Forensic Nanotechnology
Forensic Nanotechnology Crafted by-
Dr. Ritesh K Shukla
Assistant Professor, Ahmedabad University, Ahmedabad Gujrat, INDIA
Ashish Badiye
Head & Assistant Professor
Department of Forensic Science, Government Institute of Forensic Science, Nagpur, Maharashtra INDIA
Introduction to Nanotechnology
Nanotechnology is an important and powerful tool in most of the areas including medicine, imaging, and energy sciences. It has a potential to make a significant positive contribution in forensic science towards Crime detection. In forensic nanotechnology, minute chip materials are being used instead of bulky instruments, which reduces the methods of analysis to conduct the investigation with more accuracy, precision and appropriateness. Nano-forensics is a newer area of forensic science which is highly advanced associated with the development of nano-sensors for crime investigations and inspection of terrorist activity by determining the presence of explosive gases, biological agents and residues. Nano-analysis is commonly used in the nanotechnology detection of crimes. Application of nanotechnology is likely to enhance the capacity to toxic materials, forensic evidence in tissue, materials and soil.
Here’s the short interview of Quiz makers
On behalf of Sherlock Institute of Forensic Science we had a short interview with quiz makers and here is what they says to all the student community and life time learners.
1. Forensic nanotechnology is a new Branch of Forensic in India. How would you like to explain the scope of this subject in our country?
In India, scope of forensic nanotechnology is very bright but students should keep in mind one thing ‘this is a applied field, so first they learn about nanotechnology then apply for forensic application’. To do this students need to change their mind -set and join premier research Institution in the field of Nanotechnology in India. Such as IITs, IISERs, IISc, CSIR.
2. Would you like to share your experiences in making this quiz ?
My experience was good, but I think students could not relate much because forensic nanotechnology is generally not a part of the syllabus.
3. I do understand from this short conversation that this subject is an emerging branch. So talking about the global perspective where do you see this subject in the next few years?
In the global perspective, forensic nanotechnology is one of the leading emerging branch of forensic in terms of research and development. Various innovative tools and techniques have been developed in abroad which are nano-based and are being ready to use in forensic investigation.
4. I really appreciate your time sir for giving us such insights into the subject and also for preparing such an engaging Quiz. What would be your message for the aspiring Forensic Nanotechnology students?
My only message to the students who are aspiring for research is Passion, Patience, hard-work, logical input and attribute not to give-up are make you a good researcher and these are the key to success in the field of Research & Development.
Here is the List of Questions with Answers along with explanation
Ques 1. The term "nano" originated from a
a) French word meaning billion
b) Greek word meaning dwarf
c) Spanish word meaning particle
d) Latin word meaning invisible
Answer – (b) Greek word meaning dwarf
Explanation : The word ‘Nano’ comes from Greek word means dwarf, which refers to one billionth (10-9) mean about nanometer (nm). In general, to understand one nanometer is about 3-5 atoms wide or 40,000 times smaller than the width of human hair or a virus that typically 100 nm in size. It deals with emerging material or devices having size equal to 100 nm or lesser.
Ques 2. Concept of Nanotechnology was first given by
a) R Menzel
b) R Feynman
c) Z Zhang
d) N Taniguchi
Answer - (b) R Feynman
Explanation : The American physicist and Nobel Prize laureate Richard Feynman introduce the concept of nanotechnology in 1959. During the annual meeting of the American Physical Society, Feynman presented a lecture entitled “There’s Plenty of Room at the Bottom” at the California Institute of Technology (Caltech). In this lecture, Feynman made the hypothesis “Why can’t we write the entire 24 volumes of the Encyclopaedia Britannica on the head of a pin?”, and described a vision of using machines to construct smaller machines and down to the molecular level. His new idea demonstrated that Feynman’s hypotheses have been proven correct, and for these reasons, he is considered the father of modern nanotechnology. After fifteen years, Norio Taniguchi, a Japanese scientist was the first to use and define the term “nanotechnology” in 1974
Ques 3. One nanometer is _________ of a meter.
a) one trillion
b) one million
c) one billion
d) one gazillion
Answer – (c) One billion
Explanation : A nanometer, or nanometre, is a unit of length equal to one billionth of a meter. A nanometer is one billionth of a meter, 0.000000001 or 10-9 meters.
