Selectivity and specificity: pros and cons in sensing

Sensing using specific and selective receptors provides two very different but complementary strategies. This Sensor Issues article will discuss the merits and challenges of specific sensors, and selective sensors based on synthetic arrays. We will examine where each has been successfully applied to a sensing challenge, and then look at how a combined approach could take elements of both to provide new sensor platforms

Synthesis and Characterization of Naphthalenediimide-Functionalized Flavin Derivatives

Two acceptor–acceptor dyads have been synthesized featuring a flavin moiety and a naphthalenediimide (NDI) unit. The NDI unit is linked to the flavin through a short spacer group via either the N(3) or N(10) positions of the flavin. We have investigated the UV-Vis and redox properties of these multi-electron accepting systems which indicate that these materials display the collective properties of their component systems. Fluorescence spectroscopy measurements have revealed that their emission properties are dominated by the flavin unit

Array-Based Detection of Persistent Organic Pollutants via Cyclodextrin Promoted Energy Transfer

We report herein the selective array-based detection of 30 persistent organic pollutants via cyclodextrin-promoted energy transfer. The use of three fluorophores enabled the development of an array that classified 30 analytes with 100% accuracy and identified unknown analytes with 96% accuracy, as well as identifying 92% of analytes in urine

Biochemical and biomechanical drivers of cancer cell metastasis, drug response and nanomedicine

Metastasis, drug resistance and recurrence in cancer are regulated by the tumor microenvironment. This review describes recent advances in understanding how cancel cells respond to extracellular environmental cues via integrins, how to build engineered microenvironments to study these interactions in vitro and how nanomaterials can be used to detect and target tumor microenvironments

Correction: Zainalabdeen, N., et al., Synthesis and Characterization of Naphthalenediimide-Functionalized Flavin Derivatives. Int. J. Mol. Sci. 2013, 14, 7468–7479.

Note: In lieu of an abstract, this is an excerpt from the first page. In the original version of the manuscript [1] some of the analytical data for compounds 1 and 2 were incorrect. The correct NMR data are presented below. The authors apologize for any inconvenience this may have caused to the readers of this journal. Compound 1: 1H NMR (500 MHz, DMSO-d6) δ 11.64 (s, 1H), 8.73 (s, 4H), 8.57 (d, J = 1.4 Hz, 1H), 8.16 (dd, J = 8.9, 1.4 Hz, 1H), 7.81 (d, J = 8.5 Hz, 2H), 7.64 (d, J = 8.5 Hz, 2H), 6.99 (d, J = 8.9 Hz, 1H), 4.08 (t, J = 7.0 Hz, 2H), 3.28 (m, 2H), 1.69 (quin, J = 7.0 Hz, 2H), 1.33 (m, 8H), 0.86 (t, J = 6.8 Hz, 3H). 13C NMR (125 MHz, DMSO-d6) δ 162.6 (2xC = 0), 162.3 (2xC = 0), 158.9, 155.1, 151.9, 140.8, 136.6, 136.1, 135.2, 133.7, 131.1 (2xC), 130.5 (4xC), 130.3 (q, J = 4 Hz), 128.6 (q, J = 4 Hz), 128.4 (2xC), 126.6, 126.5 (2xC), 126.4 (q, J = 31 Hz), 126.3 (2xC), 126.2, 123.2 (q, J = 271 Hz), 117.8, 39.9, 30.9, 28.5, 28.3, 27.1, 26.3, 21.9, 13.7. Compound 2: 1H NMR (500 MHz, CDCl3) δ 8.77 (s, 4H), 8.58 (d, J = 1.4 Hz, 1H), 8.03 (dd, J = 9.1, 1.4 Hz, 1H), 7.87 (d, J = 8.4 Hz, 2H), 7.76 (d, J = 9.1 Hz, 1H), 7.27 (d, J = 8.4 Hz, 2H), 5.37 (s, 2H), 4.61 (br s, 2H), 4.19 (t, 2H), 2.47 (sept, J = 6.7 Hz, 1H), 1.74 (m, 2H), 1.47–1.23 (m, 10H), 1.07 (d, J = 6.7 Hz, 6H), 0.87 (t, J = 6.9 Hz, 3H). 13C NMR (125 MHz, CDCl3) δ 163.1 (2xC = O), 162.9 (2xC = O), 159.0, 155.0, 149.9, 138.9, 137.5, 135.2, 134.9, 134.3, 131.7 (2xC), 131.5 (2xC), 131.2 (q, J = 4 Hz), 131.1 (4xC), 130.9 (q, J = 4 Hz), 128.6 (2xC), 127.1 (2xC), 127.0 (q, J = 28 Hz), 126.8 (2xC), 123.1 (q, J = 270 Hz), 116.9, 51.5, 44.9, 41.2, 31.9, 29.4, 29.3, 28.2, 27.6, 27.2, 22.8, 20.2 (2xC), 14.2

