Although gold nanoparticles (AuNPs) have been known for over 2500 years, their potential applications in medicine has gained burgeoning attention in the 21 st century. Bulk gold is well known for being inert, however, the nanoparticulate sizes of gold display astronomically different chemical reactivity and photophysical properties. The high reactivity of AuNPs with a plethora of chemical and biochemical vectors continue to produce a wide spectrum of hybrid AuNPs that have sizes within the cellular regime yet retaining most/all of the properties specific to nanosizes. This size similarity and recognition of hybrid AuNPs (and other nanoparticles) with cellular species within the biological domain has motivated researchers toward applications of nanotechnology for site/cell specific labeling of hybrid nanoparticles for the detection and therapy of different diseases including cancer. The multifunctionality and the unique reactivities of AuNPs would allow to build hybrid nanoparticles carrying imaging and therapeutic properties to target cancer cells. Inherent features of nanoscience and nanotechnological developments are the culmination of expertise and complementary research efforts from chemists, physicists, biologists, engineers, clinicians and theoretical experts. Nanomedicine research in Dr. Katti’s program is focused on the development and applications of Nanotechnological innovations for the diagnosis and therapy of cancer. The current research will address fundamental scientific, technological and product developments aspects involved in the design and development of hybrid nanoparticles for use in imaging and therapy of prostate cancer. Although the overall objective is to develop innovative imaging and therapeutic approaches to combat prostate cancer, new knowledge base that will be developed from the current research will have significant impact in improving our understanding of the underlying biology of human cancer and help in the development of nanotechnological products for the accurate diagnosis and effective therapy for various different types of cancer. Specifically, this research is exploring whether gold nanoparticles can cause contrast enhancement (x-ray attenuation in computer tomography and backscatter in ultrasound) so that computed tomography (CT) and ultrasound imaging (US) can be used in the armamentarium of precise and accurate functional/molecular imaging of prostate cancer.
On the therapeutic front, the overall objective within Dr. Katti’s research program is to evaluate whether hybrid Gold-198/199 nanoparticulates will deliver effective therapeutic response for treating prostate cancer. Nanoparticulates of gold contain multiples atoms of that specific isotope. Therefore, higher therapeutic dose is inherent when nanoparticles of the β emitting Gold 198/199 are used in cancer therapy. Gold isotope produced at the University of Missouri Research Reactor (MUUR) has two beta emitting isotopes of appropriate energy to achieve therapeutic response. Optimization of nanoparticles production processes for the two Gold198/199 isotopes is an integral part of the nanoplatform research and product development efforts. Hybrid Au-198/199 nanoparticulate conjugates are being prepared via conjugations with prostate cancer specific bombesin peptide. Bombesin (and other tumor-avid peptides) peptide analogs are gastrin releasing peptides that high affinity toward receptors on prostate, breast and small cell lung cancer cells. Dr. Katti’s research efforts are addressing several issues in nanomedicine, including (1) in vivo evaluation of the effect of multiple atoms of Gold198/199 present in gold nanoparticles (AuNPs) to achieve prostate cancer targeted multitherapeutics in tumor bearing SCID mice; (2) whether the high affinity AuNPs toward prostate cancer vasculature will lead to sufficient accumulation of the beta emitting gold nanoparticulates to achieve therapeutic doses of hybrid nanoparticles at the tumor site.
Knowledge on the localization of AuNPs in vivo is of fundamental importance for the development of imaging or therapeutic agents that utilize gold nanoparticles. Therefore, in vivo studies in SCID mice and in pigs are being undertaken to evaluate the pharmacokinetic and biodistribution patterns of AuNPs. This research activity is aimed at answering such important questions as to what is the nature of interaction of AuNPs with prostate cancer PC3, LnCAP and Du-145 cells? Whether hybrid AuNPs are internalized into prostate cancer cells via endocytosis? This investigation will include non radioactive as well as MURR produced AuNPs using Au-198/199. Studies will also include theoretical modeling and simulations to develop fundamental understanding on the interaction of gold nanoparticles at the cellular levels.
