DNA Nanotechnology Lecture 2024 PDF

Contact: [email protected] 2024  What is Nanotechnology? nanos, the Greek word for “dwarf” ‘’ Nanotechnology is the manipulation and manufacture of materials and devices on the scale of atoms or small groups of atoms’’. According to Encyclopædia Britannica The “nanoscale”...

Contact: [email protected] 2024  What is Nanotechnology? nanos, the Greek word for “dwarf” ‘’ Nanotechnology is the manipulation and manufacture of materials and devices on the scale of atoms or small groups of atoms’’. According to Encyclopædia Britannica The “nanoscale” is typically measured in nanometres, or billionths of a metre (10-9 meter) Materials built at this scale often exhibit distinctive physical and chemical properties  Nanotechnology fields This nanoscience has emerged as a new field for three decades. It is highly diversified and involves many disciplines (i.e. branches), including Physics (such as surface science and semiconductor manufacturing). Chemistry (such as organic chemistry, biochemistry, and analytical chemistry). molecular biology.  DNA Nanotechnology Is branch which aims to create novel, controllable nanostructures out of DNA by using its unique molecular recognition properties and to achieve molecular self-assembly through the manipulation of DNA. It is a technology in which molecular components spontaneously organize into stable structures; this form of structures is induced by the physical and chemical properties of the components selected by the designers  In nanotechnology, nucleic acids serve as engineered building blocks rather than genetic information carriers. The major properties of DNA for the self-assembly of functional nanostructures include the following: 1. The base-pairing rules of nucleotides 2. The ability of a single strand of DNA to bind a complementary sequence of DNA with high affinity. 3. The stability of DNA over a wide range of environmental conditions. 4. Hybridization of DNA is reversible and can be controlled by temperature.  DNA fundamentals Deoxyribonucleic acid contains the four nucleotides, each of which is made up of a five-carbon sugar (deoxyribose), a heterocyclic base, and a phosphate group. Nucleotides include two purine molecules, adenine (A) and guanine (G), as well as two pyrimidine molecules, cytosine (C), and thymine (T).  DNA fundamentals (cont.) In DNA, two antiparallel polynucleotide strands are held together in a double helix by hydrogen bonds. The double helix is a nanoscale material, with a diameter of ~2 nm and a helical repeat of ~10 -10.5 nucleotide pairs, resulting in a pitch of ~3.4-3.6 nm.  Conformations of DNA A-DNA Wider right-handed spiral, dehydrated samples B-DNA right-handed, most common in cells, high hydration levels Z-DNA DNA where bases have been chemically modified, turn about the axis on the left-hand Adapted from http://ezbiomed.vghtpe.gov.tw/files/Presentation%20Files%20of%20G side ood%20Seminars/0328%20seminar/0328%20seminar.files/slide0041 _image021.jpg  DNA fundamentals (cont.) Three hydrogen bonds form between cytosine and guanine molecules, and two hydrogen bonds form between adenine and thymine molecules; these nucleotide-nucleotide units are referred to as base pairs. DNA base pairing is the basis for the fabrication of many DNA- based nanostructures.  DNA fundamentals (cont.) Hydrogen bonding between two complementary single DNA strands to form a double helix is called hybridization. When double-stranded DNA is heated to a sufficiently high temperature, the DNA will denature. The two strands will start to dehybridize and dissociate to single strands. If this denatured DNA is then cooled, the two single stands will rehybridize and reform a double helix structure at locations where complementary sequences exist.  Melting temperature (Tm) The melting temperature (Tm) is defined as the temperature at which 50% of the DNA species form a stable double helix and the other 50% have been separated to single strands. This value depends on both the length and the nucleotide sequence composition of the specific DNA molecule.  The guanine-cytosine (GC) content of the sequence gives a fair indication of the Tm. Tm can be calculated: Tm = [4(G + C) + 2(A + T)] °C where Tm is the melting temperature in degrees Celsius. In other words, the melting temperature gets two degrees for each A:T pair in the duplex, and 4 degrees for each C:G e.g. Oligonucleotide composition :GACTGCGTTAGGATTGGC; count the number of G+C and A+T and enter into the formula. Hence, Tm = [4 (10)+ 2 (8)] °C = (40+16) °C = 56°C  These materials may be used as building blocks for the assembly of larger two-dimensional and three-dimensional nanostructures. As a result of these unique properties, the DNA double helix is an ideal material for controlling the assembly of nanostructures. https://www.youtube.com/watch?v=o_-6JXLYS-k