Dr. Lance J. Twyman
Senior Lecturer in Chemistry
Dr. Twyman obtained a BSc in Chemistry from King's College London in 1991, which was followed by a PhD from the University of Kent in 1995. After his PhD he became a postdoctoral research associate at the University of Cambridge and a Research Associate at Girton College. In 1997 he became a postdoctoral research fellow at the University of Oxford. In 1998 he was appointed as a lecturer at Lancaster University. In 2000 he was appointed as lecturer at the University of Sheffield, where he was promoted to senior lecturer in 2008.
Biomimetics, dendritic molecules, supramolecular chemistry, ecapsulation and drug delivery.
Organic Chemistry; Characterization, Molecular Orbitals
- Controlling microenvironments and modifying anion binding selectivities using core functionalised hyperbranched polymers.
Mann G, Twyman LJ & Gale PA, Chem. Commun., 52(36), 6131-6133, (2016).
- Exploiting dense shell/packing principles to invoke stereoselectivity in a reaction accelerated by a chiral dendrimer..
Ellis A, Wallace M & Twyman LJ, Chem Commun, 49(73), 8063-8065, (2013).
- Bimolecular catalysis and turnover from a macromolecular host system..
Ellis A, Gooch D & Twyman LJ, J Org Chem, 78(11), 5364-5371, (2013).
- Pseudo-Generational Effects Observed for a Series of Hyperbranched Polymers When Applied as Epoxidation Catalysts.
Zheng X, Oviedo IR & Twyman LJ, MACROMOLECULES, 41(21), 7776-7779, (2008).
- Dendrimers as size selective inhibitors to protein-protein binding..
Chiba F, Hu TC, Twyman LJ & Wagstaff M, Chem Commun (36), 4351-4353, (2008).
- Porphyrin cored hyperbranched polymers as heme protein models..
Twyman LJ & Ge Y, Chem Commun (15), 1658-1660, (2006).
- Postsynthetic modification at the focal point of a hyperbranched polymer..
Gittins PJ & Twyman LJ, J Am Chem Soc, 127(6), 1646-1647, (2005).
- Total core functionalization of a hyperbranched polymer.
Gittins PJ, Alston J, Ge Y & Twyman LJ, MACROMOLECULES, 37(20), 7428-7431, (2004).
- Dendrimers as scaffolds for the synthesis of spherical porphyrin arrays.
Ballester P, Gomila RM, Hunter CA, King AS & Twyman LJ, Chem Commun, (1), 38-39, (2003).
- Formation of A2B2 supramolecular porphyrin co-polymers.
Twyman LJ & King AS, Chem Commun (Camb), (8), 910-911, (2002).
The therapeutic effectiveness of any drug is often diminished by its inability to gain access to the site of action in an appropriate dose. This is often due to the poor solubility of the drug in the body’s aqueous environment. One method of aiding solubilisation is to encapsulate the drug within the hydrophobic domains of a globular polymer. In our group we are investigating the use of dendrimers (shown in Figure 1 below), hyperbranched polymers and other polymeric systems, as encapsulation and delivery agents. Figure 1: A water-soluble dendrimers that can be used to solubilize and deliver hydrophobic drugs.
Supramolecular chemistry can be used to form discrete self assembled structures capable of performing a variety of functions. Our interest in this area has led to the development of supramolecular polymers that form a variety of structures. These include linear and dendritic polymers for use as potential light harvesting systems. We are also investigating the use of certain diblock polymers that can self assemble into spherical materials (single and bilayered) possessing microenvironments that can be exploited as catalysts for a variety of reactions.
Figure 2: Schematic of a supramolecular polymer capable of bind two reactive substrates leading to catalysis.
Model enzymes and proteins - biomimetics
Over millions of years Nature has evolved a series of molecules capable of performing a variety of important biological functions. These include catalysis, transportation and signalling. We are attempting to create much simpler synthetic analogues of these molecules. The principle aim is to engineer molecules capable of outperforming the natural systems they aspire to imitate. One example could include a catalyst that works for ALL oxidations, rather than one evolved to catalyse a single specific example. Alternatively, we could construct a catalyst that can generate non-natural isomers. As well as catalysis, related systems could be developed with important medical benefits. One such area includes our work on the development of artificial blood. Towards these aims we are exploiting a number of systems, which include self assembling polymers and globular dendritic molecules such as the oxygen binding system shown in Figure 3.
Figure 3: Porphyrin cored hyperbranched polymer that can reversibly bind oxygen, as well as catalyse as series of oxidation reactions.
