We explored the possibility of generating nonpoisonous, renewable, low cost and a completely biodegradable photosensitizer for dye-sensitized solar cells (DSSC) as an alternative to synthetic molecules that involve expensive, time-consuming tedious synthesis and purification procedures. Several natural dyes from plants and microbes had successfully been demonstrated as photosensitizers to develop biosensitized solar cells (BSSCs). The objective of this work is to develop a next generation cleaner sensitizer for BSSC using a green fluorescent protein (GFP) and its designer variant (GFPdopa) through an expanding genetic code approach. The designer protein showed higher adsorption with TiO2 surface through oriented immobilization. The nanostructured layer formed by GFPdopa with TiO2 resulted in 0.94% level of photon conversion efficiency with open circuit voltage of 0.60 V, short circuit current of 1.75 mA/cm2 and fill factor of 0.88. It is one of the better energy conversion efficiencies obtained for BSSC when compared to with earlier reported sensitizers generated through protein and chemical complex synergism. From the results obtained, it is suggested that designer fluorescent itself can generate similar photoconversion efficiency and also could serve as an environmental friendly photosensitizer. The research and efficiency level of BSSC is in the early stages, and our proof of principle opens a new avenue to synthesize biologically designer sensitizers for BSSC. It also could be widely applied to other proteins to develop efficient sensitizers for BSSC with a green approach.

We developed an accelerated strain‐promoted oxidation‐controlled cyclooctyne‐1,2‐quinone cycloaddition (SPOCQ) for protein modification. Here, dopaquinone was generated using potassium nitrosodisulfonate (PTN) in a reaction that is six orders of magnitude faster than the enzymatic one. The dopaquinone generated then reacts with bicyclononyne (BCN) derivatives in the bioconjugation. The PTN yields a single product with defined stereochemistry and temporally controlled conjugation with BCN. The feasibility of this bioconjugation was demonstrated with different proteins. Cell labeling was explored by conjugating annexin‐dibenzocyclooctyne‐PEG4‐fluor545 through the SPOCQ approach for the detection of apoptosis in HeLa cells.

Immunological memory comprising of antigen-specific B and T cells contributes to the acquisition of long-term resistance to pathogens. Interactions between CD40 on B cells and CD40L on T cells are responsible for several aspects of acquired immune responses including generation of memory B cells. In order to gain insights into events leading to memory B cell formation, we analyzed the genome-wide expression profile of murine naive B cells stimulated in the presence of anti-CD40. We have identified over 8,000 genes whose expression is altered minimally 1.5-fold at least at one time point over a 3-day time course. The array analysis indicates that changes in expression level of maximum number of these genes occur within 24 h of anti-CD40 treatment. In parallel, we have studied the events following CD40 ligation by examining the expression of known regulators of naive B cell to plasma cell transition, including Pax5 and BLIMP1. The expression profile of these regulatory genes indicates firstly, that CD40 signaling activates naïve B cells to a phenotype that is intermediate between the naive and plasma cell stages of the B cell differentiation. Secondly, the major known regulator of plasma cell differentiation, BLIMP1, gets irreversibly downregulated upon anti-CD40 treatment. Additionally, our data reveal that CD40 signaling mediated BLIMP1 downregulation occurs by non-Pax5/non-Bcl6 dependent mechanisms, indicating novel mechanisms at work that add to the complexity of understanding of B cell master regulatory molecules like BLIMP1 and Pax5.

No abstract

No abstract