
8.1.3 the choice of core should still depend on the desired overall “multifunctional” nanomedical device
8.2 “Surface chemistry” strategies for attachment of biomolecules to the core material
8.2.1 hydrophobic versus hydrophilic core materials
8.2.2 addition of biomolecules for biocompatibility
8.2.3 monofunctional versus bifunctional surface chemistry strategies
8.2.4 PEGylation as “stealth strategy” to minimize opsonification and increase circulation time
8.2.5 pay attention to overall zeta potential during the surface chemistry process!
8.3 Two main attachment strategies
8.3.1 covalent bonding strategies
126.96.36.199.2 very stable
188.8.131.52.3 can control process of bond disruption for multilayering
184.108.40.206.1 can be too stable and difficult to disassemble
220.127.116.11.2 must be careful to avoid or minimize use of strong organic solvents that can be cytotoxic even at trace concentrations
8.3.2 non-covalent (primarily electrostatic) Bonding Strategies
18.104.22.168.1 can use very gentle chemistries for biocompatibility
22.214.171.124.2 chemistry can be very simple layer-by-layer assemblies
126.96.36.199.3 easier to disassemble multilayered structures
188.8.131.52.1 instability - different pH and ionic strength environments can cause layers to spontaneously disassemble at undesired times
184.108.40.206.2 zeta potential can suddenly change as layers spontaneously strip off
8.4 Special considerations for the final attachment design
8.4.1 preparing the nanoparticle for addition of targeting and therapeutic molecules
8.4.2 what are the special requirements, if any, for these molecules?
220.127.116.11 how to attach without changing function of molecule
18.104.22.168 does this molecule need to stay attached, or not, to the nanoparticle in order to function
8.4.3 testing for targeting and therapeutic efficacy at the single cell level
8.5 Attaching different types of targeting molecules (some types and examples)
8.5.1 antibodies – which end to attach?
8.5.2 peptides – which end to attach, steric hindrance? Spacer arm needed?
8.5.3 aptamers - which end to attach, steric hindrance? Spacer arm needed?
8.5.4 small molecule ligands - which end to attach, steric hindrance? Spacer arm needed?
8.6 Testing the nanoparticle-targeting complex
8.6.1 ways of detecting this complex
8.6.2 ways of assessing targeting/mistargeting efficiency and costs of mistargeting
8.6.3 is the nanoparticle still attached to the targeting molecule?
8.7 Attaching/tethering different types of therapeutic molecules
8.7.1 antibody therapeutics - need to interact with the immune system to activate
8.7.2 peptides (e.g. apoptosis-inducing peptides)
8.7.3 therapeutic aptamers
8.7.4 transcribable sequences
8.7.5 small drugs
8.8 Testing the nanoparticle-therapeutic molecule complex
8.8.1 direct and indirect ways of detecting the therapeutic molecules
8.8.2 ways of assessing the therapeutic efficacy at single cell level
8.8.3 is the nanoparticle still attached to the therapeutic molecule? Is that important?
8.9 Nanomedical pharmacodynamics – the great unknown
8.9.1 little is known about complex nanoparticle pharmacodynamics
8.9.2 obtaining quantitative biodistribution data is extremely difficult!
8.9.3 some possible new approaches
BME 695L Lecture 9: Challenges of Proper Drug Dosing with Nanodelivery Systems
19 Oct 2011 | Online Presentations | Contributor(s): James Leary
9.1 Overview of drug dosing problem
9.1.1 Problems of scaling up doses from animal systems
9.1.2 Basing dosing on size, area, weight of recipient
9.1.3 Vast differences between adults in terms of genetics, metabolism
9.1.4 Dosing in children – children are NOT smaller adults!
9.1.5 Pharmacokinetics – drug distribution, metabolism, excretion, breakdown
9.1.6 Conventional dosing assumes drug goes everywhere in the body
9.1.7 Targeted therapies – a model for future nanomedical systems?
9.2 From the animal dosing to human clinical trials
9.2.1 Importance of picking an appropriate animal model system
9.2.2 Does drug dosing really scale?
9.2.3 The human guinea pig in clinical trials and beyond
9.3 Traditional drug dosing methods
9.3.1 Attempts to scale up on basis of area
9.3.2 Attempts to scale up on weight/volume
9.3.3 Attempts to use control engineering principles
9.4 Genetic responses to drug dosing
9.4.1 All humans are not genomically equivalent!
9.4.2 Predicting on basis of family tree responses
9.4.3 SNPs, chips, and beyond…predicting individual drug response
9.4.4 After the $ ???? individual genome scan… more closely tailored individual therapies
9.5 Dosing in the era of directed therapies – a future model for nanomedical systems?
9.5.1 How directed therapies change the dosing equation
9.5.2 Current generation directed antibody therapies dosing
9.5.3 Some typical side effects of directed therapies
9.5.4 Nanomedical systems are the next generation of directed therapies
9.6 Most directed therapies are nonlinear processes!
9.6.1 Meaning of nonlinear processes
9.6.2 Some examples of how a few directed therapies work
9.6.3 Side effects of “directed therapies”
9.7 Other ways of controlling dose locally
9.7.1 Magnetic field release of drugs
9.7.2 Light-triggered release of drugs
BME 695L: Engineering Nanomedical Systems
31 Aug 2011 | Courses | Contributor(s): James Leary
BME 695N Lecture 10: Nanomaterials for core design
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26 Sep 2007 | Online Presentations | Contributor(s): James Leary
BME 695N Lecture 13: Assessing Zeta Potentials
29 Oct 2007 | Online Presentations | Contributor(s): James Leary
BME 695N Lecture 14: Challenges of proper drug dosing with nanodelivery systems
BME 695N Lecture 15: Nanodelivery of therapeutic genes & molecular biosensor feedback control systems
30 Oct 2007 | Online Presentations | Contributor(s): James Leary
BME 695N Lecture 16: Assessing drug efficacy at the single cell level
02 Nov 2007 | Online Presentations | Contributor(s): James Leary
BME 695N Lecture 17: Assessing nanotoxicity at the single cell level
06 Nov 2007 | Online Presentations | Contributor(s): James Leary
BME 695N Lecture 18: Designing nanodelivery systems for in-vivo use
12 Nov 2007 | Online Presentations | Contributor(s): James Leary
BME 695N Lecture 1: Need for New Perspectives on Medicine
03 Aug 2007 | Online Presentations | Contributor(s): James Leary