Proteins bind and recognise each other using large surface areas. This recognition process is vital for a variety of biological applications. Understanding these interactions, as well as being able to inhibit them, may lead the development of new therapeutic molecules. Towards these aims we are exploiting the well-defined shape and size of certain globular macromolecules. Specifically we are using a series of dendrimers to study and inhibit protein-protein binding. Our initial results clearly indicate a simple size relationship between dendrimer and selective protein binding. That is, smaller dendrimers can interact preferentially with proteins possessing smaller binding areas, whilst larger dendrimers can interact preferentially with proteins possessing larger binding areas.
Figure 4: Screening results for dendrimer-protein binding.) The smaller G2.5 dendrimer is the strongest binder for cytochrome-c (smaller binding area), whilst the larger G3.5 dendrimer is the best inhibitor/binder for the protein chymotrypsin (larger binding area).
Undergraduate Courses Taught
- Characterisation (Year 1)
This segment introduces methods of determining the composition and structure of molecules.
- Structure Determination (Year 2)
This course enables you to determine molecular structures from spectroscopic data.
- Polymer Architectures (Year 4)
This segment introduces the student to methods for preparing polymers of various predetermined shapes and monomer repeat unit distributions.
Postgraduate Courses Taught
- Research and Presentation Skills
- Polymer Architectures
Tutorial & Workshop Support
- First Year General Tutorials.
- Second Year Organic Chemistry Tutorials
- Second Year Workshops.
- Third Year Literature Review.
- Fourth Year Workshops.
- Third Year Advanced Practical Chemistry Techniques
- Fourth Year Research Project.
- Twyman LJ & Zheng X (2016) A convenient synthesis of a porphyrin cross-linked polymer, its application as a size selective heterogeneous catalyst and a comparison with a porphyrin-cored hyperbranched polymer. Supramolecular Chemistry, 28(7-8), 617-623.
- Clixby G & Twyman L (2016) Self-replicating systems. Org. Biomol. Chem., 14(18), 4170-4184. View this article in White Rose Research Online
- Mann G, Twyman LJ & Gale PA (2016) Controlling microenvironments and modifying anion binding selectivities using core functionalised hyperbranched polymers. Chem. Commun., 52(36), 6131-6133. View this article in White Rose Research Online
- Mann G, Ellis A & Twyman LJ (2016) Modifying the Product Distribution of a Reaction within the Controlled Microenvironment of a Colloidosome. Macromolecules, 49(11), 4031-4037. View this article in White Rose Research Online
- Waris G, Siddiqi HM, Twyman LJ, Hussain R, Akhter Z & Butt MS (2013) Novel flame retardant poly(thiourea-sulfone-imide)s for high temperature applications: synthesis and characterization. TURKISH JOURNAL OF CHEMISTRY, 37(6), 946-958.
- Ellis A, Wallace M & Twyman LJ (2013) Exploiting dense shell/packing principles to invoke stereoselectivity in a reaction accelerated by a chiral dendrimer.. Chem Commun (Camb), 49(73), 8063-8065. View this article in White Rose Research Online
- Ellis A, Gooch D & Twyman LJ (2013) Bimolecular catalysis and turnover from a macromolecular host system.. J Org Chem, 78(11), 5364-5371.
- Ellis A & Twyman LJ (2013) Probing Dense Packed Limits of a Hyperbranched Polymer through Ligand Binding and Size Selective Catalysis.. Macromolecules (Washington, DC, U. S.), 46(17), 7055-7074.
- Kirkorian K, Ellis A & Twyman LJ (2012) Catalytic hyperbranched polymers as enzyme mimics; exploiting the principles of encapsulation and supramolecular chemistry.. Chem Soc Rev, 41(18), 6138-6159.
- Luo L, Shamsudin S, Twyman L, Cecchin D, Battaglia G, Hua P, Roehl H & Chen B (2012) Delivery systems for small molecule antiprion drug candidates. PRION, 6, 99-99.
- Twyman LJ, Ellis A & Gittins PJ (2012) Pyridine encapsulated hyperbranched polymers as mimetic models of haeme containing proteins, that also provide interesting and unusual porphyrin-ligand geometries.. Chem Commun (Camb), 48(1), 154-156.
- Twyman LJ, Ellis A & Gittins PJ (2011) Synthesis of Multiporphyrin Containing Hyperbranched Polymers. MACROMOLECULES, 44(16), 6365-6369.
- Chiba F, Mann G & Twyman LJ (2010) Investigating possible changes in protein structure during dendrimer-protein binding.. Org Biomol Chem, 8(22), 5056-5058.
