Current studies have revealed the immune effects of graphene oxide (GO) and have utilized them as vaccine carriers and adjuvants. However, GO easily induces strong oxidative stress and inflammatory reaction at the site of injection. It is very necessary to develop an alternative adjuvant based on graphene oxide derivatives for improving immune responses and decreasing side effects. Carnosine (Car) is an outstanding and safe antioxidant. Herein, the feasibility and efficiency of ultrasmall graphene oxide decorated with carnosine as an alternative immune adjuvant were explored. OVA@GO-Car was prepared by simply mixing ovalbumin (OVA, a model antigen) with ultrasmall GO covalently modified with carnosine (GO-Car). We investigated the immunological properties of the GO-Car adjuvant in model mice. Results show that OVA@GO-Car can promote robust and durable OVA-specific antibody response, increase lymphocyte proliferation efficiency, and enhance CD4(+) T and CD8(+) T cell activation. The presence of Car in GO also probably contributes to enhancing the antigen-specific adaptive immune response through modulating the expression of some cytokines, including IL-6, CXCL1, CCL2, and CSF3. In addition, the safety of GO-Car as an adjuvant was evaluated comprehensively. No symptoms such as allergic response, inflammatory redness swelling, raised surface temperatures, physiological anomalies of blood, and remarkable weight changes were observed. Besides, after modification with carnosine, histological damages caused by GO-Car in lung, muscle, kidney, and spleen became weaken significantly. This study sufficiently suggest that GO-Car as a safe adjuvant can effectively enhance humoral and innate immune responses against antigens in vivo.

Nanotechnology has given scientists new tools for the development of advanced materials for the detection and diagnosis of various types of diseases. In particular, ultrasmall superparamagnetic iron oxides (USPIOs) have been investigated in many biological applications, both in vitro and in vivo. Due to their small size (diameter < 20 nm), these particles are not immediately removed from the circulation by the reticuloendothelial system (RES), have a longer blood half-life, a wider biodistribution and allow potential targeting with appropriate bioconjugates to specific tissues both normal and tumorous. This review will mainly discuss the synthesis of USPIOs and their applications as MRI contrast agent for disease detection.

Lysosome is a highly membrane-bound organelle which possesses a sequence of biological functions including protein degradation, cell signal transduction, plasma membrane repairment, homoeostasis, and autophagy. The lysosome contains more than 50 soluble acid hydrolases, and the acidification of lysosome is the most important biological characteristic. The integrity of lysosome is of vital importance. During the past few years, it was reported that the destabilization of lysosomal membrane can result in the release of lysosomal contents into cytosol and trigger cell death in a caspase-dependent or caspase-independent pathway. Lysosome functions at the late stage of autophagy and degrades cellular components delivered by autophagosome, which is a complicated process. The present article will summarize the current knowledge on the role of lysosome in cell death regulation and the underlying mechanisms.

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