The term nanoscale is used to refer to objects with dimensions on the order of 1-100 nanometers (nm).
To understand how small a nanometer is, we typically compare the nanoscale to objects that we know how big or small they are. Here are some examples:
• a human hair is about 60,000 – 100,000 nm wide
• a fingernail grows 1 nm per second
• a DNA molecule is ~2.5 nm in width
• a 2 meter person is 6 feet 6 inches tall or 2 billion nanometers
Ques 4. The term ‘nanotechnology’ was coined by
a) ER Menzel
b) R Feynman
c) Z Zhang
d) N Taniguchi
Answer – (d) N Taniguchi
Explanation : The term “nanotechnology” was introduced by the Japanese Scientist Norio Taniguchi in 1974 during a scientific conference. He coined the term nanotechnology to describe semiconductor processes such as thin film deposition and ion beam milling exhibiting characteristic control on the order of a nanometer: Nanotechnology mainly consists of the processing of separation, consolidation, and deformation of materials by one atom or one molecule.
Ques 5. Nanotechnology in Forensics was applied for the first time by
a) ER Menzel
b) R Feynman
c) Z Zhang
d) N Taniguchi
Answer – (a) ER Menzel
Explanation : The late Dr. Menzel was the pioneer of the usage of photoluminescent CdS semiconductor nanocrystal capped with dioctyl sulfosuccinate to enhance latent fingerprint detection. His concept was to apply nanocrystal fluorescent dye on articles that have been pre-fumed with cyanoacrylate ester and also on the sticky side of electrical tape without pre-fuming.
Ques 6. Which of the following nanoparticle based fluorescent probe can be used to detect TNT in aqueous solution?
a) Gold NPs
b) Silver NPs
c) Curcumin NPs
d) TiO2 NPs
Answer – (c) Curcumin NPs
Explanation : Nanoparticles approach for the detection of trinitrotoluene (TNT) to achieve a reliable, extremely sensitive and inexpensive method. The easy availability of turmeric extracted curcumin reduces the cost of detection of the explosive for law enforcement societies. Turmeric extracted curcumin nanoparticles-based, highly selective, and ultrasensitive fluorescent probe can be used for the Trinitrotoluene (TNT) detection up to 1 nM level in aqueous solution. Curcumin NPs with explosive (TNT) , forms curcumin NPs aggregated with explosive slight changes in NPs explosive complex at higher concentration of explosive, it gives significant colour change observe in NPs explosive complex.
Ques 7. Which of the nanotechnology-based tools developed by Tanaka in 2006 that can help to read DNA sequence directly using AFM?
a) Graphene sheet
b) Carbon nanotube
c) Gold Nanocluster
d) Silver NPs
Answer – (b) Carbon nanotube
Explanation : The ultimate application of nanotechnology is the development of tools that directly read DNA sequence one molecule at a time. Currently DNA molecules first immobilized on gold pads or carbon nanotubes, where they can be probed by atomic force microscopy (AFM) or other techniques. In a study by Tanaka and coworkers, different species of tuna were identified by examining double-stranded DNA mismatches directly using AFM.
Ques 8. Which of the nano-conjugate can be used to prepare paper-based sensor for TNT detection?
a) Gold coated Silver NPs
b) Amine coated Gold NPs
c) Citrate coated Gold NPs
d) Cu-ZnCdS quantum dot
Answer – (a) Gold coated Silver NPs
Explanation : Hydrophilic amine(-NH2) protected AuAg nanoparticles (NPs) were developed and fabricated as colorimetric paper sensor for delicate detection of TNT. The as-developed nanoprobe selectively reacts with TNT through classic Meisenheimer complex formation by means of charge transfer process from an electron-rich NH2 group of β-cysteamine to an electron-deficient nitro group on TNT. Due to the absence of this particular interaction of other nitroaromatics, the proposed probe is highly selective for TNT detection with a better linear range (0–20 μg/mL) and limit of detection (LOD) of 0.35 μg/mL. It is a highly rapid and reliable approach which did not require expensive instruments.
