Biophysics is a bridge between Biology, Physics and Chemistry. Biology studies life in its variety and complexity. It describes how organism go about getting food, communication, sensing the environment and reproducing. Physics being the most basic natural science look for mathematical laws of nature and make detailed predictions about the forces that drive idealized systems. Spanning the distance between complexity of life and simplicity of physical laws, is challenge of biophysics.

Looking for the patterns in life and analyzing them with tools of math, physics and chemistry is powerful way to gain insights. The origin of Biophysics a clear boundary between molecular biology can be traced to the efforts of physicists and physical chemists to elucidate the physical (molecular) basis of biological science Surface tension, variations proteins make people respond to drugs design, diagnosis and disease control soon. Medicines will be tailored to each individual patient’s propensity for side effects.

Goal of Biophysics

Our goal of this article/unit is to introduce biophysical theory. Biophysics create simplified dynamical models of biological system and biological phenomena such as diffusion, membrane bioimpedance, electrical responses of cells / organelles of external fields.


Scope of Biophysics

Biophysics is closely related to the disciplines of mathematical and computational biology, Nanotechnology, Bioinformatics, Biochemistry and Bionics, a clear boundary between molecular biology can be traced to the efforts of physicists and physical chemists to explain the physical (molecular) basis of Genetics.

Human is not the species that meant to cry on earth

Research themes in biophysics encompass all major characteristics of life namely homeostasis, compositionzility,metabolism, adaption growth, irritability and· reproduction. Hence, they cover all levels of biological organization from the atomic and molecular level via cells, organs and_tissues to individual organisms, population, species, ecosystem, the
biosphere and astrobiology. · Modern biophysicists make extensive use of computaorial facilities, to calculate molecular structures arid interactions and, to calculate the content, transmission and transformations of matter, energy and transformation in bio systems. E.g. To stimulate physiological functions of cardiac or neural cells olr to decipher the relation between brain and mind.

There are several within biophysics like-

a) Radiation biophysics: It deals with response of organism to radiations. The radiation rays are alpha, gama, beta and X rays even UV rays. Here it is death of cells, tissues not of whole organisms.

b) Molecular Biophysics: Study of large / small molecules using electron microscope, ultracentrifuge and X rays diffraction camera. This branch disclose the physical mechanism responsible for biological functionality of molecules.

c) Theoretical Biophysics: Explain use of mathematics and physical theory to explain behaviour of living organisms=. Biological process are being explained using mathematical methods.

d) Physiological Biophysics: Use of physical mechanism to explain the behaviour and functioning of living organism to physical forces.

Biophysical Techniques and Applications:

1. Ultracentrifugation : To separate molecules of different sizes based on sedimentation principle.

2. Electrophoresis: To separate molecules of different molecular size/mass.

3. Size Exclusion Chromatography(SEC): Uses tightly packed gel beads and sedimentation based on gravity , to trap small molecules and allow large molecules to pass through gel.

4. Spectroscopy: Measuring intensity / direction / polarization of emitted radiations.

5. Absorption Spectroscopy: To find e.g. the concentration of molecules in the solution by using EM.

6. Fluorescence Spectroscopy: To characterize molecule and to follow conformational transitions, caused by absorption at one wavelength.

7. Mass Spectrometry: To measure mass or molecular weight of molecule.

8. X-Ray Crystallography: To determine relative position of atoms within crystal by using diffraction.

9. Nuclear Magnetic Resonance Spectroscopy (NMR): To obtain structural information about molecule of highest resolution.

10. Electron Microscopy: To view objects 1000-2500 smaller than those seen by light microscopes.

11. Atomic Force Microscopy (AFM): With resolution similar to TEM.

12. Optical Tweezers: To hold X manipulate microscopic parts using focused laser beams to create forces and measure forces needed to be d or break DNA.

13. Voltage Clamp: It is used in electrophysiology to determine electric currents in cell, in particular neurons.

  • Current clamp
  • Patch clamp

Medical Physics

Medical Physics is that the application of physics to medication. It includes areas such as Radiotherpy, Diagnostic Radiology physics, Nuclear medicine physics and radiation protection. Diagnostic radiology is the field of medicine that uses various imaging procedures for diagnosis of diseases using radiations. CT scans, R-Ray (radigraphy), mammography, ultrasound, MRI and fluoroscopy are included in diagnostics radiology.

In detail

Nuclear medicine physicians use radioactive materials to diagnose and treat diseases.Radiation (radiological) protection is the protection of people from harmful effects of exposure to ionizing radiation and the means for achieving this. Exposure can be from external radiation sources or due to an intake of radioactive material into the body of a human being. To measure the amount of radiation absorbed by a person from external sources, we use instruments, called dosimeters, to ensure that the absorbed dose of radiation is below the safety limit.

We shall discuss dosimeters in detail. There are many other radiation monitoring instruments used for measuring radiation levels for area monitoring. The physics of radiation protection is called Health Physics. Radiotherapy or radiation therapy uses ionizing radiation to kill cancer cells or damage them so that they cannot grow. The normal cells around the cancerous part can also get damaged by radiotherapy but they can usually repair themselves whereas cancer cells can’t. Radiotherapy can be given in three ways

Three ways of therapy


A high energy beam of radiation is directed from outside the body into the tumour/cancerous tissue.


It is also called brachytherapy. A radioactive source (or a capsule) is put inside the body into or near the tumour. Radioactive emitted by it damages the cancerous cells so that they cannot grow again


Radioactive drugs are given by mouth or put into a vein to treat certain types of cancer. These drugs then travel throughout the body.


The nature of the treatment given to a cancer patient depends upon the spread of the cancer and the organ affected. Sometimes only the cancerous tissues are treated and at some times the affected organ is removed from the body by surgery. The radiation may be used to make the primary treatment of surgery more effective by what is called the pre-operative therapy; radiation is used before surgery to help shrink the cancer to make the surgery less extensive

In all kinds of radiation treatments, a specific radiation of specific energy is required depending upon the purpose of treatment, the organ to be treated and the sensitivity of the organ to different radiation.

The amount of radiant energy required for a radiation procedure is called ‘doses’. Various radiation ‘doses’ and their units are disscussed.


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Rutuja Nerlekar

An IT Entrepreneur, owner and founder of domain name "". Currently pursing Graduation in Science. Also an AMAZON AFFILIATE MARKETER.

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