BIOPHYSICS: HISTORY, WHAT IT STUDIES, APPLICATIONS, CONCEPTS, METHODS - BIOLOGY - 2025

The biophysics is the study of physical laws operating in living organisms. It is an interdisciplinary science that applies the approaches and methods of physics to study biological phenomena.

Also known as physical biology, part of the idea that all phenomena observed in nature have a predictable scientific explanation and that all living systems are made up of processes based on physical laws.

Double helix of DNA chain. One of the main findings in biophysics. Source: Joseluissc3

The discussion in which biophysics is considered as a branch of physics, biology or both is common. In this case, it is important to note that the tendency is to consider it a branch of biology.

This is because the exchange of knowledge is usually generated from physics to biology, which has been enriched by physical advances and concepts. But the same contribution cannot be affirmed in an inverse way, that is, from the point of pure physics it cannot be said that biophysics offers new knowledge.

Biophysics provides experimental evidence to physics and thus allows it to corroborate theories, but the exchange between physics and biology is clearly unidirectional.

Biophysicists are trained in the quantitative sciences of physics, mathematics, and chemistry to study everything related to the functioning, structure, dynamics, and interaction of biological systems. These systems include complex molecules, cells, organisms, and ecosystems.

History

The origins of biophysics date back to the seventeenth century when the natural sciences had not yet been divided as separate disciplines and at the time when the first investigation of bioluminescence was located.

The first study that was detected was that carried out by the German Jesuit, Athanasius Kircher (1602-1680), who published his work Ars Magna Lucis et Umbrae and dedicated two chapters to animal luminescence.

The link between electricity and biology was the subject of speculation not only in the seventeenth century, but in the next two centuries. During his approach, the fascination of man for animal and natural electricity, such as fireflies or natural lightning discharges, became evident.

In this line of research, in Italy, and in the middle of the 18th century, Giovanni Beccaria's experiments on electrical stimulation of muscles were detected, which generated knowledge in this area.

In 1786, Luigi Galvani started a controversy around the electrical potential in animals. His opponent was none other than Alessandro Volta who, by developing the electric battery, somewhat curbed the scientific interest in the electric potential in living beings.

XIX century

One of the main contributions in the 19th century was that of Du Bois-Reymond professor of physiology in Berlin, who built the galvanometers and carried out studies on the muscular current and the electrical potential of the nerves. This object of study became one of the points of origin of biophysics.

Another of them was the forces responsible for the passive flow of matter in living organisms, specifically the diffusion gradients and osmotic pressure. Along these lines, the contributions of Abbé JA Nollet and Adolf Fick stand out.

The latter was the one who published the first biophysical text Die medizinische Physik or Medical Physics in Spanish. In Fick's work, no experiments were carried out, but rather an analogy with the laws of heat flow was raised, which made it possible to enunciate the laws governing diffusion. Later laboratory experiments showed that the analogy was exact.

Twentieth century

The twentieth century was characterized by beginning with a certain mastery of German scientists, who concentrated on studying the effects of radiation.

An important milestone of this period was the publication of the book ¿Qué es la vida?, by Erwin Schrödinger in 1944. In this, the existence of a molecule in living beings that contained genetic information in covalent bonds was proposed.

This book and that idea inspired other scientists and led them to discover the double helix structure of DNA in 1953. It was James Watson, Rosalind Franklin and Francis Crick who made the discovery.

In the second half of the 20th century there is an evident maturity of biophysics. In those days university programs were already being presented and it was popular in other countries beyond Germany. In addition, the investigation was acquiring ever greater pace.

What is studying (object of study)

Biomechanics is one of the branches of biophysics. Source: Mutuauniversal

The field of study of biophysics extends to all scales of biological organization, from molecular to organic and other more complex systems. Depending on the focus of attention, biophysics can be divided into the following branches:

- Biomechanics: studies the mechanical structures that exist in living beings and that allow their movement.