Ques 9. Which of the following statement is true for the contribution of nanotechnology in the field of Forensic science?
a) Analysis of samples in nanoscale is now possible, that could not be analyzed earlier due to detection limits of instruments
b) Development of Nanomaterials with novel properties that can assist the collection and detection of evidence which cannot be achieved previously
c) A and B Both
d) None of these are true statement
Answer – (c) A and B both
Explanation : Nanotechnology is making valuable contributions to various scientific fields in science and technology today.
Nanotechnology contributes to forensic sciences in two ways. Since it can detect and analyze samples in the nanoscale, critical evidence that could not be collected and analyzed before due to the detection limits of the instruments can now be analyzed and used to support the investigations. In addition, nano materials possess novel properties that can assist the collection and detection of evidence which cannot be acquired previously. Some examples include trace amounts of gunshot residues, heavy metals, explosives, DNA on fingerprint or palm prints, and so on.
Ques 10. Which of the following nano-particles are used to enhance PCR efficiency?
a) AgNPs
b) AuNPs
c) CuNPs
d) SiNPs
Answer – (b) AuNPs
Explanation : The PCR could be dramatically enhanced by Au nanoparticles. With the addition of 0.7 nM of 13 nm Au nanoparticles into the PCR reagent, the PCR efficiency was increased. Especially when maintaining the same or higher amplification yields, the reaction time could be shortened, and the heating/cooling rates could be increased. The excellent heat transfer property of the nanoparticles should be the major factor in improving the PCR efficiency. Au nanoparticles increase the sensitivity of PCR detection 5- to 10-fold in a slower PCR system (i.e. conventional PCR) and at least 104-fold in a quicker PCR system (i.e. real-time PCR). After the PCR time was shortened by half, the 100 copies/µl DNA were detectable in real-time PCR with gold colloid added, however, at least 106 copies/µl of DNA were needed to reach a detectable signal level using the PCR reagent without gold colloid. This innovation could improve the PCR efficiency using non-expensive polymerases, and general PCR reagent. It is a new viewpoint in PCR, that nanoparticles can be used to enhance PCR efficiency and shorten reaction times. The nanoparticle is a novel material and has many physical properties which are different from bulk materials. It has been reported that the smaller the nanoparticle the higher it's thermal efficiency.
Ques 11. Which property of nanoparticles enhance the PCR efficiency?
a) Small size
b) Distinct shape
c) Higher surface area to volume ratio
d) Super heat transfer
Answer – (d) Super heat transfer
Explanation : The excellent heat transfer properties of gold nanoparticles would enhance PCR efficiency and shorten reaction times.
Ques 12. Which of the following nano-materials are currently used to read DNA sequencing via electrical charge differences across its surfaces?
a) Nanotube
b) Nanoclusters
c) Nanopores
d) Nanosheet
Answer – (c) Nanopores
Explanation : DNA sequencing technology and the significant advantages of nanopores (biological or solid state) include label-free, ultra long reads (104–106 bases), high throughput, and low material requirement. Each of these greatly simplifies the experimental process and can be easily used for DNA sequencing applications. Nanopore sequencing technology was developed by Oxford Nanopore Technologies Ltd. and is the most powerful method for rapid generation of long-read sequences. Using nanopore sequencing, a single molecule of DNA or RNA can be sequenced without the need for PCR amplification or chemical labelling of the sample. Nanopore sequencing has the potential to offer relatively low-cost genotyping, high mobility for testing, and rapid processing of samples with the ability to display results in real time.