In a nutshell, the central objective of the current research in cancer nanotechnology platform within Katti’s laboratories will be to bring interdisciplinary professionals consisting of chemists, physicists, biologists, engineers, theoretical modeling experts and clinicians under a highly interactive and scientifically stimulating forum to: (i) develop a thorough knowledge on the synthesis of biologically robust and clinically useful hybrid nanoparticles;(ii) understand the fate and distribution of hybrid nanoparticles in vivo; (iii) develop innovative delivery methods of hybrid nanoparticles for maximum localization on tumor sites; (iv) work toward the development of a ‘multi-modality’ suite of the future for hybrid nanoparticles enhanced molecular and functional imaging of prostate cancer using computer tomography and ultrasound imaging techniques; and (iv) establish the feasibility of using hybrid nanoparticulate beta emitting Au-198/199 isotope for site specific delivery and as effective therapeutic pay loads in treating prostate cancer. In the first phase of the proposed Cancer Nanotechnology platform, nanotechnologically derived new imaging and therapeutic modalities will be tested in animal models (mice, rats and pigs). At the end of the first phase of our Cancer Nanotechnology initiative, plans will be drawn to utilize new nanotechnologically driven imaging and therapeutic products and infrastructures to conduct studies for imaging and therapy of prostate cancer in humans.
In order for a radiolabeled drug to be performance effective under in vivo conditions, the following important attributes must be met under the physiological conditions:
- Attachment of radiolabel ( b or g emitter) via the ligand to targeting vectors (peptides/proteins) should not affect the biospecificity of biomolecules.
- The attachment of the radiolabel (i.e. b or g emitting isotope) to the ligands as well as the bonding between the ligand and the biomolecule should be kinetically inert for a specific time period as determined by the half life of the radiometal and also the disease for which imaging/therapy is sought
- The radiolabeled ligand which is strongly attached to specific biomolecule should have efficient in vivo bioclearance pathways.
Therefore, it is important to design and develop ligand frameworks that are stable to in vitro/ in vivo conditions, upon radiolabeling, but also be able to from strong covalent links to specific biomolecular vectors (peptides or proteins). With the overall objective of developing appropriate ligand systems for use in the development of site-specific radiopharmaceuticals, several new water-soluble phosphines have been synthesized for use as complexing agents to Tc-99m, Re-188 and Au-198/199 precursors. Representative examples of the ligand systems are depicted below:
The results demonstrate that THMP, HMPE and HMPB ligands complex 99mTc to form single, positively charged species that have excellent in vitro and in vivo stabilities. Clearance from the blood stream is rapid, primarily via the kidneys into the urine. The 99mTc chelates with these water-soluble ligands can be formed by 1) simple mixing 99mTcO with excess ligand in water (in this case, the HMP groups will reduce 99mTc in 99mTcO even though P III centers in THMP, HMPE or HMPB are not oxidized to form P=O with molecular O 2; 2) by reduction of 99mTcO with Sn +2 or 3) by transchelation from 99mTc glucoheptonate.
In summary, these studies further demonstrate that ligands containing bis(hydroxymethyl)phosphine groups (i.e., R-P(CH 2OH) 2 are not oxidized by O 2 in aqueous solutions and can form well-defined, in vivo- stable 99mTc complexes in high yields. These properties indicate that chelators containing HMP groups will provide a novel and effective vehicle for labeling small biomolecular targeting agents with 99mTc (and 188Re) for subsequent use in development of site-specific radiopharmaceuticals for cancer diagnosis and therapy.
Recent interest in the development of new and novel strategies for the generation of gold nano particles stems from their important applications in the areas of material science and biomedicine. Gold nano particles functionalized with oligonucleotides have been used as probes in a variety of DNA detection methods. Nanoparticulate gold is of paramount importance in Biomedical optical imaging modalities because of the superior Surface Enhanced Raman Scattering (SERS) properties of Gold nano particles adsorbed on biological surfaces. Numerous methods reported in the literature rely on the generation of gold nano particles via reduction of gold(III) using Sodium borohydride as a reducing agent. Although application of sodium borohydride produce gold nano particles of varying sizes (2-200 nm) in good yields, the powerful adverse reactivity of this reagent towards functional groups present on biomolecules is a serious impediment. Therefore, there is considerable current interest in the development of gold nano particles under biologically benign conditions. As part of our research efforts in biomedical optical imaging, we have focused our efforts on the optimization of a new methodology for the generation of gold nano particles in water under biologically benign media.
