Nimisha Tehri (Ph.D. Scholar), NDRI-Karnal (INDIA)

1. WELCOME

2. Applications of Biological Pores
in Nanomedicine,
Sensing and Nanoelectronics
Nimisha Tehri
Ph. D. 1st yr. (Dairy Microbiology))

3. Carbon fullerenes
Carbon nanotubes
Biological Pores
Nanoparticle metal oxides
Nanomedicine
Nanosensing
Nanoelectronics

4. Biological Pores
 Proteins and Peptides
 Nanoscopic Pathways - Passage of Ions, other
Charged or Polar molecules
 Short peptides - Self-Assemble to Pores
 Large Transmembrane Ion Channel Proteins
 Functions - Maintaining cell homeostasis
- Signaling and Communication
- Defense against pathogens
- Transport of proteins & nucleotides

5. Toxic
Peptides
Viral Pores Porins
Translocator Biological Pores
Aquaporins
Pores of ER
Nuclear Pore Membrane
Complex Attacking
Ion channel Complex
Proteins

6. Biological Pores In Nanobiotechnology
Capability to be
Regulated
3D Structure on Specificity
the Nanoscale
Pore
Protein
Mainly Ion Channel proteins, antimicrobial and toxic peptides, complement
system are attractive for the developing field of nanobiotechnology

7. Models of Lipid Membranes
For their application in nanobiotechnology, ion
channel proteins and pore-forming peptides
typically have to be reconstituted into
lipidmembranes

8. Supported Planar Lipid Liposomes Droplet Interface
Lipid Bilayer Bilayers Bilayer Systems
Most of the applications of proteinaceous nanopores are
based on current recordings through planar lipid Bilayers. This
technique was developed in 1962 by Mueller et al.

10. Nanomedicine
Nanomedicine may be defined as the detection,
treatment and prevention of human biological
disorders at the molecular level, using engineered
nanodevices and nanostructures
Therapeutic applications
 Delivering medication to the exact location
 Application in cancer therapy
 Killing of bacteria, viruses
 Repair of damaged tissues
 Skin and dental care

11. Applications of pore-forming peptides
and proteins in nanomedicine.
1. Cancer treatment
2. Drug delivery
3. Antimicrobial drug development

12. 1. Cancer Treatment
 Targeted cytolysis of cancer cells that uses biological pores
 Endotoxin Bacillus thuringiensis
 Diptheria toxin Corynebacterium
diptheriae

13.  Using a multimeric pore with a built-in ‘trigger’
system to target and kill cancer cells
α- hemolysin pores
Bacterial pore-
forming protein,
Aerolysin

14. 2. Delivery of Macromolecules into Cells
1. Gramicidin
DNA transfection protocol has been developed using a
gramicidin–lipid–DNA complex to deliver a plasmid DNA to a
variety of mammalian cells
2. Listeriolysin O (LLO)
LLO liposomes is an efficient vaccine delivery system. Act as a
delivery vehicle for macromolecules such as proteins into cells
both in vitro and in vivo.
3. Anthrax toxin
Targeted delivery of antigens for generating protective antiviral
immunity. Goletz et al. employed this toxin to deliver a portion of
the human immunodeficiency virus-1 (HIV-1) envelope protein
to the cytosol of living cells

15. 3. Development of Antimicrobial Drugs
Pore-Forming Peptide Antibiotics
 Nystatin
 Defensin
 Gramicidin
 Melittin
 Cecropin

16. Model for membrane lysis by AMPs
α-helical peptide
6.
1.
4.
2.
5.
3.

17. Nanosensing
 Nanosensors are any biological, chemical, or surgical
sensory points used to convey information about
nanoparticles to the macroscopic world
 Detecting single molecules is a useful advancement for
applied fields such as medicine, environmental pollution
monitoring
 Sensing platforms based on transmembrane channels offer
high sensitivity, often require no labeling, and are relatively
economical

18. Applications of Biological Pores in Sensing
1. Nanopore-based sensing of polymers
2. Detection of small ions and organic molecules by
biological pores
3. Nanopore-based sensing of polynucleotides
4. Using nanopore recordings to monitor enzyme
activity

19. 1. Nanopore based sensing of polymers
α-HL pore
α-HL
To determine the size of polymer To study polymer chain elongation

20. 2. Detection of small ions and organic molecules
Resistive Pulse sensing of Analytes

21. 3. To monitor enzyme activity
α-hemolysin based platform for monitoring the cleavage of a peptide
by protease

22. 4. Nanopore-based sensing of polynucleotides
Identification of base mutations Identification of nucleotides

23. Nanoelectronics
Nanoelectronics is a branch of nanotechnology that
uses single molecules, or nanoscale collections of
single molecules, as electric components.

