Silk fibroin fiber is a natural protein with various special properties. In this research, silk fibroin
     nanoparticles were prepared by precipitating silk fibroin solution in organic solvents. The molecular
     characteristics of silkfibroin nanoparticles were investigatedusing  ATR FT-IR   microspectroscopy.
     It was found that silk fibroin nanoparticlestreated with methanol had the highest  crystalline content

                                               

     SEM micrographs of silk fibroin nanoparticles obtained by precipitation method :
     (A) Silk fibroin nanoparticles treated with methanol,
     (B) Silk fibroin nanoparticles treated with ehanol, and
     (C) Silk fibroin nanoparticles treated with iso-propanol.

     References:
     1. Joo Y., European Polymer Journal, 39, 1195-1199 (2003).
     2. Emilia B., Spectrochimica Acta Part A, 62, 105-111 (2005).
     3. Xiao H., Macromolecule, 39, 6161-6170  (2006).   

     References:
     1. Y.Q. Zhang, Biotech Adv., 2002, 20, 91-100.
     2. J.H. Wu, Z. Wang and S.Y. Xu, Food Chem.,
         2007, 103, 1255-1262.
     3. X. Hu, D.Kaplan and P. Cebe, Macromolecules,
         2006, 39, 6161-6170.
     4. K.Y. Cho, J.Y. Moon, Y.W. Lee, K.G. Lee,
          J.H. Yeo, H.Y. Kweon, K.H. Kim and C.S.
         Cho, Biol Macromol., 2003, 32, 36-42.
     5. K. Lee, H.Y. Kweon, J.H. Yeo, S.O.  Woo,
         Y .W. Lee, C.S. Cho, K.H. Kim and Y.H. Park,
         Biol Macromol., 2003, 33, 75-80.
     6. A. Kurioka, F. Kurioka and M. Yamazaki,
         Biosci Biotech Biochem.,  2004, 68, 774-780.

              Silk is a natural fiber with high strength and good mechanical properties.
     The properties of silk fiber depend on the quality of silk cocoon.  The structure of
     silk in each layer is well be obtained when the secondary structure of silk  can  be
      investigated. Moreover, the study of single fiber of silk cocoon by ATR FT-IR
     microspectroscopy is necessary for constructing the data base of Thai silk.
     ATR FT-IR technique is non-destructive, rapid analysis and sample preparation
     is not required

                                                    

                           ATR FT-IR spectra of silk cocoon fiber at innermost (A), middle (B) and outer layer (C).

      References:
     1. C. Holland., A.E. Terry. and D. Porter., F. Vollrath. Polymer, 1-5 (2007).
     2. G. Freddi., R. Mossotti. and R. nnocenti. Journal of Biotechnology, 106, 101-112 (2003).
     3. M. Kevin. and K. David. Protein-Based Materials, Birkhäuser Boster, 1997.
     4. Z. Hong-Ping., F. Xi-Qiao., C. Wei-Zheng. and Z. Feng-Zhu. Engineering Fracture Mechanics, 2006.

                     Theoretical simulation based on Mie Theory of spherical silver nanoparticles
     in water gave many insights to  the optical properties of the particle.  The underlying principles
     of these properties  are  the interactions between conduction electrons  on  nanoparticles,
     in  terms  of collective oscillation,  and  incident  electromagnetic radiation. When the particle
     size is changed, the electron distribution around the surface is also changed. Therefore,different
     optical properties of the nanoparticles are exhibited. The surrounding medium at the vicinity of
     nanoparticle  surfaces are also contributed the variation to the electron distribution. So, depend-
     -ing on material (i.e. the refractive  index of the material), the nanoparticles will response to
     this change differently. For example, in the case of air coated nanoparticles, when the thickness
     of air layer is increasing, the dipole plasmon resonance is observed at the shorter wavelength, and
     the maximum extinction efficiency is decreased (i.e. compared to the bare particles) 

              

           (Left) : Extinction efficiencies for silver nanoparticles of size 0.1 nm to 1.0 nm, step of 0.1 nm, in water.
           (Right) : Extinction efficiencies10, 40, 80 and 100 nm

       References:
      1. P. B. Johnson and R. W. Christy, Physical Review B, 1972, 6, 4370 - 4379          
      2. A. D. Rakic, A. B. Djurisic, J. M. Elazar and M. L. Majewski, Applied Optics,
         1998, 37,  5271 -5283.
      3. G.F. Bohren and D. R. Huffman, "Absorption and Scattering of Light by Small Particles",
          John Wiley & Sons, Inc., 1983.
      4. C. Noguez, Optical Materials, 2005, 27, 1204 - 1211.

