- Assistant Dean for Research and Graduate Studies and Professor
- Office Location:
- Dixon Research Center, Room 124
Ph.D. in Chemical Engineering, Illinois Institute of Technology, 2003.
M.Sc. in Chemical Engineering, Middle East Technical University (Turkey), 1998.
B.Sc. in Chemical Engineering, Hacettepe University (Turkey), 1995.
Nanotechnology: Plasmonics, Metal-Enhanced Fluorescence, Metallic Nanoparticles, Ultra Fast Surface Chemistry, Ultra Fast Nanoparticle-Based Assays, Metal-Assisted Crystallization.
Biotechnology: Medical biotechnology, Biosensors, Plasmon-Enhanced Enzymatic Reactions, Biological Hydrogen Production.
CURRENT AND PREVIOUS FUNDING (Total: $1,221,010):
JHU-CMEDE, Polymers/Composites Group (May 2015 - December 2015)
NIH, STTR Phase 1 Subaward (April 2015 - March 2016)
NSWC, Technology Evaluation (October 2014- September 2015)
TEDCO, Maryland Innovation Initiative, Phase 2 Award (September 2014-December 2014)
TEDCO, Maryland Innovation Initiative, Phase 1 Award (March 2013-December 2013)
American Chemical Society, PROJECT SEED Award (Summer 2012)
National Institutes of Health, K25 Career Development Award (2008-2013)
American Heart Association, Beginning-in-Aid Grant (2007-2009)
1. Plasmonic Biosensing
My research focuses on the development and applications of plasmonic / fluorescence-based biosensors using noble metallic nanoparticles. In this regard, we have developed a new approach to glucose sensing based on the reversible aggregation of gold nanoparticles (due to specific dextran / Concanavalin A / glucose interactions) and their respective change in plasmon absorption (and scattering) upon glucose addition. This method proves to offer an across-the-board technology for glucose sensing in different physiological fluids due to its tunable glucose sensing range, where glucose can vary significantly from tears to blood, and its optical compatibility (absorbance above 600 nm).
We have shown that a fluorescence-based detection scheme for small molecules can be realized using ligand-functionalized gold nanoparticles. The transduction scheme is based on the strong quenching of the fluorescence emission exerted by metallic surfaces on fluorophores positioned in their immediate vicinity (< 10 nm). In this regard, we have employed biotin (as a model small molecule) and its fluorophore-labeled antibody.
2. Microwave-Accelerated Aggregation Bioassays
We have also demonstrated the proof of principle of microwave-accelerated aggregation assay technology, which shortens the solution-based aggregation assays' run time to seconds (>100-fold increase in kinetics) with microwave heating using a model aggregation assay based on the well-known interactions of biotin and avidin. Biotinylated gold colloids were aggregated in solution with the addition of streptavidin, which takes 20 min at room temperature to reach >90% completion and only 10 sec with microwave heating. The initial velocity (after 1 sec microwave heating) of the biotinylated gold colloids reaches up to 10 m/sec, which gives rise to greater sampling of the total volume but not a large increase in bulk temperature. The room-temperature, steady-state velocity of the colloids was <0.5 m/sec. In control experiments, where streptavidin pre-incubated with D-biotin in solution is added to biotinylated gold colloids and microwave heated, gold colloids did not aggregate, demonstrating that nonspecific interactions between biotinylated gold colloids and streptavidin were negligible.
3. Metallic Nanostructures
I am also interested in synthesis and deposition of the metallic nanostructures on surfaces for the applications in nanoscience and nanotechnology. One particular technology is Metal-Enhanced Fluorescence (MEF), where the fluorescence emission of fluorophores in close proximity to silver nanostructures is enhanced due to coupling of oscillating surface plasmons with fluorophore's dipoles. In this regard, we have developed a new wet-chemical based methodology for the deposition of anisotropic silver nanostructures (nanorods and triangular nanoplates) on conventional glass substrates. These new surfaces are a significant improvement over silver island films for applications in metal-enhanced fluorescence, with routine 50-fold enhancement in emission intensity typically observed for protein-immobilized Indocyanine green.
