News Column

Patent Issued for Development of Phopholipid-Capped Gold Nanoparticles (PLGNPs) as Surface Enhanced Raman Scattering Probes

July 4, 2014



By a News Reporter-Staff News Editor at Health & Medicine Week -- National Tsing Hua University (Hsinchu, TW) has been issued patent number 8753541, according to news reporting originating out of Alexandria, Virginia, by NewsRx editors (see also National Tsing Hua University).

The patent's inventors are Ho, Ja-An (Hsinchu, TW); Chen, Si-Han (Hsinchu, TW).

This patent was filed on August 16, 2010 and was published online on June 17, 2014.

From the background information supplied by the inventors, news correspondents obtained the following quote: "Gold nanoparticles (GNPs) attract much interest because of their electronic, optical, thermal and catalytic properties as well as their biocompatibility and low toxicity, which have greatly impacted the biological fields of imaging, sensing and medicine in recent years (Jain et al., 2008) to detect chemicals in the sample, or microbes or particular molecules in the cells. However, GNPs only can achieve the specific sensitivity and detection limits. Energy is released by scattering if the molecules cannot absorb the photons' energy after the incident photons bombards to the molecules. Since most scattering belongs to Rayleigh scattering and Raman scattering accounts for 1/1000 of Rayleigh scattering, Raman scattering becomes the excellent tools for detecting molecular sensitivity and detection limits.

"Surface enhanced Raman scattering (SERS) is a surface sensitive technique that results in effective enhancement of the Raman scattering for molecules in the vicinity of the surface of particles for 10.sup.5.about.10.sup.6 times (Schatz, 1984). The most common application of combining SERS and GNP is to prepare the SERS nanoprobes which is to attach the Raman reporter onto the surface of metal nanoparticles, such as the thiol-related ligands bound to the surface of particles (Chompoosor et al., 2008; Hong et al., 2006). Several methods have been developed to stabilize the nanoprobes (i.e. nanoparticle-thiol molecule) by coating a shell, such as Silica (Mulvaney et al., 2003) and copolymers (Yang et al., 2009) onto the nanoprobes.

"U.S. Pat. No. 7,333,197 discloses a flow cytometry based on Raman detection, wherein cells or particles are coated with a colloidal aggregate, the colloid-coated cells or particles are dispersed, and then the emitted surface enhanced Raman scattering is detected using the flow cytometry. However, cells or particles do not bound to the molecules carrying thiol signals, and cells or particles cannot completely separate individually, so as to result in the disturbance of signal detection.

"Since the multiple nanoparticles are capped and usually aggregates in the prior art, the quantitative object to control the particular amount of nanoparticles cannot be achieved. Therefore, the technique which the single GNP is capped and can still represent Raman signal would be applied on the detection apparatus, would be applied on related detection for sera and cellular media containing salts or proteins, and have great benefit in the fields of biomedicine, medical diagnosis and environment.

"It is therefore attempted by the applicant to deal with the above situation encountered in the prior art."

Supplementing the background information on this patent, NewsRx reporters also obtained the inventors' summary information for this patent: "An enhanced Raman scattering signaling molecule is provided in the present invention, where the signal gold nanoparticle bound to the thiol molecules is encapsulated with phospholipid capping. The signaling molecule becomes a material having surface enhanced Raman scattering and can be applied on the detection device integrating optics and chemistry since the thiol molecule owns the characteristic of Raman signal. Since GNP is encapsulated with phospholipid capping, the enhanced Raman scattering signaling molecule is relatively stable in the bio-system to be applied on the related detection for sera and cellular media. Comparing with other products which cannot maintain their stability in the sample containing salts or proteins, the signaling molecule of the present invention would be widely applied in the fields of biomedicine, medical diagnosis and environment.

"A method for preparing a signaling molecule including a metal nanoparticle is provided in the present invention. The method includes steps of: (a) treating a surface of the metal nanoparticle with an acidic solution; (b) resolving the metal nanoparticle in a dimethylformamide (DMF) to obtain a first intermediate; adding a phospholipid and a thiol molecule to the first intermediate to perform a heating process to obtain a second intermediate; and (d) separating the second intermediate to obtain the signaling molecule including the metal nanoparticle.

