What are sperms?

The word "sperm" is derived from the Greek word "sperma" meaning seed. The sperm is the male reproductive cell or gamete.

A sperm is a motile reproductive cell. It comprises of a head, neck, mid-piece, and a tail with an end-piece. The flagellar tail is responsible for the locomotory function of the sperm. The sperm uses fructose as the energy source. Energy metabolism inside the sperm takes place due to the presence of the mitochondrion.

The main function of the sperm is to fertilize the female reproductive cell or gamete called the ovum or the egg cell. This is called sexual reproduction. Each reproductive cell is haploid in nature, that is, it contains 23 chromosomes.

In some cases, sperms do not contain the flagellar tail. These sperms are called spermatia. As these sperms are non-motile, they are dependent on the external environment to enable them to fertilize the ovum.

The fertilization product of the sperm and the egg cell results in the formation of the zygote.

Robotic sperms
Robotic sperms are those sperms which are embedded, immobilized or trapped within metallic nanotubes. The movement of these robotic sperms can be regulated with the help of a magnetic field.

Construction of a robotic sperm

Robotic sperms comprise of bull sperms immobilized on metallic nanotubes - for laboratory experimental purposes, bull sperms are used. Iron or titanium nanoparticles can be combined together to form metallic nanotubes having a length of about 50 micrometres, and a diameter of five micrometres at one end and eight micrometres at the other end. These nanotubes can be introduced in a liquid containing thawed bull sperm. Sperms enter the metallic nanotubes through the wider end and move towards the narrow end where they are trapped inside the tube. External magnetic fields can be set-up so as to control the movement and orientation of magnetic fields. The tail of the sperm functions like a motor which powers the robotic sperm.

Need for robotic sperms

Defects can occur in naturally-occurring sperms due to the following reasons -

1. Overheating - The temperature of the testes needs to be cooler than the rest of the body for proper functioning. Therefore, overexposure to heat can affect the functioning of the testes. This exposure to heat can occur due to exposure to hot tubs, illnesses, etc.

2. Radiation exposure - Scientific research has shown that exposure to radiation from electronic devices such as laptops and mobile phones can affect sperm count and decrease sperm motility.

3. Obesity - Increased obesity in males increases body fat percentage. This increases the production of female hormones in men which affects male fertility.

4. Consumption of tobacco, alcohol, smoking, etc., reduces the quality of the sperm and affects sperm motility.

5. Other factors such as genetic disorders, arterial blockages, cancer, sexual problems, etc.

Sperms possess the following properties due to which they can be converted into "robotic sperms" -

• Sperms are naturally-motile cells. Therefore, they do not need to be powered externally.

• Sperms can maneuver through highly-viscous environments.

• Usage of sperms in such experiments does not cause any harm to the human body.

Applications

In the present-day scenario, robotic sperms have applications in two major fields -

1. Artificial fertilization - Metallic robotic sperms could find great usage to assist in fertilization.

Robotic sperms are present in metallic nanotubes. Therefore, they can be controlled through a magnetic field. This can help in the proper locomotion and maneuvering of the sperm so that immotile sperms can also fertilize the ovum. Fertility issues can be resolved through a great extent.

2. Drug delivery - Different drug delivery systems are used for safe and effective transportation of a pharmaceutical moiety inside the body, so as to achieve the desired therapeutic effect.

The performance of these biorobots is dependent on the radius of the metallic nanotube, the penetration power of the biorobots, and the temperature of functioning. Of these factors, the temperature of functioning is the most critical factor as sperms are heat-labile, and temperature fluctuations can massively affect the effectiveness of the functioning of a robotic sperm.

Other types of artificial sperms

Besides robotic sperms, there are other types of artificial sperms which have been created through scientific experiments. However, these types of sperms have not achieved significant success with regards to their usage and effectiveness -

1. Female sperm cells - These are sperm cells which contain genetic material obtained from a female organism. This concept was first developed in the late 1990s when experiments were conducted on chicken. These sperms had great potential to solve fertility problems as well as assisting female same-sex couples to start a family since the genetic material of both the sperm and the egg cell are obtained from the female. However, the usage of these types of sperms raises many legal, moral, and ethical questions.

2. Sperms obtained through stem cells - A stem cell is pluripotent in nature. It is diploid in nature and possesses the property to give rise to different types of cells. This principle is used in the production of sperms through stem cells. For a sperm to be fully functional, certain genes are required which are present on the Y chromosome in males. With the help of an artificially-constructed Y chromosome (containing the necessary genes required for proper sperm functioning) and a pluripotent stem cell, sperm cells can be artificially constructed. These stem cells used in the construction of such artificial sperms are termed as induced pluripotent stem cells (iPSCs). However, the implications of the usage of such sperms for producing offsprings are huge as it would completely eliminate the need for sexual reproduction as humans will be able to produce babies without a partner.



References

1. http://en.wikipedia.org/wiki/Sperm
2. http://www.ncbi.nlm.nih.gov/pubmed/10408311
3. http://spermatium.askdefine.com/
4. http://www.youtube.com/watch?v=MP-Z7CRfGkQ
5. http://www.newscientist.com/article/dn24721-how-do-you-control-a-spermbot-try-a-magnetic-field.html
6. http://www.fertility-health.com/causes-of-low-sperm-count.html
7. http://sploid.gizmodo.com/scientists-create-a-controlled-cyborg-sperm-that-can-sw-1481503095
8. http://www.medindia.net/news/robotic-sperm-to-help-fertilize-eggs-129089-1.htm
9. http://onlinelibrary.wiley.com/doi/10.1002/adma.201302544/abstract
10. http://en.wikipedia.org/wiki/Female_sperm
11. http://theweek.com/article/index/235881/coming-soon-making-babies-without-sperm

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