Indian Journal of Dental Research

: 2009  |  Volume : 20  |  Issue : 4  |  Page : 511--513

Nanotechnology: Role in dental biofilms

Sonia B Bhardwaj, Manjula Mehta, K Gauba 
 Department of Microbiology, Dr. H.S.J Institute of Dental Sciences and Hospital, Punjab University, Chandigarh, India

Correspondence Address:
Manjula Mehta
Department of Microbiology, Dr. H.S.J Institute of Dental Sciences and Hospital, Punjab University, Chandigarh


Biofilms are surface- adherent populations of microorganisms consisting of cells, water and extracellular matrix material Nanotechnology is promising field of science which can guide our understanding of the role of interspecies interaction in the development of biofilm. Streptococcus mutans with other species of bacteria has been known to form dental biofilm. The correlation between genetically modified bacteria Streptococcus mutans and nanoscale morphology has been assessed using AFMi.e atomic force microscopy. Nanotechnology application includes 16 O/ 18 O reverse proteolytic labeling,use of quantum dots for labeling of bacterial cells, selective removal of cariogenic bacteria while preserving the normal oral flora and silver antimicrobial nanotechnology against pathogens associated with biofilms. The future comprises a mouthwash full of smart nanomachines which can allow the harmless flora of mouth to flourish in a healthy ecosystem

How to cite this article:
Bhardwaj SB, Mehta M, Gauba K. Nanotechnology: Role in dental biofilms.Indian J Dent Res 2009;20:511-513

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Bhardwaj SB, Mehta M, Gauba K. Nanotechnology: Role in dental biofilms. Indian J Dent Res [serial online] 2009 [cited 2021 Jun 20 ];20:511-513
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Full Text

Biofilms are surface-adherent populations of micro- organizms consisting of cells, water and extra-cellular matrix material. [1],[2] Streptococcus mutans, the principle pathogen for dental caries, co-exist with over 500 other species of bacteria [3],[4],[5] as an interactive community known as the dental biofilm, making it a unique object to study microbial interactions. It is now known that organizms living in biofilms behave very differently from those living in a free floating or planktonic state. Bacterial abilities to adhere to a privileged site to build protective structures and communicate through chemical signals enable them to balance the equation against the host's natural defenses.

 Nanotechnology in Dental Bio-Films

Nanotechnology is a promising field of science which offers better insight into the spatial relationship between different species and how their diversity increases over ttime. Nanotechnology can guide our understanding of the role of interspecies interaction in the development of bio-film. The contribution of modern technology in the field of oral microbiology started with the detection of cultivable as well as uncultivable bacteria by examining bacterial 16 sRNA and DNA. [6],[7] The spatial distribution of different oral bacteria within the plaque has been revealed by fluorescent in situ hybridization. [8] The metagenomic project for oral microbial flora will reveal the metabolic genes and virulence factors of oral microbes. [9] Nanotechnology has been used to study the dynamics of demineralization/remineralization process in dental caries by using tools such as atomic force microscopy (AFM) which detect bacteria induced demineralization at an ultrasensitive level. Using AFM the correlation between genetically modified Streptococcus mutans and nanoscale morphology has been assessed. [10] The nanoscale cellular ultrastructure is a direct representation of genetic modifications as most initiate changes in surface protein and enzyme expression, where host- cell nutrient pathways and immune response protection likely occur. The surface proteins and enzymes, common to S. mutans strains are a key contributor to the cariogenicity of these microbes. [11],[12],[13] Another nanotechnology application used so far is 16 O/ 18 O reverse proteolytic labeling to determine the effect of biofilm culture on the cell envelope proteome of oral pathogen, Porphyromonas gingivalis which is linked to chronic periodontitis. A group of cell-surface located C-terminal domain family proteins including Rgp A, Hag A, CPG 70 and PG99 increased in abundance in the bio-film cells. The other proteins which increased were transport related proteins (Hmu Y and Iht B), metabolic enzymes (Frd AB) and immunogenic proteins. [14]

Chalmers et al. [15] have applied quantum dots (QD) (semiconductor nanocrystals) based primary immunofluorence for in vitro and in vivo labeling of bacterial cells and compared this approach with the fluorophore based primary immunofluorescence. QD conjugates offered significant advantages with standard epifluorescence microscopy. Excellent single cell resolution of both in vitro and in vivo biofilms can be obtained. The photostability of QD conjugates enables micromanipulation of viable, spatially resolved communities from the enamel chip surface. These retrieved multispecies communities can be reconstituted and studied in an in vitro model, where the intimate mechanisms of cell-cell interrelationships can be discovered. [16]

Old culture techniques for detection and quantification of cariogenic bacteria in plaque or saliva sample are slow and can only detect cultivable bacteria. New antibody or nucleotide based bacterial detection techniques have been developed for detection of cariogenic bacteria. [17] Nanotechnology can further enable us to detect both cultivable bacteria and non cultivable with the help of nanochip. [18] Similarly plaque acidity which is a good index for monitoring tooth demineralization, can be monitored using a microscale planer pH sensor. Application of nanotechnology to this prototype will further reduce the size of the sensors and make the device more user friendly to both the patients and clinicians. Nanotechnology can be used to selectively remove cariogenic bacteria while preserving the normal oral flora in a more targeted and proactive approach to dental caries than the conventional operative dentistry. Several ongoing research projects (e.g. enhanced active vaccination or passive vaccination, bacterial replacement, targeted antimicrobial therapy) provide new directions in the treatment of dental caries. [19],[20],[21],[22]

A new silver nanotechnology chemistry has proven to be effective against biofilms. [23] Silver works in a number of ways to disrupt critical functions in a micro-organizm. For example it has a high affinity for negatively charged side groups on biological molecules such as sulphydryl, carboxyl, phosphate and other charged groups distributed throughout microbial cells. Silver attacks multiple sites within the cell to inactivate critical physiological functions such as cell wall synthesis, membrane transport, nucleic acid (RNA and DNA) synthesis and translation, protein folding and function and electron transport. For certain bacteria as little as one part per billion of silver may be effective in preventing cell growth. [24] Recent studies show that ionic plasma disposition silver antimicrobial nanotechnology is effective against pathogens associated with bio- films including E.coli, S.pneumoniae, S.pneumoniae, S.aureus and A.niger. [25] Hence, local nanoscale characterization of cellular ultrastructure and functional properties is an important focus for probing cariogenic nature of oral microbes.


The future holds in store a mouthwash full of smart nano- machines which can identify and destroy pathogenic bacteria while allowing the harmless flora of mouth to flourish in a healthy ecosystem. The devices will then identify the particles of food, plaque or tartar and lift them from teeth to be rinsed away. Being suspended in liquid and able to swim about, devices will be able to reach surfaces beyond reach of toothbrush bristles or the fibers of floss. As short lifetime medical nanodevices, they can be built to last only few minutes in the body before falling apart into material like fiber in the food.


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