Indeed, recently we have discovered a new and a highly effective method for the production of gold nano particles.. This method involves simple mixing of P(CH 2NHCH(CH 3)COOH) 3 (THPAL) with NaAuCl 4 in water at physiological pH. Gold nano particles generation is achieved within 5 minutes at 25 0C. Thiol stabilizers which are traditionally used in stabilizing gold nano particles pose serious problems because of their environmental hazards and optical interference in SERS related applications. Our method is unique compared to all methods known to date because THPAL serves the dual roles of gold nano particle stabilizer and a reductant.
We are currently collaborating with Professors Meera and H.R Chandrasekhar for a detailed investigation on the photo physical properties of Gold nano particles. One aspect of our collaborative effort involves for the direct application of gold nano particles for adsorption on bioactive surfaces for potential application in biomedical optical imaging using SERS. Further studies are underway to incorporate gold nano particles on target specific biomolecular vectors for use in optical imaging of tumor tissue.
Cis-platin is widely used in the treatment of various different types of cancer in humans. A major disadvantage of treating with cis-platin, especially for longer periods of time, is concerned with its acute toxicity. The high toxicity of cis-platin also restricts its utility in high doses. Therefore, development of new chemotherapeutic agents with efficiency and low toxicity would be critical development of new chemotherapeutic agents with efficiency and low toxicity would be critical determinant in the care and treatment of cancer patients. Dr. Katti and his group have recently developed a new class of Au (I) phosphine complexes. These gold complexes have demonstrated unique cytotoxic and cell cycle arresting properties which make them exciting new candidates for the development of a new class of fold chemotherapeutic agents. To date, we have gathered data demonstrating that Au-THP is cytotoxic against human androgen independent prostatic carcinoma (PC-3 cell line), human androgen dependent carcinoma (LNCap. FGC cell line), human colon carcinoma cells (HCT-15 cell lines), and human gastric carcinoma (AGS).
There remains a tremendous need to develop new therapeutic treatment strategies in end stage and chemotherapeutic resistant neoplasms. Based upon the unique cytotoxic properties exhibited by one of the gold complexes (Au-THP) developed to date, we intend to expand these preliminary studies to evaluate the potential of these types of compounds to inhibit growth of human tumors in an in vivo animal model.
Current Studies in Dr. Katti’s program include:
- Evaluation of the in vitro toxicity and establish a minimum effective dose necessary to inhibit cell regulation using Au-THP in a variety of human cancer cell lines.
- Determination of the maximum tolerable dose allowable in a rodent model using single injection multi-dose delivery schedules.
Assess therapeutic efficacy of Au-THP in SCID mice implanted with human prostate tumor xenografts. This study will be conducted to assess the ability of increasing concentrations of Au-THP to control, and inhibit tumor growth in vivo.
This study will be conducted over a 14-week period with 4 groups of animals consisting of a control group and 3 experimental groups. The drug delivery will be scheduled for 10 consecutive days with each of 3 experimental groups receiving an incrementally higher dose of Au-THP. Initial hematology profile data (platelets, RBC’s, WBC’s) will be measured immediately prior to study initiation and then measured weekly thereafter. Tumor volume and animal body weight will be measured weekly. At study termination, the liver, kidneys, heart, histopathologically analyzed to determine the extent, if any, of toxicity to the renal, hepatobiliary, and cardiac systems.
Most of the cross-linking agents use, to date, in biochemical applications, involve the interaction of NH2 groups of proteins with aldehydes. The resulting imine linkages are generally unstable under physiological conditions and often require reduction via sodiumborohydride to the corresponding amines. Such chemical manipulations generally result in side-products and also cause denaturing of biomolecules. In this context, the development of more efficient cross-linking agents that are capable of producing strong-covalent bonds between specific site(s) on the protein and cross-linker(s) will enhance the scope and utility of cross linking agents in medical applications. Our studies are directed towards the development of new class of water-soluble cross-linking agents that demonstrate very effective cross linking characteristics upon their reaction with proteins. In fact, recent studies demonstrate that water-soluble phosphine P(CH 2OH) 3 (THMP) induces effective cross-linking in respective proteins: lens crystalline protein, yeast alcohol dehydrogenase and collagen type 6. Typically, the cross-linking occurs, within a few minutes, upon simple mixing of protein solutions with aqueous solutions of the cross-linker. This cross-linking pathway is non-invasive because the cross-linker does not leave any chemical functionality upon its interaction with proteins. Specifically, water is eliminated in the reactions of this class of cross-linker(s) with proteins. The fact that some of these cross-linkers do not have any UV - absorbance presents realistic prospects for their use in ophthalmic applications as cross linkers for proteins. Cross-linking with collagen may have commercial prospects for development of new wound healing agents for surgical and non-surgical applications.