- Zheng X, Oviedo IR & Twyman LJ (2008) Pseudo-Generational Effects Observed for a Series of Hyperbranched Polymers When Applied as Epoxidation Catalysts. MACROMOLECULES, 41(21), 7776-7779.
- Chiba F, Hu TC, Twyman LJ & Wagstaff M (2008) Dendrimers as size selective inhibitors to protein-protein binding.. Chem Commun (Camb)(36), 4351-4353.
- Lam D, Little S, Rutherford J, Twyman LJ & Zheng XW (2008) The one-step synthesis of a dendronized (HBP) polymer. MACROMOLECULES, 41(5), 1584-1586.
- Pollock N, Fowler G, Twyman LJ & McArthur SL (2007) Synthesis and characterization of immobilized PAMAM dendrons.. Chem Commun (Camb)(24), 2482-2484.
- King ASH, Martin IK & Twyman LJ (2006) Synthesis and aggregation of amine-cored polyamidoamine dendrons synthesised without invoking a protection/deprotection strategy. POLYM INT, 55(7), 798-807.
- Twyman LJ, Ge Y & Gittins PJ (2006) Synthesis of porphyrin cored hyperbranched polymers. SUPRAMOL CHEM, 18(4), 357-360.
- Twyman LJ & Ge Y (2006) Porphyrin cored hyperbranched polymers as heme protein models.. Chem Commun (Camb)(15), 1658-1660.
- Burnett J, King ASH & Twyman LJ (2006) Probing the onset of dense shell packing by measuring the aminolysis rates for a series amine terminated dendrimers. REACT FUNCT POLYM, 66(1), 187-194.
- Phillips T, Rajput C, Twyman L, Haq I & Thomas JA (2005) Water-soluble organic dppz analogues--tuning DNA binding affinities, luminescence, and photo-redox properties.. Chem Commun (Camb)(34), 4327-4329.
- Gittins PJ & Twyman LJ (2005) Postsynthetic modification at the focal point of a hyperbranched polymer.. J Am Chem Soc, 127(6), 1646-1647.
- Gittins PJ, Alston J, Ge Y & Twyman LJ (2004) Total core functionalization of a hyperbranched polymer. MACROMOLECULES, 37(20), 7428-7431.
- Twyman LJ, King ASH, Burnett J & Martin IK (2004) Synthesis of aromatic hyperbranched PAMAM polymers. TETRAHEDRON LETT, 45(2), 433-435.
- Beezer AE, King ASH, Martin IK, Mitchell JC, Twyman LJ & Wain CF (2003) Dendrimers as potential drug carriers; encapsulation of acidic hydrophobes within water soluble PAMAM derivatives. TETRAHEDRON, 59(22), 3873-3880.
- Ballester P, Gomila RM, Hunter CA, King AS & Twyman LJ (2003) Dendrimers as scaffolds for the synthesis of spherical porphyrin arrays.. Chem Commun (Camb)(1), 38-39.
- Gittins PJ & Twyman LJ (2003) Dendrimers and supramolecular chemistry. SUPRAMOL CHEM, 15(1), 5-23.
- Twyman LJ & King AS (2002) Formation of A2B2 supramolecular porphyrin co-polymers.. Chem Commun (Camb)(8), 910-911.
- Burnett JL, King ASH, Martin IK & Twyman LJ (2002) The effect of size on the rate of an aminolysis reaction using a series of amine terminated PAMAM dendrimers. TETRAHEDRON LETT, 43(13), 2431-2433.
- Twyman LJ, King AS & Martin IK (2002) Catalysis inside dendrimers.. Chem Soc Rev, 31(2), 69-82.
- Twyman LJ & King ASH (2002) Catalysis using peripherally functionalised dendrimers. J CHEM RES-S(2), 43-59.
- Twyman LJ & King ASH (2002) Formation of A2B2 supramolecular porphyrin co-polymers. Chemical Communications(8), 910-911.
- King ASH & Twyman LJ (2002) Heterogeneous and solid supported dendrimer catalysts. J CHEM SOC PERK T 1(20), 2209-2218.
- Turnbull S, Tabner BJ, El-Agnaf OMA, Twyman LJ & Allsop D (2001) New evidence that the Alzheimer beta-amyloid peptide does not spontaneously form free radicals: An ESR study using a series of spin-traps. FREE RADICAL BIO MED, 30(10), 1154-1162.
- Martin IK & Twyman LJ (2001) Acceleration of an aminolysis reaction using a PAMAM dendrimer with 64 terminal amine groups. TETRAHEDRON LETT, 42(6), 1123-1126.
- Martin IK & Twyman LJ (2001) The synthesis of unsymmetrical PAMAM dendrimers using a divergent/divergent approach. TETRAHEDRON LETT, 42(6), 1119-1121.
