BackgroundBiosurfactants are amphipathic molecules of microbial origin that reduce surface and interfacial tension at gas–liquid–solid interfaces. Earlier, the biosurfactant was isolated and characterized in our laboratory from Candida parapsilosis. The property of the biosurfactant is further explored in this study by using quantum dots (QDs) as nanocarrier.Materials and methodsGraphene quantum dots (GQDs) were synthesized by bottom-up approach through pyrolysis of citric acid. GQDs were conjugated with both biosurfactant and folic acid (FA) using carbodiimide chemistry. The prepared GQD bioconjugate was studied for diagnostic and therapeutic effects against cancer cells.Results and discussionPhotoluminescence quantum yield (QY) of plain GQDs was measured as 12.8%. QY for biosurfactant conjugated GQDs and FA-biosurfactant conjugated GQDs was measured as 10.4% and 9.02%, respectively, and it was sufficient for targeting cancer cells. MTT assay showed that more than 90% of cells remained viable at concentration of 1 mg/mL, hence GQDs seemed to be non-toxic to cells. Biosurfactant conjugated GQDs caused 50% reduction in cellular viability within 24 hours. FA conjugation further increased the specificity of bioconjugated GQDs toward tumor cells, which is clearly evident from the drug internalization studies using confocal laser scanning microscopy. A higher amount of drug uptake was observed when bioconjugated GQDs were decorated with FA.ConclusionThe ability of GQD bioconjugate could be used as a theranostic tool for cancer. It is foreseen that in near future cancer can be detected and/or treated at an early stage by utilizing biosurfactant conjugated GQDs. Therefore, the proposed study would provide a stepping stone to improve the life of cancer patients.

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Congenital nasolacrimal duct obstruction (CNLDO) remains the most common cause of epiphora in infants. This retrospective study compares the success rate of nasal endoscopic-assisted probing between younger (3 years and below) and older (above 3 years) children with membranous CNLDO and its correlation with the thickness of the membrane at the valve of Hasner. Case records of a total of 38 eyes in 34 children with membranous CNLDO who underwent endoscopic nasolacrimal duct probing and irrigation under general anesthesia were analyzed. The cases were divided into two groups, Group Y (20 cases of children 3 years and below) and Group O (18 cases of children above 3 years). The success of the procedure was defined as complete remission of symptoms and a clinical examination of eye to rule out the presence for discharge or watering after three months of the procedure. Overall, 35 cases (92.1%) were successfully treated with a success rate of 95% in Group Y and 88.9% in Group O. The mid-P exact test p value for the success rate between the two cohorts was not statistically significant (p = 0.59). The thick membrane was observed in 50% cases in Group Y and 33.33% cases in Group O (p = 0.34). There is no age related decline in the overall success rate for nasal endoscopic-assisted probing and irrigation in cases of membranous CNLDO. The thickness of the membrane may be a factor for failed blind probing, but it has no correlation with the success rate if probing is done under endoscopic guidance.