PPS Blog

New tunable light-emitting oligomer

13 May 2011

In this article Jagadeesh B. Bodapati and Huriye Icil from the Eastern Mediterranean University in Turkey report on the synthesis of an oligomer showing concentration and solvent dependent fluorescent colour tunability, which has potential in various photo-sensing applications.

The oligomer was synthesised in a one-step condensation reaction and contains flexible hydrophilic hexa(ethylene glycol) and hydrophobic naphthalene-bisimide chromophores. It showed strong solvent-dependent photophysical and electrochemical properties, including a large shift of excimer emission maximum reflecting self-assembly mediated through hydrogen bonding and π-stacking interactions.

Interested in knowing more? Read the full article here. Free until 13th June.

A new tunable light-emitting and π-stacked hexa-ethyleneglycol naphthalene-bisimide oligomer: synthesis, photophysics and electrochemical properties
Jagadeesh B. Bodapati and Huriye Icil
Photochem. Photobiol. Sci., 2011, Advance Article
DOI: 10.1039/C1PP05019B, Paper

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Themed Issue: Drug delivery technologies and immunological aspects of photodynamic therapy

06 May 2011

By Anna Simpson, Executive Editor.

Issue 5 of Photochemical and Photobiological Sciences has now been published online and is a themed issue on Drug delivery technologies and immunological aspects of photodynamic therapy.

The guest editors Kristian Berg (Oslo University Hospital), Jakub Golab (Medical University of Warsaw), Mladen Korbelik (British Columbia Cancer Agency) and David Russell (University of East Anglia), introduce the topic in their editorial which you can read here.

The cover features an article from Gang Zheng and co-workers in Canada and China entitled ‘Cytosolic delivery of LDL nanoparticle cargo using photochemical internalization’. In this study endolysosmal disruption using PCI was attempted on surface-loaded, protein-loaded and core-loaded cargo incorporated into LDL nanoparticles. You can read the full article here.

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Structural Evolution of Luciferase

20 Apr 2011

By Anna Simpson, Executive Editor.

In this pioneering study a team from Brazil and China have used site-directed mutagenesis of protoluciferase to better understand the structural evolution of luciferase activity.

A major mystery in bioluminescence is how it arose during evolution. It is known that beetle luciferases evolved from AMP-CoA-ligases, also known as protoluciferases, which catalyse the activation of carboxylic acids. In this study a luciferase-like AMP-CoA-ligase from Zophobas morio mealworm was taken as a protoluciferase model. Site directed mutagenesis was used to replace residues in the carboxylic binding site with the respective ones conserved in beetle luciferases.

The team found that one substitution (I327T) improved the luminescence activity indicating the importance of the β-hairpin motif which it is contained in for bioluminescence activity in beetle luciferases. It also indicates a possible route for the evolution this activity.

Interested in knowing more? Read the full article for free until May 20^th!

Structural evolution of luciferase activity in Zophobas mealworm AMP/CoA-ligase (protoluciferase) through site-directed mutagenesis of the luciferin binding site
R. A. Prado, J. A. Barbosa, Y. Ohmiya and V. R. Viviani
Photochem. Photobiol. Sci., 2011, Advance Article
DOI: 10.1039/C0PP00392A

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Cover story: The fine tuning of flowering time

01 Apr 2011

By Kathleen Too, Deputy Editor.

The cover photograph was taken by Cristina Poetto in Tafí del Valle, Argentina

Jorge J. Casal and co-workers explain why some long-day plants flower earlier when daylight hours are long (like in the spring or summer) while short-day plants flower earlier when daylight hours are short (for example in the autumn or winter). These different classes of photoperiodic response can be observed among different species and in some cases within a given species.

The Argentinian team led by Casal explored the mechanism controlling levels of proteins such as Flowering Locus T (FT) , Constans (CO) and others. They conclude that “the existence of multiple pathways with contrasting photoperiodic effects on flowering time within a single species, suggests that the photoperiodic behaviour of plants results, at least in part, from the net balance of positive and negative effects of photoperiodic conditions on multiple regulatory pathways”.