24. Applications of Biological Pores in Nanoelectronics
1. Biological nanopores as current rectifiers
2. Biological nanopores for development of bio-
inspired batteries

25. Biological nanopores as current rectifiers
Biological pores that exhibit rectification properties have been used for
generation of membrane potentials, sensing of enzymatic reactions
and building basic bioelectrical circuits
 OmpF from E. coli
Alacaraz et al. demonstrated that its reconstitution into a planar lipid
bilayer, which separated solutions of different pH values, led to current
rectification
 α- hemolysin
By controlling the incorporation of the engineered a-hemolysin into lipid
bilayers between specific droplets, formation of droplet networks
occured that acted as rectifier circuits
 Gramicidin pores
Yang and Mayer incorporated chemically modified gramicidin pores
i.e. oppositely charged gramicidin-derivatives in each leaflet of the
lipid bilayers. These heterodimeric gramicidin pores rectified current

26. Biological nanopores for development of bio-
inspired batteries
 One intriguing development of bio- nanoelectronics is
engineering of bio-inspired mechanisms for providing
electrical power based on rectifying biological pores in
membranes.
 Using this principle, Bayley’s group recently developed a
bio-inspired battery that employed α- hemolysin pores to
generate a membrane potential across a lipid bilayer

27. Biological pores solved the following set of
challenges with synthetic pores-
1. Non-specific binding of biomolecules (in particular
proteins) to the walls of the pores
2. Limited reproducibility of fabrication on the
subnanometer and even nanometer scale
3. Electrical breakdown of extremely thin synthetic
membranes that are required to support short pores
4. Bubble formation in the pore, and pore clogging

28. Biological pores solved the issues related to
nanotoxicity
1. Silver nanoparticles which are bacteriostatic , may then destroy
beneficial bacteria which are important for breaking down
organic matter in waste treatment plants or farms
2. Some forms of carbon nanotubes could be as harmful as
asbestos if inhaled in sufficient quantities
3. Toxicity have not reported with the use of biological pores.

29. Challenges with the use of biological pores
1. In Nanomedicine
Applications of biological pores include- Cancer treatment,
Antimicrobial drug development, Drug delivery
Challenges that will have to be met for developing therapeutics
based on biological pores-
 Appropriate circulation half-life and stability in the human body
 Effective distribution to the target organs
 Release in active form at targeted tissue at doses that are
effective and elicit minimal side effects
 Possible adverse immune reactions against these constructs
 High costs of production

30. 2. In Sensing
Applications - Detection of small ions and organic
molecules, sensing of polymers, sensing of polynucleotides
and polypeptides, monitoring enzyme activity etc.
Challenges-
 Functional reconstitution of ion channel proteins into
bilayer lipid membranes is still rather an art than a science
 The availability of purified, functional biological pores is
limited to a few proteins
 The cost of available proteins is typically extremely high
 Limited stability of the lipid bilayer that supports the pore

31. Future Prospects
The fascination with biological pores includes their capability to
detect single molecules, to sequence short strands of DNA, to rectify
current, or to target and kill cancer cells
Nanopores on a chip: Applications for analytical tasks in chemistry
and biology
In a joint project at the University of Freiburg, a research group led
by Prof. Dr. Jan C. Behrends, Institute of Physiology have succeeded
in arranging biological nanopores on a tiny microchip and using it to
determine the mass polymers
Fitting a Biological Nanopore Into an Artificial One, New Ways to
Analyze DNA
Researchers at Oxford University announce a new type of nanopore
device that could help in developing fast and cheap genetic
analysis.they report on a novel method that combines artificial and
biological materials to result in a tiny hole on a chip, which is able to
measure and analyze single DNA molecules

32. "The first mapping of the human genome-where the content
of the human DNA was read off ('sequenced') -- was
completed in 2003 and it cost an estimated 3 billion US
dollars. Imagine if that cost could drop to a level of a few
100 euro, where everyone could have their own personal
genome sequenced. That would allow doctors to diagnose
diseases and treat them before any symptoms arise.”
" Professor Cees Dekker”
(Kavli Institute of Nanoscience at Delft.)

33. Conclusion
The use of biological pores can be exploited in-
Nanomedicine
Precise diagnosis and more effective therapies improved
cost-effectiveness of tomorrow's medicine
Sensing
More detailed examination of cellular processes effective in
identifying molecular targets
Nanoelectronics
Benefit the energy sector. Items like batteries, fuel cells, and
solar cells can be built smaller but can be made to be more
effective with this technology