Kingshuk Poddar

In vitro controlled release of cisplatin from gold-carbon nanobottles via cleavable linkages

Carbon nanotubes’ (CNTs) hollow interior space has been explored for biomedical applications, such as drug repository against undesirable inactivation. To further devise CNTs as smart material for controlled release of cargo molecules, we propose the concept of “gold-carbon nanobottles”. After encapsulating cis-diammineplatinum(II) dichloride (cisplatin, CDDP) in CNTs, we covalently attached gold nanoparticles (AuNPs) at the open-tips of CNTs via different cleavable linkages, namely hydrazine, ester, and disulfide-containing linkages. Compared with our previous study in which more than 80% of CDDP leaked from CNTs in 2 hours, AuNPs were found to significantly decrease such spontaneous release to <40%. In addition, CDDP release from AuNP-capped CNTs via disulfide linkage was selectively enhanced by twofolds in reducing conditions (namely with 1 mM dithiothreitol [DTT]), which mimic the intracellular environment. We treated human colon adenocarcinoma cells HCT116 with our CDDP-loaded gold-carbon nanobottles and examined the cell viability using lactate dehydrogenase assay. Interestingly, we found that our nanobottles with cleavable disulfide linkage exerted stronger cytotoxic effect in HCT116 compared with normal human fetal lung fibroblast cells IMR-90. Therefore, we infer that our nanobottles strategy with inbuilt disulfide linkage could attain selective release of payload in highly reductive tumor tissues while avoiding collateral damage to normal tissues.

Fabrication of a biomimetic ZeinPDA nanofibrous scaffold impregnated with BMP-2 peptide conjugated TiO2 nanoparticle for bone tissue engineering

A biomimetic Zein polydopamine based nanofiber scaffold was fabricated to deliver bone morphogenic protein‐2 (BMP‐2) peptide conjugated titanium dioxide nanoparticles in a sustained manner for investigating its osteogenic differentiation potential. To prolong its retention time at the target site, BMP‐2 peptide has been conjugated to titanium dioxide nanoparticles owing to its high surface to volume ratio. The effect of biochemical cues from BMP‐2 peptide and nanotopographical stimulation of electrospun Zein polydopamine nanofiber were examined for its enhanced osteogenic expression of human fetal osteoblast cells. The sustained delivery of bioactive signals, improved cell adhesion, mineralization, and differentiation could be attributed to its highly interconnected nanofibrous matrix with unique material composition. Further, the expression of osteogenic markers revealed that the fabricated nanofibrous scaffold possess better cell—biomaterial interactions. These promising results demonstrate the potential of the composite nanofibrous scaffold as an effective biomaterial substrate for bone regeneration.

Peripheral nerve fibers form multi-facet interactions with keratinocytes in a novel complete human 2D culture model.

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Nanotechnology for Sustainable Agriculture

Abstract Nanotechnology is an exciting new domain of research and technology development at nanoscale, which finds several exciting applications in agricultural science. Sustainable agriculture is the key for survival of mankind in the future, which involves holistic management of crops, livestock, and fisheries to make the farming system self-sustaining for a long period. Applications of nanotechnology to such sustainable processes can enable improved plant growth, soils and microbial stabilization, targeted application of chemicals and better plant and farmyard animal management, food processing, and rural waste management. No other technological advance can possibly integrate to multiple activities of sustainable agriculture so effectively with compatible sustainable practices. The legal and policy frameworks on nanotechnological innovations should consider potential benefits of nanotechnology in sustainable agricultural practices. However, the environmental safety concerns of widespread nanoparticle use should be carefully examined before large-scale application of such technologies.

Identification of Biofilm Inhibitors by Screening Combinatorial Libraries of Metal Oxide Thin Films

With the rise in nosocomial infections worldwide, research on materials with an intrinsic ability to inhibit biofilm formation has been generating a great deal of interest. In the present work, we describe how thin film material libraries generated by pulsed laser deposition can be used for simultaneously screening several novel metal oxide mixtures that inhibit biofilm formation in a common human pathogen, Salmonella enterica serovar Typhimurium. We discovered that in a material library constructed using two metal oxides, the net effect on biofilm formation can be modeled as an addition of the activities of the individual oxides weighted to their relative composition at that particular point on the library. In contrast, for similar material libraries constructed using three metal oxides, there was a nonlinear relation between the amount of dominant metal oxide and the formation of Salmonella biofilms. This nonlinearity resulted in several useful metal oxide combinations that were not expected from the weighted average predictions. Our novel application will lead to the discovery of additional alternatives for creating antimicrobial surfaces.

Triggers Causing Type 1 Diabetes

The precise cause(s) of T1D are not fully understood to the researchers; however, it appears to be a combination of several factors which includes genetics as well as environment. It is observed that children with parents or sibling with T1D has 2–6 % risk compared to a risk of about 0.4 % in general population. Other autoimmune diseases, such as thyroid disease and celiac disease make a patient more prone to develop T1D. Furthermore, it is observed that certain ethnicities across the world are at greater risk to develop the disease compared to other. For example: Caucasians in America are more susceptible compared to African Americans, Native Americans, Asian Americans, and Latinos.

Type 1 Diabetes: Past, Present, and Future Therapies

The first line of treatment developed for T1D was insulin. Over the last century, several new approaches to treat T1D have been adopted (Fig. 4.1), but insulin delivery still remains the main stream of treatment. The new strategies to treat T1D include replacement of β-cell via transplantation or regeneration, but are still in their infancy. Another vibrant approach in T1D immunotherapy involves compensating for the lost pancreatic β-cells and restoration of immunological tolerance by islet like cells derived from stem cells. The major benefit associated with these intervention strategies is the ease of patient identification and efficacy evaluation within a much shorter duration. Earlier reports on NOD mice had provided the basis for antigenic and non-antigenic preventive strategies to treat T1D, but a number of clinical trials have been completed with limited success so far. An ideal intervention for T1D would require an entity to halt autoimmune response along with an additional element to enhance β-cell function or expedite its regeneration. As such, combination therapy is believed to lead the treatment of T1D in the time to come.

Introduction to Diabetes and Type 1 Diabetes

The World Health Organization (WHO) classification of diabetes has been the subject of subtle iterations over the years, with their most recent classification published back in 1985. At that time an expert committee on the diagnosis and classification of diabetes mellitus identified two main types of diabetes: type 1 diabetes (T1D) and type 2 diabetes (T2D).

Predictors and Pathogenesis of Type 1 Diabetes

Autoimmune processes in general take many years before their clinical manifestation as a disease becomes apparent and T1D is no exception, sometimes taking up to a decade, or more for clinical presentation. This asymptomatic period offers a great window of opportunity for the prediction and prevention of full-blown disease.