We reported the first findings of MEF from modified plastic substrates. We have showed how plastic surfaces can be modified to obtain surface functionality, which in turn allows for silver deposition and therefore MEF of fluorophores positioned above the silver using a protein spacer. Our findings show that plastic substrates are ideal surfaces for metal-enhanced phenomena, producing similar enhancements as compared to clean glass surfaces. We speculate that plastic substrates for MEF will find common place, as compared to the more expensive and less versatile traditional silica based supports.
4. Microwave-Accelerated Metal Enhanced Fluorescence
Microwave-Accelerated Metal-Enhanced Fluorescence (MAMEF) is a new platform technology that produces definitive results for fluorescence-based surface bioassays within a few seconds; the proof-of-principle of this technique was demonstrated for the ultra fast and sensitive detection of proteins and in DNA hybridization assays. MAMEF technology couples the benefits of two technologies: (i) MEF and (ii) low power microwave heating which reduces the bioassay run time by kinetically accelerating the biological recognition events localized around the surface-bound plasmonic nanoparticles.
5. Metal-Assisted and Microwave-Accelerated Evaporative Crystallization
Aslan Research Group has reported a platform technology, called Metal-assisted and microwave-assisted evaporative crystallization (MA-MAEC), which is based on the combined use of silver nanoparticles and microwave heating for selective and rapid crystallization of small molecules. In this regard, the crystallization of a model small molecule (glycine) was achieved in several seconds. Glycine crystals grown on silver nanostructures with and without microwave heating were found to be larger than those grown on blank glass slides. The MA-MAEC technique has the potential to selectively grow the desired polymorphs of small molecules “on-demand” in a fraction of the time as compared to the conventional evaporative crystallization.
6. Plasmon-Enhanced Enzymatic Reactions
Aslan Research Group presented a detailed investigation of the dependence of enzymatic activity on the nanoparticle-enzyme distance and nanoparticle loading on planar surfaces. Please see http://nanobe.org/index.php?journal=nbe&page=article&op=view&path%5B%5D=119
In this regard, three different SIFs were prepared (low, medium and high loading) on APTS-coated glass slides. The loading of SIFs on glass slides were monitored by the absorbance of surface plasmon resonance peak of silver. These silvered surfaces and unsilvered (blank) APTS-coated glass slides (control experiment) were used for the comparison of three different enzyme immobilization strategies for plasmon-enhanced enzymatic activity. A biotin-avidin protein assay (strategy 1), SAMs (strategy 2) and poly-l-lysine layer (strategy 3) were used to vary the distance of the enzyme from the silver surface. The enzymatic activity was followed by the colorimetric measurement of the product produced as a result of enzymatic conversion of o-phenylenediamine (OPD) on silvered surfaces and blank glass slides. It was found that up to an %200 increase in enzymatic conversion of OPD was observed from SIFs with high using strategy 1, providing direct evidence that plasmon-enhanced enzymatic activity is highly dependent on the enzyme-nanoparticle distance and the extent of loading of silver nanoparticles. These findings will help the scientific community to better design enzyme-nanoparticle hybrid systems for applications in bionanotechnology.
AWARDS, SCHOLARSHIPS AND PROFESSIONAL SOCIETY MEMBERSHIPS
1998 - 1999 NATO and TUBITAK (The Scientific and Technical Research Council of Turkey) PhD Program Grant in Chemical Engineering (Illinois Institute of Technology)
2001 - Present Member of the American Chemical Society (ACS)
2004 - 2006 Member of the Biophysical Society
2004 - 2006 Member of the International Society for Optical Engineering (SPIE)
1998 - 2003 Member of the American Institute of Chemical Engineers (AIChE).
PUBLICATIONS: Out of >100:
1. Aslan, K.; Pérez-Luna, V.H. "Surface Modification of Colloidal Gold by Chemisorption of Alkanethiols in the Presence of a Nonionic Surfactant", Langmuir (2002), 18, 6059-6065.
2. Aslan, K.; Pérez-Luna, V.H. "Nonradiative Interactions between Biotin Functionalized Gold Nanoparticles and Fluorophore-Labeled Antibiotin" Plasmonics (2006), 1 (2-4), 111-119.
3. Aslan, K. "Rapid Whole Blood Bioassays using Microwave-Accelerated Metal-Enhanced Fluorescence", Nano Biomedicine and Engineering (2010), 2 (1), 1-9.
