Lionel R. Milgrom

THIRD-ORDER OPTICAL NON-LINEARITY IN ZN(II) COMPLEXES OF 5,10,15,20-TETRAARYLETHYNYL-SUBSTITUTED PORPHYRINS

Abstract Third-order optical nonlinearity χ(3) of complexes in 5,10,15,20-tetraarylethynyl-substituted porphyrins has been measured using the Z-scan technique. The real and imaginary parts of χ(3) were measured at three different wavelengths and found to be in the region 1.05 × 10−12 esu and 5.2 × 10−12 esu, respectively. Experimental characterisation shows a saturation absorption at wavelengths close to resonance and reverse saturation absorption at off-resonance wavelengths.

Targeted photodynamic therapy with multiply-loaded recombinant antibody fragments

Current photodynamic therapy (PDT) of cancer is limited by inefficiencies involved in specifically targeting photosensitizers to tumors. Although antibodies are being explored as targeting vehicles, they present significant challenges, particularly in terms of pharmacokinetics and drug‐coupling. We describe here a novel and effective system to covalently attach multiple photosensitizer molecules (both preclinical, pyropheophorbide‐a and clinically approved, verteporfin photosensitizers) to single‐chain Fvs. Further, we demonstrate that not only do the resulting photoimmunoconjugates retain photophysical functionality, they are more potent than either free photosensitizer, effectively killing tumor cells in vitro and in vivo. For example, treatment of human breast cancer xenografts with a photoimmunoconjugate comprising an anti‐HER‐2 scFv linked to 8–10 molecules of pyropheophorbide‐a leads to significant tumor regression. These results give an insight into the important features that make scFvs good carriers for PDT drugs and provide proof of concept of our unique approach to targeted photodynamic therapy (tPDT). This promises to significantly improve on current photodynamic therapies for the treatment of cancer.

A light-harvesting array of synthetic porphyrins

Abstract An array of five porphyrin molecules has been synthesized and used as a simple model of the light-harvesting complex found in natural photosynthesis. Efficient Forster energy transfer occurs from antenna zinc porphyrins to a central free-base porphyrin molecule. This central porphyrin retains long-lived singlet and triplet excited states that can be quenched by diffusional processes, Both electron and energy transfer quenching reactions can be observed.

Patient–practitioner–remedy (PPR) entanglement. Part 3. Refining the quantum metaphor for homeopathy

The notion of patient-practitioner-remedy (PPR) entanglement, previously proposed for homeopathy, is refined by adapting concepts derived from Greenberger, Horne, and Zeilingers treatment of three-particle entanglement (GHZ states), and a generalised version of quantum theory, called weak quantum theory (WQT). These suggest that for maximum PPR entanglement during the therapeutic encounter, the practitioners awareness needs to be directed inward as well as outward toward the patient, and that health and disease are mirror images of each other, similar to and represented by, the relationship of complex numbers to their complex conjugates.

Tuning the red emission of a soluble poly(p-phenylene vinylene) upon grafting of porphyrin side groups

Abstract We investigate the energy transfer in donor–acceptor systems with reduced spectral overlap to assess the scope for emission colour tunability and the influence of spectral overlap on the luminescence efficiency. We use copolymers derived from poly [2-methoxy, 5- (2′-ethylhexyloxy)-1,4-phenylene vinylene], randomly attaching tetraphenylporphyrin side-chain units. We find that both photoluminescence and electroluminescence are widely tunable via control of the porphyrin concentration, with relatively efficient energy transfer in spite of limited spectral overlap. We also find that luminescence efficiency is controlled by concentration quenching of the tetraphenylporphyrin, with only a minor effect of spectral overlap. This has implications for electrophosphorescent devices.

Fluorescence of covalently bound zinc porphyrin—viologen complexes

Abstract A series of porphyrins covalently bound to a single methyl viologen moiety has been synthesised. Fluorescence from the porphyrin is quenched relative to the parent porphyrin; the actual yield depends markedly upon the site of attachment and the length of the chain separating the two reactants. Increasing the number of viologens attached to the porphyrin ring and using non-methylated viologen can increase the fluorescence quenching efficiency. In no case was it possible to detect long-lived redox ion products originating from the fluorescence quencing process.

5,10,15,20-tetrakis(N-protected-imidazol-2-yl)porphyrins

Abstract It is shown that examples of the title porphyrins can be prepared from suitably N-protected imidazole-2-carboxaldehydes and pyrrole in refluxing propionic acid: subsequent deprotection, affords a synthetic route to 5,10,15,20-tetrakis(substituted-imidazol-2-yl)porphyrins (TIPs).

Journeys in the country of the blind: entanglement theory and the effects of blinding on trials of homeopathy and homeopathic provings.

The idea of quantum entanglement is borrowed from physics and developed into an algebraic argument to explain how double-blinding randomized controlled trials could lead to failure to provide unequivocal evidence for the efficacy of homeopathy, and inability to distinguish proving and placebo groups in homeopathic pathogenic trials. By analogy with the famous double-slit experiment of quantum physics, and more modern notions of quantum information processing, these failings are understood as blinding causing information loss resulting from a kind of quantum superposition between the remedy and placebo.

5,10,15,20-meso-Tetraarylethynylporphyrins.

Abstract examples of the title porphyrins are prepared via Lindsey s method from arylpropynals and pyrrole, and their spectroscopic properties reported. They are green with uv/visible spectra more extensively red-shifted than previously observed for alkynyl-substituted porphyrins.

TRANS-DISUBSTITUTED MESO-TETRAETHYNYLPORPHYRINS

Abstract examples of the title porphyrins were prepared (by coupling acetylenic dipyrromethanes with substituted propynals), and their spectroscopic properties reported.