Read more about this manuscript here:
Balancing forces in the photoperiodic control of flowering, Sabrina E. Sanchez, Juan I. Cagnola, María Crepy, Marcelo J. Yanovsky and Jorge J. Casal, Photochem. Photobiol. Sci., 2011, 10, 451-460, DOI: 10.1039/C0PP00252F

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Themed issue: Solar chemistry & photocatalysis – environmental applications

10 Mar 2011

By Michael Townsend, Publishing Editor.

Issue 3 of PPS has been published online. This issue is a collection of papers presented at the 6th European meeting on Solar Chemistry and Photocatalysis: Environmental Applications (SPEA6), which was held in Prague, Czech Republic, in June 2010, and was organized by Josef Krysa and Jaromýr Jirkovsky. The issue is guest edited by Josef Krysa and Sixto Malato.

The cover of the issue features a paper by Rudolf Słota and coworkers on photocatalysis by TiO₂ composites with phthalocyanines and porphyrins. They show the importance of matching the sensitizer to the nature of the TiO₂ (micro- or nanocrystalline).

Also in the issue, Maria Antoniadou and Panagiotis Lianos have made a photoactivated fuel cell that uses organic waste to produce electricity. They tested the system on a number of polyols, but suggest that almost any organic substance can be used. The cell uses UVA light, and can run on the UV component of sunlight.

These papers and the rest of the issue can be read online now.

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Laser treatment for late-stage cancer

08 Mar 2011

By Kathleen Too, Deputy Editor.

Scientists from China, the US and Peru claim to have successfully treated late-stage breast cancer patients using laser immunotherapy to stimulate patients’ own immune systems to fight the cancer.

Wei Chen from the University of Central Oklahoma and colleagues used laser immunotherapy to treat 10 patients from Peru, aged 36 to 85, considered to be out of other treatment options. Tumour metastasis – when the cancer spreads from one part of the body to another – is the major cause of treatment failure for cancer patients, says Chen. Initial results of this pre-clinical study have shown that it can reduce primary tumours and metastases with fewer side effects than traditional treatments.

The team injected a light-absorbing agent into the patient’s body and directed non-invasive laser radiation onto the area – the interaction between the two heats up the target tissue. This doesn’t result in complete destruction of the tumour cells, but it can cause the cells to swell and break down, which stimulates an immune response. Then they injected an immunoadjuvant into the centre of the tumour, which enhances the immune response. They studied the effects over a year using biopsies and medical imaging.

Laser irradiation can be used to stimulate patients' own immune systems to fight cancer

They found that the laser therapy ‘induced positive responses in most patients, including reduction, and in some cases eradication, of treated primary tumours as well as reduction, again in some cases eradication, of untreated metastatic tumours,’ says Chen. ‘So far, none of the patients who stayed in our trials has died,’ he adds.

The therapy is nontoxic, tolerated well by patients and no harsh side effects were observed, apart from local reactions such as pain, redness, swelling and skin blistering caused by the heat of the laser, but these healed quickly.

Mladen Korbelik from the British Columbia Cancer Agency and the University of British Columbia, both in Vancouver, Canada, thinks that the work is ‘highly innovative and potentially groundbreaking’. However, he says that the mechanism is yet to be fully elucidated. He suggests that ‘it appears to involve a presentation of multiple tumour antigens in the fashion of an autologous cancer vaccine [vaccines that contain inactivated tumour cells to elicit an immune response]’. Tailoring the antitumour action to individual patients, similar to photodynamic therapy-generated vaccines, elicits a strong immune response directed specifically at the patient’s tumours, he adds.

Chen plans to apply to the US Food and Drug Administration for approval to conduct human trials in the US. ‘We plan to develop laser immunotherapy into a mainstream, worldwide therapy,’ he says, adding that he hopes to use it for other cancer types such as melanoma, lung, prostrate and colorectal cancers. ‘Another goal is to introduce the therapy to developing countries, since the therapy only requires simple facilities and equipment,’ he concludes.

Taken from a Chemistry world story written by Elinor Richards on the 4th March 2011

Top ten most accessed articles in April

New tunable light-emitting oligomer

Themed Issue: Drug delivery technologies and immunological aspects of photodynamic therapy

Top ten most accessed articles in March

Structural Evolution of Luciferase

Cover story: The fine tuning of flowering time

Top ten most accessed articles in February

Top ten most accessed articles in January

Themed issue: Solar chemistry & photocatalysis – environmental applications

Laser treatment for late-stage cancer

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