Nanotech (18-20)

3 kinds of cancers

Carcinomas: in epithelial tissues, so skin membrane

Sarcomas: in connective tissue

Leukemias: in blood cells

Nanotech description

Create stuff on nano scale, so between 10^-9 and -6 meters (nanometer and um)

Nano medicine is offshoot of nanotech, specific for treatment of

Nanotech scale

1nm-1um is important, there can easily penetrate.

Polymeric nanoparticle advantage (3/disadvantages

Polymersome, dendrimer, polymer micelle, nanosphere

Advantage: precise control of particle, payload flexibility and easy surface modification

Disadvantage: Possible aggregation and toxicity

Inorganic nanoparticles Advantages (3) and disadvantages

Silica, quantum dot, iron oxide, and gold nanoparticles

Advantage: unique electrical, magnetic and optical properties. Can vary in size shape and geometry, best for theragnostic application

Can have toxicity and soluble limitations

Lipidbased nanoparticle advantages (3) and disadvantages

Liposome, lipid nanoparticle, emulsion

Advantages: Easy formulation, high F, payload flexibility

disadvantage: Limited encapsulation efficiency

3 Dispersed systems

Molecular dispersion <1nm (can't see in electron microscope and pass through stuff easily)

Colloidal dispersion: 1nm-0.5 um (can see in electron, can't pass through semipermeable membrane and diffuse slow)

Coarse dispersion: >0.5um (visible, do not pass through anything)

Liposome description

Encapsulates region on aq solution (core) inside a hydrophobic membrane. Inside core are hydrophilic drugs that can not easily pass though lipids

Hydrophobic drugs can be dissolved into the membrane of liposomes

Liposome drug release mechanism (3)

Can have diffusion through a pH change

Membrane fusion

Or endocytosis

ASO therapy

used to block synthesis of protein by binding to mRNA, complementary to chosen sequence. Can be RNA or DNA

ASO mechanism (3 things)

ASO bind to mRNA to prevent synthesis of protein

Degrade mRNA portion of duplex, releases ASO for further binding

Release of ASO into blood stream and then excretion

RNAi

Double stranded RNA inhibit gene products on posttranscriptional level (block mRNA to protein), can be induced artificially.

Co-suppression

dsRNA can inhibit gene expression. Suppress expression of gene and introduced gene.

Found when people tried making flower more purple, but instead turned it white.

siRNA proccess

Dicer enzymes cut up dsRNA into small RNA fragments called small interfering RNA/siRNA. They bind to RNA induced silencing complex/RISC (when siRNA unwinds and bind to mRNA), using antisense RNA

RISC has enzyme called slicer to cleave bound mRNA and cause gene suppression

4 Advantages of antisense/siRNA therapy

Extremely high specificity

Selective knockout of single critical target

Potential for increased efficacy

Reduced likelihood of side effects

4 Challenges with siRNA

Low stability: siRNA easily go through hydrolysis

Chemically stabilized siRNA is maintained for 30 mins while unmodified siRNA duplex is degraded in 1 min

Rapid elimination: Small size of siRNA lead to quick elimination (half life of < 5 mins)

Poor cellular internalization: delivery of siRNA across membrane is limited by negative charged siRNA by the like charged cell membrane

Dendrimer description and 3 properties

Branched molecule that resembles branch of a tree

Dendrimer can be water soluble if end group is hydrophilic group like carboxyl

Can design water soluble dendrimer with internal hydrophobicity

Volume of dendrimer increases when it has a positive charge

Highest dendrimer generation used and what 3 properties increase with each generation?

MW, diameter and surface groups (double each time) increase

4th generation is the max used.

For Poly amidoamine dendrimers (PAMAM)

Traditional vs Modified dendrimers

Traditional: has external positive charge for siRNA binding, leading to nanofiber shaped structures seen since they are not internalized

Modified: acetylated surface, internal positive charge for siRNA binding leading to internalization and well condensed spheroidal nanoparticle seen in microscope

QPAMAM-NHAc description

Is a 4th generation dendrimer with modified surface, has reduced cyto and genotoxicity, leading to good internalization.

Quantum Dots

Small semiconductor particles, only several nanometers in size. Emit frequency if energy applied and can turn frequencies by changing size and shape and stuff.

Colloidal quantum dots emit different color light.

Quantum dot nanocrystal sstructure

have a core (quantum dot), shell, polymer coating, and then biomolecule.