Further studies to understand the details such as (1) the effect of pH on cross-linking efficiency, (2) effect of concentration dependency of the cross-linker upon degree of cross-linking and (3) effect of chemical backbone of the cross-linker on the efficacy of cross-linking are currently being investigated in my laboratories.
The chemistry, physics, and biological aspects of hydrogen bonded liquids have attracted considerable theoretical and experimental interests. Water and methanol constitute important prototypes of hydrogen bonded liquids and investigations toward understanding hydrogen bonding patterns that exist within the individual liquids, and also more complex phenomenon that ensue upon mixing H 2O and MeOH, has been at the focus of attention for a number of decades. Because water plays an indispensable role in life-sustaining processes, investigations on its structure, properties and functions have received more scientific attention than any other substance. Several investigations to date, have provided evidence that the water trimer, tetramer, and pentamers have hydrogen bonded 2D cyclic minimum energy structures whereas pioneering efforts by Saykally and others suggest 3D geometries for the larger water clusters with the hexameric forms representing the transition from 2D cyclic to the 3D geometries. Recent studies are focused on unraveling structural morphologies of water cocrystallized with various chemical entities because the lattice of a crystal host offers an attractive environment for stabilizing various topologies of water clusters and thereby provide quantitative characterization of the hydrogen bonded networks that exist in liquid water. Studies toward understanding the growth and properties of water clusters that are larger than hexamers are highly relevant in understanding solvation processes although the development of large size water clusters has been a challenging scientific endeavor.
Hydrogen bonding liquid methanol (MeOH) is the simplest amphiphile functionalized with hydrophobic (-CH 3) and hydrophilic (-OH) groups. Understanding of the solvation properties of MeOH as it relates to the disposition of hydrophobic/hydrophilic groups in polar or nonpolar solvents is of fundamental importance in biological and chemical sciences because amphiphiles are essential constituents making up cell membranes and are also extensively used in chemical industries as micelles (e.g., detergent action). In fact, the eccentric properties associated with water-alcohol mixtures have been the focus of numerous scientific investigations and significant technological applications. Frank and Evans interpreted the unusual entropic changes that ensue upon mixing methanol and water by proposing that the hydrogen bonds of water act like an "ice berg" and encapsulate the hydrophobic headgroups of methanol in a clatharate-like fashion, although this model has never been confirmed by concrete structural evidence. In contrary to this widely accepted model, Crain and co-workers have recently provided experimental evidence inferring that the hydrogen bonded network structure of water is not lost upon mixing methanol with water and that the polar hydroxyl group of methanol dictates the thermodynamic properties of methanol-water mixtures.
Dr. Katti’s current research interests include: structural elucidations and understanding hydrogen-bonding properties of supramolecular networks of water and water-methanol at nanometer scales. Well characterized mixed water-methanol clusters are rare, although structural elucidation of such clusters is imperative to gaining insight into the anomalous properties and to understanding the hydrogen bonding and dynamics of water-methanol binary mixtures. Our investigations have recently uncovered: (a) the experimental evidence for the existence of a 2D cyclic supramolecular (H 2O) 18 morphology within the layers of (HOOCCH(CH 3)NHCH 2) 3P, 2, with structural features (average O-O bond distance in (H 2O) 18 = 2.858 Å) similar to those of liquid water (O-O bond distance in liquid water = 2.85 Å); (b) Our results on the application of single-crystal X-ray diffraction methods to probe the molecular scale hydrogen bonded structure of mixed supramolecular water-methanol (H 2O) 15(CH 3OH) 3 clusters and the evidence for the accommodation of methanol groups within the hydrogen bonded (H 2O) 18 framework.
Perspective view of supramolecular (H 2O) 18 hydrogen bonding arrangement of water molecules. Colors are as follows: gray, carbon; dark blue, nitrogen; green, phosphorus; red, oxygen (carboxyl); yellow and orange, oxygen (water); white, hydrogen. Hydrogen atoms in water are omitted for clarity.