"Preferably, the step (a) further includes steps of: (a1) centrifuging the metal nanoparticle; and (a2) removing the acidic solution. The step (a2) is performed by a decantation.

"Preferably, the step further includes a step of (c1) adding a water having a temperature the same in the step to result in a water-DMF volume ratio of 1:1. The preheating step is performed before the step . The heating process in the step is ranged between 60.degree. C. and 100.degree. C., and the temperature of the heating process is preferably at 80.degree. C.

"Preferably, the step (d) is performed to remove a non-signaling molecule in the second intermediate by a centrifugation or a decantation.

"Preferably, the acidic solution is a citric acid solution.

"Preferably, the metal nanoparticle is one selected from a group comprises a gold, a silver, a aluminum and a platinum.

"Preferably, the metal nanoparticle is a gold nanoparticle.

"Preferably, the phospholipid includes a dipalmitoylphospho-phatidylcholine (DPPC), and a dipalmitoylphosphatidylgly-cerol (DPPG). The DPPC-DPPG molar ratio is 10:1.about.14:1, and DPPC and DPPG are resolved in the DMF.

"Preferably, the thiol molecule is a 2-naphthalenethiol.

"Preferably, the signaling molecule has the surface enhanced Raman scattering ability.

"Preferably, the signaling molecule encapsulates a gold nanoparticle.

"A signaling molecule is further provided in the present invention and includes: a metal nanoparticle; a thiol molecule bound to the surface of the metal nanoparticle; and a phospholipid capping the metal nanoparticle and the thiol molecule, wherein a number of the metal nanoparticle is single, and the signaling molecule has a surface enhanced Raman scattering ability.

"Preferably, the metal nanoparticle is one selected from a group comprises a gold, a silver, a aluminum and a platinum.

"Preferably, the metal nanoparticle is a gold nanoparticle, and the thiol molecule is a 2-naphthalenethiol.

"Preferably, the phospholipid comprises a dipalmitoylphosphophatidylcholine (DPPC), a dipalmitoylphos-phatidylglycerol (DPPG) or a 1,2-dihexadecanoyl-sn-glycero-3-phosphoethanol-amine-N-[4-(p-maleimidomet- hy)cyclohexanecarboxamide] (PE-MCC) or other phospholipids such as, 1,2-di-oleoyl-sn-glycero-3-phosphocholine (DOPC).

"The above objectives and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed descriptions and accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

"FIG. 1 represents the preparation process for SERS signaling molecule;

"FIG. 2 schematically illustrates the preparation method of SERS signaling molecule;

"FIG. 3 represents the UV-VIS absorbance of GNP and PLGNPs (PLGNP-1 and PLGNP-2) under different wavelengths determined using UV-VIS spectrometer;

"FIG. 4 represents a transmission electronic microscopic image of PLGNP with the negative staining treatment; and

"FIG. 5 represents the UV-VIS spectrum of the single dispersed PLGNP, wherein 25.times. concentrated 2-NAT is added to the slightly aggregated PLGNP upon preparation."

For the URL and additional information on this patent, see: Ho, Ja-An; Chen, Si-Han. Development of Phopholipid-Capped Gold Nanoparticles (PLGNPs) as Surface Enhanced Raman Scattering Probes. U.S. Patent Number 8753541, filed August 16, 2010, and published online on June 17, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8753541.PN.&OS=PN/8753541RS=PN/8753541

Keywords for this news article include: Cytometry, Nanotechnology, Gold Nanoparticles, Emerging Technologies, National Tsing Hua University.

Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC


For more stories covering the world of technology, please see HispanicBusiness' Tech Channel



Source: Health & Medicine Week


Story Tools






HispanicBusiness.com Facebook Linkedin Twitter RSS Feed Email Alerts & Newsletters