- Allsop D, Gibson G, Martin IK, Moore S, Turnbull S & Twyman LJ (2001) 3-p-Toluoyl-2-[4 '-(3-diethylaminopropoxy)-phenyl]-benzofuran and 2-[4 '-(3-diethylaminopropoxy)-phenyl]-benzofuran do not act as surfactants or micelles when inhibiting the aggregation of beta-amyloid peptide. BIOORG MED CHEM LETT, 11(2), 255-257.
- Allsop D, Twyman LJ, Davies Y, Moore S, York A, Swanson L & Soutar I (2001) Modulation of beta-amyloid production and fibrillization.. Biochem Soc Symp(67), 1-14.
- Twyman LJ (2000) Post synthetic modification of the hydrophobic interior of a water-soluble dendrimer. TETRAHEDRON LETT, 41(35), 6875-6878.
- Twyman LJ & Allsop D (1999) A short synthesis of the beta-amyloid (A beta) aggregation inhibitor 3-p-toluoyl-2-[4 '-(3-diethylaminopropoxy)-phenyl]-benzofuran.. TETRAHEDRON LETT, 40(52), 9383-9384.
- Gale PA, Twyman LJ, Handlin CI & Sessler JL (1999) A colourimetric calixpyrrole-4-nitrophenolate based anion sensor. CHEM COMMUN(18), 1851-1852.
- Twyman LJ & Sanders JKM (1999) A general route for the synthesis of flexible porphyrin dimers. TETRAHEDRON LETT, 40(36), 6681-6684.
- Twyman LJ, Beezer AE, Esfand R, Hardy MJ & Mitchell JC (1999) The synthesis of water soluble dendrimers, and their application as possible drug delivery systems.. TETRAHEDRON LETT, 40(9), 1743-1746.
- Twyman LJ, Beezer AE, Esfand R, Mathews BT & Mitchell JC (1998) The synthesis of chiral dendrimeric molecules based on amino acid repeat units. J CHEM RES-S(12), 758-759B.
- Marty M, Clyde-Watson Z, Twyman LJ, Nakash M & Sanders JKM (1998) Acceleration of a hetero-Diels-Alder reaction by cyclic metalloporphyrin trimers. CHEM COMMUN(20), 2265-2266.
- Clyde-Watson Z, Vidal-Ferran A, Twyman LJ, Walter CJ, McCallien DWJ, Fanni S, Bampos N, Wylie RS & Sanders JKM (1998) Reversing the stereochemistry of a Diels-Alder reaction: use of metalloporphyrin oligomers to control transition state stability. NEW J CHEM, 22(5), 493-502.
- Esfand R, Beezer AE, Mitchell JC & Twyman LJ (1996) Synthesis, complexation and pharmaceutical applications of tetra-directional cascade dendrimers. Pharmaceutical Sciences, 2(3), 157-159.
- TWYMAN L, BEEZER AE & MITCHELL JC (1994) THE SYNTHESIS OF CHIRAL DENDRITIC MOLECULES BASED ON THE REPEAT UNIT L-GLUTAMIC ACID. TETRAHEDRON LETT, 35(25), 4423-4424.
- TWYMAN LJ, BEEZER AE & MITCHELL JC (1994) AN APPROACH FOR THE RAPID SYNTHESIS OF MODERATELY SIZED DENDRITIC MACROMOLECULES. J CHEM SOC PERK T 1(4), 407-411.
- Twyman L (2009) Medical Polymers: Biomaterials for Gene Therapy, Patent Applications: A Tool for Identifying Advances in Polymer Chemistry R & D (pp. 489-493)..
Conference proceedings papers
- Chiba F, Hu TC, Twyman LJ & Wagstaff M (2010) Dendritic Macromolecules as Inhibitors to Protein-Protein Binding. MACROMOLECULAR SYMPOSIA, Vol. 287 (pp 37-41)
- Twyman LJ, Vidal-Feran A, Bampos N & Sanders JKM (1998) Stereocontrol and rate enhancement of a Diels Alder reaction within an unsymmetrical porphyrin host. MOLECULAR RECOGNITION AND INCLUSION (pp 535-538)
- BEEZER AE, MITCHELL JC, COLEGATE RM, SCALLY DJ, TWYMAN LJ & WILLSON RJ (1995) MICROCALORIMETRY IN THE SCREENING OF DISCOVERY COMPOUNDS AND IN THE INVESTIGATION OF NOVEL DRUG-DELIVERY SYSTEMS. THERMOCHIMICA ACTA, Vol. 250(2) (pp 277-283)