Doped Carbon Quantum Dots Reinforced Hydrogels for Sustained Delivery of Molecular Cargo.

Hydrogels have emerged as important soft materials with numerous applications in fields including biomedicine, biomimetic smart materials, and electrochemistry. Because of their outstanding photo-physical properties and prolonged colloidal stability, the serendipitous findings of carbon quantum dots (CQDs) have introduced a new topic of investigation for materials scientists. CQDs confined polymeric hydrogel nanocomposites have emerged as novel materials with integrated properties of the individual constituents, resulting in vital uses in the realm of soft nanomaterials. Immobilizing CQDs within hydrogels has been shown to be a smart tactic for preventing the aggregation-caused quenching effect and also for manipulating the characteristics of hydrogels and introducing new properties. The combination of these two very different types of materials results in not only structural diversity but also significant improvements in many property aspects, leading to novel multifunctional materials. This review covers the synthesis of doped CQDs, different fabrication techniques for nanostructured materials made of CQDs and polymers, as well as their applications in sustained drug delivery. Finally, a brief overview of the present market and future perspectives are discussed.

Surface plasmon resonance based immunosensor for serological diagnosis of dengue virus infection.

Surface plasmon resonance (SPR) is a promising tool in sensor technology for biomedical applications. An SPR based immunosensor was established for label free and real time assay for the serological diagnosis of dengue virus infection employing the dengue virus antigen as the sensing element. The dengue virus antigen conjugated with bovine serum albumin is covalently immobilized on a gold sensor chip via activated self-assembled monolayer (SAM) of 11-mercaptoundecanoic acid, by amide coupling. Surface morphology of the biosensor was recorded using atomic force microscopy. Presence of dengue virus specific IgM antibodies in dengue positive sera was monitored by increase in resonance angle in direct immunoassay, whereas the principle of indirect competitive inhibition immunoassay was used to detect presence of dengue virus for early detection of the onset of dengue viral infection in clinical diagnostics. Results were compared with those obtained by MAC-ELISA. The regeneration was achieved by pepsin solution in glycin-HCl buffer (pH 2.2) and sensor surface displayed a high level of stability during repeated immunoreaction cycles. The proposed biosensor being simple, effective and based on utilization of natural antigen-antibody affinity, our study presents an encouraging scope for development of biosensors for diagnosis of dengue and dengue hemorrhagic fever (DHF) which continues to be a major health problem in the tropical and subtropical regions of world.

Rapid culture of Mycobacterium tuberculosis on blood agar in resource limited setting.

INTRODUCTION: Sputum samples collected at a teaching hospital of Jodhpur, were processed at Desert Medicine Research Centre, Jodhpur. The aim was to assess the time required for primary isolation of Mycobacterium tuberculosis (Mtb) on locally prepared sheep blood agar slants as compared to Löwenstein-Jensen (LJ) medium. METHODS: Equal volume of homogeneous inoculums prepared from smear positive sputum samples processed with the N-acetyl L-cysteine sodium hydroxide method was inoculated on slants of locally prepared 7% sheep blood agar and LJ medium. These were incubated at 37 degrees C and were observed daily for growth visible with naked eyes. Time taken in growth of Mtb was compared. RESULTS: LJ medium recovered 68 of 70 isolates (97.1%) as compared to 66 by blood agar (94.2%). The difference was not significant. Mean time to detect macroscopic colonies of Mtb on blood agar was 13.6 + or - 5.2 days as compared to 20.4 + or - 5.1 days on LJ medium (p=0.0001). More colonies were observed on blood agar than on LJ medium. CONCLUSION: Blood agar slants may be a good substitute of LJ medium for rapid detection of Mtb from sputum in resource limited settings. It may save about one third of the time.