- Bioelectricity: studies the electromagnetic and electrochemical processes that occur in organisms or that generate effects on them.

- Bioenergetics: its object of study is the transformation of energy that occurs in biosystems.

- Bioacoustics: it is the science that investigates the production of sound waves, their transmission by some means and capture by other animals or living systems.

- Biophotonics: focuses on the interactions of living things with photons.

- Radiobiology: studies the biological effects of radiation (ionizing and non-ionizing) and its applications in the field and laboratory.

- Protein dynamics: study the molecular movements of proteins and consider their structure, function and folding.

- Molecular communication: focuses on studying the generation, transmission and reception of information between molecules.

Applications

The topics investigated by biophysics may overlap with those of biochemistry, molecular biology, physiology, nanotechnology, bioengineering, systems biology, computational biology or physical chemistry, among others. However, we will try to delimit the main applications of biophysics.

With the discovery of DNA and its structure, biophysics has contributed to the creation of vaccines, the development of imaging techniques that allow diagnosing diseases and the generation of new pharmacological methods to treat certain pathologies.

With the understanding of biomechanics, this branch of biology has made it possible to design better prostheses and better nanomaterials with which drugs can be delivered.

Today, biophysics has begun to focus on issues related to climate change and other environmental factors. For example, work is being done on the development of biofuels through living microorganisms to replace gasoline.

Microbial communities are also being investigated and pollutants in the atmosphere are tracked with the knowledge gained.

Main concepts

- Systems: it is an ordered aggregate of elements included between real or imaginary limits, which are interrelated and interact with each other.

- Proteins: large molecules found in all living cells. They are composed of one or more long chains of amino acids that behave like machines that carry out a wide variety of functions, such as structural (cytoskeleton), mechanical (muscle), biochemical (enzymes) and cell signaling (hormones).

- Biomembranes: system of fluids that fulfill numerous biological functions for which they must adapt their composition and diversity. They are part of the cells of all living beings and it is the place where countless small molecules are stored and serves as an anchor for proteins.

- Conduction: it is the flow of heat through solid media due to the internal vibration of molecules, as well as free electrons and collisions between them.

- Convection: refers to the flow of energy through currents of a fluid (liquid or gas), it is a movement of volumes of liquid or gas.

- Radiation: heat transfer through electromagnetic waves.

- Deoxyribonucleic acid (DNA): chemical name of the molecule that contains the genetic information in all living beings. Their main function is to store long-term information to build with other components of cells, they also have instructions used for the development and operation of all living organisms.

- Nervous impulse: it is an electrochemical impulse that originates in the central nervous system or in the sense organs in the presence of a stimulus. This electrical wave that runs through the entire neuron is always transmitted in a unidirectional way, entering through the dendrites of the cells and leaving through the axon.

- Muscle contraction: physiological process in which muscles tighten, causing them to shorten, remain or stretch due to the sliding of the structures that compose it. This cycle is linked to the structure of the muscle fiber and the transmission of electrical potential through the nerves.

Methods

Biophysicist AV Hill considers mental attitude to be the biophysicist's main tool. With this as a foundation, he argues that biophysicists are those individuals who can express a problem in physical terms, and who are not differentiated by the particular techniques used but by the way they formulate and attack problems.

Added to this is the ability to use complex physical theory and other physical tools to study natural objects. In addition, they do not depend on commercially built instruments, since they usually have the experience of assembling special equipment to solve biological problems.

The automation of chemical analyzes and other diagnostic processes using computers are aspects to consider in current biophysical methods.

In addition, biophysicists develop and use computer modeling methods, with which they can manipulate and observe shapes and structures of complex molecules, as well as viruses and proteins.

References

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5. Byophysical Society. (2019) What Is Biophysics. Recovered from biophysics.org
6. Nahle, Nasif. (2007) Didactic Article: Biophysics. Biology Cabinet Organization. Recovered from biocab.org