2. Enzyme engineering: For example, adding protease to beef belongs to the food industry, and enzyme engineering is widely used in the fermentation of large food industries.
3. Fermentation engineering: The expression of this technology is very vague, so many people have been using it to say that their products come from biotechnology, which is correct. We can say that the production of beer and soy sauce is biotechnology, but it is an early technology. Nowadays, many oral liquids are products of fermentation technology, so the term used is biotechnology.
4. Genetic engineering: In fact, many biotechnologies we are talking about now refer to genetic engineering. If we know this term, we may be able to distinguish biotechnology from bioengineering, which mainly refers to genetic engineering.
5. protein Project: protein Project is the second generation of genetic engineering. On the basis of genetic engineering, protein was transformed.
Nanobiotechnology is the fusion of engineering and molecular biology, and its appearance has led to the birth of a brand-new multifunctional biochemical analysis equipment and system. These devices and systems have higher sensitivity and specificity, and at the same time, the recognition speed has become faster.
Nanobiotechnology, as a newly coined term, describes the result of the fusion of engineering and molecular biology, two fields that originally coexisted but were far apart. In the past 60 years, engineers have been shrinking the size of manufacturing structures to make higher density electronic chips. If these subjects can be organically combined, a brand-new multifunctional equipment and system will be born, which is superior to the existing methods in sensitivity, specificity and recognition efficiency and can be used for biological and chemical analysis.
At present, nanotechnology has shown some advantages and considerable application value in separation, sequencing and detection. Nano-materials such as carbon nanotubes and quantum dots have made a lot of progress in the development process, especially the application of nano-materials in molecular recognition. In this paper, we try to describe the future outline of these emerging technologies and infer their application in biological analysis according to their existing potential.
Molecular detection
The reform in the field of molecular detection has the following objectives. First of all, the most remarkable thing is that at present, people usually pay attention to: ① The unchangeable recognition sites printed on the solid surface are no longer used for analysis, and highly diversified molecular recognition technologies are gradually developed through reconfigurable analysis; (2) Develop a new technology to record and quantify specific binding events by electrochemical or electronic measurement, and do not need to use labels as the best. In order to achieve these arduous goals, nano-tunnels, nano-holes, quantum dots, nanotubes, nanowires and nano-capacitors in nano-tools, as possible technical solutions, have shown increasingly important significance and value.
Multi-molecular marker:
Quantum dots, nanorods and nanoprisms
Multivariate labeling of unknown molecules (such as different DNA fragments or protein) in the same sample, and subsequent labeling recognition in the flow system, provide an attractive choice for monitoring specific binding events in a planar fixed array and monochromatic detection according to location. Based on the barcode technology of quantum dots, metals and glass, highly diversified labels have developed from many other technologies. Compared with the standard fluorescent group labeling, the use of quantum dots to label molecules embodies several advantages. The absorption spectrum of quantum dots (such as colloidal inorganic semiconductor nanocrystals composed of CdSe core and zinc sulfide shell) ranges from ultraviolet region to visible region. Its absorption spectral range in the visible region depends on the particle size (the larger the size, the longer the wavelength of visible light can be absorbed) and the composition of its core. Scattered light is confined to a very narrow cross section (generally, the width of the maximum intensity is 20~40nm), and the wavelength of the center of this area depends on the particle size. Quantum dots can be excited by light with a single wavelength, producing polychromatic light with almost no photobleaching. According to the subtle differences in color, intensity and spectral width of scattered light, thousands of different marker signals can be distinguished. Nie's research group developed composite microspheres with implantable quantum dots, and claimed that its theoretical diversified labeling ability reached 6.5438+0.0000. Quantum dot signals can be identified by optical methods, but Wang recently showed that they can also be used for coding in electrochemical detection schemes.
By combining a layer of bonded silica gel or linker, such as mercaptoacid, dihydrolipoic acid or modified polyacrylic acid, the core or shell form of quantum dots can be made water-soluble and can be combined with macromolecules and ligands. Some people have successfully combined quantum dots with labeled cells and intracellular macromolecules, thus overcoming some early technical problems, such as repeatability of manufacturing, extinction in solution, adsorption and cytotoxicity when used in living cells. Regarding quantum dots, there are other problems that must be solved, including how to approach the target site in a limited cell interval or in a multi-component molecular complex; Their applications in measuring molecular association and conformation by fluorescence lifetime or fluorescence vibration energy transfer; And multiphoton technology.
