Hanging drop technique permits the examicountry of the living microorganisms, which entails fixation of microbial suspension into a drop of liquid over the glass slide. Therefore hanging drop technique is the procedure, in which the microorganisms are suspfinished right into a drop of fluid. It is a modified version of the wet mount technique.

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The form, dimension and also plan of bacteria are quickly identifiable in wet mount approach, but the bacterial motility becomes hard to study as the microbial suspension in the well of cavity slide is pressed by the coverslip. Light microscopy provides the use of wet mount strategy, smear preparation, warmth addressing and also stain films to make the organism visible to us.

Hence, a hanging drop is a sort of wet-mount approach that offers inoculum of bacteria from the liquid broth. It is an important tool to identify the intrinsic movement of the microorganisms, and also that’s why supplied to test the motility of various organisms like bacteria, filamentous fungi and also yeasts. All the bacterial cells will certainly present erratic activity, consisting of both motile and non-motile forms under the microscope, which we call as Brownian motion.

But, the self-propulsion in bacteria is established by either of the adhering to mechanisms like flagellar, gliding, corkscrew and also bending type of motion. In hanging drop motility trial and error, we have the right to see countless immortalized cells in the direction of the edge of fluid, under the microscopic observation. In this short article, we will be pointing out the meaning, procedure, notes to be considered, applications, advantages and also disbenefits.

Content: Hanging Drop Method

Definition of Hanging Drop Method

Hanging drop approach is the conventional strategy for examining the cell motility and also morphology by taking the living microorganisms from the liquid media. The hanging drop technique works on the principle of wet mount preparation, as it requires subjection of living microorganisms into a drop of fluid. It renders the use of glass slides with one small concave depression towards the centre, a coverslip, petroleum jelly, microbial suspension and also sterile inoculating loop. It was first discovered by a scientist called Robert Koch in the year 1878.

Previously, a hanging drop method was offered to research the Nocardia sp. on liquid paraffin dropallows. On even more study, the method has been used extensively to demonstrate the bacterial morphology and also motility. Later, considering the huge drop dimension in the hanging drop approach, scientists started using the micromanipulation technique to obtain manage over the drop dimension.

Procedure of Hanging Drop Method

The examicountry of microorganisms in a hanging drop technique requires the following protocol:


Take grease-complimentary or clean coverslip and also then closely dab petroleum jelly towards the edge of it by using a toothpick or earbud.After that, location a loopful of the microbial suspension on the centre of the ready coverslip.Then, take a clean or grease-cost-free cavity glass slide and also turn it upside down. Place the cavity slide in a manner that the circular concavity need to be in the direction of the drop of fluid over the coverslip.Aacquire turn the cavity glass slide in such a manner that the microbial specimales will certainly discovered inverted over the concave depression or observed hanging from the coverslip.Then put the ready society slide on the slide holder of the light microscope and change the simply in a means that the edge of drop have to be visible with the eyepiece.Use 10X objective lens and also cshed the diaphragm. Then, slowly adjust the coarse focus knob appropriately till you observe a curve that crossing the field of see, in which one half reflects the edge of the drop and also the other half shows the edge of concave depression.Adsimply the fine focus knob by looking to the specimen over the slide through the eyepiece, until the edge of the drop appears as a thick dark line.Then, look onto each side of the line and also focus onto the particulate matter in the liquid suspension. The cells might vary in colour, dimension and shape.After that, usage a 40X objective lens for greater resolution and also turn on the diaphragm lever. Then, adjust the light in order to maximize the visibility of the microorganisms.After all this set-up, carefully observe the specimen and note down the microscopic properties like the form, colour, motility of the specimales put on the glass slide. All the cells will certainly present Brownian movement, but few may possess true motility.At last, thoabout clean the depression slide by putting right into a Lysol solution for at least 15 minutes, as the microorganisms reprimary alive in such slide preparation.


Hanging drop technique is an aseptic technique for examining the specimens from liquid culture rather of a solid society tool.In the hanging drop approach, the microbial suspension is wet-mount quite than subjecting it to the techniques choose heat-resolving, smearing, staining etc.Specimens in the hanging drop approach will certainly display Brownian movement, because of which the microscopic objects in the liquid will swim erratically through the kinetic power possessed by the molecules in the bordering liquid.The true mobility is observed via the multi-directional activity of bacterial cells to longer ranges, instead of the cells relocating back and also forth. The bacterial motility can be oboffered under 10X and 40X objective, which is displayed in a diagram. In a hanging drop approach, 10X objective is initially provided to focus the microscopic picture, then later the objective is increased to 40X to acquire a enhanced view of the sample taken and also to identify in between the motile and immotile cells.
The petroleum jelly supplied on the edge of the coverslip acts as a sealing material in between the coverslip and the concave depression glass. Besides, it likewise reduces the evaporation and excludes the impact of air curleas.Overuse of petroleum jelly deserve to give false outcomes, as it might squeeze in the direction of the centre of the drop containing microorganisms or may squeeze out of the edges and also deserve to stick to the objective lens of the microscope.The disposal of the slides have to be very closely done, as after dipping the slides in Lysol solution it must be autoclaved and also deserve to be resupplied. The coverslips should be discarded and also cannot be reprovided.


The morphology of spiral bacteria can be clearly studied in hanging drop approach, as its shape becomes distorted in the warm resolving technique. Spiral bacteria prefer spirochetes need to be examined in a living state, and tright here form and also setup deserve to be well studied under a dark area microscope.

Bacterial motility or mobility have the right to be well stupassed away by employing a hanging drop strategy, in which a bacterial cell can freely move in the liquid medium.

The cytological changes that occur throughout the cell department, spore development and also germicountry of the bacteria are the occasions that must be studied in a living condition or hanging drop approach. The cytoplasmic inclusions, including vacuoles, granules and so on are easily noticeable by utilizing this technique.

AdvantagesIt is an important tool to examine the bacterial motility along with the form, size and also arrangement of the bacteria.It does not distort the cell shape and plan.Besides, the hanging drop technique offers a much better watch of motility in bacteria than the wet mount method.It is additionally valuable in the classification of the bacteria, whether they are motile or immotile.The Brownian activity have the right to be stupassed away with this technique, which causes erratic activity of the bacterial cells in the field of view due to the bombardment of water molecules.The petroleum jelly supplied in this technique seals the coverslip to the cavity slide that helps in the research of the tested speciguys for many type of times.

DisadvantagesIt is riskies for the research of pathogenic bacteria in a living problem.The depression slide is cost-effective, and also the coverslip is vulnerable to job-related with.

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As such, we deserve to conclude that the hanging drop method is the ideal means to research the different events of the organism in a living state, the mobility, form and also arrangement of the bacterial cells. Hanging drop approach is a kind of motility test, which is perdeveloped by taking the microorganisms from liquid media on the glass slide having indentation in the direction of the centre.