BACKGROUND: Increased expression of survivin in various tumor tissues can regulate cell proliferation, division, and plays an important role in protecting cells from apoptosis.OBJECTIVE: To construct the specific micro RNA (miRNA) expression vector that can block the C_(57)BL mice survivin gene by RNA interference (RNAi) technique.DESIGN, TIME AND SETTING: The single sample observation was performed at the experimental center of Department of Neurology, The First Afliliated Hospital of Chongqing Medical University from June to November 2008.MATERIALS: Ring-shaped pcDNA~(TM)6.2-GW/EmGFPmiR and BLOCK-iT~(TM) Pol II miR RNA interfered Expression Vector Kit with EmGFP was produced by Invitrogen Company. DH5a E. coli was preserved at the laboratory. Xho I and BamH I enzyme, spectinomycin were provided by Shanghai Sangon Biological Engineering Technology & Services Co., Ltd.METHODS: According to sequence of mRNA of C_(57)BL mice survivin provided by Genebank, four pairs of specific oligonucleotide sequences were designed and synthesized by using the software. The annealed oligonucleotide fragment was sub-cloned into pcDNA~(TM)6.2-GW/EmGFPmiR expression vector by gene clone technique and transformed into DH5a E. coli, subsequently, a single colony was incubated into liquid medium containing spectionmycin. Finally the plasmid was extracted.MAIN OUTCOME MEASURES: The recombinant vector was identified by sequencing and agarose gel electrophoresis.RESULTS: The sequencing revealed that insertion element was correctly cloned into the vector without nucleotide mutation, absence or insertion abnormality. The result of double enzyme digestion demonstrated that the fragment length was coincidence with expectation.CONCLUSION: The C_(57)BL mice survivin miRNA expression vector is successfully constructed.

Attributed to the miniaturized body size and active mobility, micro- and nanomotors (MNMs) have demonstrated tremendous potential for medical applications. However, from bench to bedside, massive efforts are needed to address critical issues, such as cost-effective fabrication, on-demand integration of multiple functions, biocompatibility, biodegradability, controlled propulsion and in vivo navigation. Herein, we summarize the advances of biomedical MNMs reported in the past two decades, with particular emphasis on the design, fabrication, propulsion, navigation, and the abilities of biological barriers penetration, biosensing, diagnosis, minimally invasive surgery and targeted cargo delivery. Future perspectives and challenges are discussed as well. This review can lay the foundation for the future direction of medical MNMs, pushing one step forward on the road to achieving practical theranostics using MNMs.

Enzyme-driven micro/nanomotors consuming in situ chemical fuels have attracted lots of attention for biomedical applications. However, motor systems composed by organism-derived organics that maximize the therapeutic efficacy of enzymatic products remain challenging. Herein, swimming proteomotors based on biocompatible urease and human serum albumin are constructed for enhanced antitumor therapy via active motion and ammonia amplification. By decomposing urea into carbon dioxide and ammonia, the designed proteomotors are endowed with self-propulsive capability, which leads to improved internalization and enhanced penetration in vitro. As a glutamine synthetase inhibitor, the loaded l-methionine sulfoximine further prevents the conversion of toxic ammonia into non-toxic glutamine in both tumor and stromal cells, resulting in local ammonia amplification. After intravesical instillation, the proteomotors achieve longer bladder retention and thus significantly inhibit the growth of orthotopic bladder tumor in vivo without adverse effects. We envision that the as-developed swimming proteomotors with amplification of the product toxicity may be a potential platform for active cancer treatment.