The good news for the scientific community is that these promising reagents have finally been developed and can be purchased through commercial channels. The introduction of optional quantum dot cores and shells has accelerated the realization of this process. We also look forward to the realization of various ideas about Qualcomm screening, highly diversified bioanalysis and the application of quantum dots in other fields as soon as possible.
As the quantum dot technology matures, another development of nanotechnology has gradually appeared in front of the public as a challenger. For example, multi-metal nanorods with bar code scale can be identified by reflectivity measuring instrument, which has been verified at present. Nanorods are manufactured by photolithography, and then different metal bars (bar codes) are deposited into the holes of alumina (AiyOg) films by electroplating. The subsequent reading process is through an optical microscope. This kind of nanorod labeling can be carried out simultaneously with optical labeling, because there is no suspicion of mutual interference between them, thus further increasing the diversified capacity.
Another charm of label diversity comes from the diversity of nanoparticle shapes. An early example in this field is a nano prism woven with silver (side length: 100nm). The interaction between nanoparticles of this shape and light is different from that of ordinary spherical particles, so they will show different colors. This difference provides a basis for diversified analysis, because nanoparticles as labels are all made of the same material, but their identification is based on their special shapes, thus achieving different and unique optical signals.
Improve the detection sensitivity:
Use of nanotubes and nanotube matrix
The potential to improve the sensitivity of identifying DNA hybridization events may come from the use of nano-sized electrodes based on carbon nanotubes (CNTs) technology. Li et al. developed DNA microarray analysis technology, and used polymeric multi-walled carbon nanotubes (MW-CNTs) to form a matrix on a silicon nitride template by controlled density growth, thus constructing an induction pad. The upper end (opening) of the nanotube serves as a nano-electrode, which is functionalized by combining with an ssDNA (single stranded DNA) probe. The target DNA can hybridize with ssDNA probe bound in conductive CNT, so it can be detected by electrochemical method based on ornithine oxidation reaction. The author confirmed that this method has super-high detection sensitivity in the concentration range of Atomol (10- 18 mol), and the signal-to-noise ratio (S: N) is reduced ideally while the electrode size is reduced. Under the condition of maintaining this improved ideal signal-to-noise ratio, in order to ensure the detectable signal level, multiple groups of CNTs are deposited on each sensing pad.
In the electrochemical detection experiment, the synthetic electrode used by Wang and Musameh is to disperse carbon nanotubes in PTFE matrix. This synthetic material combines the advantages of carbon nanotubes and large synthetic electrodes, and has the characteristics of accelerating electron transfer and minimizing surface pollution when glucose and ethanol are detected by ammeter.
Carbon nanotubes can also be used as narrow tubes in process-based analysis. The Coulter counter chip developed by Ito includes a single-layer film containing a single MW-CNT tunnel. The film was prepared by immobilizing an epoxy group containing a single MW-CNT tunnel on a supporting structure of polydimethylsilane (PDMS), thus allowing the measurement of the size and surface charge number of polystyrene nanoparticles terminated by carboxyl groups. This measurement method is suitable for particles of 60 ~100 nm and has a high signal-to-noise ratio.
Carbon nanotubes are also used for high-resolution imaging of DNA fragments in atomic microscope (AFM). Lieber's team designed special oligonucleotide probes, so they can only bind to completely complementary ssDNA fragments under specific hybridization conditions. Even if only one base is mismatched, the probe cannot bind. Then, they used single-walled carbon nanotubes to complete high-resolution and diversified detection of different markers.
One of the challenges that nanotube technology must face is that it must always be at the forefront of this rapidly developing field. The structure and properties of nanotubes vary greatly, including single-walled and multi-walled groups. Since its independent discovery, carbon nanotubes have gradually formed a full-fledged field, and the materials of nanotubes have also expanded to a wide range, including boron nitride (BN), gallium nitride (GaN), boron carbide (BC), organic polymers and so on. The diversity of nanotubes can be further expanded by functionalization, linking different types of molecules and filling other molecules in nanotubes (such as filling enzyme labels in CNTs or using filled CNTs as antibody labels). So many types of nanotubes will certainly provide great potential for nanotechnology tools, just like the unforgettable diversity revealed in current applications.