Perspective view of supramolecular hydrogen bonding network of water and methanol molecules in (H 2O) 15(CH 3OH) 3. Colors are as follows: gray, carbon; dark blue, carbon (methyl from methanol); green, phosphorus; red, oxygen (carboxyl); yellow and orange, oxygen (water); white, hydrogen.
Our direct crystallographic measurements of mixed water-methanol clusters in (L)-2·3H 2O·CH 3OH and (D)-2·3H 2O·CH 3OH confirm the existence of a cooperative hydrogen bonding between polar groups in methanol and water. The disposition of the hydrophobic headgroups within the supramolecular domain of the mixed water-methanol (H 2O) 15(CH 3OH) 3 cluster confirms that the hydrophobic methyl groups of methanol orient in such a fashion as to minimize disruption of hydrogen bonds in the water structure. The larger size of the water rings in (H 2O) 15(CH 3OH) 3 (and also in (H 2O) 18) clusters contrast the compact pentameric and hexameric water clusters found in a majority of structures discussed to date. The larger water rings presumably provide higher degrees of freedom and consequently favor larger distances between the hydrophobic headgroups within the (H 2O) 15(CH 3OH) 3 cluster. This spatial arrangement suggests that the cooperative hydrogen bonding of polar groups in methanol with the hydrogen bonds within the water structure is the dominant phenomenon within the larger water rings and that the well-known Frank and Evans hypothesis on the generation of clatharate-like cage water structure around hydrophobic headgroups may be limited to smaller pentameric or hexameric water structures.
Further studies are underway to advance fundamental knowledge on structures of water and mixed water-alcohol binary mixtures.
Intellectual Property Development and Entrepreneurship Statement:
I am the strongest advocate of the philosophy that fundamental research in science and technology must have an applied orientation to make the overall research endeavor sustainable and accountable. I have practiced and implemented this philosophy in my research activities at the University of Missouri-Columbia. My research work on the development of new chemical and bioconjugates have produced over 130 publications in peer reviewed journals and at the same time has generated wealth of intellectual property. With my principal inventorship, the University of Missouri has successfully obtained 14 issued US patents and an additional 4 patents have been filed. These patents relate to the development of cancer diagnostic/therapeutic agents, clinically relevant antioxidants, nanoscience/nanotechnology, molecular imaging and nuclear waste remediation technologies. Majority of the issued patents have been sponsored by industrial corporations and all patents related costs have been paid by the sponsors. :
Following is a list of my patents:
1. Kannan Raghuraman and K. V. Katti. Method for the generation of Silver Nanoparticles. Kannan Raghuraman and Kattesh Katti. US Patent Filed November 2005
2. K. V. Katti.; Gali, Hariprasad; Volkert, Wynn A. Biomolecule conjugation strategy using novel water-soluble phosphine-based chelating agents. U.S. Pat. Appl. Publ. (2004), 11 pp. CODEN: USXXCO US 2004042963 A1 20040304 Patent written in English. Application: US 99-386657 19990831
3. K. V. Katti, W. A. Volkert and T. J. Hoffman; A Broad Spectrum Chemotherapeutic Agent for Treating Cancer; US Patent Application Most Claims Allowed; (2003,2004,2005)
4. K. V. Katti, Raghuraman Kannan, Stan Casteel and Kavita Katti; Development of a New Chemotherapeutic Agent for the treatment of Wilsons Disease; Kattesh V. Katti, Raghuraman Kannan, Stan Casteel and Kavita Katti; Us Patent filed on January 15 2004
5. K. V. Katti, K. R. Prabhu, H. Gali, Pillarsetty Kishore and W.A Volkert; Bifunctional Chelating Agents For the Design and Development of Site Specific Radiopharmaceuticals and Biomolecule Conjugation Strategy; Patent US6635235B1; Issued on 10/03/2003
6. K. V. Katti, S. R. Karra, D. B. Berning, J. C. Smith and W. A. Volkert, Hydroxymethyl phosphine compounds for use as diagnostic and therapeutic pharmaceuticals and method of making same, Patent US06054115, Issued on 04/25/2000.