Microwave-Induced Chemotoxicity of Polydopamine-Coated Magnetic Nanocubes

Polydopamine-coated FeCo nanocubes (PDFCs) were successfully synthesized and tested under microwave irradiation of 2.45 GHz frequency and 0.86 W/cm2 power. These particles were found to be non-toxic in the absence of irradiation, but gained significant toxicity upon irradiation. Interestingly, no increase in relative heating rate was observed when the PDFCs were irradiated in solution, eliminating nanoparticle (NP)-induced thermal ablation as the source of toxicity. Based on these studies, we propose that microwave-induced redox processes generate the observed toxicity

Biomacromolecular stereostructure mediates mode hybridization in chiral plasmonic nanostructures

The refractive index sensitivity of plasmonic fields has been exploited for over 20 years in analytical technologies. While this sensitivity can be used to achieve attomole detection levels, they are in essence binary measurements that sense the presence/absence of a predetermined analyte. Using plasmonic fields, not to sense effective refractive indices but to provide more “granular” information about the structural characteristics of a medium, provides a more information rich output, which affords opportunities to create new powerful and flexible sensing technologies not limited by the need to synthesize chemical recognition elements. Here we report a new plasmonic phenomenon that is sensitive to the biomacromolecular structure without relying on measuring effective refractive indices. Chiral biomaterials mediate the hybridization of electric and magnetic modes of a chiral solid-inverse plasmonic structure, resulting in a measurable change in both reflectivity and chiroptical properties. The phenomenon originates from the electric-dipole–magnetic-dipole response of the biomaterial and is hence sensitive to biomacromolecular secondary structure providing unique fingerprints of α-helical, β-sheet, and disordered motifs. The phenomenon can be observed for subchiral plasmonic fields (i.e., fields with a lower chiral asymmetry than circularly polarized light) hence lifting constraints to engineer structures that produce fields with enhanced chirality, thus providing greater flexibility in nanostructure design. To demonstrate the efficacy of the phenomenon, we have detected and characterized picogram quantities of simple model helical biopolymers and more complex real proteins

Triple-Negative Breast Cancer: A Review of Conventional and Advanced Therapeutic Strategies

Triple-negative breast cancer (TNBC) cells are deficient in estrogen, progesterone and ERBB2 receptor expression, presenting a particularly challenging therapeutic target due to their highly invasive nature and relatively low response to therapeutics. There is an absence of specific treatment strategies for this tumor subgroup, and hence TNBC is managed with conventional therapeutics, often leading to systemic relapse. In terms of histology and transcription profile these cancers have similarities to BRCA-1-linked breast cancers, and it is hypothesized that BRCA1 pathway is non-functional in this type of breast cancer. In this review article, we discuss the different receptors expressed by TNBC as well as the diversity of different signaling pathways targeted by TNBC therapeutics, for example, Notch, Hedgehog, Wnt/b-Catenin as well as TGF-beta signaling pathways. Additionally, many epidermal growth factor receptor (EGFR), poly (ADP-ribose) polymerase (PARP) and mammalian target of rapamycin (mTOR) inhibitors effectively inhibit the TNBCs, but they face challenges of either resistance to drugs or relapse. The resistance of TNBC to conventional therapeutic agents has helped in the advancement of advanced TNBC therapeutic approaches including hyperthermia, photodynamic therapy, as well as nanomedicine-based targeted therapeutics of drugs, miRNA, siRNA, and aptamers, which will also be discussed. Artificial intelligence is another tool that is presented to enhance the diagnosis of TNBC

Chiral plasmonic fields probe structural order of biointerfaces

The structural order of biopolymers, such as proteins, at interfaces defines the physical and chemical interactions of biological systems with their surroundings and is hence a critical parameter in a range of biological problems. Known spectroscopic methods for routine rapid monitoring of structural order in biolayers are generally only applied to model single-component systems that possess a spectral fingerprint which is highly sensitive to orientation. This spectroscopic behavior is not a generic property and may require the addition of a label. Importantly, such techniques cannot readily be applied to real multicomponent biolayers, have ill-defined or unknown compositions, and have complex spectroscopic signatures with many overlapping bands. Here, we demonstrate the sensitivity of plasmonic fields with enhanced chirality, a property referred to as superchirality, to global orientational order within both simple model and “real” complex protein layers. The sensitivity to structural order is derived from the capability of superchiral fields to detect the anisotropic nature of electric dipole–magnetic dipole response of the layer; this is validated by numerical simulations. As a model study, the evolution of orientational order with increasing surface density in layers of the antibody immunoglobulin G was monitored. As an exemplar of greater complexity, superchiral fields are demonstrated, without knowledge of exact composition, to be able to monitor how qualitative changes in composition alter the structural order of protein layers formed from blood serum, thereby establishing the efficacy of the phenomenon as a tool for studying complex biological interfaces

Solvatochromic probes for detecting hydrogen-bond-donating solvents

Hydrogen bonding heavily influences conformations, rate of reactions, and chemical equilibria. The development of a method to monitor hydrogen bonding interactions independent of polarity is challenging as both are linked. We have developed two solvatochromic dyes that detect hydrogen-bond-donating solvents. The unique solvatochromism of the triazine architecture has allowed the development of probes that monitor hydrogen-bond-donating species including water