Nanodiagnostics
In all fields of diagnostics, a crucial ability is to be able to analyze multiple nucleotide sequences at the same time and find mutations quickly and accurately. Some studies show that the technology based on nanoparticles can detect the mutation of DNA sequence sensitively. Early studies have proved that DNA recognition based on array analysis can be completed by connecting oligonucleotides complementary to target DNA to gold nanoparticles through allele-specific oligonucleotide hybridization. The detection method is silver synergy method, which deposits silver on the surface of nanoparticles, so that the scanner can detect the position of gold nanoparticles in the array. After the silver synergistic method, the dye was adsorbed on the surface of nanoparticles through the connection with oligonucleotides, and surface gain Raman spectroscopy (SEES) could also be used for detection. The Raman spectra of different adsorbed dyes will be obviously different, which indicates that two different alleles can be typed simultaneously in the same array registration. However, at present, more research work is needed in this field to explore its full potential in the diversified analysis of genomic gene mutations with high sequence complexity.
The target detection based on comparative protein (from Atomol to Fitmore) is also realized. By using magnetic particles coated with PSA monoclonal antibodies, the biological barcode analysis of nanoparticles-coupled oligonucleotides is used to detect free prostate specific antigen (PSA). PSA is captured by magnetic particles and reacts with gold nanoparticles coated with PSA polyclonal antibody and barcode DNA mixture. The PSA sandwich complex is magnetically captured and the DNA barcode on it is released. After the barcode DNA is annealed and combined with the complementary strand, the complementary oligonucleotide used in the detection is combined with the gold nanoparticles through array detection. Before the array detection, the intermediate PCR signal amplification reaction was also carried out, thus reducing the detection limit of PSA from 30 attomole to 3 attomole. The detection limit is 6 orders of magnitude lower than the existing traditional immunoassay PSA method, but this analysis is multi-step and time-consuming, and it is not necessary to reach such a high sensitivity level in clinic. However, it also confirms the great potential of this analytical technique, indicating that it is of great value to the emerging and low-abundance protein, which is often involved in the ongoing protein omics research.
Unmarked detection: nano-capacitance, nano-hole, nano-tunnel, nano-machinery.
Most molecular recognition technologies rely on the subsequent recognition process of binding events and various optical, electrochemical or magnetic labels of molecules involved in the binding process. For this type of method, an attractive improvement scheme is to try to eliminate the labeling step, and instead detect the changes in the intrinsic properties of the analyzed object or the changes in the molecular polymerization form after binding.
Lee's research team developed a nano-gap capacitor (electrode distance is 50 nm) by using silicon lithography technology. SsDNA probe was immobilized on the electrode surface. The dielectric properties of dsDNA formed by hybridization between ssDNA probe and its target chain are different, so the capacitance of these nanogaps can be distinguished by capacitance measurement. A direct application prospect of this method is that a large two-dimensional array composed of capacitors can be used to synchronously measure nucleic acids in the same sample in a capacitive and unmarked way.
Nano-mechanical deviation on the micromachined silicon spiral arm is also used to identify the occurrence of some molecular events, such as DNA hybridization and protein binding. For recognition DNA hybridization, ssDNA was immobilized on the surface of spiral arm, and then the target ssDNA was added. The function of the spiral arm is similar to a miniature "balance", and its deviation is directly proportional to the total amount of hybridized target DNA. This slight deviation is measured by an optical detection device. It is still a challenging task to extend this method to multiple identification and inhibit nonspecific binding. However, this method itself skillfully proves how to organically combine complex micro-machining technology with analytical methods.
Nanoporous devices have been established to question the unlabeled immunoassay of particles in process systems. Sohn's team used Coulter technology to measure the particle size according to the particle's "electronic signature", which comes from the performance of the particle when it passes through the micro-fabricated PDMS hole. If an antibody binds to an antigen fixed on the surface of a particle and the diameter of the complex changes, then these nanoporous chips can be detected.
It is suggested that the sequencing of ssDNA fragments should be based on electrophoresis to transfer DNA chains through single holes made in silicon nitride films or through hemolytic holes formed in phospholipid bilayers. In both cases, the diameter of the hole should be less than 10nm. By measuring the time of passing through the hole, it is confirmed that a single polynucleotide shows a unique "signature" signal in the process of passing through the hole. This discovery may eventually lead to the birth of a low-cost, rapid and direct DNA sequence analysis method. At present, there are nano tunnels in the research stage, which can stretch DNA molecules and simplify the steps of DNA sequencing. The estimation result of sequencing rate using nanopore technology has changed from a conservative estimate of 65,438+0,000 bp per second to an optimized one of 65,438+0,000 bp per second, which greatly exceeds the current sequencing capacity of 30,000 bp per day using traditional sequencers. However, there is still a problem to be solved in nanopore technology, which is to distinguish different signals only according to the differences between sequences, and the technology needs to be further refined to reach the level of distinguishing individual nucleotides.
There are also genetically modified foods, cloning and gene therapy.
That's enough.