Membrane in Medical Science

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Dr. N.K Acharya

Applied Physics Department

The M. S. University of Baroda Vadodara


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Only in the US, the medical membrane market approaches1.5 billion dollars per year and grows steadily.

Membranes Applications :

Drug deliverySkin Grafts

Tissue Engineering

Artificial Pancreas

Artificial LiverBlood Oxygenation

Dialysisartificial kidney

Barriers


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Separation and sorting of biomolecules(Isolation and purification of molecules: Kidney applications)

Biosensing

(Reacted Enzyme detection: Sugar level, Cholesterol)

Single molecular analysis (DNA/RNA)

Immunoisolation

(Semipermeable membrane: protecting implanted cells or drug release

systems from an immune reaction)

Targeted Drug delivery (Tracers)(To enable supply of drugs locally where they are needed in a controlled

manner)


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Biodegradable materials

Membrane thickness

Pore size

Pore density

Pore distributionSmall tortuosity

Modified structural/ surface Properties (Enhance the interaction)

Plasma etchingCorona discharge

UV irradiation

Electron/Ion Irradiation

Physical, chemical,

and/or electrical

driving force

Permeate

Solute or particle

rejection

Feed or concentrate

Semi-permeable (selective) membrane

Accumulated, rejected material,

migrating back to bulk solution


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The goal of an ideal drug delivery system is to deliver a drug to a specific site, inspecific time and release pattern. The traditional medical forms (tablets,

injection solutions, etc.) provide drug delivery with peaks, often above the

required dose. The constant drug level in blood or sustained drug release to

avoid multiple doses


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In diffusion controlled membrane systems, the drug release is controlled bytransport of the drug across a membrane. The transport is dependent on the drug

diffusivity through the membrane and the thickness of the membrane, according to

Fickslaw. The membrane can be porous or non-porous and biodegradable or not.

Transdermal delivery systems

Fickslaw


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The scaffold (Membrane Structure) should be highly porous with

good pore connectivity to ensure sufficient nutrient transport

towards the cells and removal of waste products with suitable

mechanical properties.


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Definition:

Theradiation which produces any chemical or physical change in substances

when passes through it. These are harmful biologically.

Examples:

Alpha Particles

Beta Particles

Gamma RaysElectron tomography

Neutrons

X-Rays

X-ray computed tomography (CT)

Ionizing radiation can be sorted into 2 major types:

Photons (x-rays and gamma rays), which are most widely

used in cancer treatment

Particle radiation (such as electrons, protons, neutrons,carbon ions, alpha particles, and beta particles,heavy ions)


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Data Acquisition


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What are Heavy Ions?

Heavy ions are ionised atoms which are usually heavier than C.

Heavy ions are composed of Hadrons.

Heavy ions refers to atoms that are generally completely ionised, i.e. they are bare

atomic nuclei.

The nuclei can be directed to a fixed target, or can be split into two beams moving

in opposite directions that are brought into collision at a well-defined spot.

Heavy ion nuclei most often used in nuclear physics experiments include C, Si, W,

Au, Pb, U


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10 keV ElectronAccelerator (UHV)

PALS Set up

100 200 300 400

1

10

100

1000

10000

100000

Lifetime spectra of polycarbonate

Unirradiated

5 x 106

4 x 108

1 x 1012

Counts

Channel no. (58.6 ps/channel)


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ION TRACK ETCHING

Polymeric membranes Microfabricated membranesAnodized membranes Ordered nanoporous semiconductors


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Material (PC, PSf and PET)

Fabrication Method

(Solution Cast Method)

Pore Size (few nm)

The process involves irradiating a thinpolymeric film with accelerated heavy ions,

which leave so-called ion tracks.

These ion tracks can then be enlarged to

pores by chemical etching with an

appropriate reagent that preferentiallyattacks the damaged track zone.

Cylindrical or conical pores are produced

with diameters in the range of 10 nm to

micrometers.

ion tracks


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25

T

(C

)

300

1 hr

t2

complete

Imidization

time

T2

Rearrangement Heating Protocol

PIOFG


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www.nuc.berkeley.edu/sites/

www.mpi-hd.mpg.de/

www.iuac.res.in/

www.tifr.res.in/

Adiga et al., Wiley Interdiscip Rev Nanomed

Nanobiotechnol. 2009 ; 1(5): 568581.

J. Membr. Sci., 308 (2008) 134.

J. Membr. Sci., 107, 1-21 (1995)Membranes and Barriers: Targeted Drug Delivery, U.S.

DEPARTMENT OF HEALTH AND HUMAN SERVICES
http://www.cancer.org/treatment


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Membrane in Medical Science

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