Nanoneedles may be conical or tubular needles in the
nanometre
330px, Different lengths as in respect to the Molecule">molecular scale.
The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm), or nanometer (American spelling), is a unit of length ...
size range, made from silicon or boron-nitride with a central bore of sufficient size to allow the passage of large molecules, or solid needles useful in
Raman spectroscopy
Raman spectroscopy () (named after physicist C. V. Raman) is a Spectroscopy, spectroscopic technique typically used to determine vibrational modes of molecules, although rotational and other low-frequency modes of systems may also be observed. Ra ...
,
light emitting diodes
A light-emitting diode (LED) is a semiconductor device that Light#Light sources, emits light when Electric current, current flows through it. Electrons in the semiconductor recombine with electron holes, releasing energy in the form of pho ...
(LED) and
laser diodes
The laser diode chip removed and placed on the eye of a needle for scale
A laser diode (LD, also injection laser diode or ILD or semiconductor laser or diode laser) is a semiconductor device similar to a light-emitting diode in which a diode p ...
.
Usage
Impalefection
In 2005 the Research Institute for Cell Engineering at Japan's
(AIST) and
Tokyo University of Agriculture and Technology
The commonly known as TUAT is a national university headquartered in Fuchū, Tokyo, Japan. The university consists of two faculties that provide courses in agriculture and engineering.
History
The predecessor of the university was founded i ...
used nanoneedles controlled by an
atomic force microscope
Atomic force microscopy (AFM) or scanning force microscopy (SFM) is a very-high-resolution type of scanning probe microscopy (SPM), with demonstrated resolution on the order of fractions of a nanometer, more than 1000 times better than the diffr ...
(AFM) to penetrate the nucleus of living cells and insert molecules of nucleic acid, proteins or possibly to carry out cell surgery. The technique can accurately establish the position of the needle by monitoring the force exerted. Cells to be used for tracking, diagnosing, and treatment of illness may be removed from the body and replaced after being injected. The 100
nm diameter needles were cut from silicon AFM tips using focused
ion beam etching.
In 2009, researchers at the
University of Illinois
The University of Illinois Urbana-Champaign (UIUC, U of I, Illinois, or University of Illinois) is a public university, public land-grant university, land-grant research university in the Champaign–Urbana metropolitan area, Illinois, United ...
produced a 50 nm diameter boron-nitride nanoneedle with a thin coating of gold, suitable for biophysical research. Its diameter allows easy penetration of cell walls in order to deliver organic matter or fluorescent
quantum dots
Quantum dots (QDs) or semiconductor nanocrystals are semiconductor particles a few nanometres in size with optical and electronic properties that differ from those of larger particles via quantum mechanical effects. They are a central topic i ...
into the cytoplasm or the nucleus. It may also be used as electrochemical probe or optical
biosensor
A biosensor is an analytical device, used for the detection of a chemical substance, that combines a biological component with a physicochemical detector.
The ''sensitive biological element'', e.g. tissue, microorganisms, organelles, cell rece ...
in a cellular environment.
Atomic Force Microscopy
The
University of California, Berkeley
The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a Public university, public Land-grant university, land-grant research university in Berkeley, California, United States. Founded in 1868 and named after t ...
in 2008 produced
gallium arsenide
Gallium arsenide (GaAs) is a III-V direct band gap semiconductor with a Zincblende (crystal structure), zinc blende crystal structure.
Gallium arsenide is used in the manufacture of devices such as microwave frequency integrated circuits, monoli ...
(GaAs) nanoneedles which emit extremely bright light, though
not yet lasers, when
optically pumped. With a length of 3-4 micrometres, they taper to tips of 2-5 nm across. In addition to
optoelectronic
Optoelectronics (or optronics) is the study and application of electronic devices and systems that find, detect and control light, usually considered a sub-field of photonics. In this context, ''light'' often includes invisible forms of radia ...
devices, the needles will be useful in atomic force microscopy (AFM), and can be easily grown in arrays. Such AFM arrays, besides producing near-atomic resolution images of surfaces, could lead to new forms of data storage by direct manipulation of atoms. The needles may also find a use in tip-enhanced Raman spectroscopy, a process in which molecular energy levels are measured by comparing the frequency of incident light with that of outgoing light. A sharp needle tip allows for a more precise examination of the sample, down perhaps to that of single molecules.
Biomedical Research
Research at the department of NanoMedicine and Biomedical Engineering at the
University of Texas
The University of Texas at Austin (UT Austin, UT, or Texas) is a public research university in Austin, Texas, United States. Founded in 1883, it is the flagship institution of the University of Texas System. With 53,082 students as of fall 2 ...
in 2010 created a new type of nanoneedle using silicon. A solution of
hydrogen peroxide
Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscosity, viscous than Properties of water, water. It is used as an oxidizer, bleaching agent, and antiseptic, usua ...
produces porous needles - their porosity is controlled along their length by altering the concentration of peroxide over time. The coloured porous needles are constructed to biodegrade over a predictable period, and have a surface area 120 times that of equivalent solid wires, making them useful as drug-delivery vehicles. Since porous silicon does not harm cells, the needles may also be used to tag cells and monitor chemical reactions.
Ethical considerations
A note of caution was sounded by Martin A. Philbert, professor of
toxicology
Toxicology is a scientific discipline, overlapping with biology, chemistry, pharmacology, and medicine, that involves the study of the adverse effects of chemical substances on living organisms and the practice of diagnosing and treating ex ...
at the
University of Michigan, Ann Arbor
The University of Michigan (U-M, U of M, or Michigan) is a public research university in Ann Arbor, Michigan, United States. Founded in 1817, it is the oldest institution of higher education in the state. The University of Michigan is one of th ...
. ''"The ability to manipulate nanometer-scale materials at the molecular level holds the promise of conferring specificity of cellular delivery and the reduction of collateral nuisance injury to neighboring cells. In the context of environmental health, the scientific community will have to pay close attention to those physicochemical properties of engineered nanomaterials that defeat or circumvent normal cellular processes and lend themselves to indiscriminate penetration of biological barriers, tissues, and cellular systems."''
References
{{reflist
Medical equipment
Drug delivery devices
Nanomedicine
Optoelectronics