Lung on a Chip Development from Off-Stoichiometry Thiol-Ene Polymer

Current in vitro models have significant limitations for new respiratory disease research and rapid drug repurposing. Lung on a chip (LOAC) technology offers a potential solution to these problems. However, these devices typically are fabricated from polydimethylsiloxane (PDMS), which has small hydrophobic molecule absorption, which hinders the application of this technology in drug repurposing for respiratory diseases. Off-stoichiometry thiol–ene (OSTE) is a promising alternative material class to PDMS. Therefore, this study aimed to test OSTE as an alternative material for LOAC prototype development and compare it to PDMS. We tested OSTE material for light transmission, small molecule absorption, inhibition of enzymatic reactions, membrane particle, and fluorescent dye absorption. Next, we microfabricated LOAC devices from PDMS and OSTE, functionalized with human umbilical vein endothelial cell (HUVEC) and A549 cell lines, and analyzed them with immunofluorescence. We demonstrated that compared to PDMS, OSTE has similar absorption of membrane particles and effect on enzymatic reactions, significantly lower small molecule absorption, and lower light transmission. Consequently, the immunofluorescence of OSTE LOAC was significantly impaired by OSTE optical properties. In conclusion, OSTE is a promising material for LOAC, but optical issues should be addressed in future LOAC prototypes to benefit from the material properties.

Delay in presentation to primary care physicians is the main reason why patients with rheumatoid arthritis are seen late by rheumatologists

OBJECTIVES

To study the delay from the time of symptom onset to assessment by a Rheumatologist in patients with rheumatoid arthritis (RA) and to determine the contributions of patient and physician dependent factors to this delay.

METHODS

Data were collected from 169 consecutive patients with RA at the time of assessment by Rheumatologists working in hospitals serving an inner city population in Birmingham, UK. Dates were recorded for: (i) onset of inflammatory joint symptoms; (ii) initial assessment in primary care; and (iii) referral from primary to secondary care. (iv) initial assessment by a rheumatologist in secondary care.

RESULTS

The median delay from the onset of symptoms to a patient being assessed in secondary care was 23 weeks (IQR 12-54 weeks). The median delay before the patient was assessed in primary care was 12 weeks (IQR 4-28 weeks). For 96 patients (57%) more than half of the overall delay in assessment in secondary care was accounted for by a delay in assessment in primary care.

CONCLUSIONS

Patient dependent factors, leading to a delay in consulting primary care physicians, are the principal reasons for the delay in patients with RA being seen by Rheumatologists in our population. A considerable body of evidence demonstrates that the earlier that therapy is introduced the better the clinical outcome. Consequently it is important to understand why some patients with RA delay in seeking medical advice, in order to allow effective interventions to reduce this delay.