Development of Multifunctional Biopolymeric Auto-Fluorescent Micro- and Nanogels as a Platform for Biomedical Applications.

The emerging field of theranostics for advanced healthcare has raised the demand for effective and safe delivery systems consisting of therapeutics and diagnostics agents in a single monarchy. This requires the development of multi-functional bio-polymeric systems for efficient image-guided therapeutics. This study reports the development of size-controlled (micro-to-nano) auto-fluorescent biopolymeric hydrogel particles of chitosan and hydroxyethyl cellulose (HEC) synthesized using water-in-oil emulsion polymerization technique. Sustainable resource linseed oil-based polyol is introduced as an element of hydrophobicity with an aim to facilitate their ability to traverse the blood-brain barrier (BBB). These nanogels are demonstrated to have salient features such as biocompatibility, stability, high cellular uptake by a variety of host cells, and ability to transmigrate across an in vitro BBB model. Interestingly, these unique nanogel particles exhibited auto-fluorescence at a wide range of wavelengths 450-780 nm on excitation at 405 nm whereas excitation at 710 nm gives emission at 810 nm. In conclusion, this study proposes the developed bio-polymeric fluorescent micro- and nano- gels as a potential theranostic tool for central nervous system (CNS) drug delivery and image-guided therapy.

Characterization of Nanodiamond-based anti-HIV drug Delivery to the Brain.

Human Immunodeficiency Virus Type 1 (HIV-1) remains one of the leading causes of death worldwide. Present combination antiretroviral therapy has substantially improved HIV-1 related pathology. However, delivery of therapeutic agents to the HIV reservoir organ like Central nervous system (CNS) remains a major challenge primarily due to the ineffective transmigration of drugs through Blood Brain Barrier (BBB). The recent advent of nanomedicine-based drug delivery has stimulated the development of innovative systems for drug delivery. In this regard, particular focus has been given to nanodiamond due to its natural biocompatibility and non-toxic nature-making it a more efficient drug carrier than other carbon-based materials. Considering its potential and importance, we have characterized unmodified and surface-modified (-COOH and -NH2) nanodiamond for its capacity to load the anti-HIV-1 drug efavirenz and cytotoxicity, in vitro. Overall, our study has established that unmodified nanodiamond conjugated drug formulation has significantly higher drug loading capacity than surface-modified nanodiamond with minimum toxicity. Further, this nanodrug formulation was characterized by its drug dissolution profile, transmigration through the BBB, and its therapeutic efficacy. The present biological characterizations provide a foundation for further study of in-vivo pharmacokinetics and pharmacodynamics of nanodiamond-based anti-HIV drugs.

The effect of electrochemical pretreatment on the sensing performance of single walled carbon nanotubes.

In this paper, we report the effect of subsequent electrochemical anodization and cathodization subjected to single walled carbon nanotubes. The performance of the single walled carbon nanotubes before and after activation was evaluated electrochemically using different charged redox probes and a biologically important neurotransmitter-dopamine. Further, for the first time, the surface of single walled carbon nanotubes before and after electrochemical activation was also evaluated using Raman Spectroscopy. Electrochemical results indicated that the pretreatment method employed in this work greatly enhanced the performance of single walled carbon nanotubes towards the detection of the model analytes employed. The observed enhancement in the signal is attributed to the rupture of the basal plane found on the end caps of carbon nanotubes giving rise to a larger density of edge-plane like defects on the single walled carbon nanotubes surface. A detection limit of 10 nM (based on three times the standard deviation of the slope) was also estimated when dopamine was monitored using electrochemically activated single walled carbon nanotube electrodes. In addition, the electrochemically activated carbon nanotubes exhibited a improved selective and sensitive detection of our model analyte dopamine with a minimal electrode fouling of about 3% +/- 1.2% (N = 4).