Comparison of semiconducting polymer dots and semiconductor quantum dots for smartphone-based fluorescence assays

Fluorescent nanoparticles have transformative potential for smartphone-based point-of-need diagnostics because an optimal material can reduce the technical burden to meet assay performance requirements. Semiconductor quantum dots (QDs) are a now well-established example of such a material. Semiconducting polymer dots (Pdots) and conjugated-polymer nanoparticles (CPNs) are emerging materials that bring the advantages of being bright, easy to synthesize, and metal-free when compared with QDs, but they frequently present the trade-off of spectrally broad emission and less well-defined surface chemistry. Here, we compare these two classes of nanoparticles in the context of a “bare bones” device that uses a smartphone for all-in-one excitation and imaging of fluorescence. The greater per-particle brightness of Pdots provides orders of magnitude better imaging sensitivity versus QDs, and this advantage translates to a model lateral flow assay. Our data suggest that Pdots will support multicolor imaging on a smartphone in an optimized assay, although QDs are likely superior for this purpose. These pros and cons lead to discussion of how physicochemical differences between QDs and Pdots may influence assay performance beyond differences in optical properties. Overall, Pdots have great potential for enabling smartphone-based fluorescence assays with high sensitivity and low detection limits

Towards the development of robust semiconducting polymer dots for applications in bioanalysis and imaging

The full abstract for this thesis is available in the body of the thesis, and will be available when the embargo expires.Science, Faculty ofChemistry, Department ofGraduat

Analysis of patenting trends of antifungal drugs in the product patent regime in India

The present study attempts to analyze the patenting activity of antifungal drugs in the pre and post TRIPS period in India. There is a general increase in patent filing in antifungals both by Indian as well as by multinational companies, with greater filing by the latter in the post-TRIPS era. The major filings in the transition and post-TRIPS period have been due to increased product than process patent filings, wherein 75% of the total patent applications in this sector is directed towards product patents and remaining 25% is directed towards process patents. It is observed that Indian academic institutions have been more active than foreign institutions with respect to patent filings in this field.Antifungal drugs Indian pharmaceutical industry Patents Anti-infective sector TRIPS

Photoluminescent nanoparticles for chemical and biological analysis and imaging

Research related to the development and application of luminescent nanoparticles (LNPs) for chemical and biological analysis and imaging is flourishing. Novel materials and new applications continue to be reported after two decades of research. This review provides a comprehensive and heuristic overview of this field. It is targeted to both newcomers and experts who are interested in a critical assessment of LNP materials, their properties, strengths and weaknesses, and prospective applications. Numerous LNP materials are cataloged by fundamental descriptions of their chemical identities and physical morphology, quantitative photoluminescence (PL) properties, PL mechanisms, and surface chemistry. These materials include various semiconductor quantum dots, carbon nanotubes, graphene derivatives, carbon dots, nanodiamonds, luminescent metal nanoclusters, lanthanide-doped upconversion nanoparticles and downshifting nanoparticles, triplet–triplet annihilation nanoparticles, persistent-luminescence nanoparticles, conjugated polymer nanoparticles and semiconducting polymer dots, multi-nanoparticle assemblies, and doped and labeled nanoparticles, including but not limited to those based on polymers and silica. As an exercise in the critical assessment of LNP properties, these materials are ranked by several application-related functional criteria. Additional sections highlight recent examples of advances in chemical and biological analysis, point-of-care diagnostics, and cellular, tissue, and in vivo imaging and theranostics. These examples are drawn from the recent literature and organized by both LNP material and the particular properties that are leveraged to an advantage. Finally, a perspective on what comes next for the field is offered

Prenatal Sex Selection and Girls’ Well‐Being: Evidence from India

In this paper, we study the impact of prenatal sex selection on the well-being of girls by analyzing changes in children's nutritional status and mortality during the years since the diffusion of prenatal sex determination technologies in India. We further examine various channels through which prenatal sex selection might affect girls' outcomes. Using repeated cross-sections from a rich survey dataset, we show that high sex ratios at birth reflect the practice of sex selective abortion. We then exploit the large regional and time variations in the incidence of prenatal sex selection to analyze whether changes in girls' outcomes relative to boys within states and over time are associated with changes in sex ratios at birth. We find that an increase in the practice of prenatal sex selection appears to be associated with a reduction in the incidence of malnutrition among girls. The negative association is stronger for girls born in rural households and at higher birth parities. An examination of the various mechanisms linking between prenatal sex selection and children outcomes suggests that prenatal sex selection does not lead to a selection of girls into better endowed families, but there is some evidence of a larger reduction in family size for girls relative to boys. We also find an increase in girls' breastfeeding duration suggesting an improvement in parental care and treatment. On the other hand, prenatal sex selection does not appear to be associated with a reduction in excess female child mortality, or a reduction in son preference