Ques 13 ............ is the most abundantly used nanoparticles in the field of forensic science.
a) AuNPs
b) AgNPs
c) Carbon Nanotube
d) Graphene
Answer – (a) AuNPs
Explanation : Optical property of Gold NPs that is surface plasmon resonance make them most desirable nanoparticles for forensic application. Gold chemistry contributed to the fingerprint detection utilizing the single metal and multi-metal deposition techniques. This field can be expanded to serve the need for more materials in illicit drug detection as well, although slow progress has been made already. The detection of explosives and nerve gases on the crime scene is of current interest. The photophysical properties of gold are not yet utilized in this field. In search for compounds for the detection of explosives, fluorescence quenching-based detection of explosives represents one of the most promising methods. Quenching fluorescent gold complexes by nitroaromatics can be used as a chemical signature of explosives.
Ques 14. Which property of nanomaterial is the fundamental principle behind development of colorimetric nano-based biosensors?
a) Size
b) Shape
c) Surface plasmon resonance
d) Surface area to volume ratio
Answer – (c) Surface plasmon resonance
Explanation : Localized surface plasmon resonance-(LSPR-) based Nano biosensors are considered one of the most powerful tools in the biotechnology and biosensor fields. Localized surface plasmon resonance (LSPR) is induced by incident light when it interacts with noble metal nanoparticles that have smaller sizes than the wavelength of the incident light. Nano biosensors based on LSPR have the following advantages for the detection of biomolecules: high sensitivity via detection of refractive index changes, no labelling requirement because of sensing of spectral shifts, real-time assay accessibility using microfluidic systems, good reproducibility using nanoparticle substrates, and low cost and easy instrumental setup. These advantages demonstrate that nanobiosensors can be applied in a wide range of fields, such as medical, food safety, environmental monitoring, and drug screening.
Ques 15. Detection of 2,4,6-trinitrotoulene is possible by using _
a) Amine terminated nanoparticles
b) Aluminum nanoparticles
c) Curcumin nanoparticles
d) Carbon nanotubes
Answer – (a) Amine terminated nanoparticles
Explanation : Detection of 2,4,6-trinitrotoluene (TNT) from 10−12 to 10−4 molar. Amine-terminated nanoparticles were used as TNT bioreceptors to form Meisenheimer complexes. A colorimetric change from green to red was observed after TNT functionalization, which caused by the increased in the nanoparticles separation. CMSN are ideal for surface coating because the nanoparticle suspensions are stable over a long period of time. When amine-terminated colloidal mesoporous silica nanoparticles (CMSN) are conjugate with TNT as bioreceptor then it form Meisenheimer complexes. This complex provide red and green luminescence that can seen under a high resolution microscope.
Ques 16. Ultra-sensitive colorimetric changes by using gold nanoparticles and camera of a smartphone is used for the detection of which illicit drug?
a) Codeine sulfate
b) Cocaine
c) Amobarbital
d) All the above
Answer – (a) Codeine sulfate
Explanation : Detecting illegal narcotics is a challenge for many forensic scientists because of its lack of availability in pristine form in the sample, which is sent for examination. Codeine sulphate with multiple binding sites containing sulphate groups and an oxygen hybrid ring may strongly coordinate to AuNPs by the ligand exchange with weak surface-bound citrate ions, and finally cross-linked AuNPs. The colloidal stability is significantly reduced to result in the prompt occurrence of particle aggregation. The molecular linker-based aggregation offers a new approach to a simple and rapid colorimetric assay for the detection of codeine sulphate in bone, bone marrow and soil, which does not require any extra aid such as specific acceptors.
Ques 17. Micro X Ray Fluorescence (MXRF) is a process by which an image ___ of a fingerprint is produced.
a) Amino acid
b) Fatty acid
c) Salt
d) Inorganic elements
Answer – (d) Inorganic elements
Explanation : The new technique uses a process called micro-X-ray fluorescence (MXRF), which rapidly reveals the elemental composition of a sample by irradiating it with a thin beam of X-rays without disturbing the sample. Salts such as sodium chloride and potassium chloride excreted in sweat are sometimes present in detectable quantities in fingerprints. Using MXRF, the researchers showed that they could detect the sodium, potassium and chlorine from such salts. And since these salts are deposited along the patterns present in a fingerprint, an image of the fingerprint can be visualized producing an elemental image for analysis.
