BEH. 462/3.962J Molecular Principles of Biomaterials Spring 2003 Lecture 14: Nano-and micro-particle carriers Last time molecular switches Proteins as motors in nanodevices Today. nano-and micro-particle drug carriers Reading D A Hammer and D.E. Discher, ' Synthetic cells- Self-assembling polymer membranes and bioadhesive colloids, Annu. Rev. Mater Res, 31, 387-404 (2001) Nano- and Micro-scale Drug Carriers and Detection Reagents Nano- to Micro-particle polymer-protein conjugates carriers micelles nano liposomes vesicles Polymer-drug conJug polymerosomes 10nm microparticles cellular structures plasma membr Actin fibers Packed chromosomes complex 1 nm 10 nm 100nm 1000nm Image sources oPlamamembraneEm:http:/cellbio.utmb.edu/cellbio/membraneintrohtm o Ribonuclease space-filling model http://www.blc.arizonaedu/courses/181gh/rick/biomolecules/protein.html oHepatitisBvirusnucleocapsidhttp://www.cryst.bbkac.uk/pps2/coUrse/secTion11/assembli.html Lecture 14-- and micro-particles 1 of 6
BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 Lecture 14: Nano- and micro-particle carriers Last time: molecular switches Proteins as motors in nanodevices Today: nano- and micro-particle drug carriers Reading: D.A. Hammer and D.E. Discher, ‘Synthetic cells- Self-assembling polymer membranes and bioadhesive colloids,’ Annu. Rev. Mater. Res., 31, 387-404 (2001) Nano- and Micro-scale Drug Carriers and Detection Reagents Nano- to Micro-particle polymer-protein conjugates vesicles Polymer-drug conjugates micelles nanoparticles microparticles Packed chromosomes organelles Actin fibers proteins Protein complexes cellular structures carriers liposomes polymerosomes Thickness of lipid bilayer QuickTime™ and a Graphics decompressor are needed to see this picture. QuickTime™ and a Graphics decompressor are needed to see this picture. 1 nm 10 nm 100 nm 1000 nm Image sources: o Plama membrane EM: http://cellbio.utmb.edu/cellbio/membrane_intro.htm o Ribonuclease space-filling model: http://www.blc.arizona.edu/courses/181gh/rick/biomolecules/protein.html o Hepatitis B virus nucleocapsid: http://www.cryst.bbk.ac.uk/PPS2/course/section11/assembli.html Lecture 14 – nano- and micro-particles 1 of 6
BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 Applications of tiny drug carriers and cellular markers Applications Delivery to tissues from circulation tic drugs Detect tumors Intracellular delivery Va class I MHC loading-priming CD8 o Gene delivery Delivery of plasmid DNA Shutting off production of certain proteins by delivery of anti-sense oligonucleotides to bind bosomal mRNA o Intracellular toxins for cancer therapy o Ribozyme delivery drug delivery to organe drug delivery to mitochondria Objectives protection of cargos from degradation o e.g. DNA protection from DNAses o protein protection from proteases, phosphatases avoid opsonization and production of antibodies against drug molecule o opsonization: coating foreign protein, small molecule, or particle with antibodies or complement proteins leads to macrophage binding and destruction sourceofopsonizationanimationhttp://medtech.cls.msu.edu/isl/immunology/OpSoniZe.htm Lecture 14-- and micro-particles 2 of 6
BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 Applications of tiny drug carriers and cellular markers Applications Delivery to tissues from circulation o Therapeutic drugs Anti-cancer drugs 1 o Markers for analysis/detection Detect tumors Infected cells Anti-pathogen lymphocytes Intracellular delivery o Vaccines class I MHC loading – priming CD8+ T cells o Gene delivery Delivery of plasmid DNA o Anti-sense therapy Shutting off production of certain proteins by delivery of anti-sense oligonucleotides to bind ribosomal mRNA o Intracellular toxins for cancer therapy o Ribozyme delivery ? o drug delivery to organelles 2 drug delivery to mitochondria Objectives protection of cargos from degradation o e.g. DNA protection from DNAses o protein protection from proteases, phosphatases avoid opsonization and production of antibodies against drug molecule o opsonization: coating foreign protein, small molecule, or particle with antibodies or complement proteins leads to macrophage binding and destruction source of opsonization animation: http://medtech.cls.msu.edu/ISL/immunology/opsonize.htm Lecture 14 – nano- and micro-particles 2 of 6
BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 Opsonization B cell B cells binding to a foreign protein, drug, or particle can be triggered to produce antibodies against the drug or carrier Resta loM:lc° Figure 9-11 Functions of cytokines in B cell growth and differentiation argeted delivery to select tissues, cells Molecular carriers Role of polymeric carriers 1. Multivalency High avidity binding to low-affinity receptors for detection/delivery CD40-dextran conjugate example Potent delivery on per-molecule basis 1 carrier delivered 10-50 drug molecules delivered 2. penetration of tissues 3.'stealth functions Chemistry and physical chemistry of conjugation non-covalent linkages Molecular size considerations Micelle carriers Amphiphilic block copolymer structures form micelles in water o Monodisperse copolymers can form relatively monodisperse micelle spheres o Compartmentalization/association of cargo within the micelle ocalization driven by hydrophilic/hydrophobic balance Hydrophobic core-hydrophobic drug Hydrophilic drugs -only associate with corona Amphiphilic drugs- localized at core-corona interface Lecture 14-nano- and micro-particles 3 of 6
BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 Opsonization: QuickTime™ and a GIF decompressor are needed to see this picture. B cells binding to a foreign protein, drug, or particle can be triggered to produce antibodies against the drug or carrier: targeted delivery to select tissues, cells Molecular Carriers Role of polymeric carriers 1. Multivalency High avidity binding to low-affinity receptors for detection/delivery x CD40-dextran conjugate example Potent delivery on per-molecule basis x 1 carrier delivered = 10-50 drug molecules delivered 2. penetration of tissues 3. ‘stealth’ functions Chemistry and physical chemistry of conjugation non-covalent linkages o Ni-histadine linkages Molecular size considerations 3 Micelle Carriers Amphiphilic block copolymer structures form micelles in water o Monodisperse copolymers can form relatively monodisperse micelle spheres o Compartmentalization/association of cargo within the micelle 3 Electrostatic interactions 4 Localization driven by hydrophilic/hydrophobic balance x Hydrophobic core-hydrophobic drug x Hydrophilic drugs – only associate with corona x Amphiphilic drugs – localized at core-corona interface Lecture 14 – nano- and micro-particles 3 of 6
BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 人人人 AAA 5 Min aleutian f PE J ahy seg 人八人·mkwm Cr-cionis segment (Kakizawa and Kataoka, 2002) o Composition range for core-shell structure? Vesicle carriers o Mechanisms of cargo delivery Membrane fusion Receptor-mediated endocytosis(internalization by cell) o Functionalizing liposomes o' stealth’ functions o limitations difficulty in storage/stability rapid drug leakage(T M. Allen, Drugs 54 suppl. 4, 8-14 (1997) unstable drug entrapment hydrophobic drugs interact with bilayer and destabilize structure drug instability within liposomes porymerosom unmodin Droteins interact with bilayer and become denatured fied liposomes activate complement causes pseudo-allergic reactions that damate heart and liver cells o larger amphiphilic molecules than lipids larger hydrophobic blocks increase membrane stability and mechanical strength can be polymerized to make membrane associations covalent Lecture 14-nano- and micro-particles 4 of 6
BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 (Kakizawa and Kataoka, 2002) o Composition range for core-shell structure? Vesicle carriers Liposomes o Mechanisms of cargo delivery Membrane fusion Receptor-mediated endocytosis (internalization by cell) o Functionalizing liposomes o ‘stealth’ functions o limitations difficulty in storage/stability rapid drug leakage (T.M. Allen, Drugs 54 suppl. 4, 8-14 (1997)) x unstable drug entrapment x hydrophobic drugs interact with bilayer and destabilize structure drug instability within liposomes x proteins interact with bilayer and become denatured unmodified liposomes activate complement 5 x causes pseudo-allergic reactions that damate heart and liver cells polymerosomes o larger amphiphilic molecules than lipids larger hydrophobic blocks increase membrane stability and mechanical strength can be polymerized to make membrane associations covalent Lecture 14 – nano- and micro-particles 4 of 6
BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 Nano-and Microparticle carriers Approaches Electrostatic Complexation of cargo with carrier o E.g. DNa delivery by polycationic polymers Plasmid DNA comb with cationic backbone hydrophilic side chains-> nano- to micro-particles Reduce adsorption of proteins to particle surface that could trigger phagocytosis Hydrophilic, steric barrier to block uptake by rEs Nanoparticle DNA packaging Protection from DNAses Polycation backbone rophilic side chains bAckbone components aside chain components Encapsulation Surface immobilization o Conjugation of cargos/targeting agents to surface of microparticles Sialyl Lewis*& Derivatives -selectin, E-selectin Lecture 14-- and micro-particles 5 of 6
BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 Nano- and Microparticle carriers Approaches Electrostatic Complexation of cargo with carrier o E.g. DNA delivery by polycationic polymers Plasmid DNA + comb with cationic backbone hydrophilic side chains -> nano- to micro-particles x Reduce adsorption of proteins to particle surface that could trigger phagocytosis x Hydrophilic, steric barrier to block uptake by RES Nanoparticle DNA packaging + Plasmid DNA Polycation backbone* Hydrophilic side chains** ** side chain components * Backbone components PEI -(CH2-CH2-O)n - PEO PLL dextran (Park and Healy, 2003) Protection from DNAses Encapsulation Surface immobilization o Conjugation of cargos/targeting agents to surface of microparticles -OH -COOH -(CO)(NH)- 0.1M NaOH 15 min Lecture 14 – nano- and micro-particles 5 of 6 6