4. Addae, S.; Pinard, M.; Caglayan, H.; Cakmakyapan, S.; Caliskan, D.; Ozbay, E.; Aslan*, K. "Rapid and Sensitive Colorimetric ELISA using Silver Nanoparticles, Microwaves and Split Ring Resonator Structures", Nano Biomedicine and Engineering, (2010), 2 (3), 155-164.
5. Caglayan, H.; Cakmakyapan, S.; Addae, S.; Pinard, M.; Caliskan, D.; Aslan, K.; Ozbay, E. "Ultrafast and Sensitive Bioassay using Split Ring Resonator Structures and Microwave Heating" Applied Physics Letters, (2010), 97 (9), 093701.
6. Pinard, M.; and Aslan, K. "Metal-Assisted and Microwave-Accelerated Evaporative Crystallization", Crystal Growth and Design", (2010), 10 (11), 4706-4709.
7. Grell, T.A.J.; Ortiz, E. P.; Das, S.R.; and Aslan*, K. "Quantitative Comparison of Protein Surface Coverage on Glass Slides and Silver Island Films in Metal-Enhanced Fluorescence-based Biosensing Applications", Nano Biomedicine and Engineering, (2010), 2 (3), 165-170.
8. Alabanza, M.; Anginelle; Aslan*, K. "Metal-Assisted and Microwave-Accelerated Evaporative Crystallization: Application to L-Alanine", Crystal Growth and Design", (2011), 11(10), 4300-4304
9. Alabanza, M. A.; Pozharski, E.; Aslan*, K. "Rapid Crystallization of L-Alanine on Engineered Surfaces using Metal-Assisted and Microwave-Accelerated Evaporative Crystallization", Crystal Growth and Design, (2012), 12(1), 346-353.
1. Aslan, K., "Metal-Assisted and Microwave-Accelerated Evaporative Crystallization", US20130090459A1, CA2851361A1, WO2013055859A1.
2. Geddes, C.D.; Aslan, K.,"Metal-Enhanced Fluorescence from Plastic Substrates", World Intellectual Property Organization: WO2006052548; US Patent No. 8075956.
3. Geddes, C.D.; Aslank, K., "Microwave-Accelerated Plasmonics" US Patent No. 20120107952.
1. Prof. Ekmel Ozbay, Bilkent University, Ankara, TURKEY
2. Prof. Subha Das, Carnegie Mellon University, Pittsburg, PA, USA
3. Prof. Edwin Pozharski, University of Maryland at Baltimore, Baltimore, MD, USA
4. Prof. Daxiang Cui, Shanghai Jiao Tong University, Shanghai, CHINA
5. Prof. Alvin Kennedy, Morgan State University, Baltimore, MD, USA
6. Prof. Yousef Hijji, Morgan State University, Baltimore, MD, USA
7. Prof. Eugene Hoffman, Morgan State University, Baltimore, MD, USA
8. Prof. Eric Toth, University of Maryland at Baltimore, Baltimore, MD, USA
Grant Proposal: American Chemical Society, Petroleum Research Fund (2008), NSF HBCU-UP (2012-cont'd), FCT Portugal (2012-Cont'd).
Manuscript Referee: Clinical Chemistry (2005-continued), Langmuir (2005-continued), Canadian Journal of Biosystems Engineering (2007-continued), Biotechnology Progress (2007-continued), Analytical Biochemistry (2007-continued), Applied Physics Letters (2008-continued), Nucleic Acids Research (2008-continued), Analytical Chemistry (2008-continued), The Journal of Physical Chemistry (2008-continued), International Journal of Environmental Analytical Chemistry (2008-continued), Modern Physics Letters B (2008-continued), Journal of Biomedical Optics (2008-continued), Applied Surface Science (2010-continued).
Chem 101: General Chemistry - Laboratory
Chem 105: General Chemistry - Lecture / Laboratory
Chem 314: Instrumental Analysis - Lecture / Laboratory
Chem 407, Advanced Topics in Physical Chemistry - Lecture
Chem 581: Advanced Techniques in Chemistry - Lecture / Laboratory
Chem 603, Thermodynamics - Lecture