Ques 18. DNA can be isolated from Skeletal Remains by using-
a) Zinc nanoparticles
b) Silver nanoparticles
c) Gold nanoparticles
d) Copper nanoparticles
Answer – (d) Copper nanoparticles
Explanation : The unique property of Copper nanoparticles for DNA isolation from Skeletal remains samples. Copper nanoparticles synthesized in microwave by using diethylene glycol (DEG), ascorbic acid and polyvinylpyrrolidone(PVP), binds to DNA with very high affinity. The present study has advantages that it is quick with high yield, inexpensive, robust with environment friendly and does not require use of organic solvents. Moreover, the procedure also eliminates the necessity of phenol or protease K, which makes the method less hazardous and economical. This method can easily be applied to DNA isolation from skeletal remains. This present protocol is advantageous as it reduces the manual interpolation and cost to perform DNA isolation.
Ques 19. Magnetic Nanoparticles can extract DNA from-
a) Blood
b) Urine
c) Saliva
d) All the above
Answer – (d) All the above
Explanation : Magnetic particles have significant advantages in both ease of use and high purity when isolating nucleated cells and nucleotides directly from biological samples. This procedure required less handling, no hazardous reagents (e.g., chloroform), and could be carried out in single microcentrifuge tube within 30 min. These methods, while simple, rapid, sensitive, and environmentally friendly, are suitable for routine laboratory use, but also hold promise for the construction of automated urine extraction systems for various diagnostic purposes. Magnetic particles have been successfully used to extract genomic DNA from body fluids, such as blood, saliva, and semen [Montpetit et al 2005]. However, reports of urine DNA extraction with magnetic particles are very limited. Recently, Siddiqui et al. 2009 has developed a solid-phase method for human gDNA isolation from urine using a variety of commercially available magnetic micro-beads (Genpoint AS, NorDiag ASA, Oslo, Norway).
Ques 20. Gold and silver nanoparticles can be used in powder form to develop fingerprints from _______________
a) Porous surface
b) Non-porous surface
c) Both a and b
d) Submerged objects
Answer – (b) Non-porous surface
Explanation : Fingerprint powdering remains the most commonly-used technique for the detection of fingerprints on non-porous surfaces at the scene. Gold and silver nanoparticles could be used in powder form to develop latent fingermarks on non-porous surfaces. It was proposed that oleylamine-stabilized gold nanoparticles deposit onto fingerprints due to the lipophilic interaction with the fatty components in fingerprint ridges. These nanoparticles enhance the detection limit of the illicit drugs in fingerprint samples.To achieve better contrast between the background surface and the print, nanoparticles in the form of nano-powders are being used to develop fingerprints from the non-porous surface that was previously used by traditional fingerprint powders.
Ques 21. Why are ‘nanoparticles’ studied as ‘novel’ phenomenon?
a) Physical properties change significantly
b) Chemical properties change significantly
c) Physical and chemical properties change significantly
d) Small size
Answer – (c) Physical and Chemical properties change significantly
Explanation : Nanoparticles are tiny materials having size ranges from 1 to 100 nm. They can be classified into different classes based on their properties, shapes or sizes. Nanoparticles possess unique physical and chemical properties due to their high surface area and nanoscale size. Their optical properties are reported to be dependent on the size, which imparts different colors due to absorption in the visible region. Their reactivity, toughness and other properties are also dependent on their unique size, shape and structure. Due to these characteristics, they are suitable candidates for various commercial and domestic applications, which include catalysis, imaging, medical applications, energy-based research, and environmental applications. NPs possess unique physical and chemical properties due to their high surface area and nanoscale size. Their optical properties are reported to be dependent on the size, which imparts different colors due to absorption in the visible region.
