Methods to measure calcitonin receptor activity, up-regulated in cell stress, apoptosis and autophagy

The expression of the calcitonin receptor (CT Receptor) is widespread throughout the life cycle of mammals and in many diseases, and in these contexts the functions of the common isoforms is largely unknown. The relatively recent development of anti-CT Receptor antibodies that bind separate epitopes on the CTa Receptor and CTb Receptor isoforms has advanced our knowledge and understanding of these events. CT Receptor at the protein level is upregulated in programmed cell death including apoptosis (as described in a previous publication) and autophagy, which is discussed in our upcoming, unpublished review. Incomplete data sets are cited in this review on the upregulation of CACLR (encoding CT Receptor) mRNA, in particular the insert-positive isoform (CTb Receptor), in response to cell stress. Cell stress is induced by growth in depleted foetal bovine serum (dFBS) or without FBS, both of which induce degrees of starvation and autophagy, or dFBS plus staurosporine, which induces apoptosis. Details of the methods deployed to generate these data are described here including measurement of the upregulation of CTb Receptor mRNA with qPCR and nanopore long range sequencing. An anti-CT Receptor antibody also known as CalRexinTM, which binds an epitope in the N-terminal domain, was conjugated to either fluorophore 568, which is accumulated into apoptotic cells as previously reported, or pHrodo Red, a pH dependent fluorescent dye, which is accumulated into autophagic and apoptotic cells. These conjugates are under development to image programmed cell death. The methods for conjugation and high content imaging on the Operetta platform are described. The high fluorescence intensity at low pH of CalRexin:pHrodo Red in both autophagic and apoptotic cells suggests localisation in autophago-lysosomes and lysosomes respectively. Overall, these observations and the methods that underpin them have contributed to our understanding of the widespread expression of CT Receptor isoforms.

Tetraphenylethylene-conjugated polycation covered iron oxide nanoparticles for magnetic resonance/optical dual-mode imaging

Magnetic resonance (MR)/optical dual-mode imaging with high sensitivity and high tissue resolution have attracted many attentions in biomedical applications. To avert aggregation-caused quenching of conventional fluorescence chromophores, an aggregation-induced emission molecule tetraphenylethylene (TPE)-conjugated amphiphilic polyethylenimine (PEI) covered superparamagnetic iron oxide (Alkyl-PEI-LAC-TPE/SPIO nanocomposites) was prepared as an MR/optical dual-mode probe. Alkyl-PEI-LAC-TPE/SPIO nanocomposites exhibited good fluorescence property and presented higher T2 relaxivity (352 Fe mM−1s−1) than a commercial contrast agent Feridex (120 Fe mM−1s−1) at 1.5 T. The alkylation degree of Alkyl-PEI-LAC-TPE effects the restriction of intramolecular rotation process of TPE. Reducing alkane chain grafting ratio aggravated the stack of TPE, increasing the fluorescence lifetime of Alkyl-PEI-LAC-TPE/SPIO nanocomposites. Alkyl-PEI-LAC-TPE/SPIO nanocomposites can effectively labelled HeLa cells and resulted in high fluorescence intensity and excellent MR imaging sensitivity. As an MR/optical imaging probe, Alkyl-PEI-LAC-TPE/SPIO nanocomposites may be used in biomedical imaging for certain applications.

Using Cu2+ ions as a detection material to verify the synthesis mechanism of Au nanoclusters mediated by wool keratin and silk fibroin resilience network

Nanoclusters, with their ultrasmall sizes, have emerged as an indispensable tool in designing structural materials with a wide range of applications, but predicting the synthesis mechanism and structures remains challenging. This work delineates a synthesis mechanism of gold nanoclusters (AuNCs), which is realized by functionalizing a wool keratin (WK) and silk fibroin (SF) resilience network structure via self-assembly with controllable microstructure transformation. We synthesized such AuNCs by reducing the thiol groups of WK into WK@AuNCs and then entering the WF&SF resilience framework during the reconstruction, achieving WK@AuNCs/WK&SF with high fluorescence intensity for selective quenching of heavy metal Cu2+ ions. Further investigation indicated that α-helix and β-crystallites resulted in a soft–hard molecular segment denoted as WK&SF resilience network, which held and separated the WK@AuNCs into the nanocages. Owing to the synergism of these features, WK@AuNCs/WK&SF displayed superior fluorescence performances compared with WK@AuNCs.

A facile fabrication of conjugated fluorescent nanoparticles and micro-scale patterned encryption via high resolution ink-jet printing

Conjugated fluorescent materials are getting more and more attention in biomedical area due to its high fluorescence intensity, non-bleaching and good biocompatibility. However, conjugated fluorescent materials are still not widely...

Rational design of fluorescent barcodes for suspension array through a simple simulation strategy

The quantum dots (QDs)-encoded microbeads as optical barcode with high fluorescence intensity and fluorescence uniformity, excellent stability and dispersity are greatly important for suspension array (SA). However, the size distribution...

Preparation of fluorescent polystyrene nanoparticles mediated by a multi-functional amphiphilic iridium complex under visible light irradiation in aqueous solution

Amphiphilc iridium(iii) complex has been synthesized and served as both a photoinitiator and a surfactant for the preparation of nanoparticles with high fluorescence intensity and uniform morphology by visible light irradiation of styrene in aqueous.