A Study on Size and Shape of Erythrocytes of normal and malarial

blood using Laser Diffraction Technique

By done

Amar Yahya Yahay Alansi

MS.C (Biophysics)

INTRODUCTION of Blood Blood is a connective tissue in fluid form.

‘fluid of life’ because it carries oxygen from lungs to all parts of the body and carbon dioxide from all parts of the body to the lungs.

‘fluid of growth’ because it carries nutritive substances from the digestive system and hormones from endocrine gland to all the tissues.

‘fluid of health’ because it protects the body against the diseases and gets rid of the waste products and unwanted substances by transporting them to the excretory organs like kidneys.

PROPERTIES OF BLOOD

Color :Blood is red in color. Arterial blood is scarlet red because it contains more oxygen and venous blood is purple red because of more carbon dioxide.

Volume :Average volume of blood in a normal adult is 5 L. In a newborn baby, the volume is 450 ml. It increases during growth and reaches 5 L at the time of puberty. In females, it is slightly less and is about 4.5 L. It is about 8% of the body weight in a normal young healthy adult, weighing about 70 kg.

pH :Blood pH in normal conditions is 7.4.

Viscosity: Blood is five times more viscous than water.

COMPOSITION OF BLOOD

INTRODUCTION of Malaria

Malaria is one of the most successful parasites ever known to mankind. After thousands of years, it remains the world's most pervasive infection, affecting at least 91 different countries and some 300 million people. The disease causes fever, shivering, joint pain, headache, and vomiting. In severe cases, patients can have jaundice, kidney failure, and anemia, and can lapse into a coma.

It is ever-present in the tropics and countries in sub-Saharan Africa, which account for nearly 90 percent of all malaria cases. The majority of the remaining cases are clustered in India, Brazil, Afghanistan, Sri Lanka, Thailand, Indonesia, Vietnam, Cambodia, and China. Malaria causes 1 to 1.5 million deaths each year, and in Africa, it accounts for 25 percent of all deaths of children under the age of five.

. Plasmodium vivax, Plasmodium ovale, Plasmodium malariae, and Plasmodium falciparum

Forward Fraunhofer Diffraction of laser light

Different methods adapted for particle size analysis:

Particle-Size Measuremen

tTechniques

Sieving MicroscopySedimentati

onPermeametr

yElectrozone

SensingLaser

Diffraction

Methods applied for the size range of particles:

Disadvantages of other methods: Sieves: This is readily usable for large particles such as

are found in mining.Not possible to measure sprays or emulsions. Cohesive and agglomerated materials e.g. clays are difficult to measure.

Sedimentation: This has been the traditional method of measurement in the paint and ceramics industry and gives relatively low answers!

The applicable range is 2-50 microns. Electrozone sensing: This technique was developed in the

mid 1950’s for sizing blood cells. The method requires calibration standards which are expensive, difficult to measure emulsions and Porous particles give significant errors.

Microscopy: It is not suitable as a quality or production control technique.

LASER DIFFRACTION:

Applicable range: 0.1-3000 μm Principle: The method relies on the fact that

diffraction angle is inversely proportional to particle size.

Instruments consist of:

1)A laser as a source of coherent light of known fixed wavelength.

Eg: He-Ne gas lasers (λ=0.63μm).

2) A suitable detector

Eg: A slice of photosensitive silicon with a number of discrete detectors.

Laser diffraction (LD) is a method used for particle size measurement that is based on the properties of particles to scatter light.

This method has become the preferred standard in many industries for characterization and quality control.

There are two principal optical models for analysis of diffraction spectra:

Fraunhofer Scattering,

Mie Scattering.

Fraunhofer Scattering:

This method is based on diffraction scattering only, and it won’t take into the consideration of others like absorption, refraction and reflection, where as Mie scattering will.

The scattering pattern produced by a single spherical particle consists of

a series of light and dark concentric bands that decrease in intensity with increasing radial position.

Contd… 3). The equation describing this distribution

of intensity (I), is called the Airy function and is given by

where J1 is the first-order spherical Bessel function,I(0) is the scattered intensity on the optical axis, and X is a dimensionless parameter given by the following expression, where f is the focal length of the receiving lens and R is the radial distance in the focal plane as measured from the optical axis.

2) MIE SCATTERING: The Mie model takes into account both

diffraction and diffusion (absorption, refraction and reflection) of the light around the particle in its medium.

The dimensionless size parameter (X)

(here we need refractive

index of the particle)

where d is the particle diameter,

and m is the refractive index of

the particle.

Laser diffraction gives the following advantages:

Flexibility. This method is rapid producing an answer in

less than one minute, unlike other techniques. A wide dynamic range(0.1- 2000 microns) The method is non-destructive and non-

intrusive. Hence samples can be recovered if they are valuable.

Dry powders can be measured directly, although this may result in poorer dispersion than using a liquid dispersing medium.

This method gives more detailed particle size distributions than the other techniques stated.

Contd…

Speed of measurement -- single measurements can be made in 400 [micro]sec, allowing the dynamics of drug delivery from aerosol devices to be followed.

Measurement repeatability -- the ability to acquire data rapidly allows many thousands of measurements to be averaged when reporting a single result, delivering excellent repeatability when compared with techniques that deliver results based on one-off measurements.

Range of applicability -- sprays, dry powders, suspensions and sprays can all be characterized using the same technique, allowing different formulation types to be compared in a realistic way.

Samples collection

Experimental set up

Procedure and analysis

Results and Discussions

Thank you