Ques 22. Nanotechnology applies in forensic science as ___
a) Investigative and preventive aspect
b) Preventive and synthesis aspect
c) Synthesis and Investigative aspect
d) Investigative, Preventive and Synthesis aspect
Answer – (a) Investigative and preventive aspect
Explanation : Nanotechnology in forensic science will significantly transform the processes of investigation by making them faster, more accurate, more effective, more sensitive, and easy to apply that explains the indisputable significance of this technologies. It has significant application in security, drug screening, explosive detection, and DNA analysis which enable forensic investigators to perform complex analysis or to discover even the smallest traces of evidence at the crime scene. Nanotechnology applied for forensic document examination which examine the document as to maintain the integrity of the document (preventive aspect) and to differentiate between genuine and counterfeit document (investigative aspect).
Ques 23. Which of the following is not a method used in nanotechnology?
a) Solid Metal Deposition
b) Multi Metal Deposition
c) Vacuum Metal Deposition
d) Single Metal Deposition
Answer – (a) Solid Metal Deposition
Explanation : There are multiple different coating methods available to deposit nanoparticles. The methods differ by their ability to control particle packing density and layer thickness, ability to use different particles and the complexity of the method and the instrumentation needed. Multi-metal deposition (MMD) is the two-tier chemical process in which small particle reagent (Gold) and of a physical developer (Silver) involved for latent fingerprint development. Stauffer et al. 2007 have proposed a new method known as single metal deposition (SMD). In this method, the second step (Silver developer step) of the MMD method replaced with gold enhancement step. VMD is the physical process of coating evidence with very a thin metal film under high vacuum. Gold, Zinc, Silver, Tin, Aluminum, and some alloys are used to coat the substrate. The result is a reversed developed latent print. Since the process coats the substrate and not the latent print. But the result quality was poor, therefore, instead of alloy, nanoparticles were used which give better quality of result compared to conventional method.
Ques 24. Citrate ions act as ______________ in the synthesis of Gold nanoparticles (of 16 nm) using Turkevich method.
a) Reducing agent
b) Stabilizing agent
c) Both a and b
d) None of the above
Answer – (c) Both a and b
Explanation : One of the most well-known techniques for the synthesis of AuNPs is based on the reduction of HAuCl4 by citrate in water, which was first designed by Turkevich in 1951. In this method, the HAuCl4 solution is boiled, and the trisodium citrate dihydrate is then rapidly added into the boiling solution under vigorous stirring. After a few minutes, the color of the solution changes from light yellow to wine red. This method results in AuNPs measuring about 20 nm in diameter. In this technique, citrate ions play a double role, as both stabilizing and reducing agents. AuNP synthesis can be traced back to 1940 when the formation of colloidal gold upon reacting gold chloride (HAuCl4) and trisodium citrate (Na3C6H5O7 or NaCt) was first reported (Hauser E.A. and Lynn J.E., 1940). The detailed work of Turkevich and his coworkers (Turkevich J. et al., 1951) has become one of the milestones of AuNPs synthesis. In this synthesis, reduction of Gold chloride occurred when dropwise trisodium citrate added on it. Concentration of trisodium citrate used to control the size of AuNPs. Here, Citrate ion is form which regulate the size of AuNPs.
Ques 25. In Multi-Metal Deposition method, the pH of the colloidal gold solution is kept ______
a) High
b) Low
c) Neutral
d) pH is not important in this process.
Answer – (b) Low
Explanation : Multimetal deposition is a versatile technique of detecting latent fingerprints on porous items, for example, fabric tape, masking tape, cardboard; on semi-porous items, for example, expanded polystyrene, latex gloves, waxed paper; as well as on non-porous items, for example, metals and plastics. It is so named because it is a two-step process, the first involves deposition of gold and the second deposition of silver on the ridges, thereby visualizing the latent impressions. Colloidal gold at low pH is used to “stain” proteins.