7. K. V. Katti, S. R. Karra, D. B. Berning, J. C. Smith and W. A. Volkert, Hydroxymethyl phosphine compounds for use as diagnostic and therapeutic pharmaceuticals and method of making same, Patent US06054115, Issued on 04/25/2000
8. K. V. Katti, D. B. Berning, W. A. Volkert, A. R. Ketring and R. J. Churchill, Conjugate and method for forming aminomethyl phosphorus conjugates, Patent US05948386, Issued on 09/07/1999.
9. K. V. Katti, P. R. Singh, V. S. Reddy, K. K . Katti, W. A. Volkert and A. R. Ketring, Hydroxyalkyl phosphine compounds for use as diagnostic and therapeutic pharmaceuticals, Patent US05876693, Issued on 03/02/1999.
10. K. V. Katti, S. R. Karra, D. E. Berning, C. J. Smith, W. A. Volkert and A. R. Ketring, Hydroxymethyl phosphine compounds for use as diagnostic and therapeutic pharmaceuticals and method of making same, Patent US05855867, Issued on 01/05/1999.
11. K. V. Katti, D. E. Berning, W. A. Volkert and A. R. Ketring, Hydroxyalkyl phosphine gold complexes for use as diagnostic and therapeutic pharmaceuticals and method of making same, Patent US5843993, Issued on 12/01/1998
12. K. V. Katti, W. A. Volkert, A. R. Ketring and P. R. Singh, New multifunctional ligands for potential use in the design therapeutic or diagnostic radiopharmaceutical imaging agents, Patent US05601800, Issued on 02/11/1997.
13. K. V. Katti, W. A. Volkert, A. R. Ketring and P. R. Singh, Multifunctional ligand for use as a diagnostic or therapeutic pharmaceutical, Patent US05478774, Issued on 05/14/1996.
14. K. V. Katti, W. A. Volkert, A. R. Ketring and P. R. Singh, Method for treating liquid wastes, Patent US05478474, Issued on 12/26/1995.
15. R. G. Cavell and K. V. Katti, Carbonylation of methanol using a novel transition metal catalyst, Patent US05352813, Issued on 10/04/1994.
I strongly believe that discovery oriented research with potential for intellectual property development is of paramount importance within the student training process. Indeed, almost every graduate student/post doctoral fellow working within my research program are key participants in the discovery research. Through this approach, most of the students/post doctoral fellows have served as co inventors for several patents. This entrepreneurship approach to student training has been the corner stone of my educational missions.
Recently, we have taken our discoveries to product development stages through an entrepreneurship based incubator company. I am one of the founder members of a nanotechnology company that was recently established at the University of Missouri-Columbia. Nanoparticle Biochem Inc (NBI).; is a start up company with nanotechnology and biochemical products that include, nanoparticles and specialty biochemicals. Currently NBI has over 15 products for sales to research and industrial corporations. NBI is actively involved in research and development toward the utility of nanoparticles for the design and development of new generation of molecular imaging agents. Current focus of NBI includes development of hybrid nanoparticles for use in ultrasound imaging and X ray contrast enhancement. Work is also underway toward the design and development of hybrid nanoparticles for potential applications as site specific probes for cancer diagnosis and therapy.
Professional Affiliations and Other Professional Activities
Alexander von Humboldt Foundation, FRG, 1985-present
American Chemical Society 1989-present
Society of Nuclear Medicine 1990-present
Sigma Xi; Member 1991-present
International Association of Radiopharmacology, 1992-present
Fellow of the Royal Society of Chemistry, London (1995-present)
Executive Editor of the journal of "Synthesis and Reactivity in Inorganic and Metal-Organic and Nano-Metal Chemistry”; A Taylor & Francis Group journal(from April 2004-Current)
Editor (for the US and North American Region) for the journal of Applied Organometallic Chemistry (in the Biorganometallic Chemistry section) (Wiley Editorial Member of the Journal of Inorganic Chemistry published by the American Chemical Society (1999-2002)
Panel member for reviewing papers to American Chemical Society Journals
Actively involved in refereeing papers for:
J. Chem. Physics
J. .Medicinal Chemistry
J. Am. Chem. Soc.
European Journal of Inorganic Chemistry
J. Chem. Soc. Dalton Transactions
Inorganica Chimica Acta
J. Nucl. Med. & Biology
J. Org. Met. Chemistry
J. Photochemistry Photobiology
J. Mol. Structure