                    This research has a major   aim  at  developing a technique for producing
          large amount of controllable  size,  highly concentrated (10,000-100,000 ppm) and highly
          stabilized silver nanoparticle. A nebulization or atomization technique was employed for
          the nebulization of solution of silver salt into the solution of a reducing agent. The plasmo-
          - nabsorptions of high concentration of silver nanoparticles were measured.  The  plasmon
           absorptions  indicated that  the synthesized silver nanoparticles has smaller size and narrow
          size distribution then these of the commercial due to  the lower plasmon band

                             

                    (Left) :  The plasmon absorption bands of diluted 1,000 to 10,000 from high
                                concentration of silver colloid  
                                (a) Our synthesized silvernanoparticles (lMax = 399 nm).
                                (b) Commercial product (Max = 405 nm).
                   (Right) :  TEM image of synthesized silver colloid has mean diameter of ~10 nm.

     References:
     1. D.L. Van Hyning and Zukoski C.F "Formation mechanisms and aggregation behavior of  
         borohydride reduced silver particles." Langmuir, 1998, 14, pp. 7304-7046.
     2. W. Hongshui, Q. Xueliang, C. Jianguo, W. Xiaojian and D. Shiyuan "Mechanisms of PVP
         in the preparation of silver nanoparticles" Mater. Chem. Phys. 2005, 94, pp. 449-453.
     3. P. Raveendran, J. Fu and S.L. Wallen "Completely "Green" synthesis and stabilization of
         metal nanoparticles" J. Am. Chem. Soc. 2003, 125, pp. 13940-13941.
     4. B.J. Wiley, S.H. Im, Z.-Y. Li, J. McLellan, A. Siekkinen and Y. Xia "Maneuvering the surface
         plasmon resonance of silver nanostructures through shape-controlled synthesis" J. Phys. Chem. B
         2006, 110, pp. 15666-15975.

                    
                    Silver nanoparticles are non-toxic and antibacterial agent. In this work, the antibacterial efficacy
          of silver nanopartilces on cotton and polyester was investigated.   Padding  process  has been used for
          the immobilization of silver nanoparticles onto the surfaces cotton and  polyester fabric.  The size,  size
          distribution and morphology of  nanoparticles  was  characterized  by   UV-visible spectroscopy  and
          transmission electron microscopy  (TEM).  The silver sol had narrow size distribution with the average
          size of 5-10  nm. At  low  padding concentrations (20-50ppm), silver nanoparticles  show  excellence
          antibacterial activity.

     References:
     1.  D. P. Dowling, K. Donnelly, M. L. McConnell, R. Eloy, and M. N. Arnaud, Thin Solid Films,   
          2001, 398-399, 602-606.
     2.  J. M. Schierholz, L. J. Lucast, A. Rump, G. Pulverer, J. Hosp. Infect. 1998, 40, 257-262.
     3.  C. Chug, M. Lee, E. K. Choe, Carbohydr. Polym. 2004, 58, 417-420.
     4.  S. H. Jeong, Y. H. Hwang, S. C. Yi, J. Mater. Sci. 2005, 40, 5413-5418. 
     5.  H. J. Lee, S. Y. Yeo, S. H. Jeong, J. Mater. Sci. 2003, 38, 2199-2204.

                    Food packaging was analysed by the novel slide-on diamond ?IRE and slide-on  Ge  ?IRE combined
          with the "contact and collect" technique. Contamination on a surface can be deposited onto the tip of both
          mIREs by directly deposition or by using an  organic liquid  (i.e., mineral oil and fluorolube)   to pick-up the
          contaminants from the surface. This technique  is  non-destructive,  ease to operate,  and  does  not   require
          an additional sample preparation. The result  is  accurate and reliable as the trace contaminants on a  surface
          can be separated from the substrate, and characterized  under  the ATR mode without any interference from
          the substrate. From polypropylene bag, polyethylene bag and  disposable chopsticks analysis, we found that
          there was oleamide on the surface  of  polypropylene  bag.  On the surface of chopsticks, there are talc and
          wax that can be assigned to octadecanoic  or  stearic  acid.  However,  we  did  not find a contamination on
          polyethylene bag.

     References:
     1. S. Ekgasit, N. Pattayakorn, D. Tongsakul, C. Thammacharoen, T. Kongyou; Anal. Sci., 23 (7), 863, 2007

                    The dome-shaped Ge mIRE  is the accessory for ATR FT-IR spectral acquisition using  infrared
          microscopy for forensic analysis of paper and pen inks. The  dome-shaped  Ge  mIRE  was employed.
          Since contact area of the Ge mIRE  is small  (50x50 mm2),  a  trace  of inks on paper can be analyzed
          without an additional sample preparation.  The observed spectra show unique spectral feature of each
          type,  brand,   and   color  of  ink.  The unique spectral feature associated with chemical composition of
          an individual ink can be employed for forensic applications in order to differentiate cross line of ink trace.

                                        

     References:
     1.David F.R., Chem. Soc. Rev. 2005, 34, 1021-1030.
     2.Williams D.M, Forensic Sci. Int. 2005, 152, 241-247.
     3.Gemma P., Talanta  2005, 67, 334-344.
     4.Ashwini K., Vib. Spectrosc., 2006, 40, 270-277.