Superparamagnetic iron oxide (SPIO) Nanoparticles description and application (2)

Used as contrast agents for MRI, allow targeting of vectors to desired locations through magnetic fields

Can act as miniature heaters that can kill cancer cells.

CD44 antigen

Cell surface glycoprotein used for interaction, adhesion and migration, important marker for cancer stem cells.

Cancer stem cells/Initiating cells description

Responsible for initiation, extensive proliferation of primary tumor and spreading of metastases.

Can self renew

Non targeted vs LHRH targeted dendrimer affect

Non targeted, still the dendrimers localized everywhere, but for LHRH receptor targeted dendrimers, see them pretty much only in the tumors.

CD44 suppression effect

Suppression of CD44 in cancer stem cells ENHANCE antitumor effect of anticancer drug, limiting tumor growth and preventing adverse side effects of chemotherapy

Suppression of P-gp effect

Lead to increased drug accumulation inside cancer cells and suppresses drug resistance.

Personalized Medicine Definition

Right treatment for right patient at right time. Understand genetic make up to understand biology of tumor.

3 Steps to create personalized medicine

1: Analyze patient individual profile

2: Anticipate patient reaction to certain drugs

3: Overcome potential complications or adverse side effects

5 Limitations of systemic lung delivery

Enzymatic Degradation in Gi Tract and Liver

Short half life and degradation of drugs in blood stream

Low accumulation and retention of drugs in lungs

Low efficacy of treatment

possible adverse side effects on other organs and tissues

3 Advantages of local inhalation drug delivery directly to the lungs

Enhanced accumulation and retention of drugs in lungs

Prevention/limitation of penetration of drugs into blood stream and accumulation in other healthy organs

High efficacy of treatment

Main challenge of lung delivery

Most free dugs can not be delivered into drugs by inhalation so need special delivery system

Nanotech drugs (4) and where in nLC

Anticancer, anti inflammatory, antioxidants, PGe2, on the inside of NLC

Nanotech nucleic acids and where in NLC

SiRNA, ASO.

Choose from lots of factors, is on the inside of NLC

Nanotech targeting agents and where in NLC

LHRH on the outside of NLC.

Nano tech DSPE-PEG-Polyethylene glycol

Molecules introduced to NLC (nanostructure lipid carrier) to stabilize against aggregation

DOTAP for nanotech and where in NLC

NLC prepared through incorporation of DOTaP into naoparticle structure

Inhalation delivery of lipid nanoparticle leads to?

Preferential accumulation in the lungs mainly. IV can go anywhere but inhalation is lungs.

Virus like particle vaccines, example and when first introduced

HPV use this

1986 first introduced for HepB

Nucleic acid vaccine, example and first introduced

SARS-Cov-2 use this

introduced in 2020

Human Coronavirus structure

Has single strand positive sense RNA surrounded by membrane. Envelope has glycoprotein.

Coronavirus replication 9 Steps

1: Bind and viral entry through receptor mediated endocytosis

2: Release of viral genome

3: translation

4: RNA replication

5: Subgenomic/nested transcription

6: translation of viral structure protein(N,S,E,M) (S=Spike,m=membrane,e=envelope, n=nucleocapsid), SEM go to ER.

7: S, E and M protein combine with nucleocapsid (S=Spike,m=membrane,e=envelope, n=nucleocapsid)

forms ERGIC

8: formation of mature virion inside a golgi vesicle formed from the SEM bound to the ER.

9: exocytosis

How does coronavirus replication start?

Have a host cell to attach to through the spike glycoprotein binding to the angiotensin converting enzyme 2 receptor protein on the host cell and invade.

2 approaches for therapeutic treatment

Prevent virus entry into host cell (Target ACE2 receptor)

Suppress various steps in virus replication inside cells (Target RBD of spike protein)

Acute immune response to corona

Activation of ACE2 activates inflammatory factors to kill, and kills lung epithelial cells

Acute response provides immediate protection, but in the long run adaptive long term immune response should be initiated not acute anymore.

2 Types of COVID vaccines

mRNA encoding SARS-COV2 Spike protein or

Adenovirus vector encoding S protein.

Basically help differentiate naive T cells to recognize the S protein and train them to kill SARS COV2.

mRNA based COVID 19 Vaccines description

Lipid nanoparticle encapsulated mRNA

Lipid nanoparticles done through rapid mixing with microfluidic devices. Formed by merging smaller lipid vesicles.

3 Main strategies for RNA type and delivery system

mRNA, sa(Self amplifying), RNA

LIPID nanoparticles (CNE)

Cationic Nano emulsions (CNE)