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Rationally designed peptide probes for live cell imaging and highly selective bioanalysis
 Date: 27-07-2013  Page Views:

Given the increasing interest in developing chemical tools for biological research, effective small molecules that recognize the distinct molecular features of diseases are receiving intensive attention. Peptides with predictable conformations, built from various optional building blocks, are versatile and can act as excellent probes in disease diagnosis and target therapy.

Prof. Rui ZHAO’ group in CAS Key Laboratory of Analytical Chemistry for Living Biosystems focuses on the development of novel strategies for directional design and efficient identification of targetable peptide probes, with the emphasis on their application in highly-selective detection and analysis of living biosystems.

A robust strategy combining the antisense peptide approach and affinity chromatographic screening was developed, which provides an effective shortcut for designing and selecting peptides with reinforced affinity to the target molecules. A peptide AP2H was successfully screened for a novel cancer biomarker lysosomal protein transmembrane 4 beta (LAPTM4B). Fluorescence imaging assays indicated that AP2H can recognize live cancer cells by recognizing cell-surface localized LAPTM4B protein with high specificity, low cytotoxicity and desirable cell penetrability (Figure 1). Taking advantage of the concept of ‘‘lab on a chip’’, an integrated continuous-flow microfluidic system was designed for solid phase peptide synthesis. The transfer losses, hazardous handling and time-consuming processes in traditional peptide synthesis were avoided by being replaced with the on-chip cleavage treatment. Six peptides from an antibody affinity peptide library against beta-endorphin with different lengths and sequences were obtained simultaneously within a short time. For the subsequent affinity peptide screening, a tetra-layer microfluidic hybrid chip with 36-chamber array was developed. The combination of fluoroimmunoassay with the microfluidic technique facilitated multi parameter screening and significantly simplified reagent delivery procedure in a micro-scale (Figure 2). For the rapid and highly selective detection of important proteins, colorimetric method for direct detection of tryptophan in proteins was also developed via DMSO acceleration, which could benefit the study of the diseases related to the metabolic disorder of Trp as well as Trp-containing proteins (Lab Chip 2011, 11, 929; Chem. Commun. 2011, 47, 8319; ChemBioChem 2011, 12, 1209; J. Mol. Recognit. 2008, 21, 122; Talanta 2012, 89, 531; Analyst 2013, 138, 2890-2896).


Figure 1 Design and screening of a peptide probe towards LAPTM4B proteins and its application in live cell imaging



Figure 2 Design of the peptide screening microfluidic chip and fluoroimmunoassay. 



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